Oem Lp Gpm ????

[rjwest]

Anyone know the OEM Lift Pump Gallons Per Minute rating and also Pressure??

[Hubert]

I think there are different pumps for different years. I think they are all interchangeable and of course there are different manufacturers of LP's.

Its a one sided spec for minumum flow.

According to alldata dot com for my 97 its ok if at least 3 psi pressure and 0.5 pints per 15 seconds (15 GPH or 0.25 GPM).

[94 at Large]

I don't know if all years are interchangeable but the FP905 by Delphi puts out the most. I swapped mine out for that model and it looked identical to the OEM so the internals must be different.

[a5150nut]

I don't know if all years are interchangeable but the FP905 by Delphi puts out the most. I swapped mine out for that model and it looked identical to the OEM so the internals must be different.

Would yo happen to have the GPM and output pressure on that model?

[bcbigfoot]

The Delphi pump fp 905 puts out 35gph in free flow conditions and max pressure of the pump is 9.5 to 14 psi. The best Carter pump is the 74143 pump and it lists as having 10-15 psi and a free flow pumping capacity of 32gph.

[JohnC]

The DB2 uses housing pressure to affect injection timing. Lift pump pressure is important and too much volume might overpower the return valve and mess up the timing. The DS4 does not use housing pressure for control; lift pump pressure is irrelevant as long as the delivery volume is there.

[rjwest]

bcbigfoot,: THANKS, been searching for these numbers for a long time...
Excellent info ::::

[a5150nut]

:rolleyes: Just got to love the welth of information available on this board. Thanks to all that provide it!

[bcbigfoot]

The DB2 uses housing pressure to affect injection timing. Lift pump pressure is important and too much volume might overpower the return valve and mess up the timing. The DS4 does not use housing pressure for control; lift pump pressure is irrelevant as long as the delivery volume is there.


Thats good to know thanks. The recommended pump for my truck is the Delphi 905 lift pump and most of the 88 to 93 C/K trucks with 6.2's and 6.5,s with the DB2 pumps so I should be good to go with the 10 to 15psi range. Carter however recommends thier p74001 lift pump with only 20gph and 10 to `14psi max pessure, I am however going to install the Carter p74143 with 35gph flow and max pessure of 10 to 15psi. I will post back if I see any problems.

[DmaxMaverick]

Pump ratings (mfg claims) are rather subjective. The same pump can have several different ratings (and labels), depending on the conditions they are tested. With any pump, volume can be traded with pressure.

Consider the "el cheapo" 12V air compressors. A 250 PSI rating is a selling point to the unknowing, but that pump will take half a day to fill the normal truck tire, and most don't survive long enough to fill 4 tires after a trip to the dunes. Who needs 250 PSI at .1 CFM?

Marketing. It's all marketing. If I were a fuel pump mfg, and wanted to sell my pumps to a broad market, I would test/rate it under different conditions. For example, a pump capable of producing 15 PSI @ 20 GPH, could also be the same pump sold (even with a different part #) with a rating of 7 PSI @ 35 GPH, or 4 PSI @ 50 GPH.......

[bcbigfoot]

I am seeing a problem running the Carter fp 74143, which is the highest pressure and volume pump Carter makes. The problem isn't the high pressure it seems to be low pressure from this pump, I'm only seeing 4psi from this pump at idle. The original pump with 180,000 miles is getting 5.5 to 6.5psi.

The problem seems to be that I,m getting a rough idle with the Carter pump and low fuel pressure. The original pump starts at 6.5 and drops to 5.5psi as the fuel warms up, the idle seems to get a little rougher but not as bad as the Carter lift pump only running 4psi.

A question for John C and all the 6.5 experts. Could the low 4psi of the Carter pump be throwing the DB-2 injection timing off and causing a bit of a rough idle? It seems to be but wanted a little confirmation before buying another lift pump.