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95 Chevy k3500 Silverado 7.4 won't idle poor acceleration


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95 Chevy k3500
Novice

Jun 25, 2017, 3:04 PM

Post #1 of 15 (775 views)
  post locked   95 Chevy k3500 Silverado 7.4 won't idle poor acceleration  

Had to replace distributor pick up went bad. Had a bad explosion when installing new distributor. I have replaced the I a c (a couple of them) m a p and the throttle position sensor and computer and changed the prom to the new computer. No codes recording at this time


Hammer Time
Ultimate Carjunky / Moderator
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Jun 25, 2017, 3:25 PM

Post #2 of 15 (770 views)
  post locked   Re: 95 Chevy k3500 Silverado 7.4 won't idle poor acceleration  

So, what is the issue now? What is your question?

You DO realize you need a professional scan tool to install that distributor.



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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.



95 Chevy k3500
Novice

Jun 25, 2017, 3:35 PM

Post #3 of 15 (764 views)
  post locked   Re: 95 Chevy k3500 Silverado 7.4 won't idle poor acceleration  

Won't idle at start up when warmed idle is up and down and stalls sometimes when coming to a stop and poor acceleration. Also I have replaced plugs and wires. I set the timing with the wire unplugged to the computer as suggested in the repair manual.


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Jun 25, 2017, 3:40 PM

Post #4 of 15 (760 views)
  post locked   Re: 95 Chevy k3500 Silverado 7.4 won't idle poor acceleration  

Yes, you're right. I thought it was a later model.

Double check your firing order and wire locations.






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

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.



95 Chevy k3500
Novice

Jun 25, 2017, 3:50 PM

Post #5 of 15 (756 views)
  post locked   Re: 95 Chevy k3500 Silverado 7.4 won't idle poor acceleration  

I have checked and rechecked all the wires. I have checked all the sensor wires back to the computer with a tester


95 Chevy k3500
Novice

Jun 25, 2017, 3:55 PM

Post #6 of 15 (754 views)
  post locked   Re: 95 Chevy k3500 Silverado 7.4 won't idle poor acceleration  

Also have a popping in the motor when trying to make hard acceleration this happens when transmission shifts into next gear


Hammer Time
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Jun 25, 2017, 4:01 PM

Post #7 of 15 (748 views)
  post locked   Re: 95 Chevy k3500 Silverado 7.4 won't idle poor acceleration  

Have you checked for codes?
Double check your timing again.
Check your fuel pressure, noting what it does when shut off.



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

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.



95 Chevy k3500
Novice

Jun 25, 2017, 4:12 PM

Post #8 of 15 (742 views)
  post locked   Re: 95 Chevy k3500 Silverado 7.4 won't idle poor acceleration  

I have rechecked the timing its set at 4 degrees btdc. I don't have fuel pressure port . I have a snap on scanner it doesn't show fuel pressure it has fuel trim it is between 154 @start up and goes down to 137 does that help Idk what fuel trim number should be


Hammer Time
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Jun 25, 2017, 4:17 PM

Post #9 of 15 (739 views)
  post locked   Re: 95 Chevy k3500 Silverado 7.4 won't idle poor acceleration  

Are you reading block learn or integrator? Long term or short term?



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

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.



(This post was edited by Hammer Time on Jun 25, 2017, 4:18 PM)


95 Chevy k3500
Novice

Jun 25, 2017, 4:27 PM

Post #10 of 15 (733 views)
  post locked   Re: 95 Chevy k3500 Silverado 7.4 won't idle poor acceleration  

Not sure what that is


Hammer Time
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Jun 25, 2017, 4:31 PM

Post #11 of 15 (727 views)
  post locked   Re: 95 Chevy k3500 Silverado 7.4 won't idle poor acceleration  

There is a short term reading and a long term reading. In the early years they called it block learn and Integrator. More recently it is called long term and short term fuel trim. I need to know if that reading was from the short term or long term.



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

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.



95 Chevy k3500
Novice

Jun 25, 2017, 5:02 PM

Post #12 of 15 (723 views)
  post locked   Re: 95 Chevy k3500 Silverado 7.4 won't idle poor acceleration  

The scanner is an older snap on how can I find out which one it is


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Jun 25, 2017, 5:06 PM

Post #13 of 15 (721 views)
  post locked   Re: 95 Chevy k3500 Silverado 7.4 won't idle poor acceleration  

There is a label next to the number. How did you know it was fuel trim? What exactly did it say. The acronym should start with either LT or ST or BLN or INT.

If you are using an MT2500, it should tell you that.



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

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.



95 Chevy k3500
Novice

Jun 25, 2017, 5:22 PM

Post #14 of 15 (715 views)
  post locked   Re: 95 Chevy k3500 Silverado 7.4 won't idle poor acceleration  

It's a 2597-2995 snap on it is long term


Hammer Time
Ultimate Carjunky / Moderator
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Jun 25, 2017, 5:30 PM

Post #15 of 15 (709 views)
  post locked   Re: 95 Chevy k3500 Silverado 7.4 won't idle poor acceleration  

OK, that helps.
Your scanner is a 2500 with graphing nicknamed the brick.

The center or ideal point is 128. Anything higher than that and the computer is adding fuel to overcome a lean mixture. Anything less than 128 and the computer is taking fuel away because it's too rich.

Your's is reading high which means you have a lean mixture for some reason. First use the scanner and verify temp reading for the ECT and IAT. They should match each other if the engine hasn't been running.

If nothing found there, look for other possible reasons. Look at both fuel injectors with the engine running and make sure you are getting a good, steady pattern. Check for any possible vacuum leaks.

You still may have to test fuel pressure. They make an adapter that goes in place of the fuel filter with a service port.



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

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.



(This post was edited by Hammer Time on Jun 25, 2017, 5:35 PM)






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