I have an S13 w/ sr20det, I didn't do the swap but got it that way. Has FMIC, BOV vented to atmo, walbro & Z32 fuel filter, T28, 3" exhaust and otherwise mostly stock. Has been running and boosting fine, only problem it ever had was a little rough idle. Problem started intermittently for a second every now and then, then it got worse and started doing it more, now the car is undriveable. Now it has a rough idle with lots of misfires and when you try to drive it it's ok under 2000 but over that it bucks at half throttle and just stumbles and does nothing at full throttle. In neutral it does the same thing but sometimes revs up a little better. Car has never died on me and boost gauge stays between 500-700 then goes up to zero but rarely makes it further than that. This is one of those weird sr problems that could be fixed by any number of things. I don't want to start throwing parts at it and I don't want to admist defeat and take it to a shop. This is what I've done so far...
-Swapped out MAF, checked wiring, grounded black MAF wire to chassis, no change. When car is running and I unplug MAF it dies.
-Checked ecu codes- #55
-Checked fuel pump and fuel filter, sounds and looks good not clogged. Unplugged FPR vacuum line and blocked it off at TB, idle did not change much.
-Checked battery and grounds and ecu harness and it all appears fine. Car wiring and harness has some hacking but nothing too bad.
-Swapped out coils and ignitor, no change. New plugs gapped properly. Old plugs looked fine nice and brown.
-Checked all vacuum lines and connections, everything is tight. BOV is vented to atmo and screw is out most of the way.
-Tried to check timing but gun doesn't work. The CAS is all the way to the right so I believe it is advanced. Idle adjustment screw is adjusted in to bring idle down to around 800.
-Checked TPS, was at 2.5. Tried to adjust to .45 but haven't gotten there yet, it's around .90 at the moment, no change. When I unplug TPS while car is running the rough idle and misfires go away but it still doesn't rev up.
s13 w/ redtop- stumbles, breaks up bad, no boost.....
Re: s13 w/ redtop- stumbles, breaks up bad, no boost.....
For the hell of it, try blocking the BOV or remove it and block the hole, whichever is easier. sometimes they can stay open and suck up air, this obviously confuses the ECU. This might not be it, but it won't cost you anything to try.
Re: s13 w/ redtop- stumbles, breaks up bad, no boost.....
I don't think it's the BOV but I'll check it out. It's a sequential hks so you can see the duel stage as it opens. It would have to be stuck all the way open to have my symptoms I think, they're bad.
Re: s13 w/ redtop- stumbles, breaks up bad, no boost.....
So I figured out what the problem was, my TPS was bad. I tried adjusting it forever and could not get it anywhere close to .45 it kept jumping around. Swapped out the one from the other sr and car ran just like before. Tucked everything back into place and now it wont start. Now I have to figure that out. Hopefully I just flooded it.
Re: s13 w/ redtop- stumbles, breaks up bad, no boost.....
Well it's alive again, and back to the original running state it was two months ago before the whole issue began. I think my non start issue was because the engine was flooding. The way I figured out the TPS was bad was because I tried forever to adjust it and it was jumping all over the place with just the slightest touch. It wasn't until I adjusted the tps on my other sr that I realized how bad that other one was. If tps is working it takes like one minute to adjust it in.