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Forum namePerformance/Engine
Topic subjectCar runs like crap!!!!
Topic URLhttps://forums.2gnt.com/dcboard.php?az=show_topic&forum=i5&topic_id=100714
100714, Car runs like crap!!!!
Posted by BoostedEclipse, Aug-29-06 03:46 PM
Ok, sorry this is so long but I'm having like the worst luck on trying to figure this out. It is literally making me loose sleep. I recently installed some 450cc injectors with the safc2 and sfmu and resistor pack. When I first cranked it up it idled really rich. I had already set my fuel pressure so I tried leaning it out a little on the safc. It did nothing, still runs rich as hell. I just bought a new map sensor while I did all these modifications so i don't think it could be that. I took my throttle body and iac motor assembly off and cleaned them. Well now my car will only idle at about 10-12 mm/hg. I'm pretty sure when I cleaned my iac I probably f-ed it up, but I don't know if that will solve the problem. I need to figure out why I have all that fuel dumping into my engine, even when my safc is leaned all the way out to -50%. I've checked all my vacuum lines like a hundred times and everything seems fine. I've heard that it could be my coolant temp sensor but I need advice on what you all think. Could it be my safc or resistor and injectors are hooked up wrong, even though I just checked all the wires and they were right. Please give me some insight or advice on what this could be. PLEASE!!!!!!
100716, RE: Car runs like crap!!!!
Posted by rs_sleeper98, Aug-29-06 04:59 PM
when it idles rich is the engine warm or cold? how does the fuel map look? good everywhere else except for at idle?
100729, RE: Car runs like crap!!!!
Posted by eclipse982nrRST, Aug-30-06 08:58 AM
Since I have had my S-AFC hooked up, I have been through 3 MAP sensors if that tells you anything.

If I were you, I would start by disconnecting the SAFC and clearing the ECU to just see what happens.
100732, RE: Car runs like crap!!!!
Posted by DarkOne, Aug-30-06 12:57 PM
COuld try lowering your fuel pressure, too.
100734, RE: Car runs like crap!!!!
Posted by BoostedEclipse, Aug-30-06 01:27 PM
I just checked my engine coolant temp sensor, intake air temp sensor and my tps sensor and I couldn't get it in the specific range that chiltons says they should be in. My ect sensor read like 7.86 kilo ohms. My IAT sensor read about the same thing. Then my tps sensor read like 26.7 kilo ohms I think. I don't know what to do. Even with those 450cc injectors with no safc, will it even idle? If just like 1 of those sensors would have tested bad then I would suspect that, but sense all of those tested crappy I have no idea what to do????????? I'll try the unhooking my safc and directly hook my map sensor wire back up i guess.
100735, RE: Car runs like crap!!!!
Posted by eclipse982nrRST, Aug-30-06 01:53 PM
Originally posted by BoostedEclipse
I just checked my engine coolant temp sensor, intake air temp sensor and my tps sensor and I couldn't get it in the specific range that chiltons says they should be in. My ect sensor read like 7.86 kilo ohms. My IAT sensor read about the same thing. Then my tps sensor read like 26.7 kilo ohms I think. I don't know what to do. Even with those 450cc injectors with no safc, will it even idle? If just like 1 of those sensors would have tested bad then I would suspect that, but sense all of those tested crappy I have no idea what to do????????? I'll try the unhooking my safc and directly hook my map sensor wire back up i guess.


Yes it run. I ran 440cc injectors all last summer sometimes without an s-afc. Remove the safc, wire the MAP up correctly again, lower your FP to probably around 18-22psi idle, and report back.
100737, RE: Car runs like crap!!!!
Posted by BoostedEclipse, Aug-30-06 01:58 PM
I'll go try it, thanks man.
100736, RE: Car runs like crap!!!!
Posted by BoostedEclipse, Aug-30-06 01:57 PM
Well, I just tried to adjust my fuel pressure down a little bit. It got too dark for me to start snipping wires on my safc and ecu. I got my fuel pressure to 35 psi at static and about 20 at idle. It idled a little bit better. It didn't sound like it was missing as much. But I could still smell how rich it was. My vacuum is constant at like 12 hg at idle, but when ever i press the gas till about 2500 and let off it will drop to about 20 hg vac. Also when I tried to back out of the drive way and I went to give it brake and let off the gas it went dead and would just barely crank back up. How do I clear my ecu? Do I just unplug it and let it sit for a little while? Anyways I might just put my stock injectors back in and rip the safc out and see how it does. Anymore suggestions please????
100738, RE: Car runs like crap!!!!
Posted by eclipse982nrRST, Aug-30-06 02:07 PM
Originally posted by BoostedEclipse
Well, I just tried to adjust my fuel pressure down a little bit. It got too dark for me to start snipping wires on my safc and ecu. I got my fuel pressure to 35 psi at static and about 20 at idle. It idled a little bit better. It didn't sound like it was missing as much. But I could still smell how rich it was. My vacuum is constant at like 12 hg at idle, but when ever i press the gas till about 2500 and let off it will drop to about 20 hg vac. Also when I tried to back out of the drive way and I went to give it brake and let off the gas it went dead and would just barely crank back up. How do I clear my ecu? Do I just unplug it and let it sit for a little while? Anyways I might just put my stock injectors back in and rip the safc out and see how it does. Anymore suggestions please????


