Question about HPFP and LPFP

Quick question. When I run my 310 tune I run 14.00's all night long but when I run my 345 tune I run 14.1's but my 60 ft are better in my 345 tune. Is this the FPFP not being about to keep up with the demamd or in my LPFP not able to feed my HPFP fast enough? Also I get a P0003 fuel volume regulator control circuit low when I run the 345 tune. If this is a LPFP issue I am thinking air dog but what one do I want?
Thanks
Nick

you should be running way faster then 14's with the 310 and 345. But the 310 does 1/4 faster from what Ive heard.

If I didn't weigh 10,000 lb I would lol.

LOL yeah I read your sig after I posted.

I was getting that code too. My truck is in the shop right now because of this and I'm pretty sure the HPFP wire harness is bad on it. My truck got as bad as stalling out on me and would just kill.

benbou00 said:

I was getting that code too. My truck is in the shop right now because of this and I'm pretty sure the HPFP wire harness is bad on it. My truck got as bad as stalling out on me and would just kill.

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My truck was doing that and going into a "limp" mode but got a new HPFP and wire harness and that fixed that but I got this code after and only at WOT on the track in 345.

Could be the fuel rail pressure sensor.

Could be but my main question is am I at the limit of my HPFP or is my LPFP not able to flow enough to the HPFP which is why my 310 runs faster then my 345?

Watch rail pressure at WOT with both. See which tune maintains higher pressure.

weekendwarriorfsw32 said:

My truck was doing that and going into a "limp" mode but got a new HPFP and wire harness and that fixed that but I got this code after and only at WOT on the track in 345.

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Mine only threw the code twice while I was just cruising and then got down on it. A few weeks later it then started acting up on me. I have a modded pump in mine so it may not have anything to do with the HPFP.

I see rail pressure of about 24,500 with the 345 and with the 310 it'll spike to around 28,000 and won't go any lower than 25,000 I think. It's been a while since I've driven it so I don't really remember the exact numbers.

weekendwarriorfsw32 said:

Quick question. When I run my 310 tune I run 14.00's all night long but when I run my 345 tune I run 14.1's but my 60 ft are better in my 345 tune. Is this the FPFP not being about to keep up with the demamd or in my LPFP not able to feed my HPFP fast enough? Also I get a P0003 fuel volume regulator control circuit low when I run the 345 tune. If this is a LPFP issue I am thinking air dog but what one do I want?
Thanks
Nick

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Are you running the kem 310/345 or the Spartan 310 and the Kem 345? I would not expect the Kem 345 to be faster then the Spartan 310. With a stock fuel system, I don't get any codes even running the Spartan 350. I would guess the code is more related to the kem 345 then your truck.

You really need to watch rail pressure at wot before we can be much help.

Sounds like the pump might be starting to get a little tired, but i have had my truck not maintain pressure at all with no codes or anything... so my guess is alot of it is tuning

I thought the whole time the 310 has always been a faster tune? Plus the 345 makes its power down low hence the better 60'

So far I tired the 310 and doing 30 to 110 the FPFP holds 24,500 the whole way will do 345 later today.

24500 is perfect so i would say your fuel system is ok, try the 345 and let us know what happens

So all out in the 345 tune is 22,000. What is the point where I should be concerned on fuel press?

I think that is getting border line.

Shouldn't drop under 24k I believe.

desired with all tunes to my best knowledge is 24500, so what i would do now is run that 345 and check low pressure fuel and see what it falls to when the rail pressure falls to 22k

Dzchey21 said:

desired with all tunes to my best knowledge is 24500, so what i would do now is run that 345 and check low pressure fuel and see what it falls to when the rail pressure falls to 22k

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Whats the best way to check the LPFP? There is no factory sensor for it correct?