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1992 GMC sierra, 350 cid new plugs, wires,cap,rotor, distibutor. 150 psi comp. Missing on number 3 cly. Replaced intake gasket. Still the same, have tried new map sensor, exchanged the comp nothing number 3 still not working. So I know I have spark and compression. Help
Thanks, It was a broken valve spring on the exhaust valve down at the bottom of the spring. Changed spring runs great.Thanks, It was a broken valve spring on the exhaust valve down at the bottom of the spring. Changed spring runs great.
Hey thanks it was a broken exhaust valve spring right near the base. Changed spring runs great.Hey thanks it was a broken exhaust valve spring right near the base. Changed spring runs great.
Have you checked the Valve Springs on that Cylinder? Often Valve Springs break down near the base and will sometimes allow the valve to seal at cranking speed but not with the engine running.Have you checked the Valve Springs on that Cylinder? Often Valve Springs break down near the base and will sometimes allow the valve to seal at cranking speed but not with the engine running.
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I saw what you replaced, didn't see any testing? Any applicable trouble codes? Use a gage and check proper fuel pressure, TBI--9--13 psi. As an example, 5 psi fuel pressure makes a nice looking injector spray pattern, but, 5 psi won't start and run a v8. My opinion.
Could be other issues.
Clean mass air flow sensor with a nonchlronated brake cleaner,install new air filter and check all vacuum lines for leaks then check for vacuum leak around or at intake manifold.Code P0140 is for mass air flow sensor code P0300 is a multiple misfire which more than likely is a vacuum leak possibly intake manifold gaskets leaking.
Go to the parts store and get a noid light for your truck, plug it into the injector electrical and turn the engine over to see if there is electrical pulse, also check the fuel pressure, the pump needs 9-13 psi with the engine running. you know if there is no pulse your going to need to check the wireing first. let me know
1-8-4-3-6-5-7-2 Distributor turns clockwise Number one should be in the 5 oclock position. You should be able to draw an imaginary straight line between the coil tower and number one tower on the cap and the number one spark plug.
I would test for a leaking intake manifold gasket. WITH A WATER SPRAYER , and the engine running at operating temps and at idle, spray some water where the intake meets the cylinder head. If you hear a little SUCKING SOUND, and the engine smooths out temporarily, thats it Hope this helps
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.
Thanks, It was a broken valve spring on the exhaust valve down at the bottom of the spring. Changed spring runs great.
Hey thanks it was a broken exhaust valve spring right near the base. Changed spring runs great.
Have you checked the Valve Springs on that Cylinder? Often Valve Springs break down near the base and will sometimes allow the valve to seal at cranking speed but not with the engine running.
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