Help! Supra doesn't run right

[Abe's 1987]

Well I learned another thing. Learned about the j-tube. Went and checked on mine and it is still there, has not been bypassed, and has not been drilled out.

Question, if I do drop in the walbro 255 without bigger injectors or adjustable fuel pressure regulator would I need to bypass the j-tube.

I would later on plan to at least push 350 rwhp in the future so might as well go with the walbro 255 right?

 

[plaaya69]

Question, if I do drop in the walbro 255 without bigger injectors or adjustable fuel pressure regulator would I need to bypass the j-tube?

You can leave the j-tube in place for now.

 

[f00g00]

I have used the Walbro 255 and am using an AEM 340 fuel pump right now and they don't seem to have built in check valves in them to retain pressure. I turn off the ignition and my AFPR goes to 0. If you want to retain pressure and use an aftermarket pump then you will need an inline check valve, otherwise go with a MKIV Denso pump.

 

[3p141592654]

First, the J-tube needs to be drilled out. You can certainly continue to use it, but if left as is your pressure will not be controllable with a bigger pump.

Everything I read says the walbro 255 has a check valve, but I don't own one.

 

[Abe's 1987]

So to add a walbro I have to drill out the j-tube? Can the stock fpr work for the walbro pump?

I did pull off the rail today to check if injector are stuck open which they are not. More then likely will put new seals on the injectors later, they look good but would rather have seals new. I will crawl under one more time to triple check to make sure the fuel lines are good. I will be ordering the fuel pump in the next couple of weeks. But other then that all is moving along slowly.

I did order a new efi main relay.

 

[3p141592654]

Stock FPR is fine. It is typical to replace with an adjustable FPR, but that is really only needed if you do the lexus AFM/550inj mod. Yes, drill out the J tube. Its the only way you are going to handle the higher return fuel flow with a bigger pump.

The idea behind the j-tube restriction is that if the FPR fails, the restriction will create enough backpressure that the car will still be drivable.

 

[Abe's 1987]

As I wait to get a new fuel pump, I'm looking into other problems the supra is having.

Figured out why the passenger side headlight didn't work, one of the harness wires where cut. Fixed it and got it working.

Installed my foglights i got but they didn't turn on so have some diagnosing to do on those.

Got the new efi relay and installed it in. Will test out to see the difference tomorrow.

I do have a couple questions. These are general question, not pertaining to my supra.

1. Will the car ran properly with the fpr vsv bypassed?

2. What is the benefits of running the car without the egr system?

3. What's the benefits of running the car without the evap system?

4. Has anyone done a throttle body/iacv coolant hose bypass? Would that be worth looking into?

5. Could the iacv be deleted? Would there be any benefits to deleting it?

6. Could the cold start injector be deleted? Any benefits to that?

 

[3p141592654]

The fogs as wired stock only come on with the headlights low beams on.

1) Yes, if bypassed means connected to manifold vacuum 100% of the time.
2) None. Only active at cruise, so no impact on WOT. Bonus, keeps exhaust gas temps lower during cruise conditions.
3) None. Evap trapped gas is vented through engine during cruise, so tiny improvement in mileage. Also, keep 0.5psi pressure in tank which helps fuel pump prime.
4) Some do it. Consider that as air transitions from atmospheric pressure to vacuum its temperature drops. This can lead to icing in humid conditions well above freezing ambient temps.
5) If you like an engine with no fast idle that stalls a lot when cold, then yeah, its great.
6) Sure, but hard starts in cold weather. I'm not sure what the attraction is to remove this kind of stuff. But that' sjus tme.

 

[Abe's 1987]

The fogs as wired stock only come on with the headlights low beams on.

1) Yes, if bypassed means connected to manifold vacuum 100% of the time.
2) None. Only active at cruise, so no impact on WOT. Bonus, keeps exhaust gas temps lower during cruise conditions.
3) None. Evap trapped gas is vented through engine during cruise, so tiny improvement in mileage. Also, keep 0.5psi pressure in tank which helps fuel pump prime.
4) Some do it. Consider that as air transitions from atmospheric pressure to vacuum its temperature drops. This can lead to icing in humid conditions well above freezing ambient temps.
5) If you like an engine with no fast idle that stalls a lot when cold, then yeah, its great.
6) Sure, but hard starts in cold weather. I'm not sure what the attraction is to remove this kind of stuff. But that' sjus tme.

I'm keeping my supra stock for now but just wanted to know why some other remove some of these systems. From what you said there are no benefits to removing them.

I'll be ordering the pump by Monday and then swapping it out. Fingers crossed.

 

[suprarx7nut]

The fogs as wired stock only come on with the headlights low beams on.

1) Yes, if bypassed means connected to manifold vacuum 100% of the time.
2) None. Only active at cruise, so no impact on WOT. Bonus, keeps exhaust gas temps lower during cruise conditions.
3) None. Evap trapped gas is vented through engine during cruise, so tiny improvement in mileage. Also, keep 0.5psi pressure in tank which helps fuel pump prime.
4) Some do it. Consider that as air transitions from atmospheric pressure to vacuum its temperature drops. This can lead to icing in humid conditions well above freezing ambient temps.
5) If you like an engine with no fast idle that stalls a lot when cold, then yeah, its great.
6) Sure, but hard starts in cold weather. I'm not sure what the attraction is to remove this kind of stuff. But that' sjus tme.

