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GMC Repair/fuel pump-GMC


Dave wrote at 2006-12-21 01:12:43
I have a 1997 GMC 5.7 2WD. It is the fuel pump. Repalced mine the first time with an aftermarket pump. Went out in 1 year. This time, repalced with OEM pump. Mine would not start after sitting overnight or for a couple days. Same thing, shot a squirt of either down the carb and fired right off and would start everytime after that until it sat awhile again.

br_549 wrote at 2009-12-27 03:14:47
I searched & searched internet & asked questions on this prob from everyone... I had an indication it was fuel pump but wanted almost a definite diagnosis before I invested time & money... so here goes... it did it again on Wed nite, Christmas coming up & Mom & Dad wanting me home for holiday... bound & determined that it was a "voltage" issue that was somehow affecting fuel delivery...

This is what answered my question as symptoms of vehicle 1 (third paragraph)... Thursday morning dropped money for fuel pump (OEM), fuel strainer and fuel filter... threw in front seat & set off to mom & dads... had parts if I had issue!

This morning replaced fuel pump & associated parts and has never started any better... my issue resolved.

It seems that when I placed jumper cables or battery charger it gave pump just enough voltage to increase pump rpms by a few PSI that allowed it to start & run...

Hope this helps a least one person, so God Bless & Good Luck!

bob white auto wrote at 2015-01-02 21:50:58
what about cold start valve there is no choke on f/injection so they use a cold start valve if it runs pumps OK also fuelpump relay is also workink its OK if you can get at it to test pull it out turn key to on with it connected not to start just on it should spray fuel for 2 secondsif it dosent it mighjt be bad pump preasure gauge is a great way to check preaure and volume hope it works out ok BOB WHITE'S AUTO

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Jim Gautreau


I can answer just about any question to do with GM products, mostly Buick, Pontiac, GMC, and Chevy. I was an electrical, trim, and A/C specialist, and I am now a driveabilty specialist at a dealership. I have also done work in all other areas except for transmission overhauls.


6yrs as a dealership technician
ASE Certified Master Technician
GM Mark of Excellence Platinum Award 2005, Gold Award 2004

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