Help me! sr runs rich/lean between 3-4k only

Car dumps to much or to little fuel at all rpm between 3k and 4k inconsistently. At cruising speed on highway, it will just randomly happen once or twice and then go away, and then come back sometimes.

According to the power fc, say for example i was at 3500rpms, and the injector duty cycle is normally 12%, for a split second i will get 5% or 25%, lean or super rich, engine will sputter and i either let of gas or floor it and it goes away. Sometimes it comes back right away, sometimes i don’t’ see the problem for another 15-30 minutes.

I still have full boost and make the right amount of power above and below the 3-4k range.

I’ve looked around for vacuum leaks and checked my maf for loose connections and it all checks out.

I recently changed my sparks also.

Any ideas?

Try checking grounds too. Bad grounds will do fucky shit like that.

Is your duty cycle changing because of the rich/lean condition, or is it causing it?

well those readings are a result of something. they aren’t causing anything, as they are simply just digital gauges

Who tuned the PFC?

^ it was actually tuned by you Dan, the sr and pfc were in another car originally, 240sxfanatic or something, and through a series of transactions the motor and pfc ended up with me.

Its stock t25 tuned at 10psi, they said it had 228whp, 230rwtq.

---------- Post added at 05:31 PM ---------- Previous post was at 05:31 PM ----------

^ it was actually tuned by you Dan, the sr and pfc were in another car originally, 240sxfanatic or something, and through a series of transactions the motor and pfc ended up with me.

Its stock t25 tuned at 10psi, they said it had 228whp, 230rwtq.

Ah cool…send me a PM then. If you take a drive to Miississauga I’d gladly take a look at it…I’m sure 15 minutes of street tuning could clear up any issues.

(Also, swap in some new NGK BKR7E plugs, gapped to .028)

gapped plugs to 0.028, found that 3 of the 4 coil packs were cracked, replaced those. This all fixed the random misfires i was having at lower rpms.

HOWEVER, i still have serious problems between 3 and 4k. The car runs super rich injector duty according to pfc, and it tries to correct itself by going lean for a split second also. Bogs like a mofo.

If someone can help me out it woudl be greatly appreciated. As i want to make it to drift ops drift day on Sunday.

My offer still stands, come to Mississauga and I’ll look at it…I should be home all afternoon

Try cleaning your maf, it might help.

when the problem occurs, feels like the engine lacks power? hesistates? but runs fine over 4k? buddy of mine was having similar problem (showing lean on wideband)… turned out being a faulty knock sensor. either that or it is loose to the engine block causing the ECU to pull (retard) timing under 4k… try disconnecting and see if it fixes the prob.

So ahhh,

On my way to shannonville this past weekend, my car had this problem to a severe range.

It was at almost all rpms in all gears, and even in neutral. So bad that i couldn’t keep my car at a constant speed.

I would see 100% fuel injector duty, i woudl see the engine doing funky things with timing, and i noticed that going over the various bumps in the road, that it got worse over bumps.

I’ve changed my entire plugs and coil packs, and usually the problem goes away for short drives initially, once i go on a long drive like this one, the problem kicks back in.

Right now im leaning on it being a knock sensor, gonna see if that changes things, hopefully it does. Right now i want to hit my sr with a sludge hammer.

did you find out the problem
?

Naw man, I got so upset with this engine, i honestly just parked my car for the winter pretty much. I m in my last year of university so i don’t want to be spending hours upon hours diagnosing and checking connections when i should be studying the income tax act. werd!!!

However, I think this problem does have to do with the ect sensor. And as a result of the bad ect sensor, my spark plugs keep fouling and my o2 sensor is fouled and probably ruined also. Outside of that, I have no idea.

Why didnt you take dan up on his extremely generous offer?!?!?!?!

+1

wasn’t a tuning issue guys, i did consult him. He is a very generous dude.