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.

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
47,513 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