RB25 Running Rough

[redline racer510]

Got a S1 rb25det stock everything except FMIC and exhaust. Went for a spirited drive the other day and came to slow down for a stop light and car started acting really bad. On the stop light it didn't want to hold an idle and when the light turned green and I put it in gear it started bogging making it nearly impossible to speed up to get into second gear. Every time I give it more than a quarter throttle it bogs and starts an erratic acceleration and bogging. After getting home i start checking the basics and notice it smells like a ton of fuel when idling and when giving it gas it spits out blackish gray smoke(running extremely rich). I removed the spark plugs and they were all soaked with fuel, checked for codes and there wasn't any. I am starting to think the timing belt might have slipped causing improper ignition timing. I just want a second opinion and any thoughts on what i should do next?

[slidewayz240]

How long has the swap been in the car and running? I had this issue when I first did my swap. The Walbro 255 I had was making too high of a fuel pressure causing it to run rich. I got a Nismo adjustable fuel pressure regulator and an Apexi safc to "fine tune" with. It did the trick and ran like a completely different motor.

[redline racer510]

I had the motor in the car running fine for a little over a year and the problem started three days ago. It doesn't want to hold an idle and when i give it gas it hesitates and stutters and as soon as I take my foot off the pedal it wants to stall. I t went from driving good to horrible almost instantly which leads me to believe it might be the timing belt is off be a tooth, I might have to pull the timing cover off and check it. I just want to know if this could possibly be the problem so i can pinpoint my effort at solving the problem rather than being all over the place inspecting every little thing?

[slidewayz240]

I have had 2 other instances where my car did what you are describing. One time the wire on the coolant temp sensor plug in broke, and it was running so rich it would barely hold idle and load up under throttle. The other time the plug for one of the knock sensors came unplugged. This caused a rich issue that was also similar to what you are experiencing. I would not completely rule out a jumped tooth, but I would be more likely to think it was a bad sensor or wiring.

[redline racer510]

I agree with what your saying but wouldn't there be a code or a check engine light, and also did this happen instantly or did it gradually get worst? Yes I have a walbro but do FPR just go bad instantly? BTW i did notice my car running I little rich at times. I have a spare OEM FPR do you think I should swap it out to see what happens?

[91drftr]

i know u said u checked the basics but have u looked at all ur couplers on ur intercooler piping.... bcus exactly what ur describing the car does, happens when a coupler pops off the ic piping

[redline racer510]

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^
It was exactly that. [email protected]@@@@@@@@@@@@@@@@@@CCCCCCCCKKKKk
Why didn't I think of that???????????????????? I guess I went full retard for a few days.

THANKS man, really. Im such a newb that should have been the first thing I checked.
Went to go check and surely enough the coupler was just dangling on the IC pipe. Note to self check IC couplings first. Man if i was near you I would of
bought you lunch or a drink or whatever.

[slidewayz240]

glad ya got it figured out dude!