Lift pump inlet pressure?

BRE

BRE

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May 19, 2010
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Alright guys I have searched and searched. How much pressure is ok to pump to your factory lift pump?
And also is it neccesarily a must to have a fuel pressure gauge ran when you stretch the OFV spring?
 
I understand I need one and for a note I plan on and want one. However im trying to track down some issues at the moment and a kid in college has to budget his money in case something is to go wrong because I dont run to my parents evertime something goes wrong.
 
BRE said:
I understand I need one and for a note I plan on and want one. However im trying to track down some issues at the moment and a kid in college has to budget his money in case something is to go wrong because I dont run to my parents evertime something goes wrong.
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I hope that wasnt an insult to me.

If you can't afford it then fix what you can when you can.
 
No not an insult at all. I dont even know how old you are lol It wasnt meant toward anybody I was just explaining why my situation was what it was.
And Im just tryin to track down a little studdering problem slash random slight miss. The reason i ask about inlet pressure is I have a basically brand new 24v lift pump laying around and had thought about using it to pump to my lift pump.
 
Lol ok bud. That would have been the first time I've been insulted here. I've held a pretty good track record for CompD

I don't think the 24v lift pump will do much. The vp runs at less than half the pressure of the p7100, so I don't think the lift pump works that hard. And it will probably die on you soon anyways :D
 
I'm running 15 psi to mine and no problems. After looking at the internals of my stock lift pump, I think you'll be just fine with anywhere from 5 to 50 psi feed pressure. If you get the overall pressure too high by pinching the overflow return line at the injection pump 70-100 psi, I could see fuel getting pushed past the shaft seal on the lift pump and getting into the crank case/engine oil.
 
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madmikeismad said:
Lol ok bud. That would have been the first time I've been insulted here. I've held a pretty good track record for CompD

I don't think the 24v lift pump will do much. The vp runs at less than half the pressure of the p7100, so I don't think the lift pump works that hard. And it will probably die on you soon anyways :D
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Yea I am on here all the time but as you can see I just dont post a whole lot and stay out of the way.

I'm running 15 psi to mine and no problems. After looking at the internals of my stock lift pump, I think you'll be just fine with anywhere from 5 to 50 psi feed pressure. If you get the overall pressure too high by pinching the overflow return line at the injection pump 70-100 psi, I could see fuel getting pushed past the shaft seal on the lift pump and getting into the crank case/engine oil.
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So I guess this is my next question. Is it worth it or am I waisting my time? I just figured that away the factory lift pump wouldn be working so hard to the fuel to it.
 
If it flows enough, I suppose it would be better than nothing since you already have one.
 
Well its brand new, been on for like 2 weeks. Pulled it off and put an airdog on. Whats the factory specs on those like 10-15 pounds? If memory serves me right.
 
If you're looking for power, I would feed the factory lift pump with an electric pump pushing 15 to 25 psi, and 50+ at the injection pump. If you're not looking for 400+ HP, the factory lift pump with a modified overflow valve is enough lift pump to get the job done.
 
Alright thank you sir. If I have time im gonna put that 24v lift pump on and I need to order a steering column pod and fuel pressure gauge... but!
 
On another note since I can never find what im looking for. What atf should I try running or 2 stroke to see if maybe there is some film built up in my pump causing this erratic lope/miss im trying to find.
I can find anything else for someone using search but not for myself :bang
 
ATF is cheaper than 2 stroke oil. ATF has more detergents so it will do a better cleaning job!

Any ATF will work, the cheaper the better!
 
Does it matter if it's synthetic or not? Sometimes I come across new unopened jugs of ATF, and dump it in the tank. I've always wondered if synthetic would hurt anything.
 
I always used to run powerservice but I picked up some marvel mystery oil and im gonna give that a shot.
 
Yeah, sefoam is nice. I even ran some through the sleds once. I think you can use it as dish soap if you want, that stuff cleans everything.
 
I've pushed as much as 50psi through a stock lift pump, just make sure to remove your fuel heater as it will be the first thing to go.

I did see your post about your issue last week and I think Weston is right about a plunger issue. I've seen similar issues on quite a few 94-95's(160/175hp pumps), my 95 had the pump replaced before I bought it because of erratic idle and erratic throttle response.
 
Well Im really hoping a plunger issue isnt the problem. However it looks like it is. Im just gonna keep driving it until it drops.
 
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