service engine light

i had just filled my 97 pontiac gp up with fuel ( 92 octane ) , when leaving the gas station the light came on i did fill it way over the full marker. like i always try to do. but i just tuned it up ( spark plugs,wires, pvc valve, oil, air filter). but now the check engine light is on. first time i filled after tune up seems odd sounds like it running same just cant figure out why its on. gonna go get codes tommorow but need some insight. thanks guys. i also added tranny fluid, maybe i overfilled?

i had just filled my 97 pontiac gp up with fuel ( 92 octane ) , when leaving the gas station the light came on i did fill it way over the full marker. like i always try to do. but i just tuned it up ( spark plugs,wires, pvc valve, oil, air filter). but now the check engine light is on. first time i filled after tune up seems odd sounds like it running same just cant figure out why its on. gonna go get codes tommorow but need some insight. thanks guys. i also added tranny fluid, maybe i overfilled?

It might be helpful to provide the mileage on your GP and the odb-ii DTC error codes when you get them.







http://i5.photobucket.com/albums/y186/lizzywiz/gtp.jpg
Thrasher CAI, DHP v1.0 PCM, SLP Headers,
3.25 SC pulley, CAIT GMAF, 2.5 DP/Hi-Flow CAT,
u-bend delete, 160 TS, ZZP Stage 1 72mm TB,
TB spacer, MSD 8.5mm wires, Autolite 103,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials
1/4 ET: 13.210 sec. @ 104.490 mph
0 - 60 ft: 1.945 sec.

the car has 103,000 miles on it. and the trouble code is p0401. any ideas on where to start. says "exhaust gas recirculation flow insufficient detected". the guy turned off the light and it hasnt returned yet after 30 minutes but he said it will re appear until problem fixed. dont knopw what the problem is

the car has 103,000 miles on it. and the trouble code is p0401. any ideas on where to start. says "exhaust gas recirculation flow insufficient detected". the guy turned off the light and it hasnt returned yet after 30 minutes but he said it will re appear until problem fixed. dont knopw what the problem is


You didn't by chance recently replace the PCV valve? I've seen P0401 show up after a PCV valve changeout (normally done improper). It may clear itself up after a few drive cycles but if not:

You can remove the EGR valve. There should be two 13 mm nuts holding it onto the flange. Undo the electrical connector and lift up. Then clean as much carbon off that you can. Take WD40 and lubricate the pintle/spring and make sure it moves freely. If cleaning doesn't work, then the EGR valve is defective electrically (solenoid).






http://i5.photobucket.com/albums/y186/lizzywiz/gtp.jpg
Thrasher CAI, DHP v1.0 PCM, SLP Headers,
3.25 SC pulley, CAIT GMAF, 2.5 DP/Hi-Flow CAT,
u-bend delete, 160 TS, ZZP Stage 1 72mm TB,
TB spacer, MSD 8.5mm wires, Autolite 103,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials
1/4 ET: 13.210 sec. @ 104.490 mph
0 - 60 ft: 1.945 sec.

and the funny thing is now that i think about it is... the guy was twisting on the egr valve thinking the pcv valve was underneath until realizing it was wrong side of engine, and wrong part. should i put pcv valve in again?

and the funny thing is now that i think about it is... the guy was twisting on the egr valve thinking the pcv valve was underneath until realizing it was wrong side of engine, and wrong part. should i put pcv valve in again?

It's a simple DIY job. I would double check his work on the PCV valve and make sure he did not leave out any o-ring seals or break the MAP sensor. We can post pics and a procedure for you.

On the EGR valve, try disconnecting and re-seating the electrical plug. The mechanic may have screwed up the connection or worse yet broken wires. Good luck!







http://i5.photobucket.com/albums/y186/lizzywiz/gtp.jpg
Thrasher CAI, DHP v1.0 PCM, SLP Headers,
3.25 SC pulley, CAIT GMAF, 2.5 DP/Hi-Flow CAT,
u-bend delete, 160 TS, ZZP Stage 1 72mm TB,
TB spacer, MSD 8.5mm wires, Autolite 103,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials
1/4 ET: 13.210 sec. @ 104.490 mph
0 - 60 ft: 1.945 sec.

could a loose gas cap trip that code? I've seen many a strange emission code set by not tightening the fuel cap correctly, especially when the tank is overfilled.

could a loose gas cap trip that code? I've seen many a strange emission code set by not tightening the fuel cap correctly, especially when the tank is overfilled.

The one I get from an evap emissions system problem when leaving the cap off or if loose is P0440.






http://i5.photobucket.com/albums/y186/lizzywiz/gtp.jpg
Thrasher CAI, DHP v1.0 PCM, SLP Headers,
3.25 SC pulley, CAIT GMAF, 2.5 DP/Hi-Flow CAT,
u-bend delete, 160 TS, ZZP Stage 1 72mm TB,
TB spacer, MSD 8.5mm wires, Autolite 103,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials
1/4 ET: 13.210 sec. @ 104.490 mph
0 - 60 ft: 1.945 sec.

