Rough running

Tiny
WEEKEND WRENCHER
  • MEMBER
  • 1993 BUICK GRAN SPORT
  • 3.8L
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 85,644 MILES
Starts but runs real rough until it shuts off. Can keep it running by pumping the gas peddle fast.

If I release the pressure on the shrader valve with key on will it continuously shoot out fuel?
Wednesday, July 19th, 2017 AT 10:49 PM

7 Replies

Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Check fuel pressure with a gauge and scan for codes by crossing A and B with a paper clip with key on then either go to where are codes are under repair guides or get back with the number. auto parts rent gauge which should range 41-47 psi no less. Also, check for a vacuum leak as some of the older Buick's would crack the intake being plastic. See link.
https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator
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Thursday, July 20th, 2017 AT 5:35 AM
Tiny
WEEKEND WRENCHER
  • MEMBER
  • 4 POSTS
Thank you it gave me a direction to go rented a pressure tester only getting 10 - 12psi at the Schrader valve. C/O pump and in line filter?
Thanks
The weekend wencher
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Friday, July 21st, 2017 AT 5:07 PM
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Yep sounds like a fuel pump
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Saturday, July 22nd, 2017 AT 6:04 AM
Tiny
WEEKEND WRENCHER
  • MEMBER
  • 4 POSTS
Hi reading the istructionpapers that came with New fuel pump in said a bad oil pressure sensor could also cause a problem is this so?
Thanks the W.E.W.
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Friday, July 28th, 2017 AT 5:17 AM
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
I don't think so if it powers up when you turn key on andyou only get 10-12 psi then it's the pump. The oil pressure switch keeps it running when you start the car
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Friday, July 28th, 2017 AT 6:35 AM
Tiny
WEEKEND WRENCHER
  • MEMBER
  • 4 POSTS
Hi changed the fuel pump, retested fuel pressure now reads 47-50psi running great thanks HMCA 300 you were most helpful thanks again.

The WeekendWrencher.
Oh yea now the Little woman wants to for drive on Sunday.
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Saturday, July 29th, 2017 AT 7:47 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 42,889 POSTS
Nice work, we are here to help, please use 2CarPros anytime.

Cheers, Ken
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Sunday, July 30th, 2017 AT 5:44 PM

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