1990 k5 tbi issues and stalling.

[wayne711]

Hey guy's i've been working on this issue for sometime. My blazer has been stalling out only when warm. I've read many threads and nothing has stuck. Replaced all sensors blocked off egr valve ran better but not great just took it off to test it and looks like in working order cleaned it up. Going to but back on tomorrow. Just wanted to see if anyone had and ideas how to fix this.

 

[SurfinCR]

have you swapped out the iac valve? or tried to replace the pick up coil?

i had an issue with my 88 2500 stalling when hot replaced just about everything the two things that made the biggest difference on mine was putting in a new iac valve which brought the idle up to where it should be and i swapped out the distributor. now it no longer stalls out when hot. i'm still stuck with a random surging idle but i'll take that over stalling all the time

 

[wayne711]

Yes I just replaced the iac like 2 weeks ago. No I haven't touched the coil. I have tried swapping distributors tho.

 

[diesel4me]

Maybe the EGR valve opens when it shouldn't be,or is stuck partly open with carbon build up--the egr passages often clog with carbon too...seeing it only operates once the engine is at operating temparature,thats a possibility...I know you tried removing it and blocking it off,sometimes that throws other sensors off and might not "fix" the trouble..

it will affect idle quality if it stays open ,its like having a vacuum leak ,only its exhaust being sucked into the intake instead of air (which is even worse probably!)..the intake could be cracked internally or have vacuum leaks at the gaskets ,that might only show up after its warmed up and any cracks expand,or the gaskets let more air sneak by them..

 

[wayne711]

Yeah I have the valve off now. Gasket looks good and I manually compressed the valve and plugged the hole and it did not let anything out. This whole this started after I replaced the motor. It never happened before this.

 

[dyeager535]

What did you replace it with? Exact stock replacement?

 

[wayne711]

Replaced it with a rebuilt motor from a performance shop locally. Only thing different is cams. He assured me that those cams will work with stock tbi application

 

[dyeager535]

Work? Sure. Work right? Meh.

Have you set minimum air? If not, worth a shot. Different engines require different amounts of air at idle.

Vacuum leak however can cause all sorts of issues, you need to be darn sure that's not a problem before going down any other road.

 

[black dawg]

yes, need to do the min idle set procedure.

 

[eagle mark]

First thing you need to do is read codes...