High IdLE???

[v2500burb]

Hey guys and gals
I am new to this...
I have a 1990 Suburban V2500
I just out a tach on it and I think it idles high
These are all in park
First start up is about 900-1000rpms (no a/c)
Warmed up it has 1100-1200 rpms

I just replaced all the vacuums lines I could visually see
New plugs
New Wires
New Cap
New rotor

Help!!!!

 

[highdesertrange]

it is high. I was going to say turn the idle down but I see it's a '90 so it's tb. vacuum leak? is the check engine light on? does it work? this should probably be moved to the engine section. more responses. highdesertranger

 

[v2500burb]

No check engine light
I replaced all the vacuum lines I could see
Any vacuum line spec sheet?

I don't know how to move this thread to the engine section

 

[mtnmankev]

Just a shot in the dark .............
No matter what kind of FI system an engine has, shouldn't it have some sort of throttle position sensor to tell the computer how much fuel is needed?
Maybe an adjustment on it would cure the problem.

 

[v2500burb]

No clue
I know it has a TPS
not sure if it has any adjustment
Any easy way to test it??

 

[v2500burb]

Help

 

[350runner]

Throttle position sensor. You can ohm the connections/ wires on it while it's disconnected.

 

[firebane]

Throttle position sensor should not need to be touched and is something set from factory. I still agree with the possibility of a vacuum leak and would be diagnosing that first.

 

[350runner]

Hope this helps http://www.gmtuners.com/tech/TPS_IAC.htm

 

[Chaz]

Common problem is vac leak at the base of the throttle body but could also be vac leak from somewhere else,,,,is the motor all stock? Any aftermarket bs parts on there?

 

[jt1200r]

its your speed sensor. its the large hex head with a wire connector on the end on the left rear side of the throttle body.

 

[89Suburban]

I have that problem with mine and I think it has to do with the neutral safety switch on the bottom of the column. When I wiggle the shifter to a certain spot in neutral the it will idle down to normal if it is warmed up. Not sure how that is hooked up to or handled by the ECM.

 

[mtnmankev]

I have that problem with mine and I think it has to do with the neutral safety switch on the bottom of the column. When I wiggle the shifter to a certain spot in neutral the it will idle down to normal if it is warmed up. Not sure how that is hooked up to or handled by the ECM.

That's WEIRD ..........
But I would not be surprised for something like that to happen to me with all the weird **** that goes on in my world that defies logical explanation.

 

[89Suburban]

Yah I'm leaving it alone like that because in the winter I can let it high idle longer to warm up better. Sometimes I pull up to a light and can tell the idle is high and if I kick it into the neutral sweet spot it will idle right down, very strange.

 

[v2500burb]

I replaced all the vacuum lines I could find
Anything hidden I may have missed??
Vacuum at the bottle if the throttle body??
How can check/adjust?