Guide : Installing Lexus AFM, 550s and AFPR

[JSeaman]

This document is compiled from my experience and a number of sites/forums/sources. Reg Riemer's SONIC document also helped and I hope he doesn't mind me stealing some info & putting them in my own words. Thanks to all those who have provided me with information, special thanks to John89t for the parts & advice and Marty (Bondango) for the tips & info

NOTE : You should have already done basic performance upgrades (BPU) such as exhaust, induction kit, preferably at least a hybrid turbo etc. before looking at a mod such as this. Ensure your cooling system is in top shape (new stat, rad cap, rad etc where necessary) and preferably ARP studs and a metal head gasket. If you run more boost you are more likely to start killing motors, maintain your car well or suffer the consequences. Oh, and check your timing, mine was way out!

Timescales - If you really know what you were doing you could fit the afm, injectors, afpr and safc in a day. If you are reasonable with spanners then a weekend should easily be sufficient. This is the route I chose, starting on a Friday night and finishing on a Sunday (I did cheat and pick a bank holiday weekend just in case!)

Some background to the Lexus AFM + 550cc injector mod / Lexus Riemer mod - it's quite lengthy but hopefully comprehensive, believe me it took longer to right than it will to read!!

 

[JSeaman]

Injectors
=========

You should consider a few properties when uprating your injectors, these include:

Size - The amount of fuel they flow when the injector is fired, measured in cubic centilitres (cc)

Duty cycle - This is the amount of time they are 'switched on' and is controlled by the ECU. Note that it is generally accepted injectors should have a duty cycle of no more than 80%.

Feed point - Injectors can be top feed or side feed. Our cars are top feed and, as the name implies, the fuel rail connectS to the top of each injector to feed it fuel.

Impedence - similar to resistance, this is to do with current flow supplying the injectors. All you need to know is that we use LOW impedence injectors (apparently 2-3 ohms in case you were wondering!)

Connectors - Ensure that your injectors are either compatible with the stock connections or come with all the clips necessary to wire them in to the stock loom. For this guide I will show you how to wire in the injectors that have a different connector.

You need to pick an injector that will flow enough fuel for your needs at a duty cycle that is reasonable. By upping the fuel pressure and running higher duty cycles you can eek more power out but I highly recommend you buy an injector suibtable for your application.

Stock injectors flow 440cc of fuel. The Lexus/550 mod increases the size to 550 CC which is exactly 25% more than stock. By fitting larger injectors, the fuel system has a greater demand placed on it to supply fuel so we need to consider additional components.

Figure 1 - A 550cc injector - the green ring at the top (an 'O' ring seal) is where the fuel rail connects so supply the feed of fuel from the fuel rail. There is a black rubber grommet at the bottom to seal the injector in place. The connector on the side has 2 wires coming off which will need to be joined to the stock loom.

Figure 2 a and b - 550 side by side with a 440

Figure 3 - The feed point for the injector

Figure 4 - The nozzle to disperse fuel

 

[JSeaman]

AFPR
====

AFPR - An adjustable fuel pressure regulator allows us to vary the amount of fuel pressure in the fuel rail. With fuel injection, a fuel pump will move petrol from the fuel tank at the back of the car up into the engine bay. The fuel enters the fuel rail (essentially a tube of metal which connects to the fuel injectors), and is then returned to the fuel tank. By placing a restriction on the return line to the fuel tank, pressure builds up in the fuel rail and can be maintained at a set level. For a stock car, the fuel pressure regulator is at a fixed value, the ability to modify and control this value helps us with the tuning stage.

Note that the fuel pressure is set at idle. As the revs increase, the fuel pressure will rise accordingly. By modifying the AFPR value, you change the baseline for all values on the fuel map so you use this to make large changes. An air/fuel controller can then be used to trim in the smaller adjustments. You can attempt to perform this mod without the AFPR but you might find you have problems getting a stable idle.

