Engine cranks over but no start?

Tiny
DANIEL BARLAU
  • MEMBER
  • 1988 CHEVROLET SILVERADO
  • 5.7L
  • V8
  • 2WD
  • AUTOMATIC
  • 200,000 MILES
I have the truck listed above 1500 model with the first gen throttle body injection. At first we were not getting fuel to the throttle body we replaced the fuel filter and started getting fuel to the throttle body but the accessory pump to the injectors was not moving fuel from the lines to the injectors. So we replaced the pump and injectors and was getting fuel to the cylinders, still no start. (Bearing in mind it's never been touched up to this point as far as I can tell) once I had fuel and no start I checked spark and distributor timing and found I wasn't getting any spark/signal from ignition coil to distributor, no signal from ICM in distributor to coil so I replaced the coil and distributor, had spark. Then no spark to plugs wires were tested on another Chevrolet I have laying around, wires send strong signal, checked plugs and they were fried so I replaced. I now have fuel and spark and good compression but still will start it was driving literally 10 hours ago then it was parked and not ten minutes later went to start it and it just cranks. What am I missing? My fuel pressure is 13 psi and compression is 176 +/- 2 psi in both directions. I'm seriously at a loss at this point.
Sunday, July 19th, 2020 AT 3:30 PM

13 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Hi,

If you have spark, fuel, compression, and correct timing, the engine has no choice but to run. What happens if you use starting fluid? Will it start for a couple seconds and then stall or does it make no difference? Also, you mentioned that you replaced the distributor. Was the ignition control module replaced as well?

Also, have you checked for diagnostic trouble codes? This has an OBD1 system that doesn't require a scan tool to check. All you need is a short jumper wire or even a paper clip. Here are the directions. Do this if you haven't already.

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

When you turn the key to the on position without cranking the engine over can you hear the fuel pump run in the tank for 5 seconds?

https://www.2carpros.com/articles/car-cranks-but-wont-start

Please run down these guides and report back.

Let me know.

Joe
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Sunday, July 19th, 2020 AT 4:16 PM
Tiny
DANIEL BARLAU
  • MEMBER
  • 8 POSTS
So I did the ICM when I did the distributor (sold as whole unit) and starter fluid does absolutely nothing and no codes are coming from the computer (did jumper test already) the only other thing I've been kicking around in my head is the crank sensor is faulty, but I cant seem to find the thing. But that would send a code if it was. It was running great yesterday. I've replaced basically everything on the ignition side of things with the exception of the switch. I'm basically down intermittent fuel pump failure or sensor malfunctions.
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Sunday, July 19th, 2020 AT 4:41 PM
Tiny
DANIEL BARLAU
  • MEMBER
  • 8 POSTS
And I was mistaken before it's the k1500 not the c (4wd).
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Sunday, July 19th, 2020 AT 4:42 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
I assume the pick up coil was replaced in the distributor. Since it does nothing with starting fluid, then it's not fuel related.

I have a stupid question. Did you confirm the distributor is turning? Remove the distributor cap and crank the engine. See if it is turning.

Also, I attached an OEM wiring schematic of the ignition switch below (pic 1). If you look at pic 2, I highlighted a fuse. Make sure it's good. If it is, make sure there is power to it.

https://www.2carpros.com/articles/how-to-check-a-car-fuse

Let me know what you find.

Joe
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Sunday, July 19th, 2020 AT 8:35 PM
Tiny
DANIEL BARLAU
  • MEMBER
  • 8 POSTS
I thought that too, but it is indeed spinning. I also checked the fuses and all light up but what I did find is a manufacturer defect on my plug wires and all of them are arcing on the exhaust manifolds. So I'm going to replace them tomorrow and cross my fingers because I have literally replaced everything on the ignition side and everything but the actual fuel pump has been replaced on the fuel side.
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Sunday, July 19th, 2020 AT 9:55 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
If they are all arcing, that's the issue.

Let me know if that takes care of the problem. Also, I attached a pic below of the factory wire routing. I don't know if you need it, but thought I would add it in the event it would help.

Take care,
Joe
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Monday, July 20th, 2020 AT 2:17 PM
Tiny
DANIEL BARLAU
  • MEMBER
  • 8 POSTS
Well, it solved the arcing problem and back only 4 cylinders firing. I think I got a faulty ICM at this point I pulled the plugs and 3, 5, 6, 8 all smell of heavy fuel. So I flooded it at this point so I'm airing the cylinders and replacing the module again and see how that goes. It's under warranty.
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Monday, July 20th, 2020 AT 6:47 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
That's interesting. That nearly follows the firing order (1, 8, 4, 3, 6, 5, 7, 2). So you are only getting spark to 1, 2, 4, and 7?

Let me know if the module changes it.

Joe
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Monday, July 20th, 2020 AT 7:06 PM
Tiny
DANIEL BARLAU
  • MEMBER
  • 8 POSTS
So I'm firing completely on all cylinders and am immediately shooting flames out the throttle body. So I'm going to reset timing and hopefully it fires up.
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Thursday, July 23rd, 2020 AT 9:43 PM
Tiny
DANIEL BARLAU
  • MEMBER
  • 8 POSTS
This is the third time I've reset timing fortunately it's easy, lol.
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-1
Thursday, July 23rd, 2020 AT 9:45 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Wow, that doesn't sound good. Are you sure you didn't mix up the wires to the plugs? I attached a pic to help confirm that.

Joe
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Thursday, July 23rd, 2020 AT 9:51 PM
Tiny
DANIEL BARLAU
  • MEMBER
  • 8 POSTS
I got the wiring right it's the base timing I got to set. Basically my exhaust valve is opening on the compression stroke and sparking the fuel. I'm fairly (80%) confident it will fix the problem.
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Thursday, July 23rd, 2020 AT 10:17 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Did you have the timing chain apart or the distributor out?

Let me know.
Joe
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Friday, July 24th, 2020 AT 5:55 PM

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