No spark to the plugs

TINY1980

MEMBER
1990 GMC SIERRA
5.7L
V8
4WD
MANUAL
70,000 MILES

I have no spark to the spark plugs. I replaced the distributor it's brand new. I have replaced the ignition coil. I have replaced the plugs and the wires but I still have no spark to the plugs even though I have power to the coil and the distributor what could it be please God help me.

3 Replies

JACOBANDNICKOLAS

MECHANIC
109,747 POSTS

Hi,

First, check to see if there are diagnostic trouble codes stored. This has an OBD1 system that doesn't require a scan tool. All you need is a short jumper wire or even a paper clip.

Here is a link that explains how it's done:

https://www.2carpros.com/articles/buick-cadillac-chevy-gmc-oldsmobile-pontiac-gm-1983-1995-obd1-code-definitions-and-retrieval-method

Also, did the new distributor come with a new ignition control module? See pic below.

Let me know.

Take care,

Joe

See pic below.

Image (Click to make bigger)

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Friday, May 5th, 2023 AT 11:12 PM

TINY1980

MEMBER
3 POSTS

Joe,

Yes, it was a complete distributor with all the bells and whistles. Yesterday I got to checking my timing marks and TDC to the placement of the rotor and found I was about 20° out, so I corrected that. But still no spark. I just want to throw something out there, it is a standard transmission, how would I check to see if maybe it could be the switch that goes to the clutch? I also want to say that I have checked all the fuses and the relays, and they are also all in working order

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Saturday, May 6th, 2023 AT 2:41 AM

JACOBANDNICKOLAS

MECHANIC
109,747 POSTS

Hi,

The clutch safety switch won't prevent spark. It will prevent the starter from engaging, but nothing more.

As far as timing, even if the distributor timing is off 180 degrees, it won't prevent spark. It will just happen at the wrong times.

I want you to check something for me. You will need a helper. You indicated there is power to the coil. Do you have power to the coil when the key is in the start position? I ask because it could be related to the ignition switch.

Let me know.

Joe

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Saturday, May 6th, 2023 AT 7:03 PM