Faulty fuel pump or carburetor

Tiny
CONSTANT GUAY
  • MEMBER
  • 1993 CHEVROLET TRUCK
  • V8
  • 2WD
  • AUTOMATIC
  • 104,600 MILES
We enjoyed our motor-home for the past five years. The speedometer shows 165,000 km, it functions very well and gives us great pleasure.
Unfortunately the engine stopped on the highway a week ago and we had to be towed. The mechanic at the garage found and repaired the lack of current to the gas pump. We got back home from there without a problem until the next morning when we tried to re-start the vehicle; it started but the engine did not function until we poured a couple a table spoons of gasoline in the carburetor, and it stayed that way every time we want to start the vehicle. The gas pump is functioning good and shows a pressure of 20 psi. At start, but twelve hours after the vehicle was stopped the pressure dropped to 10 psi. We checked all the fuses, all okay.

This is a Chevrolet 1993, 7.4 litres, 454, with a registration #1GBJP37NOT3307605.

The gas reaches the carburetor without problem, but it appears that a last valve on the carburetor does not open until the engine starts. Could it be a relay problem?
If not what could it be? Could you help us resolve this problem? We would really appreciated it.
Thank you very much for the attention given to our request.
Constant Guay
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Saturday, October 1st, 2016 AT 11:14 AM

7 Replies

Tiny
HMAC300
  • EXPERT
It may be the accelerator pump or the float is not high enough or rotted out in center. If you get gas to carburetor with at least 4 psi is good enough for a carburetor. It is probably time for a carburetor rebuild.
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Saturday, October 1st, 2016 AT 12:58 PM
Tiny
CONSTANT GUAY
  • MEMBER
Thank you for your advice, but it did not solve the problem. You have to know that the engine work with TbI so it has nothing to do with the float. C. Guay
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Sunday, October 2nd, 2016 AT 6:47 AM
Tiny
HMAC300
  • EXPERT
With TBI the fuel pressure should be 9-11 psi also if no signal from ignition TBI will not fire the injectors. Try scanning for codes cross A and B on aldl which is where you get codes to read then turn key on and see if you have any with check engine light. Also check vacuum lines as line to map sensor if old will suck together and map cannot work.
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Sunday, October 2nd, 2016 AT 7:45 AM
Tiny
CONSTANT GUAY
  • MEMBER
Thank you for your answer, I will take your suggestion and check it out in my spare time.
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Saturday, October 8th, 2016 AT 12:30 PM
Tiny
KEN
  • ADMIN
Here is a guide to help you

https://www.2carpros.com/articles/buick-cadillac-chevy-gmc-oldsmobile-pontiac-gm-1983-1995-obd1-code-definitions-and-retrieval-method

Please let us know what you find so it will help others.

Best, Ken
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Sunday, October 9th, 2016 AT 12:20 PM
Tiny
CONSTANT GUAY
  • MEMBER
After many tests and searthes we found out that the filter fuel filter was defective.
Many thanks for your implication
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Wednesday, October 19th, 2016 AT 2:05 PM
Tiny
KEN
  • ADMIN
Good to hear, please use 2CarPros anytime we are here to help.

Best, Ken
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Wednesday, October 19th, 2016 AT 6:43 PM

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