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Fuel Pump Pressure
Posted: Thu May 05, 2005 2:52 pm
by Dreded
Can someone take a quick look in a shop manual and check to see what pressure the 1990 intank fuel pump puts out. I noticed there is no pump on the frame rail anymore in the '90.
Posted: Thu May 05, 2005 8:17 pm
by DBrown
I can't remember the exact amount but I think it is only like 7-8psi. it is just a feeder pump to get fuel to the high pressure pump on the frame rail. that pump gives somewhere around 80-100psi.
I have herd of people running a carb off the feeder but I have never tried it myself.
Posted: Thu May 05, 2005 9:29 pm
by Dreded
Not to be rude DBrown i appreciate the response but as I said THERE IS NO PUMP ON THE FRAME RAIL ON A '90 only an intank pump but thanx again for responding
Posted: Fri May 06, 2005 5:36 am
by DBrown
lol, sorry man, I completely missed that......I would think that the in tank would be the same as the one on the rail. if it had the 2.9L it should be 80-100 to run the motor. the 4.0L is 85-100 I think. that is what autozone told me when I was doing the 4.0L swap. they never said anything about only one pump. they just said pressure at the rail would be that, then the regulator would knock it down to around 35psi. not sure about the 2.3L
again sorry......
Posted: Fri May 06, 2005 8:44 am
by Dreded
no worries but using a regulator does it hurt the pump at all to knock it from 80 psi down to like 5-7? because none of the regulators have a return.
Posted: Fri May 06, 2005 10:25 pm
by Exhauster
the working pressure for the intank pump on an 89 & newer is 40ish lbs.... you can't use it with a carbed engine. if you choke it back that far it will overheat and burn up the motor in it. you could probably use an 86-88 intank feed pump for a carb.
Posted: Sat May 07, 2005 2:02 am
by Dreded
In my '86 I was just using the feeder pump but it was noisy when pushing fuel that far. I was hoping to get a quiet solution.
Posted: Sat May 07, 2005 5:15 am
by DBrown
in my 76 the guy that converted it over to elec fuel pump just used an off the shelf pump from autozone and it has worked well so far. I think he only paid like $20. it is not that bad. but he mounted it up at the engine and you can hear it but it is not too loud. I would mount it on the rail and it should be pretty quite. another thing to think about is it is easier to push liquid then it is to pull it so back at the tank is deffinatly the place to put it if you can.