haven't been on in a long time so if my sig isn't there anymore...
1988 TPI 5 liter in an 84 s-15. TPI has ALL stock wireing except for under dash(power for injecters and that goodness) and the fan control. by stock wireing i mean its wired stock, i did replace connecters and stuff like that...


i've gone through 4 pumps in less then a year(they were all under warrenty at the parts store so i didn't pay 50 billion dollers )

i have NO idea whats going on here! voltage is fine back by the pump. ground is great. cleaned it each time i put a pump in(even though it was clean from the first time), wireing is fine, no possible way for shorts...

whats goin on here?! last time my pump went i did notice that my oil pressure switch was disconnected for some reason. i plugged it back in and it kept constant power to the pump so replaced it. it works fine now. would that have caused all these pumps to go and you think i'm good to go now? my pump now i noticed makes a whining noise, not to load, after driving around for a bit but if i shut the truck off and start it again theres no whining...

and just so i know, how EXACTLY does the whole fuel pump power supply system work? i see it as, the relay provides those 2 seconds to prime the system at start up and also provides power when starting and running. but ALSO the oil pressure switch provides power when the oil pressure gets to a certain point. but isn't that switch supposed to shut off power to the pump in the event of low oil pressure? how could it do that if the relays also providing power? this wireing harness was messed with a bit from the previous owner(well, 2 owners ago, my brother had this engine before me but he didn't mess with anything ) so thats why i'm asking how the power supply works...

i did a search and this and VATS has something to do with turning the relay on? well i don't have VATS. do i need that?

also during that search i see that a crushed fuel line can ruin a pump pretty quickly. well i have 3/8 inch line all the way up to my -06 SS braided line. back by the tank i bent the line out with a pipe bender for the fuel filter, kind of like 2 L's to get the line away from the frame so i could fit the pump, would that liiiiiitle bit of restriction from bending the pipe cause the pump to go? its not nearly kinked but the tool did a kind of cheap mandrel bend(the kind where theres a bit of restriction on the inside of the turn?)

the tank has no dirt in it either. a good 40-45 PSI that wa cheaked with 2 seperate guages.

SORRY FOR THE LONG POST BUT I'VE BEEN POSTING ON S-SERIES AND V8S10 AND NOONE CAN HELP ME. I'VE DONE EVERYTHING THEY'VE TOLD ME AND CAME UP WITH NOTHING. I'M STUMPED

 

The auxilliarry oil pressure switch is NOT a safety shut-off switch for low oil pressure. It is merely a redundant path for power to the pump in the event of a relay or ECM output failure.

The ECM will operate the pump power relay for two seconds when the ignition is turned on. It will do this every time the ignition is turned on after having been off for at least 20 seconds.

The ECM will also operate the pump power relay whenever it receives distributor reference pulses, so as soon as the engine is cranked for starting, the pump relay should close.

The oil pressure switch will provide power to the pump when oil pressure increases to anything over 7 PSI, and will maintain power until oil pressure drops below 4 PSI.

It's all fairly clear in the schematic:



Any restriction will increase load on the pump, including a filter, the supply line set, having excessive regulated pressure, intake "sock" filter restriction, and restriction in the fuel return line set.

If the standing pressure is 40-45 PSIG, that should be correct. Actually, the design pressure is 37 PSIG ±3 PSIG with the FPR under vacuum, and 44 PSIG ±3 PSIG with no vacuum.

 

Do you have a properly vented tank? If you JUST have feed and return, then the answer is no. The tank will take on a vacuum as the fuel is used, and quickly ruin pumps.

 

well i put a new filter in today to make sure. didn't do anything. also put all enw relays in because the mounting ears were snapped on mine. both things didn't do anything.

i also have a filter ment for a carb up by the engine.

JEGS High Performance - Russell Competition Fuel Filters


that one to be exact. could that be restricting the flow at all? it is ment for high flow and all...it is a pretty open screen too.

my return line is half a 3/8" line and half a 5/16" line(i can't find AN fittings for a 5/16" line) is that too small? the supply line is all 3/8"

i went and got a new pump today, becuase its all under warrenty and all, and got a new sock too.

i do have a vent line and all the camaro lines on the canister and its all hooked up correctly as far as i know. not alot of vacum gets sucked in when i release the cap either. so i'm assuming its working correctly. how could i test the vacum opperated valve(forget the name) and the purge solinoid?

 

I once had a defective oil pressure switch in my firebird, the switch wasn't opening when the oil pressure bled off and caused the fuel pump to run constantly even after the engine was shut off. I had to unplug the ops to turn the pump off.

 

Ditto

 

yea its a new switch too. my switch did that when i noticed it was unplugged for some reason about a week ago. then i replaced it and its all fine now. would that have caused this pump i just replaced today go? no oil pressure switch?

i replaced the pump again today. cause one, its free(warenty at NAPA), two, i could get new wires(i've been told a couple times that GM had numerous problems with the wiring from the sending unit to the pump), and three, gave me a chance to look over the wireing. i did noticed the ground was corroded inside the insulation on about half the wire. so i redid that, ran a new ground, and where it attachs to the sending unit, i soldered TWO wires on instead of the stock single one.

today i also redid the battery ground. it was fine, but i took apart where it attachs to the frame, ground down the paint i covered it with to prevent rust, and made the contact area bigger and better by putting a fender washer underneath the ground with one of those washers with the little teeth underneath that. so ALL my ground are good. i re-did all them, all over, in the past 2 days.

so what else could this be. i don't need this new pump going out on me now too...