If you get a Supra-specific AFPR kit then it will probably contain the 'j tube' bypass. The j tube is a restriction in the fuel return pipe that is used on a stock car as a safety measure in case the fuel pressure regulator fails. When we start to flow more fuel, the restriction can cause a build up of fuel pressure and so we bypass this completely (alternatively it can be enlarged). You will see more about this when fitting the AFPR

Here is a picture of the AFPR kit I had and a close up off the liquid-filled gauge (make sure you get one with a gauge for easy installation/set up)

Figure 5 - The AFPR kit

Figure 6 - Liquid filled gauge

 

[JSeaman]

Fuel pump
=========

The other important component to upgrade in fuel delivery is the pump itself. A walbro fuel pump is effective when performing the lexus/550 upgrade as this is able to increase flow over the stock unit. The pump itself sits in the fuel tank and can be a bit of a swine to do but that's not covered here. Suffice to say, uprate the fuel pump if you are doing this mod (as above, it can be done and has been on a stock pump but why cut corners).

You may hear of the fuel pump relay bypass mod. Basically, the fuel pump can run at either 9V or 12V as governed by the ECU. You can bypass this to ensure there is always a 12 volt feed but I am not convinced it is necessary (I didn't need it) so will not go into any more detail here

 

[JSeaman]

AFM
===

Simply dumping more fuel into the cylinders (don't forget the ECU won't know it is firing 550cc injectors) will make the car run rich. We also need to modify the amount of air that is allowed to enter the combustion chamber to create an effective burn. To match the fuel increase gained with 550cc injectors, the airflow meter of a Lexus V8 4UZFE engine can be bolted directly on instead of the stock AFM.

Both the 7MGTE and the 4UZFE (amongst others) use the same technology in their AFM, the Karmann Vortex. The principal behind this is :

a) First, we 'Straighten out' the flow of air (which is done by the mesh at the front of the AFM)
b) Next, create an obstruction within the AFM body (Done by the special plastic probe attached to the 'black box' on the side)
c) Finally, we measure the disturbance created (The 'black box' of electronics does this)

When you disturb the air, a number of vorteces (swirls) are produced. The number/frequency of vorteces is proportional to the flow of air through the AFM. Downstream of the vortex generator, an LED and mirror are used to monitor the vorteces. The Lexus V8 AFM produces signals (5V square waves with varying frequency) that are identical to the 7MGTE unit whilst providing 25% greater flow of air.

Figure 7 - Shows the AFM body without the electronics on.
- The mesh at the top of the picture is what 'straightens' the airflow
- The large hole in the middle is filled with the black box of electrics and houses the protrusion that makes the vorteces
- The smaller hole at the bottom with the rubber O-ring is filled with the inlet air temperature sensor. Note that additional sensors such as a temperature and HAC - high altitude compensation (at high altitudes you get less air), are combined with the Karmann frequency to work out air/fuel ratios. You wouldn't need to do this in a MAP -Manifold Absolute Pressure- style system which is one of the benefits of swapping to MAFT PRO or full standalone style arrangements.

Figure 8 - The adjustment screw that allows up to 85% of the unmetered air passageway to be closed off

Figure 9 - Inside the AFM, here you can see that there is a seperate section (top of the picture) from the area containing the vortex generator. This is contains unmetered air and you can see that the adjustment screw will increase or reduce the amount of airflow by blocking off this chamber (Air in this chamber is not seen by the Toyota Computer Control System or TCCS)

Note you will use the 'black box' off your stock AFM housing.

 

[JSeaman]

Timing
======

Ignition timing is a very important topic, it is basically the point at which spark plugs should be fired in the combustion cycle. When performing the Lexus AFM and 550cc injector mod, we make no effort to control the timing (Stock is at 10 degrees before TDC-top dead centre). This is one of the limitting factors to tuning with this style of 'piggy back' add-on (Note : You can get a piggy back such as an Apexi Ignition Timing Controller, or ITC, which will give basic control over timing). We are fooling the ECU into thinking it is firing stock 440cc injectors when it isn't whilst it also believes it has an airflow signal from a 7MGTE AFM - which it doesn't. The reason you can't just stick 880cc injectors in and run two stock AFMs is because your timing would be thrown very far out and can lead to disastrous consequences. When you start tuning beyond the Lexus/550 stage you may want to consider full aftermarket ECU because ignition timing will need to be modified (MAFT PRO offers this but cheaper).

I'm not going to get too involved with timing but basically the ECU has a table of values for timing which are based on various factors and feedback from sensors including the RPM, air+coolant temp, throttle position and importantly the air flow meter. The rpm can be combined with the AFM values to determine how much air is flowing into the combustion chamber. This allows the ECU to figure out how much fuel to dump in and it also decides on the optimum time to fire the spark plug. If you modify the values e.g. make the ECU think we are adding less air than we really are, the timing values will still remain the same. Depending on how much we lie to the ECU, this can cause us to be firing the cylinders too early or too late in the combustion cycle which can be catastrophic.

