Maft Pro tuning help

MK3_TJ

MK3_TJ

New Member
May 21, 2008
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Kettering, OH
I'm having problems with getting the car to run right. At idle it will go very lean...like 19:1 cold. Once it warms up it will run between 16:1 and 18:1. If i give it some gas it will rev, go rich(10:1-12:1) then fall to idle and try to stall (19:1 AFR), then eventually go back to around 17:1 or so. I did have the car running pretty well on the stock turbo and injectors just a month or so ago. I've read the manual several times. I guess I don't really know enough about the whole process to really get a handle on it yet.

I have an 87 7mgte, 550 injectors, Walbro pump, aeromotive fuel pressure regulator, maft pro running speed density, VRP61 bolt on turbo, FFIM, 90mm throttle body

Fuel pressure 35ish psi vacuum disconnected
fuel pressure 30ish psi vac connected

Since all this has not done anything I have setup the maft like stock except for -24% main scale for the 550 injectors.

Any ideas/help would be great. Thanks
 
awsom-0

awsom-0

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May 8, 2005
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Dallas, Tx
i'm having the same problem as you but with an upgraded CT-26. I'm going to do a boost leak test to see if they're any leaks.
 
ValgeKotkas

ValgeKotkas

Supramania Contributor
Apr 14, 2006
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Over the pond
I did the Supra quick start 5.0 with the 5.22 software and also was very lean, BUT I had many many vacuum leaks :) After removing those it ran nice and safely-rich.
Right size TB must be entered into the MAFT too, no?
 
MK3_TJ

MK3_TJ

New Member
May 21, 2008
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Kettering, OH
CajunKenny- I imagine you have the same name on full throttle tech? I have added fuel at idle to get Vf reading about 2.05. But still runs at like 16-17.5 AFR. I'm going to recheck again for a vacuum leak.
 
CajunKenny

CajunKenny

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Nov 15, 2007
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Yep, that's me. :)

Did you add fuel using the VE Table like in the mkiiitech.com link? Whatever you did improved it quite a bit.

Post up a copy of your settings. 'Config' and 'System Setup'.

What version firmware are you running?
 
MK3_TJ

MK3_TJ

New Member
May 21, 2008
37
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Kettering, OH
Runnig 5.22 on the maftpro. I used the Ve table. I had to change it a bunch to get it take any effect...leading me to think it has a vacuum leak some where. Could the EGR cooler gasket cause it to run lean?

I'll post up the settings after work. There some settings either not in the maft or they have different names or values so I am unsure if they are all correct. Also I have a 90mm throttle body. What size TB should I put in the Maft?
 
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MK3_TJ

MK3_TJ

New Member
May 21, 2008
37
0
0
Kettering, OH
Here are all the settings

CONFIG SELECT

Vehicle Select: Mode 2 (previously set to 0 per paper manual)
# of cylinders: 6 cyl
Displacement: 3 liter
Airflow mode: speed density
Map source: GM 3 bar
Load src: use map
Baro mode: read at key on
F-Out mode: MK3 supra
V-out1: use max setting
V-out2: use max setting
afr source: aem 5v (I have a plx wideband)
F-in mode: none
aux 1 trig: OFF
Flow errror mode: sd/maf (I don't have a afm connected though)

SYSTEM SETUP

Main Scale: now -14 (was at -25)
V-Out1 max: 2.5
V-Out2 max: 3.8, (had set to 3.6 per paper manual included with MAFT Pro)
Afterstart: 10 ( I have no idea if this helped with lean-ness on startup but this is what its at now)
Lo load: 36.4
Mid load: 100.1
Hi load: 143.0
F-Out max: 0
Tm base: 0.0
Tm correct: 1.27
IAT airflow: 35 (there is no designated setting anywhere that I have seen)
FE smoothe: 30 (left this alone as well)
Ve table: table 1 (whats the difference between the tables?)
Spk base: 15 (another setting that is not designated)

RESPONSE

TPS enrich: .50
TPS decay: .80
TB size: 7 (what do I set this to for a 90mm TB)
TPS MAP max: 85.8 ( no designated value so I left it alone)
Map enrich: .40
Boost enrich: .10 (none designated left alone)
MAP TPS min: .76 (about .05 above idle TPS)
MAP rpm min: 2560 (none designated left alone)
MAF limit TPS: 0.0 (left alone)
MAF limit 0.0 (left alone)
MAF/kRPM: 0.0 (left alone)
Lim MinRPM: 0.0 (left alone)
Lim Time: 0.0 (left alone)
offIdle% 5.0 (left alone)

