Low rail pressure on race tune?

[Devon]

Ok running a race tune I data logged a 0-105mph run noticed the pulse width would run 3075 and my rail pressure was holding 19k-22k and threw a p0087 code,on the 2700 tune(economy tune) it would hold 23k-24k..I belive the race tune Is over fueling, should I turn the tune down to 2900-3000? It's doggin out while this code is thrown which is explainable..also I'm only running 13.1's at 103.5 with this race tune...what can I do?

06lly with airdog,trans,race valve,ect.


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[SteveFord]

Filters are good? I know some guys have had problems with thed race valve if its not tight enough. That pulse I wouldn't think it would throw a code but your rail does drop a lot from something. Maybe your cp3 is a weaker one? Just throwing out ideas.

 

[dieselboy04']

I'm guessing weak cp3 as well, I could be wrong, but that's what happened to me. good luck

 

[Devon]

Yea I don't know, on the 2700pw tune it's fine, I'll log the hot street tune and see what that brings


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[xcablb7]

How old is your fuel filter ?? If its fresh check the race valve, if that's ok cp3 is weak

 

[SSchmi5519]

Whats the smoke level like on the big tune, full boost?

 

[Devon]

Reason for racevalve was I thought my shimkit was leaking because of that damn 0087 code, I only run the airdog as my stock fuel filter is deleted, race valve Is tight and u get smoke pretty much the whe way down the track, not as bad as it us before the turbo light but definatly noticeable


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[xcablb7]

Great that you eliminated that **** factory filter but how old is the air dog filter ? Is your supply pressure to the cp3 from the air dog ok ? Spring possibly weakened up in the a/d regulator

 

[Devon]

Probably 5 or6 months old. Bought it in the beginning-middle of winter.havnt checked the spring,how easy is it to turn the pulse width down say 100 or so just to see where it holds decent pressure? Is 23-24k ok??


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[xcablb7]

As close to desired as possible I try and keep it within 1000 psi, like others have said your pw shouldn't be an issue I've run that much and more on 01 lb7's with over 100k on the pump

 

[Devon]

So you think it may be the spring on the airdog??


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[xcablb7]

Could be its something worth checking

 

[SteveFord]

Have you logged voltage to the regulator to see what it's doing?

 

[Devon]

If it happens to be the cp3 is becoming weak, how much of a pita is it to put a new one in? I mean I have no problem buying another, if that's the problem but how long of a job on average? Also is it worth having say Danville mod it for me even if I have stock injectors?


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[Devon]

Have you logged voltage to the regulator to see what it's doing?

No,that is something I didn't think of, will do it tomorow for sure.


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[x MadMAX DIESEL]

I have the same problem, same basic setup up. Dont think yours is lift pump related or fprv either, just like mine. Mine holds 21700 on average looking at a log, which is within 4,500 psi from the desired level. Low but i wish it wouldnt pop that code for that little of amount difference. I hate my 0087 popping up. It pops up at anywhere between 75 and 100. Sucks for racing, because the last 17mph of the pass the fuel is cut in half. I'd like to say I could make a 12.50 pass if I didn't pop up.... That run was either a 12.9 at 100 or 12.8 at 102, always gotta be something to go wrong though...

 

[Devon]

Exactly my problem, you think it's your cp3 aswell??


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[JoshH]

There's no reason a 2700 uS pulse width tune shouldn't hold 26k PSI of rail pressure if your lift pump is on and working properly unless you have high return rates on injectors or a weak CP3. Could be a tuning issue, but if it's one of Dustin's tunes, I would be surprised.

 

[Devon]

well I forgot to mention that cyl 3 injector is in the 5-7 range,while all others are -/+ .8-2.0,would one bad injector make that much loss of rail pressure? and or a performance loss? Also,hypothetically,can a airdog be installed wrong and not really notice?,I do not have a fuel pressure gauge yet to see if I am running 10psi with the ad165...

 

[skintback]

I would start with new filters being you can not hold 26k on your small tune and then go from there

filters 40
injector 375
cp3 700