In our case, we are providing a greater airflow than the ECU is 'seeing' so the timing will be advanced more than we would ideally want. This means the spark is fired relatively early on in the compression cycle (the spark is fired as the piston is heading up the chamber on the compression stroke so that the full power of the explosion is applied on the combustion stroke of the cycle). If we ignite the mixture too early then the force of the explosion acts against the piston that is still rising on the compression stroke. This is bad news!

 

[JSeaman]

SAFC
====

Once we've upgraded the fuel pump, afpr, injectors and AFM we have one last thing to tackle, air/fuel ratios. The ideal 'chemically correct' ratio of air to fuel that produces optimum power versus emissions + economy is 14.7:1, that is to say we want 14 parts of air to each 1 part of fuel. The air/fuel ratio needs to be modified to ensure we fall within a safe range across the whole rev range.

Why didn't we need this before? Well, you did, kind of. An air/fuel controller such as the Apexi SAFC II, allows you to control the air/fuel (A/F) balance by tweaking values to the ECU. Even a stock car can gain both power and economy by mofiying values across the rev range. For example, the 7M runs pig rich at WOT (wide open throttle) and so you could trim some of the fuel there to provide better fuel economy. When increasing the power with the Lexus/550 mod, it is essential you maintain proper A/F ratios or you risk detonation which will kill your engine. Get a wideband or go to a dyno to get this done (or if you know what you are doing with det cans then you can tune it yourself).

The SAFC works by intercepting the signal from the AFM to the ECU and modifying it (by up to +- 50&#37. The ECU then performs its calculations for providing adequate fuel (modifying the duty cycle for the injectors) based upon the SAFC's readings. The tricky bit is making sure the SAFC knows what is going on well enough to modify the stock ECU's actions. To do this, the SAFC has a series of maps (tables) which use rpm and load (provided by the throttle position sensor), to modify the signal to the ECU. Note : The stock system is by no means simple or inadequate, it's a very complex and effective system that can actually trim the fuelling from its initial sensor-derived values by up to 40% based on what it has 'learned' (The fuel trim or learned value is known as Vf).

The Vf factor is applied in both open and closed loop control :
Closed loop is where the ECU uses feedback from sensors such as the lambda/O2 sensor to determine and adjust fuelling
Open loop uses internal maps and is used incertain circumstances such as cold starts and wide open throttle (WOT)

Vf caters for general component wear and changes to the combustion process such as air leaks. You can see what Vf is being applied through the diagnostics port (Between E1 and Vf1) which will be a value between 0 and 5 volts in 1.25V steps.

0V = The maximum amount of fuel is being subtracted from the base calculations from sensors (You are running rich)
1.25V = Some fuel is being subtracted
2.5V = No modification (A/F ratio is somewhere around 14.7:1)
3.75V (May be 3.5V) = Some fuel is being added to the base values
5V = The maximum amount of fuel is being added to the calculations (You are running lean, very dangerous)

In the SAFC you specify a number of correction factors for specific rev ranges and the SAFC will scale up/down the readings to the ECU based on this. If you asked for a 10% reduction at 1,000 rpm and a 20% reduction at 2,000 rpm then the SAFC would be able to effectively draw a line between these two points to figure out you'd want 15% reduction at 1,500 rpm. In a similar manner you would specify values based upon load (how much you are accelerating) and these two sets of maps will be interpolated (combined together) to modify the signal to the ECU.

Figure 10 - The SAFC II screen

Figure 11 - You should have a harness that extends the short cable from the SAFC to open ended wires for the ECU

Figure 12 - The wires you need to connect to the ECU

 

[JSeaman]

That's it really, you get big injectors for more fuel, add a fuel pump and pressure regulator to ensure the fuel supply is available, then add an AFM to fool the ECU into matching the injectors and use the SAFC to tune it all properly. Here's everything except the fuel pump:

Figure 13 - Everything!

