Will not start

JAC73

MEMBER
1986 GMC S15
2.8L
6 CYL
2WD
AUTOMATIC
138,000 MILES

Will not start. I thought it was the ignition control module but did not fix it. So I replaced the fuel pump and cap rotor wires and plugs checked all vacuum lines. I am getting fire and fuel but it will not start. I am out of ideas now thinking of either putting carburetor on it and doing away with computer or just dropping old school 5.7 in. Need help very frustrated.

Thursday, January 12th, 2017 AT 7:34 AM

3 Replies

HMAC300

MECHANIC
48,601 POSTS

Scan for codes first and check resistance of pickup coil should be 400-1000 ohms have ignition module checked at auto parts. Also, check resistance of coolant temperature switch should be high when cold and drop resistance as it heats up.

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Thursday, January 12th, 2017 AT 8:07 AM

JAC73

MEMBER
2 POSTS

I have replace ignition module, but have not checked ohm's on coil and did not think about coolant temperature sensor. I had same problem on another vehicle. Thanks for responding and the information helps greatly.

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Thursday, January 12th, 2017 AT 8:18 AM

KEN L

MASTER CERTIFIED MECHANIC
50,193 POSTS

Hey JAC73,

Lets check to see if the engine has compression enough to run, here is a guide to hep show you what to do.

https://www.2carpros.com/articles/how-to-test-engine-compression

Please let me know what happens so it will help others.

Best, Ken

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Wednesday, January 18th, 2017 AT 1:27 AM