new motor dies at idle....

[beaver2489]

I have the setup in my sig. once I drive it for a few minutes and come to a stop or push the clutch in it dies. It won't stay running if I push the clutch in. If I keep the gas pressed it will stay running. Sometimes (rarely) it will idle when I come to a stoplight. When it does that it idles at about 1000-1200rpm. It kinda hesitates in 2nd gear too. before I rebuilt the motor, it had a surging idle at times but never died on me. So I'm thinking since I had a suging idle problem before the rebuild...could it be the IAC? The dieing at idle happened with (after rebuilt motor) speed density and mass conversion. I have the fuel pressure at 36, I tried 32, 34, and now 36 and it dies still. The mass air meter I have installed is a Pro Flow, which I was told is same as Pro-M. Its a 75mm calibrated for #24 injects which I have. any other ideas besides IAC?

 

[shttygtstang]

shouldnt the pressure be higher like 42 or so im not shure pull a plug see wuts going on in there

 

[HISSIN50]

im not smart with the modded stuff, but i think i agree with shtty. the speed control should keep the idle elevated when coasting to a stop in neutral (or clutch in).

you hit my other thought in the head - clean the IAC. the idle is set properly, right?

MAF wire clean?
good luck.

 

[beaver2489]

I've cleaned the IAC, the mass air meter is brand new...but it did this before I converted to mass air also.

 

[BlackFox5.0]

Stock fuel pressure is 38psi. You converted to maf....did you hook up the VSS signal to the computer? If not this will cause stoplight stalling.

 

[beaver2489]

I'll turn the fp up to 38 next and try that. where in the wire harness is the VSS connection? I'm sure I hooked everything up, but **** happens. also the stalling happened before the mass air conversion too.

 

[beaver2489]

I have the fuel pressure at 39, it will idle without dieing now..but only when I first take it out driving and the engine is cold. Once the motor gets warmed up it dies everytime I stop. Would a crazy ECT sensor do this?

 

[beaver2489]

ok, the stang has been in the garage for a few months now. I gave up for awhile, too frustrating. Income tax return coming up around the corner and I want to give it another shot. This Focus zx3 is not fullfilling my torque needs

The last time I drove it I put the FP up to 42 then about 45...still dies evertime I push the clutch in. I pulled the plugs and they are oil coated which really ****ing sucks. But thats whats causing the motor to run rough when driving probablly..I had checked the plugs several times while having this idle problem and they were not oil covered. So the oil is something new. I need to do a compression test. The tps won't set right, its way off. I have the power products TB (gonna replace that junk) and it won't let me set it right. The IAC has been cleaned, but its the stock one with 145,000mi + on it... all sensors are old stock ones EXCEPT O2 and TPS are new.

now for the oil fouled plugs. It happened after I did the mass air conversion. I added the 24lb injectors and I then had light blue smoke out the exhaust. I realized that in our motor rebuild, we overlooked the valve covers. They have one hole for oil..we forgot to vent the valve covers So I'm trying to find a in filter/oil cap. I have replaced the PCV valve. It could also be the rings went bad already (omg) or the valve seals (omg#2). sorry I rambled on, I'm tired

 

[HISSIN50]

glad to hear you are workin on it again.

couple thoughts. have you cleaned the IAC VERY recently? if you are blowing oil through everywhere from crankcase ventilation issues, it could be all pooey again.
i bet valve cover breathing does some good.

what is the TPS issue? is it in the ballpark or way off? does it go up to ~5 volts at WOT (or does it seem like a wiring issue)?

good luck.

 

[TrickStang37]

does it supposed to go to 5v at WOT? mine goes to about 4.4. also, way back when, my car used to die ALL THE TIME when i would be coming to a complete stop. this was right after i did heads/intake/cam with a BBK 65mm TB. it was completely cured with a 1/4 in. hole in the TB butterfly. helped me.

 

[HISSIN50]

does it supposed to go to 5v at WOT? mine goes to about 4.4. also, way back when, my car used to die ALL THE TIME when i would be coming to a complete stop. this was right after i did heads/intake/cam with a BBK 65mm TB. it was completely cured with a 1/4 in. hole in the TB butterfly. helped me.

as i recall, 4.5 volts is good for WOT (now thinking, i believe WOT = ~4.5X volts signal return). you are right in the ballpark and sound good. sorry if i caused confusion.

the TB hole, much like the bypass plates, is a way to allow more air flow. some TB's come with the hole stock.

 

[TrickStang37]

yeah, my stock one had one too, but i seen a bunch of stock ones that dont.

 

[beaver2489]

thanks for replying. also can someone help out on how to set my idle screw on the throttle body...if this is set way off, could it cause the dieing at low rpm? The closest I can get the TPS with key on, engine off is like 3.something volts...which is obviously not right. I've changed the TPS voltage on the 89 5.0 I used to have, and on this stang when it had the stock TB several times with no problems. This power products TB has 2 allen head bolts that allow TPS adjustment..even when I drill out the TPS holes it still doesn't come close. I don't get it lol. but if the idle screw on the TB and the TPS is way off, could it cause the engine to die every time I come to a stop? Also, even though I've cleaned the IAC several times, could it be bad? how do I check, voltmeter? Thanks

 

[TrickStang37]

maybe its the tps sensor. my proproducts tb worked out fine for me.

 

[HISSIN50]

thanks for replying. also can someone help out on how to set my idle screw on the throttle body...if this is set way off, could it cause the dieing at low rpm? The closest I can get the TPS with key on, engine off is like 3.something volts...which is obviously not right. I've changed the TPS voltage on the 89 5.0 I used to have, and on this stang when it had the stock TB several times with no problems. This power products TB has 2 allen head bolts that allow TPS adjustment..even when I drill out the TPS holes it still doesn't come close. I don't get it lol. but if the idle screw on the TB and the TPS is way off, could it cause the engine to die every time I come to a stop? Also, even though I've cleaned the IAC several times, could it be bad? how do I check, voltmeter? Thanks

yep, if the idle is set out of whack, it can get funky real fast. remember the puter knows what the stock idle is - if one really tries to raise it, the puter will try to compensate in the ways it can, which can lead to issues. that is one reason it is important to set it right. clean the IAC (if applicable). the stop screw gets set first. then the TPS.

here is a decent write up on it all (sift through the pages to get info on setting it all, if interested).
http://www.muscularmustangs.com/iac.html

good luck.

 

[HISSIN50]

oh yeah, hopefully your stop screw is all out of adjustment - once that is reset (along with other things), the TPS might get close. i would think you are tossing a TPS code with it reading a base of 3.XX volts.

good luck.