LLY: Still having Rail pressure problems

[sweetdiesel]

Ok, so based on the logs, you find the regulator is bad? As a note, I logged the same PIDs and under the same circumstances (4th gear ODLO, WOT) and it held rail pressure. I'm guessing the stock tune isn't stressing it much... On my way home I'm going to log the Predator 85HP tune...

For a stock regulator, is there any difference between a LBZ and LMM? Either way (stock or modded), I'm going to have to live with it for a bit and save my pennies.

I dont think so lly and lb7 are different

 

[2wd_Sled_Puller]

Turn the fuel up on the lift pump

 

[JoshH]

Turn the fuel up on the lift pump

There are no adjustments on the KD lift pump.

 

[2wd_Sled_Puller]

Sorry thought he said he had a ppe pump. My ppe is pushing 12psi and its turn down i only turn it wide open when at the track.7 psi seems low but its consisted

 

[05smoker]

I'm not sure what kind of pulse LLYs usually run, but 3350 sounds like a pretty big shot of fuel. I wouldn't be surprised if you are just running too much fuel for a stock CP3 to keep up with.

X2 - sounds big for a Lily, especially if it is consistently in that 3k range across the table.

If it was the regulator, wouldn't it idle like crap??

I thought an LB7 and LLY regulators were the same, just the plug is turned a different direction?? I had an LB7 reg on my LLY for a while and it was fine.

 

[Cougar281]

Ok, I did some logging of stock tune and a Predator 85HP tune... The stock seems to have held good, predator 85 for the most part too. I've attached the logs. It has had a bit of a lope at idle for a while (not enough to register on the tach, but enough to hear and feel a little) that seemed to get a little better after I installed the lift pumps. It looks like over 2000uS PW is where it's starting to have issues. The stock tune never went near 2000, and it seems that when the predator tune headed for 2000 is when it started to drop pressure.

 

[sweetdiesel]

X2 - sounds big for a Lily, especially if it is consistently in that 3k range across the table. I missed that part

If it was the regulator, wouldn't it idle like crap?? I would think so

I thought an LB7 and LLY regulators were the same, just the plug is turned a different direction?? I had an LB7 reg on my LLY for a while and it was fine.

yes they are the same inards but like you said the plug is different,he may have a hard time getting a lb7 reg to fit because of it

 

[JoshH]

I don't ever see your regulator commanded to 0%. Shouldn't it go to 0 for the most fuel? I don't ever see it go much below 25%. I wonder if that has something to do with your problem?

 

[othrgrl]

I was dropping rail pressure bad (not getting above 15K PSI on 3100 PW) and replaced the filters on my motor and AirDog and toqued the piss out of my PPE race valve and now I'm holding over 20K PSI @ 3200 PW all the way down the track out of my stock LLY CP3. I also had low miles on my filters and was reluctant to change them.

 

[rcr1978]

I don't ever see your regulator commanded to 0%. Shouldn't it go to 0 for the most fuel? I don't ever see it go much below 25%. I wonder if that has something to do with your problem?

I never see my LMM go to 0% like you said around 23%, the rail pressure takes a serious dive clear to 8500 psi sometimes to. Either I don't understand whats going on with the % or ma of the regulator or we are missing some things to properly log or tune what is going on with the regulator. I found those pids don't play nice with others at least on the LMM, I have not played with them on anything else for a long time.

 

[Cougar281]

Well, a new twist... I lost prime yesterday (ran waaay low on fuel ), and disconnected my lift pumps so they wouldn't be runnig without prime. After I refueled, I left them disconencted as I heard some cavitation when I powered them up, so I'll run the truck for a bit without since I'm running the small "economy" tune. Anyway, it appears that my rail pressure seems to drop about the same on the small tune both with and without the lift pumps. The big tune (that dyno'ed 446) drops much less with the lift pumps than without.

 

[duratothemax]

Sorry thought he said he had a ppe pump. My ppe is pushing 12psi and its turn down i only turn it wide open when at the track.7 psi seems low but its consisted

fourth word of the first post, he said KD lift pimp.


Dave did you try disconnecting the regulator at all

 

[Cougar281]

fourth word of the first post, he said KD lift pimp.

:rofl:

Dave did you try disconnecting the regulator at all

Not yet... it's on my list to try...

 

[othrgrl]

If you are having the same problem with or without Lift Pump and the regulator isn't the problem I would say it's the Fuel Pressure Relief Valve. If you screwed up the threads or the flare on the end or in the rail it will bleed of pressure really bad. Try torqueing it tighter - if you can't get it any tighter then do a bottle test to be sure it's not the FPRV.

 

[Cougar281]

Well, I pulled the the "valve" this afternoon, the threads are perfect. The end is clean and perfect. I looked into the end of the rail with a mirrir and it looked like there may have been something on the surface, so cleaned it out and it looked nice and clean. Put the valve back in (threaded it in by hand until it stopped), then tighetned it down as tight as I could (as tight as I could with my 16" ratchet, then another 45* or so with half my jack handle on the end of the ratchet). It's DEFINATLY tighter than last time. I'll try a bottle test when I get a chance to be sure, but I think that unless either the valve or my rail is defective, the "valve" isn't the issue.

Is it possible that the DS rail is holding pressure, and the drop I'm seeing is the result of the restrictive fittings betweem the DS and PS rails?

 

[othrgrl]

I don't have ported valves yet and don't have rail pressure issues now that I have clean filters and tightened the PPE Race valve - so I doubt that's it with the tuning you're running

 

[Cougar281]

Ok, just did the bottle test. After flogging it with 5 WOT runs on the PPE 330 tune, which was dropping 6kPsi, and two with the "Economy tune" which was dropping about 3k, the bottle didn't have a drop of fuel in it. The nipple on the end of the rail had fuel in it, but none in the hose, so I'm pretty sure that fuel got fed back in from the return, judging from the gurgling I got when I unhooked the return and unplugged it after the test. Soooo..... Now what?

 

[othrgrl]

Either a bad regulator, bad CP3, dirty filter(s), or a clog somewhere.

 

[Cougar281]

Either a bad regulator, bad CP3, dirty filter(s), or a clog somewhere.

Well, the same exact thing happened with a brand spaking new fresh filter, so I doubt that's the issue... Since I've never gotten any horribly bad fuel and my tank was clean when I was inside it installing the KD pickup, I doubt it's a clog, so that leaves CP3 or regulator.... The two most expensive parts of the fuel system... Happy days... Not...

 

[Cougar281]

If my CP3 and/or regulator was going bad, could that have an effect on my mileage?