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Do I really need the Fuel Pump Oil Pressure switch??

Clod_King said:
I have this problem!
My trucks engine will only fire around 200 Kpa (roughly 30 psi i think).
Click to expand...

I'm also having a similar problem with one of my other trucks. I have yet to begin trouble shooting. A few questions for you. Are you sure it's the pump that's not kicking in until 30 PSI and not the injectors not firing?

You might try disconnecting the puel pump lead back at the fuel tank and put a tester on the hot side while someone cranks the engine. If you get power right off the bat, it isn't the fuel pump.

If that's the case, plug the fuel pump back in and pull off the air cleaner lid. Take a look at the injectors while someone cranks. Are you seeing fuel squirting into the throttle body from the get go or does that not happen until you reach 30 psi?

That's as far as I got with my truck. My issue is the injectors not firing. I'm not sure why .... maybe next weekend I'll start looking closer at this problem.

Good Luck,
Post up if you figure it out before I do.

Eric M.
 
What is this 30psi that is being talked about now? If it is fuel pressure, TBI does not run that high. TBI pumps are low pressure between 7-14psi roughly. The only way you'll get pressures any higher than that is if you've swapped in a high pressure pump.
 
4X4HIGH said:
What is this 30psi that is being talked about now? If it is fuel pressure, TBI does not run that high. TBI pumps are low pressure between 7-14psi roughly. The only way you'll get pressures any higher than that is if you've swapped in a high pressure pump.
Click to expand...

Woops, sorry, we got side tracked for a few posts there. Clod_King had another issue which I was commenting on. It's a page back. The 30 PSI we're talking about is oil pressure.

Hi Jacked my own thread .....

Eric M.
 
So is the purpose of the oil pressure/fuel switch to keep the fuel pump running if the relay fails?
 
I made up my mind. I'm gonna dump the switch. Two of these switches have failed on me in the last 3 years. Over the last 20 years I've seen a real decline in the quality of aftermarket parts. Dorian may be correct that a Delco unit may be of higer quality, but considering it is for an older vehicle, GM may have begun relabeling the same part I get from Kragens.

It is a back up system that is causing more problems than the system it is backing up. Of all the parts I might want to back up, the fuel pump relay is pretty low on my list. I'm going to take the advice of one of the above posts and install a back up fuel pump relay next to the stock one. It's cheaper and a hell of a lot easier to install than the switch. Granted, the truck will still stall if the relay goes out until I swap it over, but my truck was stalling when the switch shorter out.

I'll post up if this turns out to be the wrong decision.

Eric M.
 
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