Car will not start after replacing intake manifold gaskets

MARTINEZ_45198

MEMBER
1996 CHEVROLET SILVERADO
4.3L
V6
2WD
AUTOMATIC
1,950,000 MILES

Okay, so I replaced the intake manifold gaskets and put everything in the proper way the car won't start. I've already checked just the distributor. I checked for spark, I checked for coil, check for fuel. I do not know what is up with the car. Running out of options and need this car up and running soon.

5 Replies

KASEKENNY

MECHANIC
18,907 POSTS

Hi Martinez,

An engine needs three things to start and run, fuel, spark, and compression. You said you checked fuel and spark, and I assume you are saying that you have them. If so, have you checked compression? Let me know what the compression is for each cylinder and just confirm for me that you do in fact have fuel and spark.

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

Also, was the engine running before you replaced the intake gaskets? I am wondering if the plugs are fouled from fuel due to cranking and not firing. This will cause the plugs to not be able to deliver the spark and it will just crank. If this has been cranking for a while and the injectors are spraying fuel, you may want to change out the plugs just to be sure they are not causing the issue.

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Saturday, June 22nd, 2019 AT 9:49 AM

MARTINEZ_45198

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2 POSTS

Yeah, my compression is 125 psi on most of them. It just cranks but doesn't fire. It used to run perfectly.

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Sunday, June 23rd, 2019 AT 2:54 PM

KASEKENNY

MECHANIC
18,907 POSTS

Okay. So if you have compression but it just cranks then you are missing one of the other two. Fuel or spark.

I would put a fuel pressure gauge on it while cranking and see what the pressure is while cranking. It needs to be sufficiently high to fire the engine. Then when you checked for spark did you pull the plugs and ground them against the block to check for spark?

If you have all three then the engine should start.

If all you did was change intake gaskets and now it doesn’t start the only other thing I can think is you have a large intake leak allowing to much unmetered air in the engine so you air fuel mixture is way too lean.

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Monday, June 24th, 2019 AT 7:25 PM

KIM AMACK

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4 POSTS

I just had upper and lower intake manifold gaskets replaced in a 2004 grand prix had it couple days, made coughing sound, died went start and my radiator hose is collapsed

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Tuesday, April 5th, 2022 AT 10:09 PM

KASEKENNY

MECHANIC
18,907 POSTS

At this point this may not be related to the manifold gaskets as the hose collapsing is most likely a vacuum in the cooling system or a faulty radiator cap.

so, we need to check the radiator for a restriction and then the cap for a leak.

However, if the engine will not restart, we need to check to find out if we have a head gasket issue as well.

Here is a guide that will help with this:

https://www.2carpros.com/articles/head-gasket-blown-test

There could be something else going on, but we need to start with this and go from there.

Thanks