Too much fuel

[solson1041]

Hey guys, I've got a 93 tsi, I recently tried to cap the emissions lines on the TB as per recommended by the "free mods" section of the website. I don't know what happened, but something went very wrong. I didn't do it right initially and it decided to run very rich with almost no power and backfires, then I put all the lines back on, then I took them off and was careful to do it all correctly, now the lines are on once again. All the while, the car's performance didn't change a bit once it started running terrible.

Apparently, somewhere in my initial "work" I broke something permanently, as reversing my "work" did not fix the problem. I am certain all lines are on correctly, the ECU has been reset multiple times and there is no boost/intake leaks.

I'm beginning to look at the fuel system. One of the lines from the TB elbow runs to the Fuel Pressure Regulator. To my knowledge, this piece is responsible for getting extra gas to the cylinders to start when it's cold out. A choke essentially. Is it possible that this piece has malfunctioned and is now sending far too much gas to the cylinders at all times?

If it were to break, would it do that?
Is there some way I can test if it is exactly my cause?
Could something else be the cause of these symptoms?


Not that it's very pertinent, but while I was searching for problems, I figured I'd run a compression test while I was checking the spark plugs. The plugs are ridiculously fouled up and black, and they were not before these problems started. Less than a month old before the problems started. Also, compression is a nice ~170 across the board with a freshly rebuilt head.

Thanks so much, I really need help getting my car running again.

 

[Calan]

Do a BLT and find the boost leak you created.

 

[solson1041]

Do a BLT and find the boost leak you created.

I have tested twice and found no boost leaks as I said in the OP. Are these symptoms impossible to have outside of a boost leak? Should I test one more time? What should I do when this test tells me I don't have any leaks like it has twice already?

 

[jtmcinder]

One of the lines from the TB elbow runs to the Fuel Pressure Regulator. To my knowledge, this piece is responsible for getting extra gas to the cylinders to start when it's cold out. A choke essentially. Is it possible that this piece has malfunctioned and is now sending far too much gas to the cylinders at all times?

Short answer: Probably not.

Long answer: That is not a choke; that's the reference line for the FPR so that the pressure in the fuel rail is raised and lowered when the intake is under boost or vacuum. Blocking this line will cause the car to run rich at idle (or any time the intake is under vacuum) and very lean under boost. Moving this line to being on the wrong side of the throttle plate will also cause grief (but I'm too tired to work it out and then write in down). Odds are, unless all you've been doing is idling the whole time since you messed up your car, this is not the cause of your problem. As suggested above, 99% of all rich problems are from boost leaks. But if you really have been just idling since the problems emerged, then it could be this line.

 

[solson1041]

Short answer: Probably not.

Long answer: That is not a choke; that's the reference line for the FPR so that the pressure in the fuel rail is raised and lowered when the intake is under boost or vacuum. Blocking this line will cause the car to run rich at idle (or any time the intake is under vacuum) and very lean under boost. Moving this line to being on the wrong side of the throttle plate will also cause grief (but I'm too tired to work it out and then write in down). Odds are, unless all you've been doing is idling the whole time since you messed up your car, this is not the cause of your problem. As suggested above, 99% of all rich problems are from boost leaks. But if you really have been just idling since the problems emerged, then it could be this line.

No, its been driven a good bit, certainly not left just at idle.

I guess I'll keep investigating boost leak issues. I suspected that at first but thought i ruled it out. i've done an air compressor style test as well as spraying starter fluid along the intake with no signs of boost leak.

Is there something in the fuel delivery system which could cause this richness?