Too much fuel

[onefast2gdsm]

I'm working on my buddy's 1g. 93 Tsi awd, automatic with 390cc injectors and a 14b turbo. Fresh 7 bolt. Car is fouling plugs and drowning the cylinders in fuel.

So far I have replaced

Cas
Transistor pack
Coil pack
Replaced maf with 2g maf
Swapped fuel rails (had 2g in)
Injectors (had 450cc in)
Fuel pressure regulator (had 2g in)
Spark plugs
Coolant temp sensors

Timing is dead on (triple checked) ignition timing is on.

I can get the car to run if I blow off the spark plugs with an air hose, once car gets slightly warm, I hit the throttle and it dies, either that or I shut it off and try to start it.again and it just cranks and spark plugs are fouled. What regulates the amount of fuel going into the motor? I'm at a loss here..

 

[Silent_White]

fuel return line. either your factory fpr is bad or return line is clogged. Does he have any tuning software? Or a fuel pressure gauge?

 

[NHerron]

-Assuming there is no air/fuel control and it's a pretty much stock configuration (no huge fuel pump or SAFC interrupting the mass airflow signal)

If you have no AFC and a slightly better flowing 2g maf, it would make things a little leaner but most people put in the 550cc's to compensate.
Check this link, and double check the wires.
2G MAF in a 1G TEL/GVR4

I don't know if anything is different besides the bolt holes on the 1g/2g FPR's, function wise.

On my 2g gsx, I have the cold start solenoid so when the engine coolant is cold, the ECU activates the solenoid (closes off the FPR from intake pressure) and brings the fuel pressure up to base pressure no matter what. When it's warm, the solenoid opens again and lets the FPR see intake mainfold pressure.

Looking at engine bay from front of car:
Pressurized fuel comes from the tank to the filter on firewall, into the left side of fuel rail, exits through FPR (on right side of rail), back to the firewall near filter, and returns back to tank.

Anyone, feel free to school me if anything is off.

 

[CrawlinZX14]

Have you run a noid tester on the injectors to make sure they are firing correctly? You could possibly have an issue with the ECU, but I would venture to say its your FPR.

You could try testing your fuel pressure on the other end of the fuel rail and see what its running at when running.

To much fuel pressure will def cause you to go rich.

-Assuming there is no air/fuel control and it's a pretty much stock configuration (no huge fuel pump or SAFC interrupting the mass airflow signal)

If you have no AFC and a slightly better flowing 2g maf, it would make things a little leaner but most people put in the 550cc's to compensate.
Check this link, and double check the wires.
2G MAF in a 1G TEL/GVR4

I don't know if anything is different besides the bolt holes on the 1g/2g FPR's, function wise.

On my 2g gsx, I have the cold start solenoid so when the engine coolant is cold, the ECU activates the solenoid (closes off the FPR from intake pressure) and brings the fuel pressure up to base pressure no matter what. When it's warm, the solenoid opens again and lets the FPR see intake mainfold pressure.

Also, maybe check the fuel filter?

Pressurized fuel comes from the tank to the filter on firewall, into the left side of fuel rail, exits through FPR (on right side of rail), back to the firewall near filter, and returns back to tank.

Anyone, feel free to school me if anything is off.

1g has fuel filter on the pass side near the battery, and the return line is near the brake master cylinder. A clogged filter would not cause a rich running issue like that.

Which FPR do you have in there? Have you checked for vac leaks on the FPR? Is there any EPROM or anything like that? Have you checked the TPS?

 

[NHerron]

A clogged filter would not cause a rich running issue like that.

Are you saying it wouldn't cause THAT bad of an over fueling because the filter normally can't get that clogged to cause such a situation? I was under the impression a clogged filter would cause a little extra back pressure=richer

 

[CrawlinZX14]

Are you saying it wouldn't cause THAT bad of an over fueling because the filter normally can't get that clogged to cause such a situation? I was under the impression a clogged filter would cause a little extra back pressure=richer

Fuel filter would cause a higher pressure between the fuel pump and the fuel filter. But it would restrict the fuel flow and thus pressure to the fuel rail which is post fuel filter. A clogged filter will cause a lean issue more than anything as its restricting the flow to the rail.

 

[jpmxrider489]

I would replace the fpr on the fuel rail. You can see if your return is cloged as well. Sounds like your getting to much fuel. Are your spark plug wires and injector clips on the right ones?

 

[NHerron]

Fuel filter would cause a higher pressure between the fuel pump and the fuel filter. But it would restrict the fuel flow and thus pressure to the fuel rail which is post fuel filter. A clogged filter will cause a lean issue more than anything as its restricting the flow to the rail.

Yup, 'tard moment. I was imagining the effect of the filter AFTER the rail, on the return side. That would be pretty pointless to have a filter AFTER what you're trying to protect.

Anyway OP, +good idea to check those vacuum hoses like CrawlinZX14 said. Maybe just do a boost leak test. It seems you always find a leak anyway...

