1986 Astro 4.3 TBI erratic and high idle
1986 Astro 4.3 TBI erratic and high idle
I've replaced TPS, IAC, gasket under throttle body, checked all vacuum lines for leaks, stalls sometimes when cold starting. Bogs a little when accelerating. No trouble codes showing. I've had the van for 15 years and it's never ran this bad.....any help would be appreciated.
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Re: 1986 Astro 4.3 TBI erratic and high idle
I think you have MAF, on intake air path. The Mass Air Flow sensor is a heated wire in a mesh grid. There is electrical connector going to MAF. Some GM engines in the mid 80's. Had a limp home mode whereby you could un plug connector to MAF and run open loop. Also, there is special spray cleaner for the mesh. If you read codes of flashing dash light on your OBD 1 , a code 34 is bad MAF. A code 12 is all systems good.
Another thing could be a clogged EGR valve with chunk of carbon. The new gasket for EGR valve has mesh screen.
If your Astro is running rich look at tail pipe and also "shoot the cat" with hand held IR temp gauge . The temperature at out out of catylitic converter should only be about 150 dog hotter than the input. If it is super high delta t, the cat is trying to burn off way too much raw fuel.
AP
Another thing could be a clogged EGR valve with chunk of carbon. The new gasket for EGR valve has mesh screen.
If your Astro is running rich look at tail pipe and also "shoot the cat" with hand held IR temp gauge . The temperature at out out of catylitic converter should only be about 150 dog hotter than the input. If it is super high delta t, the cat is trying to burn off way too much raw fuel.
AP