• The site migration is complete! Hopefully everything transferred properly from the multiple decades old software we were using before. If you notice any issues please let me know, thanks! Also, I'm still working on things like chatbox, etc so hopefully those will be working in the next week or two.

Help with troubleshooting high idle/"dieseling"

natethegreat

natethegreat

New member
Tried all i can think of and can't figure it out. Im running an 02 bottom end with a top swap from a 97.

Anyways my problem is when i'm driving after i let off the pedal from accelerating the rpms will drop down to about 1600 rpm, and stay there until i brake which then will drop under 1500 and eventually stop at 1100 rpms. I have to push pretty hard as the cars trying to push through the brakes. After i'm stopped for a while it idles down to around 750 rpms. BUT, if i try to take off to fast the car lurches almost dies and the takes off. The car also seems to run rich/er

Things i've done to try and fix this is obviously
-check for vac leaks
-replace MAF
-change front 02
-Take out rear 02 so it reads just oxygen
-Change ICV

On another note im running SD headers and i also have an exhaust leak. Theres a 2.5in band clamp on the first joint which is slighty too big, and im running just the u bolts on all other connections. Im also getting some KR too where i don't think i should

When i first had the tune done i don't remember it doing this, and there was definatly 0 knock.

Any help is greatly appreciated! This car is starting to really piss me off!
 


Who tuned it? Have them look at the tune again and see if there are any telltales.

You've changed the IAC Valve? Did you clean out the area the pintle rests against in the TB? My car did the same thing (little higher RPM though) Ended up pulling the IAC valve (new) and cleaning the Throttle body out really well, fixed it.
 
I still need to clean my throttle body, but this morning it was -2 and the problem didnt seem to be as noticeable or prevalent. Perhaps temps have an impact on it.
 
sounds like the tb is dirty or the cables are hanging up.

if you un hook the cables, fire it up, see if it idles right. then slide the throttle cable in and out to feel for it sticking.
 
Well just got done cleaning the throttle body. The throttle plate was loose so I tightened that up and cleaned the carbon off...didn't seem to make a difference so I might need a new throttle body, or something else is going on.
 


was the plate dragging the TB or showing any wear to the TB or plate? that will cause mare air then it wants to be sucked in at idle.
 
I did some more thinking on this. If it was the butterfly being stuck causing more air to come in, then why would it idle down from 1100 to 750?
 


You must log in or register to reply here.
Back
Top