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INSANE IDLE! out of nowhere. Service engine light on.

1K views 6 replies 4 participants last post by  GodMike 
#1 ·
OK yesterday i took my 99 7.3L f250 4x4 to the car wash, sprayed the motor with that green stuff and rinsed. it just had a little dust that i wanted to get rid of. after i started the truck back up, it had a weird idle for a minute or so then leveled out and drove as good as it always did.

well this morning i go to start it and the idle is FREAKIN CRAZY! like one whole bank wasnt working. i shut it off and wiggled the uvch connections and started the truck back up and it idled fine for about 15 seconds, then it went right back to the crazy idle. my service engine light is ON.

Also, my turn signals stopped working so yesterday i also replaced the flasher behind the dash with no luck, apparently i have to replace the switch in the column. the only other thing i messed with behind the dash is my trailer brake, i disconnected it.

the only thing ive checked is the exhaust manifolds on both sides and theyre both warm!! so both sides were firing at least one or two injectors.

after wiglling those uvch connection wires again it doesnt make much difference if at all.

i did notice water coming out from the bottom of the wheel wells on both sides too. wondering if i shorted out my IDM or something. i went to autozone and got a cheapo scanner and it told me there were no codes but the service engine light was clearly on so.....screw that scanner probably.

If you guys could give me an idea, im ready to rip the valve covers off and do the quarter trick but if its some other possibility i sure would appreciate your input.

Has anyone experienced this?? i just got this truck and dont need problems already.

One more note if its important, i do have a TS 6 pos. chip in there.

thanks in advance guys.
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#2 ·
The IDM is actually meant to get wet, water can get in there (mostly through the "breather) but, here's where I would start.

The "Insane" idle is probably what it sounds like running on 4clys.

You're right, the AZ scanner is useless - return it (but, so are most others gonna be too - you need a professional scanner or an AutoEnginuity) You do have codes (probably P1316) and a Buzz Test, performed by a good scanner, would help you out.

So, when it's Cold, start it up, run over to the top of each tire and put your hand on the Exhaust Manifolds (cold engine - right?). I think you'll find one side warming up and the other Not. THAT would be the Dead side...

You could look into the IDM plug maybe, see that it looks dry at least, but other than that, there's not much you can do at this point (you could try opening it, Very Carefully if you expect to use it as a core, but not much chance you're gonna be able to fix it yourself)

Next pull the ValveCover on the dead side and get a close look at the UVCH connectors In & Out. See if there are any burnt pins or evidence it's unplugging. IF NOT, I'd be thinking IDM :(

Here's a good vid -> http://www.youtube.com/v/GHwjEfJtM_g&hl
 
#3 ·
could also be an icp or ipr related issue. could try disconnecting the icp sensor. it's easy enough to do. have a look at the connector. while you're up there, have a close look at the ipr connector and valve as well.
but as mentioned, you really need a device capable of reading manufacturer spcific codes and datalogging
 
#4 ·
update...

i mentioned that i did touch the manifolds after the truck was running for about 5 minutes and they were BOTH hot. i suspected the uvch at first as well, and tried wiggling the wires to see if i got any difference in the idle.

i put some more fuel in it. sprayed half a c hairs worth of ether and it fired right up but the SES light was still on. then strangely, after i unplugged the icp sensor the SES light went off, but the motor was still idling a little rough, missing. especially when im decelerating to the point where the engine is trying to idle, but wont idle smoothly until im going like 5 mph or when the TC is disengaged. Im hoping its just the ICP but i dont know. I am no good at the electrical part of motors so im hoping theres someone out there with some experience points.

thanks for your responses so far.:ford:
 
#6 ·
i mentioned that i did touch the manifolds after the truck was running for about 5 minutes and they were BOTH hot. i suspected the uvch at first as well, and tried wiggling the wires to see if i got any difference in the idle.
Sorry, somehow, I missed that in your post..... :(

But I agree, at this point you're just shooting-in-the-dark until you can get it on the right scanner.

How's the IPR look? The tin nut, that holds the coil on, still on? The connectors wires look good? (sometimes they have exposed copper and short). Also look at the ICP's connector. As they fail, the seal inside lets oil through it and evidence of motor oil seeping in that connector let's you know you have a problem.
 
#5 ·
you need to get a hold of a device capable of reading manufacturer specific codes and viewing PIDs.
 
#7 ·
I had a recent similar problem... lopey big block idle and no guts when you stepped on the pedal... turned out that after 13 years the uvch decided to turn loose... so yes pull the valvecovers and 50 cent mod it! Mine is running much better now.... but I also threw a lot of money at my truck that wasn't needed... 50 cents and a couple hours of your time! :doh:
 
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