Question about fuel system and FPR.

[kristmen]

I have a 91 TSI A/T.. I recently did a boost leak and vac leak test and found a leak at the top of my stock FPR. At the time I had the FPR off an M/T on the car so I put my stock A/T one back on and now when I go WOT, I get this sorta brrrrrappp brrrrrappp fuel cut type sound but it leaves a trail of blackish smoke behind the car.

Ever seen one of the John Shepard race videos? When he first takes off his car leaves a trail of black smoke? Its sorta like that.

Why would this A/T FPR be causing problems now when it didnt orignally? I have installed a B16G, 550's and a Walbro 255 sence then. Also have a MAFT and AFC2 but I cant even seem to correct the problem with those.

Any ideas?

I know I should have gotten a AFPR but I'm sorta broke and my car ran fine with the stock M/T one. Idle was 750 rpm on the money and the idle 02 trim sits right about 100% so I figured why #### with it.

Thanks..

 

[temfate]

Well, the A/T fpr must not be as good as the other. They will all eventually fail when pushing pressures and flows higher than they were designed... You really need the AFPR as you suggested, is would fix the problem completely.

Most likely by letting the A/T one sit it's had some deposits of crap dry on the inside that is hindering it's ability to compensate for the higher flow and pressure.

 

[kristmen]

I think I'm just going to put the m/t one back one with the vac leak for now as it ran better even with that vac leak. Then when I've got a spare $145, I'll pick up the Full Throttle Speed AFPR.

Btw I've never messed with adjustable FPR's... What do you? Just hook it up and put the fuel pressure back to what it should be normally before like a pump upgrade or do you get it to match the injectors?

What is the pressure that should be used anyway? I know the m/t has a lower rating then the a/t stock fpr..

 

[kristmen]

Ok let me start over with what I've done to my car. My car is all jacked up.

Few days ago I found a small vac leak on my fpr. I have a full m/t engine in my car but all I had to put on was my orignal a/t fpr, car's an a/t..

I put this on and well I had the vac lines undone, I moved my boost gauge line off my throttle body into a 3 way tap on the line the fpr uses.

Ran was running like shit. Trims were all rich as hell and when I went WOT, it would spew black smoke and make a misfiring noise. Car also threw a CEL for o2 sensor twice but its gonw now.

I then tracked down another M/T FPR and put it on but the car didnt change so I next put the vac lines back the way they were before with the boost gauge hooked to the throttle body.

Still doing the same crap.

I then decided to readjust the base on my MAFT and I tried leaning it out but nothing fixed the rich ass 30~32% o2 Trim.

I'm so lost. I cant find my origanal FPR now, I think it was thrown out.

I have no idea what to do next. I cant drive the car with it running this rich.