I previously posted this in the Infiniti Forums by mistake... oops.
I'm having trouble with my spark plugs fouling up in my '92 240sx. Rebuilt motor, new Nissan OEM(Bosch) o2 sensor, and functioning EGR(to the best of my knowledge). No codes from the ECM. I ran the O2 sensor test, and it seems Ok at idle, but the CEL is on almost every second-1.5sec when cruising at 30-45. The plugs are NGK, BKR5E, stockers, with stock spec'd gap. As the picture shows the bottom threads are heavily coated with black soot(carbon?). The insulator is still white, gray near the top. The ground electrode is also an ash-gray. All signs point to me running rich, correct? What's the first place to start?
Today I checked my MAFS. It measured ~1.05Vdc, but constantly dipped down to 0.92Vdc. I think this was simply from air turbulence(I have the air resonators removed, and the stock fan really moves the air around). The voltage from shield ground(at body) to connector ground was 'nill, like 0.2mV.
Fuel pressure is good, 36psi at idle, jumps up when vac source is pulled. Also replaced my coolant temp sensor about two weeks ago. I hope I don't kill my O2 sensor, that sucker was expensive.
Thanks for any help you can offer.-Jamie
Fowling plugs in S13[pic]
Re: Fowling plugs in S13[pic] (slipnfall)
FWIW, my last fill-up was with Sheetz '89, with a bottle of dry-gas. No smoking, or soot on the bumper.
Re: Fowling plugs in S13[pic] (slipnfall)
Just a thought, would it help to advance my timing a bit? I set it dead on at 20* BTDC.
Re: (NISTECH)
Hi, Plugs are about 400 miles old. I broke down and brought it to Nissan today. I guess I wanted some reassurance that everything was OK, from the ECU's point of view. I had developed an odd noise at accelleration and popping in the exhaust anyways, so the visit was justified.
It only cost me $23 for a test drive and CONSULT diagnostics. The 'tech told me that the burnt plugs didn't bother him, that the rings may not be 100% seated just yet. He(Dana) said the fact that I couldn't drop my idle any lower(previous post, Re: vacuum/idle adjust) wasn't a reason for major concern. Injector pulse was good, rich/lean feedback OK at idle. Idling temp was only around 174*, which he said was a little low. He attempted to do an A/F mixture test, but said the CONSULT will only do it when the temp is at +176*. When he brought the RPM up to 2k to do it, the temp would drop more.
He advised me to put my Nissan Tstat in(aftermarket in now) and bring it back for an A/F test. Also turns out that my collector-to-'cat gasket was leaking, which was the reason for the odd sound/popping. Genuine gasket later, all was good.
It only cost me $23 for a test drive and CONSULT diagnostics. The 'tech told me that the burnt plugs didn't bother him, that the rings may not be 100% seated just yet. He(Dana) said the fact that I couldn't drop my idle any lower(previous post, Re: vacuum/idle adjust) wasn't a reason for major concern. Injector pulse was good, rich/lean feedback OK at idle. Idling temp was only around 174*, which he said was a little low. He attempted to do an A/F mixture test, but said the CONSULT will only do it when the temp is at +176*. When he brought the RPM up to 2k to do it, the temp would drop more.
He advised me to put my Nissan Tstat in(aftermarket in now) and bring it back for an A/F test. Also turns out that my collector-to-'cat gasket was leaking, which was the reason for the odd sound/popping. Genuine gasket later, all was good.