Question about 1995 Chevrolet Blazer
Engine has 319,000 km all highway. Vehicle just up and quit while driving down hi-way. Had spark and fuel. No codes Fuel pump & spider Injector set replaced 2 years previous ran great till now. Suspected timing chain. Had healthy spark on several plug wires, checked fuel pump pressure, up to spec, minimal leakdown even after 1 hr. moved plug wires ahead 1 space on distributor cap, engine fired right up. Ah-ha timing chain. Changed that timed on #4 tdc no start. Checked all sensors everything appears good. Checked for spark again and lo and behold none. Pulled distributor cap, hold down screws for rotor had fallen out rotor in wrong position how long had it run like that with no screws holding rotor on ?? Replaced rotor, cap, new plugs boom runs great. Fast forward 2 weeks idles really rough notice a plug wire arcing on exhaust manifold replaced 2 yr old AC wires for new still same crappy idle. Compression test lowest 110 highest 135 steady vacuum 15 psi idle. replaced all suspect vacuum hoses. Forgot to mention replaced intake gaskets and intake plenum gaskets previous to latest problems. Changed out each plug 1 at a time, no change in idle performance. Driving under load and overal performance are very good. EGR appeared good, cleaned up & replaced gasket when intake gaskets were installed. 1 month previous to all these problems vehicle wouldn't idle down, changed out IAC valve then fixed vacuum leak at intake plenum to solve actual problem. Hate spening money on parts I don't need. Every thing should be good but its not, any suggestions out there?
My problem was solved when I repaired my 4 wd activation dash switch. The switch was contacting on 2WD & 4HI at the same time. The front differential activation is vacuum activated possibly creating a tug of war that didn't actually engage it but drained off vacuum from the engine? A theory at best but stumbbled across it because I knew the switch wasn't working properly I repaired it and low and behold rough idle disappeared and all is good for 3 weeks running.
Posted on Dec 10, 2008
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