The benefits :

1. Raised 'fuel cut' point - as mentioned in the AFM section, a series of square waves are sent to the ECU and this is a key factor in hitting fuel cut. Note that fuel cut is actually cutting off the spark not the fuel. By using the larger AFM, 25% more air flows for the same square wave i.e. we flow more air and don't get the higher frequency pattern to hit fuel cut. This means more boost and more power - people have reportedly had 600rwhp in the States using the Lexus mod but you can expect to see 300rwhp+.

2. Less AFM restriction - the size of the AFM actually restricts flow of air to the turbo. By enlarging the AFM we allow a less restricted flow of air which aids spooling (Stock AFM is matched for stock turbo with stock boost levels but we assume you are going past this level with the lexus/550 mod)

3. Retain the stock fuel system so the TCCS can still function properly correcting the Vf values and STILL HITTING FUEL CUT (this is there for good reason), just at a higher level. The level at which you hit fuel cut after this mod varies between cars but is somewhere around 20psi+.

 

[JSeaman]

Step 1 - Pop the lid of the diagnostics box on the nearside wing and locate the terminals E1 and Vf1

Step 2 - Connect a voltmeter to the two terminals using the constant voltage range (V with the straight and dotted line)

Step 3 - Monitor the values here to get an idea what your stock engine does under various conditions e.g. idle on a cold engine, idle on a warm engine, under load, accelerating, decelerating. The picture shows the throttle being manipulated by hand from under the bonnet so you can see what occurs

The first 3 steps here are optional, I think it's worth seeing what happens on a stock engine so you can try and replicate it after fitting all your new bits

Step 4 - Fit your fuel pump. This would be a guide in itself and seeing as mine was already done you'll have to look elsewhere until a guide is made. You will need to drop (as in remove, not just drop!) your fuel tank (2 straps hold it in place and they will probably be very rusty and break on removal), to do this job. It's not much fun and make sure you drain your fuel beforehand or the tank will be very heavy. Always be careful around fuel, no smoking etc!

Step 5 - Follow steps 1-4 in the guide for replacing cam cover gaskets (which covers removing the throttle, PCV system & 3000 pipe). Note that you may find it easier to remove both ends of the hose in step 4 so it doesn't flap around in your way

Step 6 - Now you have access to the accordion hose (The rubber hose with a flexible joint in it), you can remove it at the turbo end (picture 1) and the air flow meter (AFM from now on) end shown in picture 2.

Step 7 - Undo the jubilee clip holding the hose shown (for the positive crankcase ventilation -PCV from this point forward- system), and slide it off. Note yours may be standard black rubber.

Step 8 - Undo the jubilee clip holding the hose shown (idle speed control -ISC form this point forward- valve), and slide it off. Note yours may be standard black rubber.

Step 9 - Twist both ends of the accordion hose to 'crack it off'. This just makes it easier to separate when we undo the rest of it

Step 10 - Undo the 10mm mounting bracket holding the AFM on to the inner wing

 

[JSeaman]

Step 11 - Disconnect the electrics from the black box of the AFM by pressing the tab in then pulling downwards.

Step 12 - Remove the small vacuum hose (power steering idle up) from the underside of the AFM

Step 13 - Remove the AFM, induction assemble and accordion hose in one go. If you have a stock air box (The big black plastic thing) instead of an induction kit like mine then you'll have to undo any bolts mounting it to the car prior to removal

Step 14 - As an aside, if you want to shim your wastegate you now have good access to the bolts. The cylinder beneath my finger is the wastegate actuator and the two bolts holding it in place need to be removed, some shims/washers need to be placed on the turbo side of the bracket then the bolts replaced. Depending how many washers you use you may need longer bolts. I thought I'd mention this because people may up the boost in this manner by doing the mod. It's more likely you will use a boost controller and this also shows the hose to the wastegate actuator that you T into to fit a boost controller (but that's a different guide!)

