1992 Chevy Blazer On going problems Can't seem to solve

Tiny
RESSAMM20
  • MEMBER
  • 1992 CHEVROLET BLAZER
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 400,000 MILES
Last year I took a trip to Oklahoma. Before the trip I never had any problems with the Blazer. While I was in Oklahoma the truck started to have problems with starting in the morning, but once it was started it would start up with no problems untill the next morning after sitting through out the night. Since I have returned home the truck will not start at all. So far we have replaced:
Fuel Pump; rotor cap; button; spark plugs; spark plug wires; battery; distributor; coil; fuel filter; ignition switch; and the fuel regulator since January and the truck has still not started since. The fuel injector unit (also termed the Spider) was replaced four years ago. The timing has been set. What am I doing wrong?
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Friday, October 1st, 2010 AT 11:06 AM

5 Replies

Tiny
WRENCHTECH
  • EXPERT
All "crank, no start" conditions are approached in the same way. Every engine requires certain functions to be able to run. Some of these functions rely on specific components to work and some components are part of more than one function so it is important to see the whole picture to be able to conclude anything about what may have failed. Also, these functions can ONLY be tested during the failure. Any other time and they will simply test good because the problem isn't present at the moment.
If you approach this in any other way, you are merely guessing and that only serves to replace unnecessary parts and wastes money.

Every engine requires spark, fuel and compression to run. That's what we have to look for.

These are the basics that need to be tested and will give us the info required to isolate a cause.

1) Test for spark at the plug end of the wire using a spark tester. If none found, check for power supply on the + terminal of the coil with the key on.

2) Test for injector pulse using a small bulb called a noid light. If none found, check for power supply at one side of the injector with the key on.

3) Use a fuel pressure gauge to test for correct fuel pressure, also noticing if the pressure holds when key is shut off.

4) If all of these things check good, then you would need to do a complete compression test.

Once you have determined which of these functions has dropped out,
you will know which system is having the problem.
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Friday, October 1st, 2010 AT 11:21 AM
Tiny
RESSAMM20
  • MEMBER
Thank you for the response.
What we have found is a dry condition in the cylinders. I can detemine this as I have pulled the #1 plug several times and it is completely dry even after several attempts to start it. I have no way of testing the injector pulse but we have voltage at the injector itself. Personally I have come to the conclusion it is the injector unit that has failed but I dont know of any testing I can do without taking to a shop. Thanks again
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Friday, October 1st, 2010 AT 12:02 PM
Tiny
WRENCHTECH
  • EXPERT
That would be pretty foolish to come that conclusion.
Someone needs to do some testing, whether it be you or someone you pay to do it.
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Friday, October 1st, 2010 AT 12:05 PM
Tiny
RESSAMM20
  • MEMBER
What testing can be done to make sure the fuel injection unit is working? Can you list alternative issues that may be causing no fuel to be in the cylinders? The fuel pressure is good since the fuel pump was replaced (it has been tested with a fuel pressure gauge). Spark has also been tested and is fine. Power is going to the fuel injector unit, but it is unknown if the unit is functioning properly because we do not know of any test without taking it to a shop. Compression has also been tested and is good.

Thanks once agian for your response
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Saturday, October 2nd, 2010 AT 8:03 AM
Tiny
WRENCHTECH
  • EXPERT
What is the fuel pressure?

As yet no one has confirmed that injector pulse signal is being delivered to the injectors. This needs to be tested before even considering that the injector could be faulty.
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Saturday, October 2nd, 2010 AT 8:32 AM

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