View Full Version : 2 stage fuel pump question
Could someone please explain the 2 stages? Especially if they affect the pressure readings I should see at different points. My Clymer manual says 30 psi, always, but doesn't mention a 2 stage pump.
05-18-2008, 02:52 PM
94 ps190 indmar 350
05-18-2008, 10:49 PM
94 ps190 indmar 350
sorry, I got nothing. I have an in-tank fuel pump.
Does it look like this? You might consider calling Indmar. Also...SkiDim carries them - they might be able to confirm for you that variable pressures means bad pump.
Yeah, that's it alright. I left an e-mail with skidim tech support so hopefully I'll know something tomorrow. Thanks for the support.
If the pressure varies with that pump, it's either not getting good supply or the pump is bad. 30 lb is what you need at key ON, idle, 2KRPM and WOT.
05-19-2008, 10:21 AM
Check the inlet screen on the inlet side of that pump.
Thanks for all the help. The inlet screen was dirty, but cleaning it didn't raise the pressure, so I guess it's time for a new pump. Anyone know if there is a automotive equivalent? It sure is an expensive pump.
It may not have raised the pressure but I would take it out and see how it performs.
If you need a new one, google the part number. If it has 81 as the first two digits, omit them.
Well, it's a hundred mile trip to take it out and test drive it, so I went ahead and changed the fuel pump out. Pressure is still at 10. Plugged the return line, pressure shot up. Yes, I know I should have done this earlier, what a dope, but here's the next problem. I inspected the regulator and it seemed fine. No debris or scoring on the valve or seat. Upon doing some research on tbi fuel pressure regulators, I find that most do work arond 10-13 psi, not 30. Then I get the idea to check the owners manual, sure enough it says 10-12 psi for the tbi. This, even though Clymers also says it should be 27-31 on tbi. I don't understand. I could try getting an adjustable fuel pressure regulator, but since the manual says its normal, would it be worth it? And why the discrepancy? Jim, I know you're the expert on these, is it 30 for sure on tbi and the manual is wrong? I guess I'm back to square one. Any ideas?
We were told that 18 lb was the proper pressure for the TBI and initial EFI, which then went to 30 lb. The only thing they needed to do to accommodate the higher pressure is decrease the pulse width, so it wouldn't deliver too much fuel.
I'm not really the expert but what manual were you looking in? I tend to not trust third party manuals, personally.
Engine Nut- are you out there?
Clymers says 27-31. The Mastercraft Owners Manual says 10-12. It is available on line. Had never looked at it before. As you know, most owners manuals don't give fp specs. Thanks for the help. Have a nice Memorial Day.
Checked with Indmar Tech Support today. 10 psi for tbi is good. Wasted $300 on a fuel pump thanks to Clymers Manual. Now I don't know where to go next.
Oh, sorry. I forgot the problem was in another thread.
It runs ok at wot for a while. 10 minutes or so, then cuts back to 3000 rpm. No codes. No overheating.
Anyone? Engine Nut.
Thanks in advance