7.4/454 wont start

[bulldog]

Looking for help on my 97 k3500. So, a couple weeks ago driving home, I round a curve, get back into the throttle, and she dies down. Try to start back and it was acting like it was almost backfiring every 3rd or 4th revolution. Get her towed back home and commence the diagnosis. Two months ago I did a full tune-up. (plugs, wires, new dist, cap and rotor, injectors and fuel pressure regulator) Seems to be getting plenty of fuel. Checked spark on #2 cylinder and it was there. Tried the starting fluid in the intake and still no start. If u try to start it, it acts like it wants to fire every few rounds, just wont kick off though. Sorry for the long post, just wanted to give as much info as possible. PLEASE HELP!! Winter is on the way and I NEED my 4x4......

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[BNielsen]

Did you replace the distributor shaft too or just cap and rotor? It sounds like you stripped out the gear where the cam meets the shaft maybe?

I know my dad's 99 C3500 had the rotor screws back off and bound up under the cap which was similar to what you described, but you already replaced all of that; I think one or two other members had an issue like this with their 454s and it turned out to be the whole shaft instead of just the cap or rotor.

 

[east302]

Do you have any codes?

Since it won’t fire on starting fluid, you can probably rule out a fuel issue though it wouldn’t hurt to check fuel pressure.

Do you have good spark on all cylinders? Your post just mentioned #2. If it’s good on some but not all, check spark at the cap to rule out either a bad plug wire or distributor issue.

Is the cap still held on? Not sure if the big block used the same plastic distributor housing as the small block, but the mounting ears tend to crack apart.






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[454cid]

Get your ICM checked...it's next to the coil.

 

[bulldog]

Did you replace the distributor shaft too or just cap and rotor? It sounds like you stripped out the gear where the cam meets the shaft maybe?

I know my dad's 99 C3500 had the rotor screws back off and bound up under the cap which was similar to what you described, but you already replaced all of that; I think one or two other members had an issue like this with their 454s and it turned out to be the whole shaft instead of just the cap or rotor.

Yeah, whole shaft, cap and rotor assembly. Pulled it all back out tonight and it still looks brand new.

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[bulldog]

Do you have any codes?

Since it won’t fire on starting fluid, you can probably rule out a fuel issue though it wouldn’t hurt to check fuel pressure.

Do you have good spark on all cylinders? Your post just mentioned #2. If it’s good on some but not all, check spark at the cap to rule out either a bad plug wire or distributor issue.

Is the cap still held on? Not sure if the big block used the same plastic distributor housing as the small block, but the mounting ears tend to crack apart.






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Fuel pressure showed 55 with a guage. No codes thrown.

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[bulldog]

Get your ICM checked...it's next to the coil.

That's what I'm thinking.... What do u mean by checked? Is there a test I can do?

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[454cid]

That's what I'm thinking.... What do u mean by checked? Is there a test I can do?

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The parts stores have a machine that can check it. My local Oreilly didn't have the connector so the guy and I had to hold 4 or 5 probes onto the contacts, but Autozone could just plug it in. Someone on here mentioned that it's a good idea to have the run the test several times because heat can be a factor.

I've had mine go bad twice... and it behaves just like you're describing, every few revolutions it sort of coughs and shakes, and acts like it just might fire, but then doesn't. The thing that is different is that I've never had it go bad when driving. Both times, it's been running fine, I shut it off, and then it won't start again.