NEED HELP Died going down road and wont start. Cranks has spark has fuel pressure. Code it threw was p0155

Cfarley1337

New Member
Been trying to diagnose this 2002 blazer 4.3 that died on us and wouldn't start back up. Checked spark its good fuel pump licks on fuel pressure is good. Shot starting fluid in intake an won't start. Thought it was distributor button replaced it still nothing now someone is saying its the distributor but don't want to keep buying 200 to 300 parts that isn't what's wrong. Is there anything anybody can suggest that I could check and possibly get it running again
 

swmyersva

New Member
Been trying to diagnose this 2002 blazer 4.3 that died on us and wouldn't start back up. Checked spark its good fuel pump licks on fuel pressure is good. Shot starting fluid in intake an won't start. Thought it was distributor button replaced it still nothing now someone is saying its the distributor but don't want to keep buying 200 to 300 parts that isn't what's wrong. Is there anything anybody can suggest that I could check and possibly get it running again
This sounds like an oxygen sensor or the wiring for it is shorted out. Check both to make sure not shorted out. There is also the possibility that the ECM went bad, sure hope that is not the case. Hope this helps you out.
 

TJBaker57

Well-Known Member
Been trying to diagnose this 2002 blazer 4.3 that died on us and wouldn't start back up. Checked spark its good fuel pump licks on fuel pressure is good. Shot starting fluid in intake an won't start. Thought it was distributor button replaced it still nothing now someone is saying its the distributor but don't want to keep buying 200 to 300 parts that isn't what's wrong. Is there anything anybody can suggest that I could check and possibly get it running again
So to clarify a thing or two. This is not a Trailblazer (which never offered a 4.3) but a Blazer with a 4.3 V6??

And I believe oxygen sensors cannot stop a vehicle from starting.
 

Mooseman

Moderator
So to clarify a thing or two. This is not a Trailblazer (which never offered a 4.3) but a Blazer with a 4.3 V6??
I would assume so since he mentions a distributor.

And I believe oxygen sensors cannot stop a vehicle from starting.
Exactly.

So basics are air, fuel, compression and spark. So air, fuel and spark check out. Do a compression test to check that the timing chain hasn't jumped a tooth, which would also screw up the spark timing. I'd also eliminate the injectors not firing since starting fluid doesn't start it, unless it's badly flooded.
 

gmcman

Well-Known Member
When cranking the engine, remove the coil wire so you can see the spark jump, but be careful not to be in contact with anything that could get you zapped.

Does the coil lead fire 6 times per 2 revolutions? Is the spark bright and loud or weak?

When it died, was it like a key was shut off or did it sputter and act like it was running out of fuel?

Can you smell fuel coming from the tailpipe?

I have to ask but how low on fuel are you?

Could be a crank sensor that finally broke the thin wire, not sure exactly how the 4.3 is setup in 2002. But since you have spark I'm guessing that's not the case.

Does the fuel pump prime then shut off when the key is turned or keep running?
 

TollKeeper

Well-Known Member
Since its not starting even with starting fluid, I would pull your oil cap, and see of you can see a valve or a rocker, if you can, have someone try to start the truck while you look at that rocker. If it doesnt move (it wont move much, but it should move), it means you have something in the timing system broke, likely a timing chain, but it could even be a broken cam, or a broken chain sprocket. If you cant see a valve under the oil cap, you would then have to pull the valve cover, and try it that way.

I will be honest, I would be very surprised if you have anything broken in the timing system. These 4.3 engines are one of the top three best 6 cylinder engines ever made, the other 2 are a 3.8 GM 90*, and the 4.0 Jeep engine.
 
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