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1994 gmc 4.3L will not start and run..


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jamesg1551
User

Aug 16, 2021, 11:06 AM

Post #1 of 4 (501 views)
1994 gmc 4.3L will not start and run.. Sign In

 i replaced with new: distributor,pcm sent off and tested(good),injectors,pressure regulator,fuel pump,plug wires,dist. cap,coil and timing chair set. has fire and injectors working. hits 2 0r 3 times, put pettle on floor will hit 2 or 3 times and try to run and stops. tapped on convertor herd nothing falling. don't know whats next.. please help.any idea is welcome. now have to much money and time in it to give up... Help?

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(This post was edited by Hammer Time on Aug 16, 2021, 11:45 AM)


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Aug 16, 2021, 11:50 AM

Post #2 of 4 (482 views)
Re: 1994 gmc 4.3L will not start and run.. Sign In

I deleted your email address from the question. The spammers would tear you up with that.

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.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



jamesg1551
User

Aug 16, 2021, 1:44 PM

Post #3 of 4 (462 views)
Re: 1994 gmc 4.3L will not start and run.. Sign In


In Reply To
I deleted your email address from the question. The spammers would tear you up with that.

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.


In Reply To
yes have spark, injectors working, lowest compression cylinder is 125 all within 15%. balance shaft motor


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Aug 16, 2021, 1:47 PM

Post #4 of 4 (458 views)
Re: 1994 gmc 4.3L will not start and run.. Sign In

What's the fuel pressure



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.







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