Crank but no start, getting fuel and spark

Tiny
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  • MEMBER
  • 1989 CHEVROLET 2500
  • 5.7L
  • V8
  • 2WD
  • AUTOMATIC
  • 250,000 MILES
5.7l tbi new coil, distributor less than a year old, cap and rotor less than 6 months old. I'm getting spark using my spark checker all the way down to the plugs and no start. Getting fuel to throttle body and still no start. Also tried starting fluid and no start not even a backfire.
Thursday, October 29th, 2020 AT 8:48 PM

18 Replies

Tiny
STEVE W.
  • MECHANIC
  • 14,015 POSTS
I would start with a compression test along with pulling the cap and verifying that the distributer is turning. 250,000 miles could be a bad timing chain and the cam isn't moving. Or the drive gear on the distributor is gone.
If it has spark and fuel the only thing it needs is the compression and timing.
https://www.2carpros.com/articles/how-to-test-engine-compression
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Friday, October 30th, 2020 AT 12:05 AM
Tiny
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Compression is good and the distributor is less than a year old. Truck went from running and driving today to tomorrow no start condition.
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Friday, October 30th, 2020 AT 3:23 AM
Tiny
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I will pull the cap momentarily to ensure everything's turning. If I have to I will pull the distributor to check gear. Is there a way to check timing without the truck running?
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Friday, October 30th, 2020 AT 3:25 AM
Tiny
STEVE W.
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Well you could get an idea by bringing it up on TDC for #1 and see where the rotor is but that's about it on electronic ignition for static timing. You could try a timing light but at cranking speed it will only really tell you it's firing not accurately when it's firing. The main thing is to determine if the timing chain or cam are an issue. Pull the cap and no motion gives you the answer to that. If the issue was fuel related it should have fired on the starting fluid. Did you test for spark on more than one cylinder? If you have it at the cap it should be everywhere.
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Friday, October 30th, 2020 AT 5:58 AM
Tiny
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Yes, I have checked spark on more than one cylinder and I have spark and cap off everything is turning right.
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Friday, October 30th, 2020 AT 11:23 AM
Tiny
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Would a bad temperature sensor stop it from starting?
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Friday, October 30th, 2020 AT 1:31 PM
Tiny
STEVE W.
  • MECHANIC
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Not on that year. It would make it run bad but it would still start. You say you tried starting spray, have you got any carburetor cleaner around? I would give it a good spray with that and see if it does anything then. Some of the starting sprays out there are weak. This is a TBI engine so the injection system is pretty basic, however if it doesn't do anything with either spray it probably isn't fuel related as I would expect it to at least fire for a bit.
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Friday, October 30th, 2020 AT 6:31 PM
Tiny
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My spark is an orange/yellow color in my spark tester. Could that be weak spark causing my no start?
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Saturday, October 31st, 2020 AT 3:10 AM
Tiny
STEVE W.
  • MECHANIC
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It sounds a bit weak but it should still be enough to fire.
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Saturday, October 31st, 2020 AT 6:02 AM
Tiny
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Still no fire.
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Saturday, October 31st, 2020 AT 6:41 AM
Tiny
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What about the pip sensor?
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Saturday, October 31st, 2020 AT 8:12 AM
Tiny
STEVE W.
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The catch is that you have spark and fuel and it's doing nothing. That suggests a timing problem and on that engine that is pretty much just the pick-up coil and module. However you have spark. When you had the cap off did number one TDC line up with the rotor at number 1? You also said that it was running okay and then wouldn't start the next day correct? You might try using a test light to run the fuses, a sudden failure at key on could be power related or something in the ECU. However I would expect no spark or fuel if that was the case.
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Saturday, October 31st, 2020 AT 3:35 PM
Tiny
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The last time it ran the rpm would fluctuate while holding the throttle steady driving down the road. But the I'm fairly positive that when I had put my timing light on it and had the electronic advance unplugged timing was good but when I plugged the advance back in I want to say the motor never advanced back and I don't think I saw a difference in the timing either. Prior to this truck would start and run fine for about 30 minutes then would lose power and start to buck and backfire until it wouldn't move anymore as well as the passenger manifold glowing red but only on cylinders 4, 6 and 8. Now here's the curve ball: if I would shut the truck down wait 10 seconds start it up It would take full throttle again and drive fine for about a minute and go back to actin up.
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Saturday, October 31st, 2020 AT 4:06 PM
Tiny
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I've tried to bypass the ignition by running a button direct from the starter and it will crank but not start still.
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+1
Saturday, October 31st, 2020 AT 4:08 PM
Tiny
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The last time I drove it and the rpm were fluctuating ii didn't drive long enough to start having the other issues. The morning after it started last I was attempting to solve the initial problems before the no start so I stopped out my ignition coil, distributor cap and ignition control module from under the distributor cap and rotor which then the truck wouldn't start. So I switched everything back to no avail. I did have the parts store test ignition control module that I had tried to swap originally which was just one I had laying around the shop which tested bad but even after putting original parts back still wouldn't start.
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Saturday, October 31st, 2020 AT 4:21 PM
Tiny
STEVE W.
  • MECHANIC
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The timing wouldn't change at cranking rpm advance starts as rpm rises. RPM fluctuation and glowing manifold sounds like exhaust blockage. It might be a good test to drop the pipes off the manifolds and see if it fires then.

https://www.2carpros.com/articles/how-to-test-a-catalytic-converter
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Sunday, November 1st, 2020 AT 7:42 AM
Tiny
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Replaced the distributor, cap, rotor and ignition coil. Ole Chevrolet fires up as soon as you hit the key now. Thank you for your input and help.
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Wednesday, November 4th, 2020 AT 7:54 AM
Tiny
STEVE W.
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Okay, that points to it possibly being the coil or a bad module, hard to say for sure but you got it fixed which is the goal. Good job.
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Wednesday, November 4th, 2020 AT 9:10 AM

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