Incorrect fuel pressure Key on and Engine Running

Matthew Jeschke said:

I have not. You disconnect the fuel filter and turn the ignition on? Collect fuel in bucket or something?

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Correct.

I think I just need to find an adjustable regulator that is a direct fit for factory rail. Having some trouble locating one.

After that, if pump cannot keep up, I'll order a higher volume one... Perhaps from AEM.

Matthew Jeschke said:

@blondie70 Amen to that. It sucked.yhe skin pealed off my arm. It burnt horribly.

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I don't know how viable this suggestion is, but I thought it might at least be worth thinking about:

Get some painter's plastic, you'll probably want the thick stuff. Then tape it to your vehicle where the gas comes flowing out. The plastic is to channel the majority of the gas away from you.

Alternatively, you might be able to get some of those cast savers for showering.

Anyway, gas all over is not a good thing!

Or something like this:

Honestly, I'm thinking I'll pass on the taking fuel system apart to measure flow. Not even sure I have that spec on the pump. Really mainly looking for adjustable regulator at this point in time so I can set the pressure to what it needs to be KOEO. Then if pump doesn't keep up I will do a aftermarket pump. Pretty sure though the regulator must be wrong. I cannot get over 45PSI KOEO. Plus I'd like to boost that a bit over factory anyways...

Anybody done an adjustable regulator with the truck fuel rail? Not seeing a direct bolt on solution so not sure how to go about it.

I haven't whole heatedly looked for an adjustable one. But it seems you are right as I haven't found one that goes on the factory rail. Which is hard to believe with all the other aftermarket part for these.

Back to fiddling with this. My gas mileage is 15 MPG at BEST. Patched a hole in exhaust (between muffler and cats). No effect. Thought maybe it'd help. Long story short I bought a $30 fuel pump and sending unit off eBay to measure the basket size. AEM in tank pumps will fit. The pump sleeve in the housing is almost an exact fit. AEM pumps are a bit shorter but that shouldn't be any issue. I've called AEM but they were only so helpful.

Their spec says 40PSI at 340LPH. That's insane flow! I believe I need no more than 200 LPH (good for over 500 hp, I might make around 400hp but want 500hp haha)... I know pump is overkill but it's cheaper than a lower flow one and don't really want some generic pump which is well peanuts to buy.

My question is what is our factory fuel line size, 3/8"??? I think it all comes down to line size and the pressure regulator? From that along with voltage, I think but am not sure how, you can get PSI in the line prior to the regulator? **UPDATE**: Answered my own question LQ9/LM4/LM7 ID fuel supply is 0.334" OD 0.374" which is 3/8".

I have a return style system (not the newer return-less).


Link to fuel pump calculator HERE

Anybody know what gauge wire the factory puts to the fuel pump?

Guy recommended 12 gauge wire from AEM. I think I'm just going to order 12 Gauge wire but not sure where to get automotive wiring... how many strands are in it, etc.

Wallet is now $200 lighter. Ordered pump and misc parts. I think the factory pump wiring is 14 gauge. Unless somebody knows for sure.