Hmm that’s weird. I’ll have a scanner tomorrow so hopefully that’ll show me if it’s the MAP
CK5
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Lq4 won’t stay running
- Thread starter chris85
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Hmm that’s weird. I’ll have a scanner tomorrow so hopefully that’ll show me if it’s the MAP
No. Mine would die in flight. Occasionally restart and run like crap and then die again. Start and die right away.
Won't help if your fuel psi is below spec. If you decide to replace said sensor look it up on rock auto under an 04/5 silverado 2500. Find the delphi number and run it on ebay. A lot cheaper than the local chain auto part stores.
Would it be ill advised to run a permanent fuel pressure gauge on that port on the rail? Or would be best to run it in the line somewhere?
I've only used the port a few times to look at the fuel psi. helped me discover that my psi was bleeding off. I ended up putting a one way check valve in front of my corvette fuel filter and she has been happy as pie.
30 isn't enough. I'm not a fan of the goofy Vette filter/regulator. But in your case it is the cheapest part to go after.
Had it been the return style you could have pinched the return line and if your pressure came back you would know the pump is ok and the regulator on the fuel rail is leaking. I don't know how your return hose is set up off the filter but if there is a rubber section you could try to pinch it and retest.
It's quick and dirty to do before dropping the tank.
Had it been the return style you could have pinched the return line and if your pressure came back you would know the pump is ok and the regulator on the fuel rail is leaking. I don't know how your return hose is set up off the filter but if there is a rubber section you could try to pinch it and retest.
It's quick and dirty to do before dropping the tank.
Oh and you don't need to leave a gauge in all the time. After all my fuel based teething problems got sorted out I adjusted it to what I needed to be and haven't put the gauge on since. No need to as long as it's running right.
I got rubber fuel lines so I may try that tomorrow when I have some more hands.
It’s a walbro pump which I was a bit nervous about buying bc I know people have had them go out pretty frequently. Don’t know of any other in-tank pumps that will run the pressure these LS need. I have the ACdelco ep381 but I think it’s only rated for like 60psi and I’m just wondering if that would be enough cushion room.
It’s a walbro pump which I was a bit nervous about buying bc I know people have had them go out pretty frequently. Don’t know of any other in-tank pumps that will run the pressure these LS need. I have the ACdelco ep381 but I think it’s only rated for like 60psi and I’m just wondering if that would be enough cushion room.
Well now I’m seeing like 80-90 psi for the EP381. Don’t know where I got those other numbers from
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I don’t think that’s correct, but I know folks use that pump for ls swaps. I don’t know how much your cam swap will change the fuel delivery needs.
Ep381 is fine for a ls.
So this was after I let the pump run once, that’s why it’s starting at 10psi. Just realized when i did that the pump got pressure up to about 30 then dropped to 10psi once it shut off. Not sure if that’s a bad regulator or bad pump.
I'm surprised it's even running at 30.
Until you isolate the issue between the regulator or the pump it's just a guess.
But normally the pump should go to at least 55 psi and hold even with the key off for a little while. Shouldn't drop any more than 5psi in 1 minute and 10 psi in 5 minutes. Checking key on engine off.
There is a check valve in the pump that should be holding the pressure, if it's not holding it's replaced as part of the pump.
Still you have to make sure the actual fuel pressure isn't just dumping the pressure either.
Until you isolate the issue between the regulator or the pump it's just a guess.
But normally the pump should go to at least 55 psi and hold even with the key off for a little while. Shouldn't drop any more than 5psi in 1 minute and 10 psi in 5 minutes. Checking key on engine off.
There is a check valve in the pump that should be holding the pressure, if it's not holding it's replaced as part of the pump.
Still you have to make sure the actual fuel pressure isn't just dumping the pressure either.
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I assume the gauge is post regulator? If so, I’m not sure you could say for sure. I would lean toward pump, until I could verify pre reg.
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Zoomad beat me. And responded more thoroughly. Pizza joint and beer has more of my attention!
I just happen to have GM's service info open on my desktop in front of me. So I might have cheated a little.Zoomad beat me. And responded more thoroughly. Pizza joint and beer has more of my attention!
Tomorrow I’ll crimp off the return line and that should give us a better idea, but it sounds like we got it isolated to either the pump or regulator.
Thanks for everyone’s help! I just hope i don’t have to drop the tank again! Ha!
Thanks for everyone’s help! I just hope i don’t have to drop the tank again! Ha!
If you have the Vette filter and regulator combo I don't think pinching it off is going to do it. I have the same setup, don't quote me on this but I would be looking specifically at the pump unfortunately. Where did you get it? Wondering if it is a Chinese knock off that is floating around?
Got it from tanks inc. Thought they would have authentic pumps.