The "mechanic" didn't know a pcv valve from a EGR, is it possible he mis-read the code too? :screwy:

The "mechanic" didn't know a pcv valve from a EGR, is it possible he mis-read the code too? :screwy:



i had auto zone and schucks do trouble codes both came up with same code exept autozone said it was p0401 and p0402, but very possible that he would have mis read the codes if given the chance. thanks very much bnaylor and richtaz and others for help... this forum is a very good tool for repair and general knowledge of auto maintanance. makes car repair somewhat enjoyable, thanks again

i had auto zone and schucks do trouble codes both came up with same code exept autozone said it was p0401 and p0402, but very possible that he would have mis read the codes if given the chance. thanks very much bnaylor and richtaz and others for help... this forum is a very good tool for repair and general knowledge of auto maintanance. makes car repair somewhat enjoyable, thanks again

Thats very interesting because P0401 is EGR Flow Insufficient and P0402 is EGR Flow Excessive???

Anyways, you're welcome. I'd go with it being an EGR valve problem. Good luck!







http://i5.photobucket.com/albums/y186/lizzywiz/gtp.jpg
Thrasher CAI, DHP v1.0 PCM, SLP Headers,
3.25 SC pulley, CAIT GMAF, 2.5 DP/Hi-Flow CAT,
u-bend delete, 160 TS, ZZP Stage 1 72mm TB,
TB spacer, MSD 8.5mm wires, Autolite 103,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials
1/4 ET: 13.210 sec. @ 104.490 mph
0 - 60 ft: 1.945 sec.

if you over fill the gas tank you can block the vapor recovery system or fill it with fuel. that might cause the code. run the fuel tank down and reset the code and see if it comes on again. the code relates to the pollution control, but an EGR problem will usualy give a noticably rough idle or worse. the vapor recovery system can make some really strange noises while not affecting performance.

over filling the gas tank is not only a bad idea, it is actualy illegal in many states. since i track my gas mileage i never fill past the auto shutoff. i think i get a more acurate measurement that way. tracking your mileage will alert you to changes in your engine preformance.

Unless the PCM is braindead, evaporative emissions problems will give off a certain group of codes such as P0440 through P0459, etc. So I doubt that is his problem. I've taken my GTP and other "W" bodies owned all the way up to the brim and overflow with no problems.

You can have a EGR flow problem DTC error code with no noticeable change in engine performance such as rough idle, etc. The PCM runs EGR flow under a given set of circumstances. When it tests EGR functions, it commands EGR on and simultaneously monitors MAP (Manifold Absolute Pressure). The PCM will only store DTC P0401 and trigger the SES MIL light if an expected increase is not seen under certain conditions in DECELERATION only. In other words the PCM will only run an EGR flow test during gradual deceleration, a closed throttle condition, and with vehicle speed greater than 25 mph.

The GM Grand Prix service manual recommends the following course of action for DTC P0401:

Inspect wiring to EGR valve - repair as necessary

Check EGR solenoid operation - Replace if defective

Check wiring between PCM to EGR connector - check for short or open

If EGR solenoid operation is good, inspect/ clean EGR pintle and passages

Check EGR flange gasket - Replace if torn or damaged

Remove EGR inlet and outlet to intake and exhaust manifold - Check for blockage and/or clean

Inspect exhaust system for leaks - repair as necessary

Inspect EGR valve for excessive heat damage - check exhaust system for blockage or plugged CAT convertor






http://i5.photobucket.com/albums/y186/lizzywiz/gtp.jpg
Thrasher CAI, DHP v1.0 PCM, SLP Headers,
3.25 SC pulley, CAIT GMAF, 2.5 DP/Hi-Flow CAT,
u-bend delete, 160 TS, ZZP Stage 1 72mm TB,
TB spacer, MSD 8.5mm wires, Autolite 103,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials
1/4 ET: 13.210 sec. @ 104.490 mph
0 - 60 ft: 1.945 sec.

I'd remove and clean the EGR with carb cleaner and be sure to use a new gasket when reinstalling. I've never had a code from overfilling but did have same problem with EGR crusted up and giving 0401 code. New gasket was necessary.

wow.... all that research and what not and it wasnt even the egr valve. come to find out a hose underneath the air filter assembly was off. that explains the sucking air noise and poor preformance. light is off now well see if it stays off, hopefully it does. thanks again bnaylor and richtaz and forum crew will let you know.

wow.... all that research and what not and it wasnt even the egr valve. come to find out a hose underneath the air filter assembly was off. that explains the sucking air noise and poor preformance. light is off now well see if it stays off, hopefully it does. thanks again bnaylor and richtaz and forum crew will let you know.



nevermind ... friggin light back on, gonna disassemble egr valve and give thourogh cleaning, and new gaasket. im sure the unhooked hose wasnt good either. not a cheap part ( egr ) to replace

nevermind ... friggin light back on, gonna disassemble egr valve and give thourogh cleaning, and new gaasket. im sure the unhooked hose wasnt good either. not a cheap part ( egr ) to replace

Did you ever double check the work the flaky mechanic did when the PCV valve was replaced? Here's the procedure if you have a GT or SE with 3800:


http://macgp.clubgp.com/howto/engine/pcv/gt/pcv.html

It is very important that the 2 o-rings are properly installed.

IMO the EGR valve is a good starting point. Good luck!







http://i5.photobucket.com/albums/y186/lizzywiz/gtp.jpg
Thrasher CAI, DHP v1.0 PCM, SLP Headers,
3.25 SC pulley, CAIT GMAF, 2.5 DP/Hi-Flow CAT,
u-bend delete, 160 TS, ZZP Stage 1 72mm TB,
TB spacer, MSD 8.5mm wires, Autolite 103,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials
1/4 ET: 13.210 sec. @ 104.490 mph
0 - 60 ft: 1.945 sec.