12hg at idle is low. Have you checked your timing lately?
Most engines run from around 17-22hg of vac at idle.

You could have a faulty MAP too.

You can clear the ECU by unhooking the negative terminal on the battery for about 30 seconds.

Get rich to the smell though, with bigger injectors, it will always smell rich.
100754, RE: Car runs like crap!!!!
Posted by BoostedEclipse, Aug-31-06 10:19 AM
Yeah, I thought it was a little low. When I first hooked the safc up it idled around 17 hg, but now it stays at about 12hg at idle and 17hg while driving. Oh yeah, I unhooked my safc and ran the map wire like it was before the safc. It idles almost perfect. It does sound rich and you can definately smell it, but, with my idle presure about 19-20 psi it does very well. I just bought a new map sensor tuesday and I put it on with the safc, but, it was only on there like 1 or 2 times when i cranked it up with the safc. I think it might be my iac, b/c I cleaned it a couple days ago and it was idling fine before then. I think I messed it up I don't know? I really appreciate all the help though man, you helped me out a ton.
100755, RE: Car runs like crap!!!!
Posted by eclipse982nrRST, Aug-31-06 10:58 AM
Originally posted by BoostedEclipse
Yeah, I thought it was a little low. When I first hooked the safc up it idled around 17 hg, but now it stays at about 12hg at idle and 17hg while driving. Oh yeah, I unhooked my safc and ran the map wire like it was before the safc. It idles almost perfect. It does sound rich and you can definately smell it, but, with my idle presure about 19-20 psi it does very well. I just bought a new map sensor tuesday and I put it on with the safc, but, it was only on there like 1 or 2 times when i cranked it up with the safc. I think it might be my iac, b/c I cleaned it a couple days ago and it was idling fine before then. I think I messed it up I don't know? I really appreciate all the help though man, you helped me out a ton.


S-AFC's are tricky. I dont understand why. I had problems with it for like the first month I had it on there, then after that, I ran it all last summer and this summer and never had any problems at all. I dont think it is your IAC though. I wouldnt doubt it fucked up your MAP already dude. -12 of VAC is too low though, you could have a VAC leak and the ECU is giving the engine more fuel, and that could be why its unsteady. Have you checked your front o2 sensor?
100756, RE: Car runs like crap!!!!
Posted by Avenger, Aug-31-06 11:12 AM
Please put on a datalogger and log your inputs at idles. Find out what your ECU is seeing because he's sending the injector pulse width. Check the Coolant Temp, IAT, O2, MAP. Check your LTFT and STFT. Also, zero out your AFC and adjust by FP until you get it idling correctly (or until your FP gets too low ... like 20psi ish).

You can stab at everything else but the ECU tells how much fuel to send based on those inputs and whatever it's got stored up for LTFT and STFT.

Start from scratch and work up from it. I ran an S-AFC 4 years ... never lost a MAP sensor.

EDIT: Oh yeah one last thing. If you have a Missing Link. Try removing it and seeing how it runs (idles I mean ... don't go boosting the shit out of it).
100757, RE: Car runs like crap!!!!
Posted by eclipse982nrRST, Aug-31-06 11:37 AM
Originally posted by Avenger
Please put on a datalogger and log your inputs at idles. Find out what your ECU is seeing because he's sending the injector pulse width. Check the Coolant Temp, IAT, O2, MAP. Check your LTFT and STFT. Also, zero out your AFC and adjust by FP until you get it idling correctly (or until your FP gets too low ... like 20psi ish). You can stab at everything else but the ECU tells how much fuel to send based on those inputs and whatever it's got stored up for LTFT and STFT. Start from scratch and work up from it. I ran an S-AFC 4 years ... never lost a MAP sensor. EDIT: Oh yeah one last thing. If you have a Missing Link. Try removing it and seeing how it runs (idles I mean ... don't go boosting the shit out of it).


He un-hooked up the S-AFC already, so this way it will be easier to diagnose.