Gas coming out exhaust and coating spark plugs

[jmatyas]

I was getting ready to sell my 97 GST Spyder and before I did I ended up taking it to a local high performance shop that I trust to make sure it was in correct running order to sell and not pawn any problems to the next owner. I got a call today that the car is leaking fuel out of the exhaust and running extremely rich. What would cause this?

Upgrades on car: Evo 3 16g MHI turbo, Punishment Racing FMIC, cold air intake, 1g bov, and 3" catback exhaust system. Everything else engine wise is stock and running stock 12psi of boost.

Also the NGK spark plugs I put in were coved in gas and black after a 20min test run. Kinda stumped on this one, we are about to do another boost leak test and check the timing as well.

 

[muddfisher85]

Sounds like the ecu to me I had that same issue on a 95 gst i had. It would run but crazy rich and would foul the plugs. The ecu looked fine but it was still causing the issue. Hope that helps a little.

 

[Technoklipz]

Check and make sure that your temperature sensor on the t-stat housing is in good condition. If any wires are broke or corroded it would cause this. The computer thinks that the car is cold but the car could be at normal operating temps and run way rich.

 

[chilled]

I would like blame 1 or more multiple faulty injectors before anything else. The car may also have a strong boost leak and the pcm is possibly adding fuel for air that is no longer there. Just some ideas, please check back.

 

[knochgoon24]

Is the MAF plugged in? Also check the front o2 sensor.

 

[jmatyas]

Thank you for the suggestions so far, Ill give a few responses.

1. New EPROM ecu, tried two others and same problem
2. Temperature sensor and housing are brand new
3. Boost leak test will be done later but its not just under boost, right when i start the car it already spews fuel. Injectors will be checked here soon, almost forgot about that.
4. MAF is plugged in and has not been messed with, o2 sensor is brand new as well.

Any other ideas please let me know. Odd issue that has us scratching out head to see what to look for first.

 

[knochgoon24]

4. MAF is plugged in and has not been messed with, o2 sensor is brand new as well.

Any other ideas please let me know. Odd issue that has us scratching out head to see what to look for first.

Do you have a logger to check the signals from those 2 sensors? Those 2 sensors control much of the fueling. So even if they're new and plugged in, you need to check that they're sending a signal. And do you have any CEL's?

 

[jmatyas]

Sadly I do not have a logger, that is something I need to look into. And no CEL codes, plugged it in to check and make sure the ECU wasn't messing up and not throwing codes and nothing popped up.

 

[BogusSVO]

Pull the Vac line to the FPR if it is wet or smells like gas, if it does you have a bad FPR sucking raw gas into the intake.

Do you have a Walbro 255lph in the tank?

 

[jmatyas]

Good idea on the fpr vacuum. Ill check that out asap. Also stock pump and stock injectors.

 

[jmatyas]

I'm sorry it has taken me so long to give an update but after almost a month I finally got my car back from a local performance shop and after every test they still have no clue what is causing the issue. I feel that they might have missed a few tests but I'll post what they did and if anyone has any ideas please let me know.
1. New knock sensor
2. MAF rewire
3. Stock and EPROM ECU tested
4. Three boost leak tests to make sure there are no leaks
5. Stock air intake put back in with no change
6. New spark plugs and wires again

After all these adjustments/tests there is still no change, still kicks and bucks under load at 3500-4500 rpm and runs very rich. Not sure what else to try. I have a few ideas but not sure if they are a waste of time. Let me know of which I should do and any you could add.
1. Fuel pressure test
2. Replace fuel pump
3. Replace injectors
4. Try another MAF
5. ?????

One thing we did find out is they did have some random wires tapped into the MAF which makes me think they had a translator at one time, but after fixing those wires I don't know if that would cause any problems. Thank you for any help you can give, this has been a monkey on my back for some time.