Step 15 - Sorry for the blurred picture but it shows removal of the other end of the ISC hose run, again it's just a jubilee clip then slide it off

Step 16 - Remove this pipe to the ISC valve body - note monkey wrench makes these clips easy

Step 17 - Remove the multiplug to the ISC valve, press the tab then pull towards the front of the car

Step 18 - Remove the two bolts holding the valve in place. Long extension bar for the top one is fine (picture 1) but you'll need a short extension for the other one (picture 2)

Step 19 - Ease the valve away from the inlet plenum (The plenum's the large bit of the inlet that connects to the runners-the manifold), and you will see another hose to remove. It's a bit fiddly but be careful not to stress it

Step 20 - Remove the valve body from the car

 

[JSeaman]

Step 21 - Undo the 12mm bolt holding the bracket for the EGR

Step 22 - Remove these two vacuum lines and make sure you know which one goes on which side

Step 23 - The final thing to remove is this braided line underneath, again just a spring clip and pull it off

Step 24 - Now, time to address the fuel rail (which you can clearly see now). Remove the vacuum hose to the stock fuel pressure regulator (FPR from now on). You will use this on your new Adjustable FPR (AFPR)

Step 25 - Take a look at your injectors and note the colour of the wiring and plastic connector so you don't get them muddled up

Step 26 - Remove all the connectors

step 27 - Crack off the 3 bolts holding the fuel rail in place (As with most fuel line connections, they are tight to crack off but then come off with your fingers). Leave the bolts pretty tight though to help you get purchase on the other bits you are removing. You might want to skip this step and leave it until step 47

Step 28 - Looking down under the inlet plenum you will see the infamous J tube. Loosten the jubilee clip at the bottom of the box I've drawn

Step 29 - Now pull the hose off (towards the back of the car) and expect some fuel to come out

Step 30 - Grab the hose and point it upwards to minimise fuel loss

Step 31 - Now get the only braided line from the AFPR kit that has a smooth connection on it (see picture)

Step 32 - Firmly push the two together as far as you can. Tighten the jubilee clip up and make damned sure you've got a good connection. VERY IMPORTANT : Don't screw up any fuel line connections. If there's any doubt whatsoever about the seal then take it off and do it again, the last thing you need is an engine fire

Step 33 - Now remove the small bolt (I think it was an 8mm) that holds the bracket for the FPR fuel line hardpipe to the fuel rail itself

Step 34 - Remove the other end of the J tube (spring clip as usual). The easiest way is to squeeze the clip and let it drop down onto the j tube (see picture) then just pull the pipe clear

Step 35 - Expect more fuel and don't forget to remove the spring clip

 

[JSeaman]

Step 36 - Back up top and remove the 14mm return line connection from the stock FPR

Step 37 - Now you should be able to pull the whole fuel line out

Step 38 - Remove the 17mm bolt for the cold start injector feed. Guess what, more fuel comes out! The second picture shows the banjo bolt (They have the hole in them to allow fuel to be transferred through the bolt), and the two copper washers which are either side of the feed pipe. The fuel line components such as this, FPR and pulsation damper all have these copper washers that crush and form a seal, be careful not to drop them when removing the pipes

Step 39 - Take a 22mm spanner and crack off the pulsation damper that sits at the back of the fuel rail

Step 40 - Once cracked off you should be able to unscrew and remove the damper (Which, as its name suggests, reduces the surges of fuel by providing a reservoir)

Step 41 - Back down below again - look under the inlet manifold and you should see the main fuel feed (Picture shows me pointing to the bolt)

Step 42 - Take a 19mm socket to it and remove it completely - more fuel again will be spilt

Step 43 - Remove the fuel feed line from the car. You have now seen how the fuel enters down at the bottom, travels up to the pulsation damper at the rear of the fuel rail, traverses the rail, meets the FPR and then returns (previously via the j tube restriction) to the fuel tank.

Step 44 - You can now fit your connector from the AFPR kit to the feed hole. The third slightly blurred picture shows which line it is you are connecting

Step 45 - Attach the braided line to the fitting and tighten up (18mm spanner was used for the AFPR connections)

Step 46 - I just wanted to point out that there should be a rubber seal and metal washer on the other end of this line. As we aren't connecting it to the fuel rail feed point just yet (We haven't fitted our injectors yet), be careful not to lose these

Step 47 - Fully Remove the 3 bolts holding the fuel rail in. I did three passes on each bolt because they were quite tight

Step 48 - Disconnect the coil pack (just a push tab and separate)

Step 49 - Pull the fuel rail gently free. The oil line to the cam covers is still connected (bit of a pain to refit so I left it in place), this doesn't cause a problem but just be aware of it so you ease the rail out towards the rear of the car. You'll get little/no resistance from the injectors so if it's not pulling away then check you haven't snagged any wires/hoses

Step 50 - I've tried to show the fuel in the rail here, it's still going to be full of fuel so be careful you don't spill it everywhere

