Crazy Idle

[Mr. Stroker]

Hey guys, I was helping my buddy do a rear main seal on his 94 F150 with a 351 and MAF, and he got it all put back together and in, he calles me up and says its going crazy. So i ran over there and he had the IAC valve off, i told him to put that back on and connect it for one, then he started it up and it would reve up to 4 grand or more. WOuldnt go back down so we shut it off. Im stumped. It seams like he has everything hooked up, he took his EGR crap off and made a block off late for it, New TPS, im not sure whats going on with it so i figured id ask the crew. He also is running open headers he just wants to fire it up to make sure everythings ok. Well let me know what you think. Thanks

 

[Brian_B]

You might want to ask one of the admins to move this to the ford tech forum if no one answers you soon.

Personally, I have no clue about the modern stuff. Any chance the throttle body is stuck open somehow? I had that happen on an older ranger I used to have.

 

[subford]

Sounds like he left a vacuum hose off or a vacuum leak.
Pull the plug off the IAC Valve and see what happens.
Did he mess with the do not touch screw on TB?

 

[Mr. Stroker]

Im not sure but il ask. Yea i thought about that after i posted it lol sorry. He had one of my other friends who has a 302 EFI unplug crap that he said his motor didnt need. Well il go back over there and plug it all back in. Thanks for the help

 

[Mr. Stroker]

Appartenty they got it running at a lower rpm, but is backfiring and shooting flames from where the upper meets the lower! I wanna go take a video of that! I think they got the timing so its firing when the intake valve is opening.

 

[subford]

IF it is shooting flames from where the upper meets the lower the gasket is now bad and will need to be replaced or it will never run right.

 

[d-kuzmen]

Make sure that gasket is still there between the halfs and the bolts are in and tight. Sounds like I vac leak, or the timing is way off. Just put in a new rear main and now it runs like this or other work also?

 

[Mr. Stroker]

Well they thought it would be kool the tear the WHOLE thing apart, powerwash it and paint. lol so everything was off. Yea im waiting for them to come home and i might take a run out there to make sure they dont do anything else wrong. I personally think that timing is WAAAY off

 

[d-kuzmen]

Well they thought it would be kool the tear the WHOLE thing apart, powerwash it and paint. lol so everything was off. Yea im waiting for them to come home and i might take a run out there to make sure they dont do anything else wrong. I personally think that timing is WAAAY off

Oh boy, could be water where it doesn't belong like in the harness connectors or in dist cap.

 

[Mr. Stroker]

Yea, As soon as i heard that im like OOOOOO geeez. Looks pretty good tho lol, im gonna go over there and see what they got goin on.

 

[d-kuzmen]

Water will do a number to the electrical system. A short in the right place will make some funky stuff happen.