Gasser trash of the worst variety *Now with pics*

[cmann250]

I'm dealing with a '89 F250 EFI SBF, ZF5, 4x4. I got the timing set, siphoned some fuel that looked like apple juice, and now the truck runs fine. For a while.

It starts great and after a few minutes, it starts idling at 3000 rpms. It only does this when it's warm. Everything I've read says vacuum leak. Well duh. Yes, every line is old and crusty looking, but I've poured soapy water over them and nothing happens. I don't think it's a vacuum leak because wouldn't a leak cause it to idle high all the time, right? The Haynes manual is useless and the gasser Ford forums are in the same boat.

Got any ideas?

[Hansen01]

I Feel your pain on the forum thing, went threw that when i was dealing with my car. No codes or anything? I know on like a Mercury sable, they have some vaccum lines under and behing the intake manifold that you cant hardly see or feel, so in other words have you checked there?

[ellis93]

I'm dealing with a '89 F250 EFI SBF, ZF5, 4x4. I got the timing set, siphoned some fuel that looked like apple juice, and now the truck runs fine. For a while.

It starts great and after a few minutes, it starts idling at 3000 rpms. It only does this when it's warm. Everything I've read says vacuum leak. Well duh. Yes, every line is old and crusty looking, but I've poured soapy water over them and nothing happens. I don't think it's a vacuum leak because wouldn't a leak cause it to idle high all the time, right? The Haynes manual is useless and the gasser Ford forums are in the same boat.

Got any ideas?

Yep it'll run high idle all the time if it was a vac leak,your problem is that the computer system in that truck is one of the lest helpfull systems for diagnosing problems there is.
Get it running again and let it get to that high idle again,this time while its running tap lightly on the idle air motor,round looking thing with a black plug and two wires in it. It would be located on the throttle body.

Three things are common problems with these trucks....map sensor,tps,ect sensor. From past experience id say one of those will screw you

[cmann250]

Yep it'll run high idle all the time if it was a vac leak,your problem is that the computer system in that truck is one of the lest helpfull systems for diagnosing problems there is.
Get it running again and let it get to that high idle again,this time while its running tap lightly on the idle air motor,round looking thing with a black plug and two wires in it. It would be located on the throttle body.

Three things are common problems with these trucks....map sensor,tps,ect sensor. From past experience id say one of those will screw you

I tested the TPS and I sure think it's bad. Voltage does not increase as I opened the throttle. I unplugged the idle air thing (the thing on the side of the throttle body TPS is on the bottom for reference) and it hasn't done the high idle bit since, BUT it's harder to start and obviously doesn't idle right until it's warm. Is the Tps the reason that a small coolant line goes into the throttle body? That'd make sense if it needed to see coolant temp given my problem. One of the PO's bent the throttle lever. I bent it back and threaded the screw in a little farther that it rests on hoping to gain a few rpms of idle. Haven't started it since then.

Hansen, it's never even thrown a CEL, which is strange.

[dazedandconfused]

Where are the pics of this thing?

[cmann250]

Where are the pics of this thing?

I have a Rugby phone and I didn't know any one was that interested. I have one on my phone of it on the G/N...

[dazedandconfused]

Id like to see it.

[Tacoclaw]

On all the standard Fords I own I always cut up an oil filter box and plug the IAC off. It makes it rev down normally between shifts and just makes it easier to drive IMHO, plus you can adjust the idle with the little screw you're never supposed to touch. It also means you can leave the valve plugged in so it doesn't set off codes.

Also, a gasser won't do anything with soapy water sprayed over a leak. Since it's a vacuum it's not going to make bubbles or anything. You may get a rev out of it with some ether fogged in the area.

On edit, I will say that blocking off that IAC will make them a total bitch in the cold. My ranger needs babysat when first started in the mornings, it'll hunt for idle really bad before finally just dying. If it's in something you expect to hit the key on in the mornings and run back inside until it's warm I'd skip that mod.

[ellis93]

The coolant lines serve one purpose,to warm the throttle body thats it. I was told by an old ford tech once that it kept the throttle from icing over but idk. What I do know is that truck will get horrific mpgs with out them.

your tps could very well be your problem,the idle air controll motor opens up farther with more voltage from it,another words more pedal. And unpluging the idle motor will make it go back to a neutral position most of the time,if they're good. I'd go after the tps and make sure the thing is set right,if not you'llhave the computer idle the motor up and down like taco said. It's a pain to do but it is worth it

[Mark Nixon]

...If it's in something you expect to hit the key on in the mornings and run back inside until it's warm...

Old Schooler!
This newfangled Durango thing I just bought has remote start, no traipsing out into the cold, dark, morn for some of us!



Mark.

[Tacoclaw]

I'm even older-school than that. My engine doesn't crank until I'm reaching in for the ice scraper.

If there's no ice I'll usually just stand there in tw driveway and take a leak. Proper engine warm up is important.

[Mark Nixon]

...If there's no ice I'll usually just stand there in tw driveway and take a leak. Proper engine warm up is important.

Careful, I understand that taking a leak at 20* below zero can result in "hardening of the stream" or "freezing at the tip", both are a dangerous condition that can lead to at least frostbite.

Plus, that's just too dang cold to be out "waving the flag".

Mark.

[Tacoclaw]

I'll be alright there since alcohol isn't prone to freezing.

[dazedandconfused]

Can something that small freeze even with alcohol coming out?

[Tacoclaw]

"There was shrinkage, Jerry!!!"

It's more at risk than yours is, what with you siting down and all.