 

[onefast2gdsm]

We orginaly had a 2g ffuel rail with 450cc injectors and a 2g fpr. We switched it out for a 1g rail with 390cc onjecotrs and a 1g fpr. So I know it's not the injecotrs or fpr. How do i check of the return line is clogged? And I just put the 2g mmaf on last night to see if it was the maf that was bad.

 

[Blindmouse]

Check AFR or O2 voltage before you makes some theories.

 

[fourgsixthree33]

This is my car. We have been scratching our heads for weeks. Seems like the only thing we have not checked is the return line, ecu, and windshield wipers

Tomorrow i am borrowing an ecu. We have also not reset the the ecu since we swapped the maf. Since the old maf checked out bad, MAYBE we will luck out reseting the ecu?

Also we have done a blt. Fixed a few good size leaks.

 

[Diamond Star Werks]

We orginaly had a 2g ffuel rail with 450cc injectors and a 2g fpr. We switched it out for a 1g rail with 390cc onjecotrs and a 1g fpr. So I know it's not the injecotrs or fpr. How do i check of the return line is clogged? And I just put the 2g mmaf on last night to see if it was the maf that was bad.

check if the return line is clogged by taking off the line and putting on another rubber hose same size. Clamp the other hose on and run it into a gas can that way you will know it is flowing out properly and if it doesn't change situation you can rule out the return line. Is it fouling every plug? CEL? Tps won't usually cause that problem as if it was bad it would more than likely cause a surging idle problem. Make sure its not your spark cutting out on you, just a check. As your plugs might seem fouled if you give it gas and spark quits as you would spray fuel that never ignites. Maybe you have weak spark that is dying under the extra fuel. Just a suggestion. As if the spark was to weak it could handle idle conditions but die under any added fuel.

 

[NHerron]

Make sure its not your spark cutting out on you, just a check. As your plugs might seem fouled if you give it gas and spark quits as you would spray fuel that never ignites. Maybe you have weak spark that is dying under the extra fuel. Just a suggestion. As if the spark was to weak it could handle idle conditions but die under any added fuel.

Seems obvious but maybe check the plug gap? Sounds similar to this guy: http://www.dsmtuners.com/forums/newbie-forum/424187-check-engine-light-cut-out-boost.html

Since you can't even get it to idle much higher, the gap would probably have to be huge and someone would notice that.

Is the maf all hooked up corretly?

 

[onefast2gdsm]

Maf is hooked up correctly. It did the same thing with the 1g maf, and I checked the resistance and the test failed, so I put the 2g maf on. And plugs are gapped correctly, I tried 2 different sets of ngk plugs, bpr6es and bpr7es

 

[Diamond Star Werks]

If you have an extra coil pack or can borrow one from someone. Try swapping coils. They may be producing a weak spark and the spark is blown out when you give it extra gas.

 

[onefast2gdsm]

I tried mine off my 2g, which is fully built, as well as the transistor pack and now it has a coil pack and transister pack off anither kknown good 7 bolt. I will be testing the fpr after I get off work

 

[fourgsixthree33]

Yes, we tried two separate coil packs. 3 total including the one that was originally on it. All 3 checked out good with a voltmeter. We have done several spark tests. We have great spark.

 

[Diamond Star Werks]

okay so to get this straight if you take your plugs out and clean them up and re-install them. It will run and stay running until you give it gas?

 

[onefast2gdsm]

We fixed the problem. Reinstalled 2g rail, 450cc injectors, 2g fpr, put another tps and Isc in as well as changed spark plugs.

 

[Diamond Star Werks]

hmmmm wonder which one of those fixed it?? glad you got it fixed!

 

[onefast2gdsm]

I don't know, but we were running out if options so we just changed whatever other spare parts I had. We pulled the injector clips and put the new spark plugs in, it literally ran for 30 seconds with no added fuel. That's how much fuel this car was getting, it just drenched the cylinders.

 

[CrawlinZX14]

I just question did u put 450's in in place of 390's and not adjust the fuel trim? Cause trying to fire 450's on a map for 390's would cause a rich contition due to the injectors not being right. I would bet its the FPR or injectors is what fixed it. Glad its fixed tho

 

[jpmxrider489]

So its fixed? Glad to hear the progress.

 

[AZN29]

Just had the same problem a few months ago. My problem was FPR. Good to hear that it's solved!

 

[onefast2gdsm]

Ok scratch that. Problem isn't solved. Grabbed brand new ngk plugs today, went to go start it, and the car fouled the plugs right away. We have 2 connectors not.hooked up and don't know where they go.

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We tried yet another 1g fuel rail with another set of 450cc injectors and another 1g fpr, still same thing. The car is getting too much fuel when it goes to start, and keeping the plugs from firing. Also, the maf is making a sucking noise when car turns off or stalls. We found out the turbo is bad, and the blades are hitting compressor housing. Would that cause a no start? It only rubs when you hit the throttle.