oil pump vs. fuel pump

[So broke]

i have a 95 suburban 2wd. i have had it for about 2 years. no real issues except that i thought it had a oil pressure issue. every few months the oil pressure would drop and the engine would shut off or get close. i would add a quart of oil and it would go back to normal. other than that it started and ran fine. yesterday it just shut off on me and would not restart. it cranks and turns over but will shut off right away. sometimes it will stay running but barely. i got stuck in front of merchant auto and wasn't close to home so i let them push the truck in and take a look. i told them what i thought it was and they ignored me and said it was the fuel pump. and quoted me 1100$ for a fuel pump , fuel filter and relay. (insert butthurt here) so i had it towed home. they still charged me 120 to look at it. i don't have any tools to test the pressure of the fuel. i can hear the pump prime and hum. so i went back to the first thought about fuel pressure and changed the oil pressure switch. now it still starts badly but if you give it gas it will run well. i took off the oil cap and it looks dry. i think it's the oil pump or screen. any ideas?

 

[Horns]

Your oil pump could be pumping out zero oil and the engine would still run. Merchant Auto is a very well known and respected shop through out the whole country. I would take their word for it. I wouldst spend $1200 but that price is probably factory GM parts.

-Sent from my twin turbo Desire using diesel fuel.-

 

[So broke]

i thought that if you had little to no oil pressure that would cut the fuel pump. would that look the same as if the fuel pump was going out? is the fuel pressure the same when you turn on the acc than as when the truck is running?

 

[shelbyt.67]

Yes, the oil sending unit does have a fuel cut off feature. Your pickup screen could be clogged and it could be yer oil pump. changing it would be easy on a 2wd. Also a fuel pressure tester from Harbor fright costs like $20. Way cheaper than $1200.

 

[JollyGreen]

I don't know about the computer cutting the fuel pressure if/when the oil pressure gets low, but $1100 for a new fuel pump is insane. Say the GM pump is $300, which is on the high side, that puts the labor at $800. Even at $120/hr that's 6 1/2 hours of labor. You mean to tell me it would take a good experience mechanic that long to change a fuel pump? I'm not taking anyone's word at that price.

 

[Horns]

Yes, the oil sending unit does have a fuel cut off feature. Your pickup screen could be clogged and it could be yer oil pump. changing it would be easy on a 2wd. Also a fuel pressure tester from Harbor fright costs like $20. Way cheaper than $1200.

Where is the sensor for this at?

 

[So broke]

Yes, the oil sending unit does have a fuel cut off feature. Your pickup screen could be clogged and it could be yer oil pump. changing it would be easy on a 2wd. Also a fuel pressure tester from Harbor fright costs like $20. Way cheaper than $1200.

my sub is 2wd

 

[shelbyt.67]

Where is the sensor for this at?

The oil sending unit/sensor is located at the back of the intake to the right of the dizzy.

 

[shelbyt.67]

my sub is 2wd

Dropping the oil pan on a 2wd is easy. No front diffy to get in the way. Don't need to lift the motor or nuthin. Get a chiltons manual at the local parts shop fer the procedure. Its basically unscrewin the pan bolts and then the pump/pickup screen. Its real easy once u see it. Basic set of sockets will get er done. U will need to get the right pump w/ intermediate shaft and screen if u go that route. The pan gasket should be reusable if its not leakin now.

 

[ChrisAU]

i thought that if you had little to no oil pressure that would cut the fuel pump. would that look the same as if the fuel pump was going out? is the fuel pressure the same when you turn on the acc than as when the truck is running?

You are correct. Its a safety feature, meant to cut the truck off if it rolls over and protect it from an owner who runs it with no oil in it.