Some more LLY issues

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cmitchell17
Sep 8, 2008
251
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0
So after about a year with a 500rw tune my FPRV is starting to give up and im starting to give up trying to get the valve out of the fuel rail.

It never threw a 1093 but did throw a 1094, rail pressure low during Idle/DFCO, and felt like it would hit a very violent rev limiter when the FPRV popped and rail pressure went down to 80mpa.

So i backed the pulse down to about 2400-2600us instead of 3000 and it quit, but then the fprv would only pop once it hit above 60mph and pressure would drop gradually to about 80mpa again.

Once it would do this it will stay like this even if you restart the engine. It like it limits it to somewhere around 60mm3 but there is no flat line it stays at it just jumps around there, and the funny thing is that when it shifts TLIQ comes in and jupms the fueling up to around 75 80mm3 and you can feel it while driving.

It goes away when I clear codes, but a code never shows up for it, not even a 1094. The only codes I have is a front tire speed sensor code which ive had forever, and a air bag sensor code from where I think a sensor came undone from where it was mounted near the radiator.

Theres no maf limiting going on or torque limiting so thats not the problem but the wierd thing is that there are no codes shown and it dosent look like its limited to a certain mm3. It is also holding the commanded 150mpa so I dont think the rail is popped when its doing this.
 

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cmitchell17
Sep 8, 2008
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I was just wanting to know if anyone else knew of any phantom codes or limiters that caused something like this and if there is any way to get rid of them?
 

Kat

Wicked Witch of the West
Aug 2, 2006
17,899
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Norco, CA
It's a LLY you have to shim it!!!! If you want to run your truck to it full potential :thumb:
 

whitetrash21

put on da damn helmet day
Apr 29, 2008
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That might be my problem. I get 1093 a lot..... mostly after a 4k rpm run and then lifting. Is that spiking rail psi?? pushing the fprv open???
 

The Neens

BFD
Staff member
Aug 10, 2006
4,596
1
36
Monrovia, Ca.
I was just wanting to know if anyone else knew of any phantom codes or limiters that caused something like this and if there is any way to get rid of them?

Send me your tune...

That might be my problem. I get 1093 a lot..... mostly after a 4k rpm run and then lifting. Is that spiking rail psi?? pushing the fprv open???

4,000 RPMs??????????????????

You need to quit bumping your head...
 

whitetrash21

put on da damn helmet day
Apr 29, 2008
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0
36
Vegas
4,000 RPMs??????????????????

You need to quit bumping your head...

Dead serious. Can't run 5th at the track so I run 4th all the way out. Bounces off a 4k rev limiter the last 150 ft or so. Not really a good sound but last time I tried to let it go to 5th, it made a loud bang and did some weird shifting shit for a minute so I ixnayed that.... and yeah, I know I need a trans :D
 

The Neens

BFD
Staff member
Aug 10, 2006
4,596
1
36
Monrovia, Ca.
Dead serious. Can't run 5th at the track so I run 4th all the way out. Bounces off a 4k rev limiter the last 150 ft or so. Not really a good sound but last time I tried to let it go to 5th, it made a loud bang and did some weird shifting shit for a minute so I ixnayed that.... and yeah, I know I need a trans :D

Get rid of the Hypertech bro...
 

Kat

Wicked Witch of the West
Aug 2, 2006
17,899
13
38
60
Norco, CA
That might be my problem. I get 1093 a lot..... mostly after a 4k rpm run and then lifting. Is that spiking rail psi?? pushing the fprv open???

Yes. You have to
shim it Wes. It could get you on trouble if it happened on the freeway :(
 

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cmitchell17
Sep 8, 2008
251
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On the 107 log at about frame 150 it starts loosing pressure but in that log there isnt any fuel limiting, but log 108, taken the next day something is limiting the fueling?

thanks for the help I know I need to shim the valve but im running out of options besides taking the fuel rail out.
 

Attachments

  • Broken FPRV.tun
    637.9 KB · Views: 11
  • Log 107(Broken FRP Tune.zip
    19.2 KB · Views: 8
  • Log 108.zip
    76.9 KB · Views: 9

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cmitchell17
Sep 8, 2008
251
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I found some washers but couldnt find or get a 20mm nut ordered. So I went ahead and ordered a race valve.

I put a small impact on it but it did not go anywhere. If regular hex heads keep failing am I going to hurt anything if I put a small pipe wrench with a long pipe on it since I already have a race valve?
 

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cmitchell17
Sep 8, 2008
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I went to see how far I could go with removing the fuel rail and I got to taking the metal coolant pipe off and couldnt figure out how to take it apart so I stopped.

What about when I get to the fuel lines on the fuel rail and the inlet line to the fuel rail? Are these bolts going to be as tight as the fprv is?
 

cstephens93

New member
Oct 13, 2014
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Tallahassee, FL
Unfortunately, my cousin, the OP doesnt really get on the forums anymore.

I ran his big LLY tune for a while and always seemed to have trouble making the rail pressure desired by the tune. (I think the tune is attached somewhere in this thread)

I switched over to Idaho Robs tunes, and on his max effort tune, it calls for 26kpsi, but my truck only makes about 21kpsi, maybe 22-23kpsi for a second, before it tapers off to 21kpsi consistently.

I shimmed my fuel rail as well, but I'm wondering if there's anything else I might need to do. When I trouble shot with Rob several months ago, he said it could be a weak pump since he has hundreds of LLYs running his max effort tune without any issues.

Not sure if it is my CP3 or what.
 

CaptPhil

Active member
Sep 10, 2011
1,012
0
36
Delaware
Unfortunately, my cousin, the OP doesnt really get on the forums anymore.

I ran his big LLY tune for a while and always seemed to have trouble making the rail pressure desired by the tune. (I think the tune is attached somewhere in this thread)

I switched over to Idaho Robs tunes, and on his max effort tune, it calls for 26kpsi, but my truck only makes about 21kpsi, maybe 22-23kpsi for a second, before it tapers off to 21kpsi consistently.

I shimmed my fuel rail as well, but I'm wondering if there's anything else I might need to do. When I trouble shot with Rob several months ago, he said it could be a weak pump since he has hundreds of LLYs running his max effort tune without any issues.

Not sure if it is my CP3 or what.
Your pump is getting tired or your injectors are returning too much fuel. Not much you can do about it other than pulling some pulse out of the tune our start replacing hard parts.

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