 

[JSeaman]

Step 51 - Check for your grommets that sit in the cylinder head. Notice that my 6th injector has one missing, that's because it is still in the head. Make sure every one is accounted for

Step 52 - Carefully remove any grommets from the head that got left behind

Step 53 - You should see something like this by now

Step 54 - Use a 17mm spanner to remove off the FPR (picture 1), then remove it fully (picture 2)

Step 55 - Carefully twist each injector out of the rail. You may end up selling these/refitting them at some point (Toyota Starlets use them as direct replacement upgrade) so don't damage anything. Note that you should never reuse the o rings or grommets

Step 56 - Voila six stock 440 injectors

Step 57 - That's pretty much it for the evening. I wanted to remove everything then leave the car to stand whilst any spilt fuel evaporates. If you aren't going to let it stand then be sure to mop up any spilt fuel

Step 58 - Follow steps 42-51 in the turbo timer guide to gain access to the ECU.

Step 59 - Separate the AFM from the accordion hose

Step 60 - Note the size difference with the Lexus AFM. You will need to either stretch the stock hose over it or go aftermarket with silicone couplers. The second picture shows that the dimensions at the air filter end is exactly the same

Step 61 - This is when I started day 2 (Saturday). Get yourself some o rings and 'insulators' or grommets from Toyota. They'll cost you a small fortune (Something in the region of £30) and seem like a complete waste of money but I did a bit of digging around into what goes into inector o ring seal design and it's more than you might think. The tolerances, characteristics of wear over time, temperature range, durability etc etc are all specified in great detail. You can go down the aftermarket route and grab some off-the-shelf o rings for a few pence and people have had success doing this, I didn't want to take the risk - fuel leaks aren't something I ever want to experience

Step 62 - Cut the connectors off the wiring loom for the old injectors. Try and leave as much wire on there as possible to use on the new connections by cutting close to the plastic as shown

Step 63 - Keep the connectors in order so you know which wires go where. For those that loose track :

Connector #1 (Nearest the front of the engine) : Left wire = Yellow, Right wire = White with blue stripe
Connector #2 : Left wire = Black, Right wire = White with red stripe
Connector #3 : Left wire = Red, Right wire = White
Connector #4 : Left wire = Yellow, Right wire = White with blue stripe
Connector #5 : Left wire = Red, Right wire = White
Connector #6 : Left wire = Black, Right wire = White with red stripe

Step 64 - Once you've removed all the connectors, pull the plastic sleeving up and cut enough of the end to allow heat shrink to be slid down the wire while you solder the new clips in

Step 65 - Strip the ends of all the wires (You want about 1/2 inch of bare wire), and twist the bare wires together so you don't have any strands sticking out

 

[JSeaman]

Step 66 - Do the same for the injector clips

Step 67 - Cut about 1" of heat shrink for each injector. Try and get adhesived lined heatshrink because it sticks to the wires better. Also, make sure you have the right size - too big and it won't seal, too small and you won't get it over the soldered wires.

Step 68 - Slide the heat shrink down, ensuring you can still solder the ends of the wires (If you didn't cut off enough of the sheath in step 64 then do some more trimming at this stage)

Step 69 - Do step 68 for all injectors

Step 70 - Lay one of your new injector clips down alongside the old ones so you can see which wires go where. See how the old connector fits to the injector then do the same with the new clip so you can figure out which part is the top and therefore which wire goes on the left and which is on the right

Step 71 - Tin the wires for the clips and the loom to the injectors. This is done by putting a small dob of solder on the soldering iron and then holding it on one side of the wire whilst touching some more solder directly opposite so the heat is transferred through the wire to melt the solder. This gives a better flow of solder

Step 72 - Do step 71 for all wires. Note : You are probably going to be soldering outside so make sure you get the best soldering iron you can, a cheap and nasty one will make your job much more difficult so borrow one or fork out for a decent one if you can

Step 73 - Once both wires are tinned, try and twist them together or hold them next to each other whilst applying heat from the iron, this should melt them together and leave you with your final connection

Step 74 - I messed up and put one piece of heatshrink over both wires which meant the bare solder would be touching on both wires to the injector (What can I say I'm stupid!). You should either use a piece of heatshrink for each wire or do what I did and wrap them in insulation tape first then heatshrink both together. In hindsight, this isn't such a bad idea because it keeps the two wires together and provides an additional layer of waterproofing and protection so not a major problem

Step 75 - Now slide your heatshrink up and cover the solder joint. It's very important that none of the metal is exposed so if you cut the heatshrink too short then desolder it and use another piece.