Spark Wot all set to 0 (zero)

Spark aux/Mid set to 0 (zero)

Part throttle tracking disabled

Boost control is irrelevant, but I do have it-just not hooked up

I have WOT tracking disabled. Tps threshold set higher than TPS can reach

All air temp tunes set to 0% (zero)

Aux trig tunes 0% (zero)

LO, HI, and MID user tunes all set to 0% (zero)
 
grimreaper

grimreaper

New Member
Jul 2, 2008
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Dallas
MK3_TJ;1611034 said:
I'm having problems with getting the car to run right. At idle it will go very lean...like 19:1 cold. Once it warms up it will run between 16:1 and 18:1. If i give it some gas it will rev, go rich(10:1-12:1) then fall to idle and try to stall (19:1 AFR), then eventually go back to around 17:1 or so. I did have the car running pretty well on the stock turbo and injectors just a month or so ago. I've read the manual several times. I guess I don't really know enough about the whole process to really get a handle on it yet.

I have an 87 7mgte, 550 injectors, Walbro pump, aeromotive fuel pressure regulator, maft pro running speed density, VRP61 bolt on turbo, FFIM, 90mm throttle body

Fuel pressure 35ish psi vacuum disconnected
fuel pressure 30ish psi vac connected
Since all this has not done anything I have setup the maft like stock except for -24% main scale for the 550 injectors.

Any ideas/help would be great. Thanks
Click to expand...

thats not right, you should see a 10psi increase from removing the vac line to afpr. Fix the leaks an I bet it would idle properly or at least in the tcccs range of control. check vf as well. Betting its pegged 5V.

the TB size adjust the response fuel multiplier. larger TB = Larger multiplier for more fuel. Play with this after you get a solid part throttle tune. Its a "feel" thing, not a hard data outcome.
 
CajunKenny

CajunKenny

PULL MY FINGER. PLEASE!
Nov 15, 2007
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Washington
One more question... What is your vac reading at idle?

It should be between 17 and 20 inhg. Any less and you've got a vac leak.
 
MK3_TJ

MK3_TJ

New Member
May 21, 2008
37
0
0
Kettering, OH
Grim- I will check into the fuel pressure/leaks tomorrow. And I won't worry about TB sizing for now.

Kenny- Vac is 17-18 cold. 19 warm. I checked all things vacuum and found nothing leaking.
 
CajunKenny

CajunKenny

PULL MY FINGER. PLEASE!
Nov 15, 2007
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Washington
Sorry...been away on vacation...

Vac looks good.

Every car is different; but, I've got my fuel pressure set at 42 psi w/vac and am currently at 16.5 psi of boost. When I had my pressure set to 38 psi w/vac, power suffered over 15 psi of boost. For what that's worth...

Any new progress?
 
grimreaper

grimreaper

New Member
Jul 2, 2008
2,180
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Dallas
ken your running 67 psi of fuel pressure at 15psi of boost. If the charts I have for the walbros are worth the paper they are printed on, your not to far away from maxing the pumps psi/flow. At 28psi vac on, youd be looking at 53psi of fuel pressure at 15psi of boost.
 
MK3_TJ

MK3_TJ

New Member
May 21, 2008
37
0
0
Kettering, OH
The car really does not like to run when its cold. When it sits over night it is kinda hard to start. If/when it starts it runs super rich and I have to keep on the gas to keep it from stalling. This is the biggest problem I have. Its hard to tune if it don't run.

Recently got a new job and have been focusing on other stuff. Plus the weather is crappy as ever. At idle its still leanish @ 16 to 17 at times. Vf is happy most the time.
 
MK3_TJ

MK3_TJ

New Member
May 21, 2008
37
0
0
Kettering, OH
Its been so long since I have started the car I forget what all it does or doesn't do. Sooo...

Checked the afterstart and it is at 0.0 It took about 5 seconds of cranking and pumping the gas pedal a few times to get it to start. While holding the gas it is super rich 11:1, steady rpm at 1200 or so. When I let go of the gas it goes lean and sputters out and dies. These symptoms go away gradually as the engine warms up.
 
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