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Crank no start

Tiny
SIMPERFI84
  • MEMBER
  • 1996 CHEVROLET SILVERADO
  • 5.7L
  • V8
  • 2WD
  • AUTOMATIC
  • 350,000 MILES
I have a new GM factory 5.7l vortec engine installed in my truck, along with a re-manufactured 4l60e transmission. Had everything running great. With approximately 400 miles on engine and transmission. Now I have a crank no start issue. I have confirmed good spark and fuel. I did change the fuel pump after this issue. With a Delphi pump fuel pressure is 62psi, I pulled pelium and confirmed, no leaks in injector assy, getting fuel to all eight injectors. Spark is good. Pulled distributor for visual inspection, dist is new by the way, everything looked okay. Reset engine to TDC on comp stroke reinstalled distributor. Swap rotor and cap with know good, rechecked spark which was good. I tried spraying starter fluid into intake. Still have a no start issue. Timing chain is not broken rotor spins while cranking, any suggestions as to what to check next?
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Wednesday, December 18th, 2019 AT 9:10 AM

40 Replies

Tiny
SIMPERFI84
  • MEMBER
  • 14 POSTS
I have checked the grounds, I can go back over them to confirm good clean contacts. I did swap out the cam shaft sensor with the one from the original but no joy there. I did check for good 12 v and ground. On the one in the new dist. Wouldn't hurt to get a new one. Thanks for the response. I will update my post when I install the new sensor.
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Wednesday, September 2nd, 2020 AT 6:00 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good afternoon,

Did you verify power to the spark plugs directly?

Are the injectors firing?

I would also check the compression as well.

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

The last thing I would do is check for an injector pulse. You can check it with a scan tool or use a noid light to be sure the ECM is commanding the injectors to deliver fuel.

Roy
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Wednesday, September 2nd, 2020 AT 6:00 PM
Tiny
SIMPERFI84
  • MEMBER
  • 14 POSTS
I did verify spark to all plugs, also replaced spark plug wires, I found a couple boots had cracks in the other set, plugs are new as well. I pulled the plug for the MPFI system check for power, ground and pulse with a test light. I also removed upper peluim and check for leaks while in there found none and visually check each injector for pulse and fuel spray. Confirmed all eight injectors were working. I check cylinders 1 and 2 for compression both at 186psi, I am going to check all eight this weekend. I will post my results. Thanks for the response.
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Wednesday, September 2nd, 2020 AT 6:00 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
You are welcome.

Always glad to help.

Roy
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Wednesday, September 2nd, 2020 AT 6:00 PM
Tiny
SIMPERFI84
  • MEMBER
  • 14 POSTS
Good evening Roy,

I did fail to mention the only code I have is a P0102, for MAF, At first I figured it was due to removing the breather, but it won't clear out now. I have unplugged the sensor and tried starting with no joy. I have also noticed that it won't throw a p1345 code even if I turn the distributor a little. Makes me a little suspect of the ECM. Just a thought.
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Wednesday, September 2nd, 2020 AT 6:00 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
I agree. When you turn the distributor, it should set a code for cam retard.

Sounds like you need an ECM.

Roy
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Wednesday, September 2nd, 2020 AT 6:00 PM
Tiny
SIMPERFI84
  • MEMBER
  • 14 POSTS
That has been a thought hanging in the back of my brain. How do I go about diagnosing a bad ECM? It does communicate with my scanner?
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Wednesday, September 2nd, 2020 AT 6:00 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
It can communicate and still not command injectors to fire.

Do you see an RPM reading while cranking?

Roy
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Wednesday, September 2nd, 2020 AT 6:00 PM
Tiny
DAVISMELODY6669
  • MEMBER
  • 65 POSTS
I have the same problem but my injectors are firing but no spark. New distributor new coil and module.
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Wednesday, September 2nd, 2020 AT 6:00 PM
Tiny
ASEMASTER6371
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  • 52,797 POSTS
Okay, do you have any codes set?

Do you have a test light to do some testing?

Year, make, model and engine?

Roy
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Wednesday, September 2nd, 2020 AT 6:00 PM
Tiny
DAVISMELODY6669
  • MEMBER
  • 65 POSTS
Same truck like SIMPERFI84. I did a upgrade camshaft with all new sensors I have 12v and ground to all connections, but from the coil to a ground or light tester no spark.
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Wednesday, September 2nd, 2020 AT 6:00 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Okay, test for power to the positive side of the coil. If you have power, then use the test light on the negative. You should have power there as well. Then have someone crank the motor. With the test light on the negative side. The light should flash with the engine cranking.

Roy
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Wednesday, September 2nd, 2020 AT 6:00 PM
Tiny
DAVISMELODY6669
  • MEMBER
  • 65 POSTS
On the connection to the coil I have 12v on with the key on hot and the negative side too.
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Wednesday, September 2nd, 2020 AT 6:00 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Okay, crank the engine and see if the test light flashes.

Roy
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Wednesday, September 2nd, 2020 AT 6:00 PM
Tiny
DAVISMELODY6669
  • MEMBER
  • 65 POSTS
Since I put in a new timing cover I do not know if the crankshaft sensor needs a shim. To make it start. I also changed the fuses in the fuse box and the wiring harness ain't being grounded. I'm stuck.
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Wednesday, September 2nd, 2020 AT 6:00 PM
Tiny
DAVISMELODY6669
  • MEMBER
  • 65 POSTS
So I hook up the clip to a ground and point the tester to the negative side of the connection?
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Wednesday, September 2nd, 2020 AT 6:00 PM
Tiny
ASEMASTER6371
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Yes, do the test.

Roy
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Wednesday, September 2nd, 2020 AT 6:00 PM
Tiny
DAVISMELODY6669
  • MEMBER
  • 65 POSTS
Okay I am going to try it in 2 hours. The light has to stay on while cranking, if there's no light it that a bad ground or something else? The crankshaft sensor could be a part of it to I'm not sure. Because it feels little wiggly like it needs a shim. I do not know if it's a myth about crank sensor being bad cuts off the spark.
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Wednesday, September 2nd, 2020 AT 6:00 PM
Tiny
ASEMASTER6371
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  • 52,797 POSTS
Read what I told you. You need a flashing light while cranking.

Roy
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Wednesday, September 2nd, 2020 AT 6:00 PM
Tiny
DAVISMELODY6669
  • MEMBER
  • 65 POSTS
Okay thanks, your the best. I'am going to try it.
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Wednesday, September 2nd, 2020 AT 6:00 PM

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