Main IndexAuto Repair Home Search Posts SEARCH
Who's Online WHO'S
Log in LOG

1990 Chevy S10 fuel pump

  Email This Post

New User

Mar 31, 2012, 8:49 PM

Post #1 of 8 (2938 views)
1990 Chevy S10 fuel pump Sign In

1990 Chevy S10 pickup 4.3V6 170K miles automatic. Truck was running fine. Had a mechanic install a new fuel pump, fuel pump relay, tank strainer, and in-line fuel filter a week ago as a preventative measure because of age and milage. Mechanic used all NAPA parts.
Problem: engine will not crank in afternoon without manually pouring gas into trottle body.

Info: Trucks sits at night at work for 13 hours and cranks fine in morning. Truck sits at home 10 hours during day and will not crank in afternoon without adding gas.

What I've done: Replaced new fuel relay with another new fuel relay. Have inspected, cleaned, and performed continuity tests on all wiring connectors (except the actual connection at the pump). Checked continuity of applicable fuses. Have performed all diagnostic tests per a Haynes manual. They indicate an open in the circuit between relay and pump. I believe the problem to be either a defective new fuel pump or the wiring connection at the pump is bad. Mechanic is not sure but will take truck back and trouble shoot problem.

Wanted to get you guys opinion/advice before preceding further. Thanks, FredM

Tom Greenleaf
Ultimate Carjunky / Moderator

Mar 31, 2012, 8:57 PM

Post #2 of 8 (2934 views)
Re: 1990 Chevy S10 fuel pump [In reply to] Sign In

Let you mechanic trouble shoot this but know that there are plenty of defective new parts. Seems by your description that the fuel pump just is pumping borderline pressure. Stinks to pay more but with those one from GM - OE seem to do the best,

Long retired now

Hammer Time
Ultimate Carjunky / Moderator

Mar 31, 2012, 9:09 PM

Post #3 of 8 (2918 views)
Re: 1990 Chevy S10 fuel pump [In reply to] Sign In

All you can do is test the fuel pressure during this failure.


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.

New User

Mar 31, 2012, 9:31 PM

Post #4 of 8 (2904 views)
Re: 1990 Chevy S10 fuel pump [In reply to] Sign In

Thanks for the reply. I agree about the GM parts. NAPA was $40 for the pump and Chevy dealer was $78 for AC/Delco. At my age, it's not the money but avoiding aggravation as much as possible. Only reason I let mechanic use NAPA was that he was adament about using their parts. Wish I had insisted on the AC/Delco.

Tom Greenleaf
Ultimate Carjunky / Moderator

Mar 31, 2012, 11:07 PM

Post #5 of 8 (2881 views)
Re: 1990 Chevy S10 fuel pump [In reply to] Sign In

I have had great luck with parts from NAPA but have noticed in this dog-eat-dog world that some stuff has lost some quality to lower prices or lose market share. Still unknown if this is the whole trouble but not unheard of as said,

Long retired now

New User

Apr 3, 2012, 12:19 PM

Post #6 of 8 (2811 views)
Re: 1990 Chevy S10 fuel pump [In reply to] Sign In

To All:
This info is per the mechanic.
The sending unit in the tank that the pump mounts to was bad. It was causing the pump voltage supply to be 11.6V instead of the 12V required.
He said it could have happened due to its age or simply from being jostled around while replacing the pump. I haven't gotten the truck back yet, just a phone call, but I am assuming at this time that he is correct.
(For info, because the "new" NAPA pump has been apparently trying to operate at low voltage and that I simply don't like NAPA, I got the new ACDelco pump from Chevy and told him to install that while the tank is out!)

Tom Greenleaf
Ultimate Carjunky / Moderator

Apr 3, 2012, 12:49 PM

Post #7 of 8 (2806 views)
Re: 1990 Chevy S10 fuel pump [In reply to] Sign In

Not sure 11.6 would be the total problem but your mechanic seems to have found the trouble there. Whole unit from GM has the least troubles so far to me and said by others here all over the place. No bargains in doing something twice to save a buck as we know,

Long retired now

Veteran / Moderator

Apr 3, 2012, 5:06 PM

Post #8 of 8 (2796 views)
Re: 1990 Chevy S10 fuel pump [In reply to] Sign In

They did have problems with the electrical pass thru terminals on the top of the sender melting causing high resistance in the pump circuit.

Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.

1990 Chevy S10 fuel pump

  Email This Post

Latest Forum Post
1963 FORD Falcon / installed new tank and sending unit. Gauge shows past full an...
Hi, Ii have problem with my chevy cruze 2011, my car just 37000km. Before 2 week...
i have a 1995 Eagle Talon. my car was overheaving and leaking antifreeze. i cha...
Re: 2000 Buick Century 3.1L 120,000m - I‘m having problems replacing the ...
Actually the only way I could get any pedal at all (and enough pressure to turn...
OK, so I need to reopen this thread and take back my kudos from yesterday, sorry...

Feed Button

Used Car Search
Used Car Price Ranges:
Under $5,000

Over $45,000
Search used Cars By Manufacturers:
Used Acura
Used Audi
Used BMW
Used Buick
Used Cadillac
Used Chevrolet
Used Chrysler
Used Dodge
Used Ford
Used GMC

Used Honda
Used Hyundai
Used Infiniti
Used Jaguar
Used Jeep
Used Kia
Used Land Rover
Used Lexus
Used Lincoln
Used Mazda
Used Mercedes-Benz

Used Mitsubishi
Used Nissan
Used Porsche
Used Saab
Used Scion
Used Subaru
Used Suzuki
Used Toyota
Used Volkswagon
Used Volvo
2010 Honda Civic
2004 Jeep
2012 Mustang
1997 Honda Cr-V
2010 Toyota Prius
2010 BMW 328

Automotive Forum Categories
Automotive Repair
Auto Body Repair and Refinishing
AC Auto Repair Help Forum
Automotive Wiring and Electrical

Auto Insurance and Car Financing
Automotive World
Brake Systems
Car Stereo Repair Advice
Car Troubleshooting
Engine and Car Noises
Engine Fault Codes
Engine Troubleshooting
Exhaust System Repair

Steering and Suspension
Tricks of the Trade
General Discussions
Car Shows and Events
The Bargin Bin
Motor Vehicle Inspection
Car Care Tips
Traffic Ticket Help
Car Racing

Gasoline, Motor Oils, Concept Cars
Remote Control Cars and Vehicles
Truck Repair
Truck Repair Advice

Truck Engine Repair
Truck Suspension Repair
Motorcycle Repair
Motorcycle and ATV Repairs

Motorcycle Body Repair
Motorcycle Clutch Repair
Motorcycle Engine Repair
Motorcycle Seat Repair
Car Forum Posts - Sitemap

Search for (options) Privacy