stalling after boost

Tjay

New Member
Sep 20, 2008
34
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Alberta
car is a 88 7mgte, 244,000km, mostly stock with filter,3inch straight turbo back exhaust, walbro 255lph pump. its been sitting for a year. trying to get it back on the road. heres the situation, if i hit boost and bring it up to about 4k+ rpm and let go of the gas completely with the clutch in or if i put it in neutral it stalls. I checked for boost leaks, it boosts fine so I dont think it's a boost leak as it boosts normal(comparing it to when it DID have a boost leak). it idl'es fine, right around 650rpm, if i rev it up in neutral it does not stall. greddy bov is recirculated. timing is correct, plugs and wires are new, checked for the code 51 when pushing the gas with the diagnostic wires jumpered. what else should I be looking for?
 

Tjay

New Member
Sep 20, 2008
34
0
0
Alberta
Could this still be a boost leak? or should I start looking at things like TPS and ISC? also ecu isn't throwing any codes.
 

Tjay

New Member
Sep 20, 2008
34
0
0
Alberta
So I think it is the TPS. I unplugged it and drove around and it idle's and drove exactly the same as if the TPS was plugged in. this was after I checked the TPS with a ohmmeter and IDL to E2 with both a .5mm and .9mm clearance between the lever and stop screw showed nothing on the ohmmeter. the rest of them were within TSRM spec, cept those 2. I hope that's what's causing my problem. I will be swapping the TPS with a known working one sometime this week and seeing if that fixes the problem.
 

Tjay

New Member
Sep 20, 2008
34
0
0
Alberta
Shit..can`t believe I forgot to mention that, BOV is recirculated.

Edit: Hah I DID mention the bov! almost fooled me! :D

car is a 88 7mgte, 244,000km, mostly stock with filter,3inch straight turbo back exhaust, walbro 255lph pump. its been sitting for a year. trying to get it back on the road. heres the situation, if i hit boost and bring it up to about 4k+ rpm and let go of the gas completely with the clutch in or if i put it in neutral it stalls. I checked for boost leaks, it boosts fine so I dont think it's a boost leak as it boosts normal(comparing it to when it DID have a boost leak). it idl'es fine, right around 650rpm, if i rev it up in neutral it does not stall. greddy bov is recirculated. timing is correct, plugs and wires are new, checked for the code 51 when pushing the gas with the diagnostic wires jumpered. what else should I be looking for?
 

skim1040

work in progress
First thought would be BOV...but you said it's recirculated...check the plumbing there, and make sure it is blowing the air back into the intake.

Next, check the calibration of the TPS. There is a guide in the TSRM on how to do it with a voltmeter. Easiest way to tell if it's dead or just out of alignment
 

supradjza80

Mr. Formula SAE
Apr 24, 2007
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Appleton, WI
www.uwracing.com
Tjay;1412089 said:
Shit..can`t believe I forgot to mention that, BOV is recirculated.

Edit: Hah I DID mention the bov! almost fooled me! :D

car is a 88 7mgte, 244,000km, mostly stock with filter,3inch straight turbo back exhaust, walbro 255lph pump. its been sitting for a year. trying to get it back on the road. heres the situation, if i hit boost and bring it up to about 4k+ rpm and let go of the gas completely with the clutch in or if i put it in neutral it stalls. I checked for boost leaks, it boosts fine so I dont think it's a boost leak as it boosts normal(comparing it to when it DID have a boost leak). it idl'es fine, right around 650rpm, if i rev it up in neutral it does not stall. greddy bov is recirculated. timing is correct, plugs and wires are new, checked for the code 51 when pushing the gas with the diagnostic wires jumpered. what else should I be looking for?

Well, guess I can't read :1zhelp:
 

Tjay

New Member
Sep 20, 2008
34
0
0
Alberta
Yeah I'm going to recalibrate the TPS today. it's weird though, cause in diagnostics if I push the gas I get the flashing code 51, indicating the TPS atleast knows when the throttle plate is fully closed, making me wonder. Like i said when i checked the TPS with a ohmmeter i got no reading from IDL to E2 with a .5mm gauge gapping the stop lever and stop screw, so that makes me think the TPS definitely needs to be recalibrated. and I've gone over the intake system quite a few times checking for leaks, next step will be to replace the last bit of plastic piping that goes around the fender and under the headlight with a hard pipe. I really need to rig up a boost leak tester.
 

IJ.

Grumpy Old Man
Mar 30, 2005
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I come from a land down under
Tjay;1411102 said:
car is a 88 7mgte, 244,000km, mostly stock with filter,3inch straight turbo back exhaust, walbro 255lph pump. its been sitting for a year. trying to get it back on the road. heres the situation, if i hit boost and bring it up to about 4k+ rpm and let go of the gas completely with the clutch in or if i put it in neutral it stalls. I checked for boost leaks, it boosts fine so I dont think it's a boost leak as it boosts normal(comparing it to when it DID have a boost leak). it idl'es fine, right around 650rpm, if i rev it up in neutral it does not stall. greddy bov is recirculated. timing is correct, plugs and wires are new, checked for the code 51 when pushing the gas with the diagnostic wires jumpered. what else should I be looking for?

gaboonviper85;1412433 said:
Have you actually checked codes yet?
 

TurboStreetCar

Formerly Nosechunks
Feb 25, 2006
2,776
3
38
Long Island, Ny
p1412472_1.gif
 

Tjay

New Member
Sep 20, 2008
34
0
0
Alberta
Thanks IJ! I was about to do that for the 2nd time in this thread..:biglaugh:

anyways problem *appears* to be solved, I pulled the throttle today and cleaned it up and got my multimeter out and re-calibrated it. IDL to E2 with a .5mm gap was messed up. re-installed, and re-did my timing, checked for any new codes.. and this little $2k beater supra is starting to show some real potential. Thanks for all the help guys, I really appreciate it.