Fuel issues

royaldjasperdd

02-03-2010, 10:24 AM

My son's 1996 s10 had an intermitten fuel issue- previously tapping the tank or shaking the big connector near the firewall a little would "heal" it for a while. Then it got worse... Replaced the fuel pump, wired around the slightly corroded connector, checked the relays and it is still the same. Especially if you let it die ( new driver on a standard!) you are not going anywhere without 10-15 minutes of fiddling around and then its only 50/50. Any ideas?

MT-2500

02-03-2010, 03:45 PM

My son's 1996 s10 had an intermitten fuel issue- previously tapping the tank or shaking the big connector near the firewall a little would "heal" it for a while. Then it got worse... Replaced the fuel pump, wired around the slightly corroded connector, checked the relays and it is still the same. Especially if you let it die ( new driver on a standard!) you are not going anywhere without 10-15 minutes of fiddling around and then its only 50/50. Any ideas?

What engine?
Did you use the delphi fuel pump or junk aftermarket?
Did the fuel pump come with a new wiring connector?

Does engine crank over good?
Does it get spark to all plugs when no start?
Check fuel pressure when no start?
Does the fuel pump get 12 volts when no start?
Is tank ground good?

Can you hear key on 2 second fuel pump prime up?
Does fuel pump run engine cranking?

Post back fuel pump pressure readings and what engine you have.

royaldjasperdd

02-03-2010, 04:04 PM

Thanks MT for the quick response- here comes a long answer
4 cyl engine 2.2l, bought a rebuild kit cheap- because a delphi is the 1st dead one and bought a used delphi from salvage yard- it was doa so hooked the old one back up and it sqirted 25 ft, so replaced worked 2-3 months before permanent death.
When it won't start there is no power to the pump- nor at the firewall connector. (kept the old delphi incase it wasn't the problem but the kit was only $24)
Ground is good and tight at the pump
I really thought the pump was at issue because for a while a little bang on the tank got it going, other times only fooling with the connector/relays will.
I noticed that while using a test light on the connector that sometimes worked so I jumpered around the connector- worked 3 times and now nothing.
Previous owner had similiar issues but did not inform me- 1500 dollar truck!
Next I'm going to try jumping around the relay and then the oil P switch unless you have a better idea- Here in NW arkansas the good pumps were around 400 at AZ and Oreilly- so I felt compelled to go cheap even if it was temp. relief. WHEN it runs it runs like as good as these trucks can. Pulls small boats/jetski great.

MT-2500

02-03-2010, 04:39 PM

Thanks MT for the quick response- here comes a long answer
4 cyl engine 2.2l, bought a rebuild kit cheap- because a delphi is the 1st dead one and bought a used delphi from salvage yard- it was doa so hooked the old one back up and it sqirted 25 ft, so replaced worked 2-3 months before permanent death.
When it won't start there is no power to the pump- nor at the firewall connector. (kept the old delphi incase it wasn't the problem but the kit was only $24)
Ground is good and tight at the pump
I really thought the pump was at issue because for a while a little bang on the tank got it going, other times only fooling with the connector/relays will.
I noticed that while using a test light on the connector that sometimes worked so I jumper ed around the connector- worked 3 times and now nothing.
Previous owner had similiar issues but did not inform me- 1500 dollar truck!
Next I'm going to try jumping around the relay and then the oil P switch unless you have a better idea- Here in NW arkansas the good pumps were around 400 at AZ and Oreilly- so I felt compelled to go cheap even if it was temp. relief. WHEN it runs it runs like as good as these trucks can. Pulls small boats/jetski great.

At the fuel pump relay check for good 12 volts on orange wire.
There is a red prime wire/connector there you can jump fuel pump.
Or jumper 12 volts to fuel pump feed gray wire.
With key on 2 second prime up or engine cranking you should have 12 volts on gray fuel pump feed wire and the prime up connector.

Also confirm good spark to plugs when cranking.
No spark will cause fuel pump not to run on engine cranking.

Check them wires you redone real good.
With fuel pump jumped see of it runs and has 41/47 lbs of fuel pressure.

MT-2500

02-03-2010, 04:46 PM

The oil pressure only feeds power to gray fuel pump feed wire oil pump after engine oil pressure is up.
But only if fuel pump relay fails does the oil pressur switch run fuel pump.

CONFIRM GOOD FUEL PRESSURE AND GOOD SPARK WHEN NO START.
And make sure relay is getting 12 volts on power feed wire to it.

royaldjasperdd

02-03-2010, 05:10 PM

I will not be able to try this until SAt but will let you know what happens- thanks again

MT-2500

02-03-2010, 05:36 PM

Good luck.

royaldjasperdd

02-15-2010, 08:50 AM

Ok- I tracked everything and all seemed to check out as best I could tell, but I noticed the relays in the glovebox were pretty loose- I took them and splayed the legs on each so that they were pretty hard to put back in. I also rewired the big connector on the firewall- eureka! So far in limited usage no more problems!

Darren509

02-15-2010, 07:31 PM

F.Y.I. In case you ever do need a pump in the furure, try looking at autopartswarehouse.com I believe they are about 260...good luck.

Rick Norwood

02-15-2010, 07:42 PM

F.Y.I. In case you ever do need a pump in the furure, try looking at autopartswarehouse.com I believe they are about 260...good luck.
If they are not AC-Delco Delphi pumps you're wasting your money!

Darren509

02-15-2010, 09:29 PM

Darren509

02-15-2010, 09:30 PM

My copy and paste method diddnt work that good, but yes, its a Delphi. For 282.

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