Alright I finished my single setup yesterday and started the car. I realized it idled pretty low 700-800 rpm (usually aobut 950 rpm), and this was when it was cold (usually goes to 2k rpm and lowers as it warms up). I didn't think much of it, I was just glad it started.

I started it again today and let it sit there and idle for a good long time (maybe 20 minutes) to let the PFC rerecognize everything like it did when it was first installed. Then all of a sudden the car started backfiring randomly every few seconds. It backfired maybe 10 times before I got it turned off. I then started it back up and it idled around 650-750 rpm at 14 in Hg (stock ported motor). It also seems to vibrate when I reved it up to about 1000, which I have heard can be a blown motor, but when I reved and held it at 2000 or 3000 rpm it was smooth as normal. I looked at the PFC and everything seemed normal. It also had a different exhaust tone, to hard to describe what it sounded like though.

Someone please help me out on this one, I really hope this isn't a blown motor. What else could it be that I am overlooking. I haven't pulled the plugs yet, but will tommorow so I can see how it sounds when it turns over and to make sure one plug didn't foul or anything.

Thanks.
M-P

 

Your plugs are fouled. When I did my swap to single turbo, I had to mess with my fuel map to get the a/f's down to 13...I took out LOTS of fuel.

 

If it's idling, it's probably not blown. Mine wouldn't idle unless I held it at around 2k rpm when it was blown. And that fact that it took so long until it started being crazy makes me agree with jspec that it very well could be the plugs.

 

I agree with the guys above. Plugs. CJ

 

Holy crap thanks alot. This is the best day of my life.

Thanks again,
M-P

 

Did you pull em out? CJ

 

Did you mess with PIM setting?

 

No I didn't mess the the PIM setting and I just pulled them out. The trailing ones def. looked fouled, so I changed them. Started it back up and it still idled really low and didn't want to work well. So I checked the leading plugs and they looked almost exactly like I put them in last week, just with a little bit of fuel. Put them back in and now it won't start.

So I did the whole unflooding procedure and what-not just to be sure and it still won't start. What could be wrong now. I might just go out and buy all 4 new plugs just to be sure. Any more suggestions?

 

Vaccum line to FPR verified?

PRC solenoid present or not?

 

Yes there is a vacuum line to the FRP, now what is the PRC solenoid and where is it? I probably know what it is and am having a brainfart you know, but it happens.

M-P

 

OK just looked at the good old vacuum hose diagram and found the prc valve solenoid and realized I took it out with the rest of the solenoid rack when going single. What should I do about that? I would post this in the single forum also, but there is very little traffic there.

 

Well truthfully you shouldn't even need this solenoid. It's only used to boost fuel pressure during a hot start. You can try throwing it back in there but I honestly would have thought the FPR lines to be the culprit.

But also go back and verify the injectors are connected properly.

 

BTW, also know that whatever it is it is not serious or engine-threatening right now. Just trying to get the car to idle and figure out why there is an over-abundance of fuel is the goal here.

 

my car fouled with plugs that were only a week old. i had to put all new ones in it to get it to start and idle right again.

also check your map sensor. if mine pops loose, it doesn't want to idle or do anything right. i've also had a tendency to forget to plug the tps back up if i've had the TB off, so check all that too. i'm sure this is all common sense stuff, but it helps to trace your steps

 

Yea i got it running. The car was massively flooded due to the FPR not being hooked to a proper vacuum source. Little did I know there was some nipples on the LIM that were not a vacuum source but rather just thuogh pipes. Thanks anyways.

M-P

 

it's always good when the owner diagnoses the problem themselves. good luck with gettin it tuned and stuff. i'm gettin ready to order my t78, so i'm going to be havin lots of fun soon

 

correct me if I"m wrong but I thought idle around 750 was completely normal.

 

eh, any thing less than 1k is good enough.

 

yeah i wouldent worry about 750, Its when your car idles anywhere from 500 - 1400 that you gotta get pissed off, (like my car ) The lower vaccuum numbers are due to the lower idle. Your engine cant make the same numbers without it, Also im sure a tune wont hurt

edit: nevermind, i see that you already fixed it now, i must have skimmed that post