 

[JSeaman]

Step 76 - Use a heatgun to apply hot air to the heatshrink. Don't just hold the gun on it, rotate it around the wire so it shrinks universally and forms a good seal.

Step 77 - Your final connection should look like this

Step 78 - Once all the wires are insulated and lined with heat shrink you should look something like this

Step 79 - Time to attack that fuel rail. Get some carb cleaner and spray it on (picture 1), then rub it with a rag. It should come up quite nicely with minimal effort (picture 2). You don't need to go crazy, just keep things clean and it prevents dirt entering the fuel system

Step 80 - Now we can start putting the injectors in. Dip your o rings in fuel (this just provides a little lubrication when sliding them onto the injectors which stretches them).

Step 81 - Once dipped in fuel you hook the o ring over one side of the injector and then push it over the lip using your thumb in a circular motion

Step 82 - Ensure the o ring rotates freely and isn't damaged

Step 83 - Twist the injector into the fuel rail

Step 84 - Repeat for all 6 injectors

Step 85 - Carefully insert the insulators into the recesses in the head

Step 86 - Take your newly built fuel rail over to the car. Note the injectors are all facing the wrong way (the connectors are hanging over the rounded edge of the rail), this is so I can twist them into their final position once they are seated on the insulators

Step 87 - Carefully place the rail into position, make sure you don't get caught on any of the cables/hoses and gently lower it so the injectors line up with the insulators

Step 88 - Gradually the rail will sit lower as you twist each injector round into position ensuring it seats properly in the insulator. Make sure that you dont start pulling the injector out of the fuel rail, lower the rail not the injector

Step 89 - Insert the three bolts that hold the rail in place

Step 90 - Line up all the connectors for the injectors. The injectors will be a lot stiffer now but free to turn a little. The new connectors on mine were a very close fit so it was good thath the injectors were all tweaked into position at this stage

 

[JSeaman]

Step 91 - Now the rail is back in place we can insert the next connection from the AFPR, this is the feed to the rear of the fuel rail (the one with the rubber and metal washer. For me this was a tight fit so I got the old pulsation damper and screwed the in to clean out the threads a little but it still needed a reasonable amount of torque to turn the bolt once it got to the stage shown in picture 1. A socket was used for the most part (picture 2) then it was nipped up with a spanner as shown in picture 3 (If you have a long reach 18mm socket you could just use that but my 19mm short reach was enough to do most of the leg work)

Step 92 - Reinstall the feed to the cold start injector using the two copper washers. You should really replace these after they are used once although I didn't have any so had no choice (no adverse side effects yet but I don't recommend this for the sake of a few pence)

Step 93 - The final fuel rail connection is the feed to the AFPR body and is done in the same way as all the others (see pictures)

Step 94 - Check your old vacuum line will be long enough to reach your AFPR wherever you mount it, of not replace it and attach it to the port on the AFPR

Step 95 - Use the L shaped fitment (picture 1) and the blanking bolt (picture 2) to determine which side of the AFPR will take the fuel feed. The third picture shows my install

Step 96 - Attach all the retaining clips to the injector connectors. I found the best way was to slide over one side of the metal clip fully then use a small screwdriver to ease it over the other side gently

Step 97 - Plug them all in and you have 550cc injectors (pat yourself on the back)

Step 98 - The final thing to do is slide up the old plastic covers so they meet the heat shrink

Step 99 - Time to test, put your keys in and turn to the 'on' position. DON'T CRANK THE ENGINE!

