Fuel Pressure PSI

diezelraccoon · Sep 1, 2024

strutaeng said:
Interesting. Yeah, that seems like flex fuel label. Are you the original owner of this truck?

Can you post a photo of the injectors? The L59 are visually different than those from the non flex-fuel variants.

Things get swapped over the years and ownership. Possibly engine, glovebox or fuel door are not original?

For example:
On my 99 Silverado I swapped the engine from a V6 to an L59, transmission from a 4L60e to a 4L80e, and last year I deleted to center console to a jumpseat (including the glovebox with another truck's RPO code label.) I did keep my old glovebox, and I was going to swap the lid, but even then, stuff doesn't match exactly. LoL

Do I need to remove an injector or what does the pic need to show?

strutaeng · Sep 1, 2024

diezelraccoon said:
Do I need to remove an injector or what does the pic need to show?

Just the connector. Check out this website: https://www.chevelles.com/threads/how-to-identify-visually-l59-flex-vs-lm7.1104796/

diezelraccoon · Sep 2, 2024

Fless said:
I think the 8th digit is an alpha character, not a number. Would you take another look at your VIN? Bet it's a "Z."

Not sure how I got that wrong. The 8th digit is a Z. So it’s flex fuel?

diezelraccoon · Sep 2, 2024

strutaeng said:
Is this an LM7 or L59 engine? The L59 had lower pressure than the LM7.

I was wrong. The 8th digit is a Z.

Fless · Sep 2, 2024

diezelraccoon said:
Not sure how I got that wrong. The 8th digit is a Z. So it’s flex fuel?

Yes, it's Flex Fuel. Unless the engine type has been changed, it's an L59.

diezelraccoon · Sep 3, 2024

Fless said:
Yes, it's Flex Fuel. Unless the engine type has been changed, it's an L59.

So thoughts then on the fuel pressure? Fuel pump giving out?

rockola1971 · Sep 3, 2024

diezelraccoon said:
So thoughts then on the fuel pressure? Fuel pump giving out?

Your pump isnt meeting min spec at KOEO. Its done. Stay away from aftermarket pump modules unless you like changing fuel pumps...alot.

Fless · Sep 3, 2024

rockola1971 said:
Your pump isnt meeting min spec at KOEO. Its done. Stay away from aftermarket pump modules unless you like changing fuel pumps...alot.

Then, again, practice makes perfect!

diezelraccoon · Sep 4, 2024

rockola1971 said:
Your pump isnt meeting min spec at KOEO. Its done. Stay away from aftermarket pump modules unless you like changing fuel pumps...alot.

Can you link me to where you recommend? I usually only do OEM so in this case would be ACdelco more than likely.

strutaeng · Sep 4, 2024

rockola1971 said:
Your pump isnt meeting min spec at KOEO. Its done. Stay away from aftermarket pump modules unless you like changing fuel pumps...alot.

Looks like PO is 2 psi below spec. I would have thought this was close enough, but I don't know.

On my older SBC/4.3 Vortec, they always primed a few psi below spec, but still fired up. The spider injectors I always read really needed the minimum to fire, but mine didn't have that issue it seemed.

I'm still learning the LS engines, so that's why I'm asking.

I would still like to see OP cap the return line to see maximum pressure developed by the pump, in case maybe it's a fuel pressure regulator issue? IDK

Fuel Pressure PSI

diezelraccoon

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strutaeng

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diezelraccoon

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diezelraccoon

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Fless

diezelraccoon

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rockola1971

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Fless

diezelraccoon

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strutaeng

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