Fuel Problems??? Please Help

[b11dragone]

This has been a long and tedious process so anyone that is willing to help it would be greatly appreciated. Ever since the first mods I did on my car I have been having problems. I presented these problems on the forum several times and have tried every solution to "get my car to run right". It seems as though it has something to do with my fuel because after getting my exhaust,intake, and intercooler piping my car would studder at wide open throttle. On my air/fuel gauge it would show rich as long as the throttle was under 40% but as soon as I brought it past that my car would jump to lean and studder. So what do I do, buy every part to try and fix this problem. So after buying a walboro, fpr with gauge, safc-II, I still have the problem. In fact I had Pruven Performance install my downpipe and FPR on Friday and it got worse. Now my car at idle reads lean...and it stays there, no matter what. I can't get on my car at all and its not getting any fuel it seems like. I just want my car for the summer and if anyone knows any solutions please present them to me because I am stuck. Thanks for your time. Dominick

 

[talon1979]

You need to throw a logger on that car and see what it is doing. Do not trust your a/f gauge, it is worthless. The only thing it is good for is to see if your o2 sensor is working. Your car studdering at WOT could be a variety of things, you may be running to rich, too lean, your plugs or wires could be fouled, your o2 sensor/s may be bad, you may have boost leaks, your power transistor aka control module may be having issues.

 

[crankbender]

Can we have some more info please. What boost pressure are you running?

Are you absolutely sure the car is firing on all cylinders? What does the compression look like? are all the gaskets in the exhaust track? Did you replace the ground on the exhaust (it is important believe it or not)?

It is possible that you are getting knock (boost leak/high intake temps) and/or fuel cut at WOT. Both should be easy fixes.

 

[b11dragone]

I am bringing my car back to Pruven today. Hopefully they will give me some answers. My car will not even go to full boost before starting to act up. I don't believe its fuel cut because the bucking isn't based on my boost pressure (15psi), but its is based on my throttle position. And there is knock, according to my AFC-II it went all the way up to 60. All the flanges on the exhaust should be intact, Pruven does very good work I don't think they would mess that up.

 

[o0_pyro_0o]

I am having that same problem. I recently changed my plugs and found they were burned suggesting a lean mixture. However I still have the problem. I could use some specific help because I'm running out of ideas and I don't want to spend a lot of money on new parts that don't help the problem. BTW The only mods I have are a cone filter, 3"catback exhuast, and venom 400 performance module.

 

[talon1979]

What is this performance module? Is it a control module?

 

[o0_pyro_0o]

It's a control module made by venom performance. It controls the air/fuel ratio at certain rpms. You can read about it at http://www.venom-performance.com/nf/html/products/v400/v400.htm#v400

 

[Omega]

The knock function on the AFC does not work with your 2G. Do NOT believe those numbers. Your air/fuel ratio meter is also crap. It is just a useless light show.

It sounds like you have a boost leak. Make a leak tester from some parts from home depot and test it.

Are you venting to the atmosphere? If you are, hook it back up.

What are the settings on your AFC?

 

[markgholland]

This is a long shot, but have your caps been replaced in your ecu any time recently? I know this sounds weird, but my buddy was having the same problem with his 91 and then smelled something weird one day and I told him it was his caps. You may want to pull your ecu out and smell the caps. This caused similar symptoms in my friend's car. Just my $.02.
~Mark

 

[markgholland]

Oh, you have a 2G, just kidding. You still may want to look into a possible ecu issue...

 

[b11dragone]

I already checked for boost leaks. I don't have any. I pressurized my turbo and upper intercooler piping to 20 psi and no leaks, it can't be that. My fuel gauge was working properly untill the fuel pressure regulator was installed. But the fuel pressure regulator is working because it reads 40psi at idle. I have no idea at what is wrong with my car. It can't be spark plugs or wires, changed them yesterday, it can't be the fuel pump, or fpr, it not a boost leak, I have no idea what is going on. And one more thing, my 2g does have a knock sensor, and it only knocks when I push down on the throttle and that is also when my car starts running like crap, so it can't be that inaccurate.

 

[b11dragone]

The air/fuel gauge may be a useless light show when it comes to accuracy. However, it is telling me that my car is running insanely lean all the time, so in that sense it is helping me.

 

[gixrman]

Get A wideband o2 sensor/logger, on a 2g once you go outside the factory ECU settings you are tunning blind. A pocketlogger will only get you so far and you will be wishing you bought the wideband setup. You need to map out your A/F ratio thoughout your rpm to get the most out of your mods.

 

[Omega]

Yes your 2G has a knock sensor. It doesn't mean the AFC can properly translate the signal.

I assume that this would be 40 PSI with the vacuum hose disconnected. Just want to make sure the FPR is set up correctly.

What are your AFC settings? I would think they are pretty close to zero since you have the stock fuel injectors.

Have you replaced the O2 sensor recently?

 

[b11dragone]

No the vacuum his connected. But with the hose connected its supposed to be 38psi, so the guy at pruven put it at 40psi. He said if anything that would make it run alittle richer. My afc settings are at 0, I didn't want to mess with them untill I got a logging tool. I replaced the rear O2 sensor, and I am going to replace the front one in the next couple of days. I don't think it is the sensor though because it worked fine, untill the fpr was put on.

 

[Omega]

Hmm.. What about the fuel filter? It could be blocked (crudded up) which would cause the car to run lean when it needs lots of fuel.

That said, what is the FP when the car starts to run like crap? The FPR is a 1:1 ratio so check the see if the FP is reacting accordingly.

Too bad your are not closer to me. I have a logger and a WB O2 that I could diagnose your car with.

 

[b11dragone]

Thanks man that is really nice of you. I am changing the fuel filter in the next couple of days as well. I just don't believe that it will work because I started having these problems when I started to mod. If worse comes to worse I'll drive down th nj. Thanks.

 

[Omega]

This is bugging me, the more I ask, the more you are on the right track.. I don't get it.

The only thing I can come up with now is that the AFC is wired/setup incorrectly. Didn't you say that the car acted up before the AFC install though?

What is the exact parts list of aftermarket items that you first installed when it started to run like crap?


No problem... You are about 2 hours away. If you really get stuck it might be possible to meet half way. The only downside is if you have a cat, the WB won't work. You need to have the sensor before the cat.. which requires the exhaust to have a bung welded in.

 

[gixrman]

did you set up the AFC for Karman? I know this is a stupid Q but when I hooked up my AFC it ran pig rich til I figured this out.

 

[leet]

Originally posted by o0_pyro_0o
It's a control module made by venom performance. It controls the air/fuel ratio at certain rpms. You can read about it at http://www.venom-performance.com/nf/html/products/v400/v400.htm#v400

Wrong. All it does, is tell your car to go WOT, even when your foot is not all the way down.

It's only as powerful as your car is.

 

[b11dragone]

No the problem started before I had the afc. The problem started when I put the thermal 3 inch exhaust, k&n intake, and greddy upper intercooler piping with type s bov. Ever since then all the parts that I have purchased have been to fix this problem. No I don't have a cat because I have the apexi downpipe.

 

[b11dragone]

And all the setting for the initiale setup for the afc are correct. I have not changed the fuel settings due to lack of a logger though.

 

[o0_pyro_0o]

Originally posted by leet
Wrong. All it does, is tell your car to go WOT, even when your foot is not all the way down.

It's only as powerful as your car is.

Can I see a source for that theory?