Installed new TPS and now truck wont even start!

[atvkid4eva]

ok guys well i was having some idle issues and stalling so it was suggested that i replace the TPS so i did...now before doing this the truck WOULD start up fine and idle fine and now sice i have put the new TPS in the truck WONT start it just cranks and cranks...i even tried putting the old TPS back on and for some reason now it wont start with the old one either? any ideas?

 

[rags]

Just for the heck of it try unplugging the TPS and see if it will start. If so .. you installed the TPS in the full throttle position and that will shut the injectors off .. I have run into that before

 

[atvkid4eva]

ok so it turned out to be a bad (new) IAC that i got from advanced auto...replaced it with one from napa and the truck starts and idles fine... the bad IAC and the new TPS must not of got along too good lol.

 

[atvkid4eva]

ok i lied...it seemed to have been fixed last night but now im still having the same problem...when i decelerate the RPM will fall slowly until about 1000rpm and then randomly jump up to 1500rpm and then slowly come down to about 1000rpm where it stays when i stop..should go down to about 700rpm..sometimes it will decelrate normally but it seems as the motor runs longer the worse it gets...sometimes it will idle perfect while stopped....and today when i went to start the truck it would not start just cranked..so i held the gas pedal to the floor and started it and it started up and you could tell the engine was flooded? what would cause these problems...new IAC,MAF cleaned but not replaced,new DPFE, and i cant find any vacuum leaks...anyone have anything else?
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[creepinjeepster]

Did you reset ecu after changing part again?

 

[atvkid4eva]

yes...it has nothing to do with resetting the computer.

 

[BlackBII]

I went through this whole ordeal last week, in regards to the funky idle anyway.

Turned out to be a sticky throttle cable, it would get stuck and the throttle plate wasn't closing all the way.

 

[atvkid4eva]

woul it do what mine is doing on deceleration? idle up while the rpm decrease? tell me more.

 

[BlackBII]

idle up while the rps decrease?

This makes 0 sense...what do you mean?

 

[atvkid4eva]

i meant RPM...when my RPM is decreasing when i slow down it will randomly rev up and then back down before i stop.

 

[BlackBII]

If the RPM is flucuating, I doubt it's the throttle cable, but you never know

Sounds like the IAC is fighting something to get the idle correct, given the inputs it's receiving from the various sensors.

 

[atvkid4eva]

i know thats what i believe is happening too...would a bad MAF sensor cause this? i did clean it but it could still be acting weird.

 

[atvkid4eva]

so i went over to my friends house to see if maybe he knew what was causing the weird revving problem...on the way there it ran fine at high speeds on the highway but when i was getting off the on ramp while dropping the rpm as i slowed down the engine started revving up again..it did this all the way through the city to his house...i pulled in his driveway shut the truck off for 5min and went and got him we got back in the truck and started it up and its running fine from then until now...the temperature outside did drop a bit but not much and of course i couldnt show him the problem since the truck was running normal...this is intermittant...hmmm..any ideas?

 

[Nhaz]

Unplug the IAC after warming up the truck do the rpm's drop and stay down?

If the IAC is erratically the cause of the problem Like mine was last spring I bypassed the IAC and installed a manual switch for it. Its supposed to stay off anyways once the truck warms up.

In any case my IAC problem was the ECC-IV computer going bad due to being a pile of corrosion. you may want to check that too.

 

[PlumCrazy]

Do you have a K&N filter? When I put a K&N in my 2.3 and my 4.0 they both would rev to 1500 then drop to 1000 when I slowed down in neutral. I am assuming it is because the K&N allowed more air to be pushed into the intake through the air duct. It never bothered me because it always cleared up when I stopped and it never tripped a CEL.

-plumcrazy