Autotech internals, 390 - 400 psi idle fuel pressure

[Domino81]

I know 390-400 psi is fine for idle, especially when it begins to slowly rise the longer I let it idle. But, it's down 30 to 40 psi. It was ALWAYS up around 420-430. And pressure is fine once I'm into boost or really anywhere else. It just makes me a little nervous that it's down with or without the compressor on. Am I being paranoid?

[Sid3wayS]

Damn iirc pressure from the in tank pump is like 50psi and you are reading under that? Is your ap and map updated with the latest version?

[CCC]

^^I think he meant its just reading that much under his normal 420-430 psi

[Domino81]

I monitor with my Dashhawk

[Etipp98]

How many miles on the internals?

[Domino81]

Probably barely 75-100.

Just getting it broken in.

[SofaKingAwesome]

hmm same thing is happening to me now. Always 420-430, saw 390 this morning and last night. Thoughts?

[SRTie4k]

I would think a slightly lower idle psi would be fine so long as your AFR stays around stoic. If you see it deviating from 14.7, then I'd start getting worried.

[SofaKingAwesome]

yeah, still idle fine, but this literally just started happening yesterday. My internals have about 5k on them.

[Sid3wayS]

O I C now... Reading > me
Yeah mine is normaly in that 430 range never really noticed them fall under that unless I was costing in neutral. Might want to take a log at idle and like said up top make sure your afr is staying at stoich.

[mw6886]

Since you are pushing more volume with the new internals, I would think it would be safe to say that you would need less pressure. Just makes sense to me.

[Lex]

Was it really cold? HPFP pressure drops a bit when cold. How is the pressure when running WOT? If it's fine and rises quickly to ~1800 and stays there I wouldn't worry about it.

[Domino81]

Rises extremely quick, I even see peaks of 1900+.

[SofaKingAwesome]

Yeah I hold pressure fine too, just found it weird that after 6 months of the exact same idle value it dropped 30-40psi suddenly

[triplejumper18]

Originally Posted by Sid3wayS O I C now... Reading > me Yeah mine is normaly in that 430 range never really noticed them fall under that unless I was costing in neutral. Might want to take a log at idle and like said up top make sure your afr is staying at stoich.

Dropping when coasting in neutral is normal according to Braden from Cobb.

[SofaKingAwesome]

this is sitting at stop lights.

[DownSideFX]

I just installed the AT internals, I have been seeing ~450 psi at idle. However when I drive around for a while I notice in my low/high psi it going as low as ~260, I was trying to figure out when.. I think maybe when getting off the throttle in 3rd or 4th gear. Has happened once or twice.. I see 1800+ psi though whenever I'm on it and it holds there fine.

I don't think there is an issue, the car seems to be running fantastic. Just curious.

[bigriver]

Subbed.

I typically see 420+ at idle with AC off. Dropping 30-40 psi seems odd to me too. I have 8k on my autotechs and would get a bit worried to see a sudden drop like that.

Dropping under 300 when letting off throttle is normal.

[Meder]

mine idle closer too 400 as well, pump working fine. 500+ miles on internals...

[SofaKingAwesome]

Originally Posted by bigriver Subbed. I typically see 420+ at idle with AC off. Dropping 30-40 psi seems odd to me too. I have 8k on my autotechs and would get a bit worried to see a sudden drop like that. Dropping under 300 when letting off throttle is normal.

All of this. What would make it suddenly idle lower?

[Domino81]

I'll see 387 and slowly begin to rise. It's 33 here today.

[HPFPUPGRADE]

Originally Posted by Domino81 Probably barely 75-100. Just getting it broken in.

Very common after break in, just watch the upper RPM and make sure they hold pressure in the upper RPM band when under boost.

Originally Posted by SofaKingAwesome hmm same thing is happening to me now. Always 420-430, saw 390 this morning and last night. Thoughts?

Very common after break in, just watch the upper RPM and make sure they hold pressure in the upper RPM band when under boost.

Originally Posted by SRTie4k I would think a slightly lower idle psi would be fine so long as your AFR stays around stoic. If you see it deviating from 14.7, then I'd start getting worried.

The AFR's will stay at stoic if the fuel pressure is set to 100 psi. The ECU is very smart and will do everything it can to achieve that number at idle.

Originally Posted by SofaKingAwesome Yeah I hold pressure fine too, just found it weird that after 6 months of the exact same idle value it dropped 30-40psi suddenly

Watch this close, if after 6 months this shows up it could be showing signs of wear.

[backward_0]

Mine do the same thing they are all over the place at idle between 390-430 but hold pressure great up top. I got about 2 months on mine.

Sent from my SGH-T959 using Tapatalk

[Domino81]

Every time I've driven it since I'm looking at 410-430.

[G26]

I think you guys are having the same thing as a couple of us in the thread a little higher than this Low idle fp @ idle cpe pump.

Heres the situation, I don't know what causes it either.

After you get on it a little, or do a wot pull, and pull up at a light, NOT while coasting, while completely stopped, my idle fp will be 350-400 (depends on how long I got on it), and will gradually rise back to 410-430.