High ide, red headders.......HELP

[Whitesnake95]

Idle problem:
I recently ran 50/50 mix of Chevron 100 no lead and 91 grade fuel, this is the second time I did this with the car really running great. Read on…
The TPS is getting a 5 volt signal no matter how I position it on the throttle body ( I have an adjustment plate ) or even when I unplug it and take a direct reading from the connector. The idle air control vale checks in limits with 9 ohms reading. No engine check light.
My engine is idling at 14-1500 all the time, when first started there is a low moan that may be coming from the air pump (hard to tell with all the crap under the hood). I also noticed my headers starting to get red, I am afraid to take it anywhere because of his problem and I don’t trust a lot of the locals with the car. I have done most of the modifications myself and it has performed flawless, I would like to keep it that way…….
Help……any suggestions ???

1995 5.0 GT, 5 speed, Cobra R intake, 70mm body, Vortec SQ kit, MSD-6, coil, Ceramic shorties, Flo- Masters, 2.5 exhaust system, pulleys, the usual suspension mods. 65,000+ miles

[poochie50]

timing is off! go over everything make sure firing order is right for cam if you changed it,make sure distrub is in phase zero top dead center take number one plug out to feel when compression builds up,stop and look @your timing marks set on zero use your hands to turn if not a wrench will do, but zero the marks out i use white out for the markings, with everything lined up-get your timimg light out hook up on #1 spark plug wire, zero the light also if it has a degree dial on back of it! do your car have a spout if so start the car/check timing-pull spout out set timing with this out 10-12 degrees maybe more,after this put spout back in thats it no more red headers.that sure cure the high idle also your o2s might be cooked also change them set your tps,go over the car good get a sct 4 bank chip have tuned gears you should be set.

[Whitesnake95]

Thanks for the reply P50, the car was running fine until a 650 bemer tried to kill me by running me into the back of a garbage truck on the freeway, I got on it hard, too late, and shut it down real hard to avoid the collision, almost too late. Car has not run the same since.
I did find a bad gasket on the idle motor next to the TPS, in the process of working out the bugs. I read a tread about a bad ground to the TPS causing high idle..................

[gtnby2]

One other thing to try is to disconnect the battery for 10 minutes to clear out anything in your computer. it will reset it. after, reconnect the bat and start the car...since it's got alot of mods, it might freak out for a few minutes ( wont idle or surge some) but it should settle down and take it for a short drive. don't hammer on it but run through the gears so the ecm has a good range of timing and 0-2 ranges to recalibrate by. P 50 is right though, i also think it is mainly a timing issue and with 100+ octaine, fried 0-2's are very possible with a hard run. keep us posted on progress....
Brad/ GTNBY2

[Old Man]

Originally Posted by Whitesnake95

Idle problem:
I recently ran 50/50 mix of Chevron 100 no lead and 91 grade fuel, this is the second time I did this with the car really running great. Read on…
The TPS is getting a 5 volt signal no matter how I position it on the throttle body ( I have an adjustment plate ) or even when I unplug it and take a direct reading from the connector. The idle air control vale checks in limits with 9 ohms reading. No engine check light.
My engine is idling at 14-1500 all the time, when first started there is a low moan that may be coming from the air pump (hard to tell with all the crap under the hood). I also noticed my headers starting to get red, I am afraid to take it anywhere because of his problem and I don’t trust a lot of the locals with the car. I have done most of the modifications myself and it has performed flawless, I would like to keep it that way…….
Help……any suggestions ???

1995 5.0 GT, 5 speed, Cobra R intake, 70mm body, Vortec SQ kit, MSD-6, coil, Ceramic shorties, Flo- Masters, 2.5 exhaust system, pulleys, the usual suspension mods. 65,000+ miles

Red hedders are a sign of a very lean mixture. It can also be grossly retarded timing with much of the mixture burning in the hedder instead of the cylinders, but that usually means a poor idle.

High uncontrolled idle is often a sign of a vacuum leak, which will also make a lean idle.

My bet is, since you have both high idle and hot exhaust at idle, that you have a vacuum leak. Could be something else, but that is what to check first.

TOM

[USMC302]

It does sound like it could be a vacuum leak, but I would still try pulling codes and looking for any O2 sensor errors, if they went bad and are constantly reading rich, then the computer will try to ensure a lean condition is used while the TPS tries to compensate to keep the car running by increasing idle. Not all codes will trip the check engine light. Eitherway, the TPS should not be reading 5v, what wires are you connecting to to test and are you using a digital volt meter? Let us know.

[Old Man]

Originally Posted by USMC302

It does sound like it could be a vacuum leak, but I would still try pulling codes and looking for any O2 sensor errors, if they went bad and are constantly reading rich, then the computer will try to ensure a lean condition is used while the TPS tries to compensate to keep the car running by increasing idle. Not all codes will trip the check engine light. Eitherway, the TPS should not be reading 5v, what wires are you connecting to to test and are you using a digital volt meter? Let us know.

Yeah, you're right. Could be an O2 sensor or something in the computer thinking the mixutre is rich when it is really lean.

Most times I've seen it, it has been a bad vacuum leak but these computers can really add problems if they try to correct for a non-problem.

Good suggestion, especially since he mixed up some custom fuel. :-)

Tom