Question about 1990 Chevrolet K2500
Been Parked for a while; changed out- fuel pump, MAP sensor, AIC, fuel injectors, EGR valve/silenoid, and spark plugs.... still running rough at idle. checked timing/cables/rotor,-- im lost?????
Check the CO/Temp sensor in the exhaust manifold. It may tell the ECU that the engine is hot when it is cold or cold when hot, getting the mixture wrong.
Posted on Mar 25, 2014
Testimonial: "Thanx- changed the temp sensor by thermostat and upstream oxygen sensor.... runs better. NOT smooth just yet... someone told me to change the knock "sensor".... we'll see....."
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Posted on Jan 02, 2017
its just white cuz i too the cat off..
cuz i thought my proble could have been to do with the cat...
cuz i lost power driving up hills and on highways now it just will start the die right away
or start and idle really bad...
i was thinking crank sensor.. or injectors
Posted on Oct 01, 2008
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
That eliminates the crankshaft and camshaft position sensors. Have you checked the fuel injector itself for an open winding or stuck valve plunger? There should not be a steady 12 volts to the injector--if good injector, it would be spraying fuel steadily into the throttle body. But at least the engine should try to run if poorly. Take the injector out, dry it off with air, and intermittently apply 12 volts to one terminal while grounding the other. You should hear a click from inside every time you touch 12 volts. If not, replace it. If it does, it may be plugged with debris. Try blowing through it in reverse with compressed air.
Posted on Jul 17, 2009
Check your MAP and TP sensors. Your throttle body may be having trouble determining position and is compensating by adjusting RPMs.
Posted on Nov 30, 2010
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