well ive done plenty of research and talked to many of people but cant figure it out. my cold starts are horrible. car bucks, horrible idle and backfire in the intake of course. changed the coolant temp sensor, its not throwing codes....im just tryin to think of anything else it can be.
So once the car warms up, it runs fine? How does it run at WOT when the car is warmed up. What about when it's warm, but just crusing?
Pull the spark plugs, and see what's going on. You may find one bank is running lean/rich, or 1 cylinder is running rich/lean. Should narrow the problem down.
Scott
yup...after she warms up (starts to nudge the N) she runs like a dream. WOT is perfect. hell, she feels better than she really ever has lately. it has been going on for awhile now and i cant really pinpoint when it started but its worse than ever lately. ill try to find time to pull the plugs tomorrow.
Well that narrows it down a little further. If when the car is warm, and both WOT and normal cruise seem to be fine, then your MAF/ECT/IAT/O2's are fine.
So it has to be something to do w/ temperature. Hmm.......very strange.
The only thing I could think of is the ECT sensor. But you replaced that. I can't think of anything else that is temperature dependant.
Maybe something to do with the distributor. PIP module, or something. That is the only thing that I can think of that is subject to heat that could cause the problem. I mean, the dist. shouldn't be affected by heat, but it is one of the few things that runs through the engine block.
Try disconnecting the battery, let it sit for a few minutes, then reconnect, and drive for 20 miles. If the computer can detect a problem, it might need a fresh start to do so. Just another thought.
Scott
well ive been having some charging problems (new alt and battery and nothing is running in the car as far as i know) so my computer has been reset pleeeenty of times in the past few weeks .
im confusing a lot of people with this cause no one can figure it out. i hope within like 2-3 weeks im gonna be able to put her on a full diagnostic computer but until then, i wanna try and figure her out
I have similar problems with my car, but I have H/C/I and a chip. During cold start the car revs from 1500 then dies to 800 then revs up again. I haven't talked to JMS yet, but some people told me it might be a timing problem because the computer uses timing to help control rpm at start up.
check your timing....after my manifold install when i put the dizzsy back in the timing was off...and before the car warmed up it would seriously run like it was dead....popping like crazy....once it warmed up it ran perfect untill about 5500RPMS and it would fall on its face....but i adjusted the timing back to normal and hasnt done it since....just something to check!....
well timing is at 14* like it has been for the past 3 years. i really havent done much since last fall and that is when i refreshened my engine and a few minor other things.
im just curious cause i turned down my f/p from 40 down to 37 but at idle the f/p is exactly the same and maybe 1-2 psi higher (its at like 30 normally and sometimes 32ish). well at startup i smell major major richness. after it warms up, i smell at idle a pretty good rich smell but not all the time. the other 9/10 of the time it smells like a normal o/r pipe. when i turned my f/p down from 40 to 38 (vac off of course) i notice a few lean codes here and there when i hammer it down so im gonna get her back up to 39 or 40 tomorrow. im also gonna try to unplug the o2's when she is cold and see if i can get a normal idle outta her. maybe i can find out if the o2's are messed up somehow if i unplug them when its cold.
A bad ACT (IAT) sensor would definitely cause the problems you're experiencing. A sensor can be bad, yet not through a code. I had some similar problems on my 95 GT. A new ACT sensor solved most of my cold start bucking problems. You should also clean you're MAF sensor if that hasn't been done recently.
One more thing, the O2 sensor's aren't used when the car is cold. Once the engine is warmed up and the EEC goes into closed loop, the EEC uses their input (warmed up......can't remember the exact temp)
thats kinda what i figured with the open loop in the beginning and closed when warmer. well im gonna flat out replace the iat cause ive cleaned it but im sick of people telling me to replace it. i can spare that money. my maf is clean and ive checked for any type of leak in my intake gaskets with the brake cleaner. im gonna try the iat tomorrow and after that, im gonna be open for business again
I'm sure you know this already, but I'm going to say it again anyways. Remember to unplug you're battery for 30 min to reset your EEC after you change the IAT sensor.
I have the exact same problem as you. I figure its running so rich that its fouling the plugs and takes a few mins to clean themselves. My car fouled a plug a few weeks back that never came clean so i was running on 7 cyl.
Im hoping to have this problem fixed with the new PMS unit, PMS allows you to adjust richness at idle and low rpms... If this thing is as good as it supposed to be I will wonder why i ever got a chip...
I am having the same probelm as you as well. I have cleaned my IAC a good few times now. People still say to replace that or reclean it. My problem started ocurring after I did a H/C/I. I am wondering if I damaged the ECT or ACT in the process. I am running 30# injectors so I am just wondering if it is running too rich with them on startup. I have a pro-m 75mm calibrated at 30#ers. I am going to check spark plugs and see but then I guess I will start replacing the ACT or ECT. This is the worst problem to diagnose and it really sucks if you have to replace everything to find the one problem.
yeah, ive replaced a ton. put my stock maf on there and it did nothing. my problem kinda developed under my nose a few weeks ago cause i havent really worked on my car in a long while so i dunno what would have caused this. i hate throwing money out the door at good parts when im just guessing they are bad but ive replaced a bunch of things and it still does this.
im sort of starting to think that possibly my kirban fpr is going out. its less than a year old but ive noticed ive gotten a few lean codes at WOT and at idle she varies from about 30-33 psi. i have her set to 38 w/ vac off. i dont wanna buy a new regulator if i dont think its that
How much would ford or a shop charge for a full diagnostic to identify all problems?
I'm going to check a few spark plugs today. What woudl the problem be if some are fouled and others are fine? I did notice that when my intake was off there was a bit of a fuel soakin on the rear of my take gasket towards the firewall. Why would it only be around those cylinders?
Also replacing sensors is costly, but would it be best sticking to oem sensors or would aftermarket be ok?
i think its around $80-$100 for ford to run a diagnostic test on ur car. im gonna check my plugs again later tonight when i come home. im hopin all of them would be runnin rich and not just a few. could be signs of bad injectors other things that i dont know and maybe someone can shed some light on