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Mr_Wrench
Mr_Wrench, ASE Certified Technician
Category: Chevy
Satisfied Customers: 395
Experience:  24yr gm Drivability & Electrical
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I have a 1995 5.7 Tahoe that is a no start. It has no spark

Customer Question

I have a 1995 5.7 Tahoe that is a no start. It has no spark and no injector pulse. All fuses are good, ECM grounds are good, distributor replaced including module (4x), new ECM, coil, and ignition switch. As far as I can tell it does not have a security system. It started as an occasional no start and then went completly out.
Submitted: 6 years ago.
Category: Chevy
Expert:  Mr_Wrench replied 6 years ago.
Hello! Do you know if you have engine rpm while cranking on the scan tool?
Customer: replied 6 years ago.
Unfortunatly, I no longer have a scan tool. I closed up a shop ten years ago and am trying to fix this on my own. I do have a snap on timing light that picks up rpm and I used it. It appears to be picking up a 1200 rpm crank speed.
Customer: replied 6 years ago.
Maybe a coincidence but this problem began shortly after pressure washing the engine.
Expert:  Mr_Wrench replied 6 years ago.
No sure than, The crank sensor has been a problem with some or even the connector it self, But I don't think it had any cranking rpm when the crank sensor wasn't working. I would still look at the wires.
Customer: replied 6 years ago.
I was under the impression that this did not have a crank sensor. It is not on the timing cover or front of the engine anywhere.
Expert:  Mr_Wrench replied 6 years ago.
It does ! I looked it up in alldata, I wasn't sure either.
Customer: replied 6 years ago.

Can you tell me the location?

Customer: replied 6 years ago.
Even the dealership is not showing a crank sensor. This problem is absolutely driving me crazy.
Expert:  Mr_Wrench replied 6 years ago.
sorry I looked up a 96 R motor, yours is a 95 k motor, i need to check on this I'll be back.
Customer: replied 6 years ago.
Thanks for your help. I will try anything at this point.
Expert:  Mr_Wrench replied 6 years ago.
Is there power on one side of each injector with a test light,? I know you said it had no pulse.
Customer: replied 6 years ago.
Yes it has steady power on one side in key on and crank mode. Nothing on other side in either.
Customer: replied 6 years ago.
Any other ideas? I have not used a sight like this before and I'm not sure how much I get for the $15. I will be able to pay some more if we can get this figured out. Obviously, I have already spent a lot on trying to do it myself. I have never had a simple system like this give me so much grief. I know the security systems can can problems but this does not have the security light come on in the key on position and I dont know how else to see if it has a system.
Expert:  Mr_Wrench replied 6 years ago.
You definably have a problem, Here is what I would try, At the pcm w/key on try momentary ground the pins that pulse the injectors looks like pin a8 dark green and a16 dark blue, to make sure the wiring is good, I can't help but think the distributor is the problem area, But you have changed the it, It's real hard to tell some one all the tests that I would just do normally.
Expert:  Mr_Wrench replied 6 years ago.
I have another idea, pull the dist cap, take a test light with the clip end to battery power and the key on touch the pickup coil leads that go into the ign. module and see if you hear the coil activate or inj. noid pulses.
Customer: replied 6 years ago.

Ok, I did the second test and yes one injector pulsed when I touched and released on the green wire of the pickup coil. Nothing on the other wire. Should I still do the first tests on the PCM?

Expert:  Mr_Wrench replied 6 years ago.
Yes just to make sure wires are good
Customer: replied 6 years ago.
#8 did nothing and #16 fired the same injector as when I tested it at the module.
Expert:  Mr_Wrench replied 6 years ago.
I am not sure now, When you are cranking it it should fire at least the one injector, I just don't think I can help with this one, You will probably need to take it in to shop. sorry
Customer: replied 6 years ago.
Is it possible that I got two bad distributors? does all the signs point to the disributor still?
Expert:  Mr_Wrench replied 6 years ago.
I can't see how you could have 2 bad distributors, But the test you did with the test lamp tells me that the module and all wires are ok at least to the one injector,It rules out everything except for the pick up coil and the distributor shaft, If you have the old distributor you could plug in the wire and just turn the shaft to simulate eng. cranking yo check everything.The distributor needs to have a good ground also.
Mr_Wrench, ASE Certified Technician
Category: Chevy
Satisfied Customers: 395
Experience: 24yr gm Drivability & Electrical
Mr_Wrench and 5 other Chevy Specialists are ready to help you
Customer: replied 6 years ago.
Thanks for the extra effort on this. I think it might be worth exchanging the distributor 1 more time as a last effort since I dont have the original.
Expert:  Mr_Wrench replied 6 years ago.
Good Luck I hope that is it, I just can't see it .

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