Step 100 - Short out B+ and FP in the diagnostics block. This will power the fuel pump without the engine running. Note : Some say to remove the vacuum line at this stage but we aren't running the engine so the pressure on the vac line should be atmospheric anyway so I didn't see the point, you can if you like though

Step 101 - Check your AFPR gauge and see that it reads 35 (ignore the fact mine shows about 38 in the picture). If not, adjust it using the allen key fitting and nut on the AFPR. You need to really force the nut round as it will be stiff and make sure the allen bolt doesn't move then doing this

Step 102 - Check all connections to make sure you have no leaks, smell for fuel too

Step 103 - Disconnect the wires from the diagnostics block, turn the ignition off, and do something else for a few minutes. I took this opportunity to start regapping my plugs to 0.7mm because I want to run about 20psi of boost (0.8mm is the norm for my copper plugs)

Step 104 - The fuel pressure should now have dropped by a few psi, if you are much below 20 then check for leaks/bad seals and if you can't find one then your injectors or afpr may be faulty. Note that when you eventually start the engine, the pressure should sit around 26-30 psi

Step 105 - I took this opportunity to install a manual boost controller (See separate guide) but this is optional, you may already have a controller or you may be fitting an electronic one. Either way, now is as good a time as any seeing as you have the accordion hose off and are upping the fuelling so presumably you want more boost too

 

[JSeaman]

Step 106 - Right, onto the AFM side of things now. Remove the old clip from the accordion hose (You'll need a bigger jubilee clip to go round the Lexus AFM)

Step 107 - Remove the 3 screws holding the electronics onto the old AFM

Step 108 - Carefully remove the box by pulling it straight up from the AFM housing

Step 109 - This is the inlet air temperature sensor (the small dimple on the left) and the vortex generator (the long probe with the hole in it). Place this carefully to one side

Step 110 - Undo the 4 bolts holding the air filter onto the AFM body

Step 111 - Ease the two apart, if necessary use a flatblade screwdrive to get it started but be careful not to damage the rubber gasket

Step 112 - Remove the gasket, we will re-use this on the new AFM

Step 113 - If you are going to use the mounting bracket again then undo these two screws (Mine wouldn't shift so I decided not to bother using it)

step 114 - The two AFMS. Picture 1 shows the Lexus on the left, note the threaded holes instead of bolts. Picture 2 shows the Lexus unit at the top and you can see the size difference. The third picture shows the massive difference in the unmetered air section and the general size increase in the diameter of the unit (Lexus unit on the left if you didn't know)

Step 115 - Place the rubber gasket on the new AFM

Step 116 - Find 4 10mm bolts and use them to attach the air filter to the AFM

Step 117 - Install the black box to the new AFM, careful not to bash it about when fitting

Step 118 - Now for the painful bit, try and get the accordion hose over the new AFM. Apply some fairy liquid (picture 1), but not too much and make sure it gets nowhere near the electronics. Use a screwdriver to ease the hose over the AFM body. It's a bit of a pain and a nice stainless one with silicone couplers is preferable but it does go (see picture 3 for proof!!). If your accordion hose is brittle then you may tear it doing this but leave it to stand in some hot water to soften it before trying. Mine was quite soft so stretched over without this but it was quite tricky and could've done with a helper

Step 119 - It might be worth taking some time to clean up the connections on the electronics if they aren't looking to tidy, just wire wool or something similar will be fine

Step 120 - Install a huge jubilee clip over the hose connected to the AFM because your new one will be too small

Step 121 - Finally back to the car, pop it back on and stick all your PCV, 3000 pipe, throttle body, ISC valve etc back in place

 

[JSeaman]

Step 122 - Fire it up and your car should hopefully idle. Mine stuttered and died the first time I tried then I left it for thirty seconds and tried again and it ran perfectly. I didn't drive anywhere, just idled, checked that a bit of throttle didn't kill it then turned it off.

Step 123 - After leaving the car overnight I came out with my volt meter again and checked the fuelling (as mentioned in steps 1-3). I was running mega rich so am happy the car can be driven. Next I'll hook up the SAFC and see how it runs.

Step 124 - See the guide for installing the SAFC (I separated this for those installing an SAFC without the other bits).

Step 125 - You will need to use a wideband O2 sensor and preferably EGT (exhaust gas temperature) gauge to monitor the engine's performance (1450 degrees fahrenheit when the sensor is after the turbo is where you should start to worry, add 100 degrees if you fit it before the turbo) when setting up this mod. Alternatively, if you don't know what you are doing then go to somewhere with a dyno and pay them a couple of hundred quid to tune it. Even if you do get someone else to set the car up, an EGT or air/fuel gauge might just help save your engine one day so is a worthy investment.

I went to John Noble Motorsport in Chesterfield and paid £140 inc VAT for a couple of hours. Other quotes were around the £200 mark to give you an idea what to pay