The benefit is wire tuck lyfe yo! Super clean!

... /sarcasm.

I don't get it either. When I've looked at buying a MK3 it's one of the first things that could disqualify a purchase.

I'm keeping my supra stock for now but just wanted to know why some other remove some of these systems. From what you said there are no benefits to removing them.

I'll be ordering the pump by Monday and then swapping it out. Fingers crossed.

If you're going standalone then those systems might add some complexity that some people don't want to deal with or which they deal with by using a different part that serves a similar purpose, but integrates easier into the new ECU. I think people have gotten confused along the way and thought that "That high powered car I saw at the meet/online deleted their [fill in the blank] so if I do it too, it'll be like I have a high powered, special car!! Silly Toyota putting stuff in the engine that makes the car slow!"

The EGR thing throws people off all the time as well. It's hard to grasp that recycling hot air could actually cool the system overall. Add to that it's an emissions device and lots of people write it off as unneeded, unfortunately.

 

[3p141592654]

Some of those topics are literally religious for some people. I would say you can find at least one heated thread for each of them on this site.

 

[Abe's 1987]

The benefit is wire tuck lyfe yo! Super clean!

... /sarcasm.

I don't get it either. When I've looked at buying a MK3 it's one of the first things that could disqualify a purchase.



If you're going standalone then those systems might add some complexity that some people don't want to deal with or which they deal with by using a different part that serves a similar purpose, but integrates easier into the new ECU. I think people have gotten confused along the way and thought that "That high powered car I saw at the meet/online deleted their [fill in the blank] so if I do it too, it'll be like I have a high powered, special car!! Silly Toyota putting stuff in the engine that makes the car slow!"

The EGR thing throws people off all the time as well. It's hard to grasp that recycling hot air could actually cool the system overall. Add to that it's an emissions device and lots of people write it off as unneeded, unfortunately.

Which kinda brings me to the point, why do those who have no clue try to do?

The front upper radiator/headlight support on my supra Has been hacked away. Therefore causing a lazy eye headlight on my passenger side. Now i got to find a good one and have a body shop weld it on. I've ran into guys multiple times wanting to make a track or drift car then cutting at the frame of the car. Ok cutting at the bumpers that can be replaced easily is ok but why cut the welded frame. There are ways around that.

 

[plaaya69]

The JDM 7mGTE motor's did not come with a egr valve and had factory block off plates from the start. The OEM JDM ecu is tuned for this and if you have the right tune with a standalone or buy a JDM ecu you can get rid of the egr set up as well but it does help lower the combustion temps with the egr in place. I am not running a egr because I am going with a standalone, do not want my intake manifolds turning dirt black inside and I do not want hot exhaust building up in the egr cooler on the back of the cylinder head causing a BHG on cylinder 6.

If you take off your throttle body and take a look inside the port where the exhaust gasses meet the fresh air you will see soo much dirty carbon build up and most likely it will be clogged like mine was when I removed my old motor. Here is a thread with a few pictures of what a dirty egr path in the intake manifold looks like:

http://www.celicasupra.com/forums/showthread.php?44651-How-to-clean-out-your-EGR-system-(56k-beware)


Personally, if you plan on running the OEM ecu then keep the EGR in place. If you are going to for big power and have your motor tuned right with the proper engine management then it is up to you if you want to remove it or leave it in place.

 

[3p141592654]

PCV causes the intake buildup, not EGR, since blowby consists mainly of sticky aromatics and organics. Compare the backside of the intake and exhaust of well used valves to see what I am talking about.

 

[Abe's 1987]

So pretty much the emission systems cause the engine to get buildup? Without the emission systems the engine would run cleaner?

 

[3p141592654]

This is what happens to an engine where the PCV is weak or disabled (this was epidemic in the 90s on some toyotas). The function of the PCV is first and foremost to get blowby out of the crankcase.

1MZ

 

[Abe's 1987]

This is what happens to an engine where the PCV is weak or disabled (this was epidemic in the 90s on some toyotas). The function of the PCV is first and foremost to get blowby out of the crankcase.

1MZ
View attachment 80302

Hot diggity damn that is bad. My pcv is still intact so hopefully my engine isn't like that. Who knows what the previous owners have done. I need to check to see if the hg has been replaced with the arp stud and nuts!

 

[3p141592654]

That was mostly due to an industry shift in the 90s to long oil drain intervals, and reduced ventilation for emissions. I've never seen a 7M that has anything like that going on. But, if you disable or mickey-mouse the PCV you are asking for trouble on a daily driver.

 

[Abe's 1987]

That was mostly due to an industry shift in the 90s to long oil drain intervals, and reduced ventilation for emissions. I've never seen a 7M that has anything like that going on. But, if you disable or mickey-mouse the PCV you are asking for trouble on a daily driver.

Would it be a good idea to consider adding a oil catch can to the pcv system to help reducing the oil flowing back into the intake system or is the oil beneficial to the intake system?

 

[3p141592654]

Stay focused on getting it running well. Plenty of time for that stuff later.