car is back running

[dmw319]

got the car back today. the s/c has about 50 miles or so on it and i have some more questions. it seemed to run really rough and hesitating, almost like a misfire, whenever i get on it, and the idle sometimes is rough. then when the car runs for about 10 minutes and warms up everything runs better, but still a little hesitation on WOT. ive been watching my fuel pressure and its generally right around 40, gets to about 45 when i give it some gas, but for some reason one time i drove my car around for about 15 minutes and the gauge was reading 30 the whole time, even when i gave it gas.. drove it 10 minutes later and it was fine. i dont know whats going on, or if the car is just getting used to the extra air still.. also i have tons of new rattles and junk. oh well. any ideas or thoughts?? thanks guys..

[Shodown]

Re: car is back running

I had a similar problem with the fuel pressure gauge. I found that I had a bad ground wire and it was sticking and not reading properly. Just something to look into. As for the rest of your troubles, sorry bro but I have no idea.

[dmw319]

Re: car is back running

also, my voltage is low. i am running about 12.5 when the car is off, and then about 12.0 when the car is at idle. any ideas? is this maybe because the belt isnt tight enough?


EDIT: or TOO tight?

[dmw319]

Re: car is back running

ok well i recharged the battery and everything is fine now, but my car is still running sluggish and sputtering!!!! any ideas?

[Shirl]

Re: car is back running

Should be around 45psi at idle. 60-65 at wot.

[dmw319]

Re: car is back running

its around 40 at idle and 50, maybe 55 at WOT.

do you think maybe my FMU is messed up? or maybe i need a new fuel pump? or maybe a tune?? idk :( HEEEELP

[01PewterDropTop]

Re: car is back running

are you using the stock pump? if so how many miles

[dmw319]

Re: car is back running

actually i monitored the fuel pressure more carefully, and im at 40 at idle, and 60 at WOT. so i think that im ok...? either way its still kinda sputtering and rough.

yes, and the stock pump has 84K on it. when do most need to be replaced?

[Mighty Thor]

Re: car is back running

actually i monitored the fuel pressure more carefully, and im at 40 at idle, and 60 at WOT. so i think that im ok...? either way its still kinda sputtering and rough.

yes, and the stock pump has 84K on it. when do most need to be replaced?

Your Fuel Pressure reading is the same as mine and I have Walbro255.

The best thing to do is to take off the SC and see if your car still runs the same as NA.

Or you could have it dynoed. With the dyno you could see if your Air/Fuel mixture is OK. But since you only have 50mi on it I say keep driving till you have 2000mi then dyno. This way it will give the computer enough time to adjust.

By the way, where is our fearless main man, Grayman? He usually never miss a beat on topic like this.

[dmw319]

Re: car is back running

its been driven about 75-80 miles now, and the sputtering is still there. it did that weird thing with the pressure again where its stuck at 30 and doesnt move at all, then i started it 10 minutes later and it was at 41.. then on WOT it only went to 55. im so confused.

[Mighty Thor]

Re: car is back running

its been driven about 75-80 miles now, and the sputtering is still there. it did that weird thing with the pressure again where its stuck at 30 and doesnt move at all, then i started it 10 minutes later and it was at 41.. then on WOT it only went to 55. im so confused.

At idle it should be around 40-41 and sometimes 39 when the weather is really hot. In S. Calif when the weather gets around 110* my FP reads 38-39.

When you say 30 are talking about idle or is it when the car is running? I'm sure you meant idle. I guess it'd be best to have a performance shop check your fuel pump.

I think a couple of years ago SSM5411 had the same problem. He understood the problem to be fuel pump related. He checked the wires that leads to the pump and found that the ohm was very low.

I guess your pump might definately be the problem. Like I said, try removing the SC head unit. You don't have to remove the gauges or anything, just the head unit and see how your car is running. It should only take you 20 min. to do this and have your normal intake back.

[dmw319]

Re: car is back running

ok well i let the guy at the shop run my car around with me and he thinks i should try the fuel FILTER first. so im gunna try that here in a minute. then after that he will check the fuel pump.

he thinks that might have something to do with why my gauge is acting up sometimes. and thor when i said 30 i meant ALL THE TIME. from start to idle, to WOT, everything. like its stuck at 30. its a brand new gauge so idk why it would be acting weird. oh well. im gunna try some of that redline fuel injector cleaner stuff too.

[Mighty Thor]

Re: car is back running

ok well i let the guy at the shop run my car around with me and he thinks i should try the fuel FILTER first. so im gunna try that here in a minute. then after that he will check the fuel pump.

he thinks that might have something to do with why my gauge is acting up sometimes. and thor when i said 30 i meant ALL THE TIME. from start to idle, to WOT, everything. like its stuck at 30. its a brand new gauge so idk why it would be acting weird. oh well. im gunna try some of that redline fuel injector cleaner stuff too.

It could be the filter then but I have some doubts about it. Check and see how the FP unit is wired. I had problems when I installed mine awhile back. Installing the boost gauge was the easiest thing but I had a perf. shop install the FP for me.

I think in the previous post we did mention filter. Try that first then and see what happens. 30 is really bad, your car will definately stumble.

[dmw319]

Re: car is back running

when it was at 30 there was no performance difference when it was running 40 at idle and 60 at WOT.

UPDATE AGAIN:
changed the filter and the problem is still there. :( my fuel gauge reads 39-40 at idle and about 50-52 at WOT. whats next to do/try?

[Shirl]

Re: car is back running

Correct gap on the plugs? If so, check anyway... one could be fouled. Sounds like a mis.