[hetdiesel]

Hello guys,
I have been doing research on trucks going into low rail psi limp mode.
Here is what ive done I did a shim on the psi relief valve the ppe larger fuel rail fitting and the fuel line from the filter to the cp3 with larger fitting also new fuel filter.
I have a quadzilla stealth 2 at the 70hp setting and i when i go to WOT i can actually feel the truck seem like it hits a dead spot and does not accel anymore. I found the thread someone said the fuel lines under the truck are sucking shut i did look under the truck and cant seem to pinpoint where that is if someone can chime in and let me know that would be great. also if someone can take a pic so future people doing research on this common problem will be able to learn from the thread.

thanks for any help,
Corey

 

[TDFDiesel]

Do you have the ability to monitor rail pressure? Friend with a v2? Edge Insight?

Do you have a lift pump? With a data log via a v2 you can get an idea what possible causes are.

 

[hetdiesel]

No I do not have anything to do that with I just recently bought the truck and the kid who had it before me bought the qs2 and Ive been going to sell it buy i need 25 plus posts to sell it to go to efi live 5 pos switch and an edge insite gauge monitor.

The truck does not have a aftermarket lift pump and I think i have a scan tool at work but not sure if it will do any of that sort i think it just reads codes. I have read posts with you responding about this before and my guess you want me to see if it could be injector issues right?

 

[DuraVette]

the quad can read fuel pressure, i dont know if its at the rail though, i know because ive been experiencing fuel issues to and the quad will show desired and actual fuel pressure.

 

[TDFDiesel]

No I do not have anything to do that with I just recently bought the truck and the kid who had it before me bought the qs2 and Ive been going to sell it buy i need 25 plus posts to sell it to go to efi live 5 pos switch and an edge insite gauge monitor.

The truck does not have a aftermarket lift pump and I think i have a scan tool at work but not sure if it will do any of that sort i think it just reads codes. I have read posts with you responding about this before and my guess you want me to see if it could be injector issues right?

No... if you are having fuel limp issues it can be caused by 5 or more things. Try to post up someone local that has a v2 that can do a data log. You want to data log desired vs actual frp. That will show when the rail pressure is dropping and what the likely cause is instead of throwing parts at it.

 

[hetdiesel]

No... if you are having fuel limp issues it can be caused by 5 or more things. Try to post up someone local that has a v2 that can do a data log. You want to data log desired vs actual frp. That will show when the rail pressure is dropping and what the likely cause is instead of throwing parts at it.

you say 5 or more things not that would be ? lift pump, fuel lines,filter restriction,cp3 failure? I dont really know anyone local to me that we can do a scan hope someone will help me out i can drive to them on a upcoming weekend.

 

[hetdiesel]

I see there is a meet nov 5 in altoona pa maybe ill drive down and see if some guyse will help me out

 

[TDFDiesel]

1. Fuel Filter
2. FPR
3. FPRV
4. CP3
5. Pulse Width in tune that CP3 can't keep up with. A first step is a lift pump, as you build bigger this is addressed differently.
6. Collapsing Fuel Lines

These are just a few things that can cause a P0087.

 

[danhr]

7. Herpes.... Herpes causes low fuel rail pressure.


seriously though... as TDFDiesel mentioned, you need to figure out a way to watch fuel rail pressure. It is the first logical step in trying to figure out why it's throwing that code.

Just randomly replacing parts at it is like trying to play darts blind folded.

 

[TDFDiesel]

7. Herpes.... Herpes causes low fuel rail pressure.


seriously though... as TDFDiesel mentioned, you need to figure out a way to watch fuel rail pressure. It is the first logical step in trying to figure out why it's throwing that code.

Just randomly replacing parts at it is like trying to play darts blind folded.

Signature worthy...

 

[hetdiesel]

I understand and im not just throwing parts at it All the parts i bought are normal parts for and mods most people have done to there trucks to build more power I am mechanic and understand diagnosis of a problem before cure part is determined.

 

[TDFDiesel]

I understand and im not just throwing parts at it All the parts i bought are normal parts for and mods most people have done to there trucks to build more power I am mechanic and understand diagnosis of a problem before cure part is determined.

You can create a secondary problem before you diagnose the cause of the first problem. Then you have two problems and will chase them forever.

Hopefully at the meet you can find someone with a v2 to help data log your rail pressure. You might also look at an AutoCal, just make sure you buy it from the tuner you plan to buy tunes from eventually.

 

[hetdiesel]

You can create a secondary problem before you diagnose the cause of the first problem. Then you have two problems and will chase them forever.

Hopefully at the meet you can find someone with a v2 to help data log your rail pressure. You might also look at an AutoCal, just make sure you buy it from the tuner you plan to buy tunes from eventually.

so honestly do you think intsalling a fprv shim kit , ported rail fitting and the feed line was throwing parts at it ?

 

[DMAXchris]

What codes are you getting?

 

[TDFDiesel]

so honestly do you think intsalling a fprv shim kit , ported rail fitting and the feed line was throwing parts at it ?

IMO if you were having an issue with fuel limp - p0087 I do.

Those are reasonable upgrades, but an upgrade shouldn't be installed to fix a problem. It may just end up hiding a problem that needs to be diagnosed and fixed before installing upgrades.

My FPRV is NOT shimmed and has never popped, popping is a safety feature when rail pressure reaches a certain pressure. The shim just increases the pressure required to pop it. Most guys don't shim the FPRV until it's an issue.

 

[hetdiesel]

so on this forum the hundreds of posts about that code saying the shim kit solved the problem they should not have tryed a $15 mod to try and fix the problem?

 

[hetdiesel]

What codes are you getting?

p0087 but after shutting the truck off and turning the key back on the qs2 stated there are no codes present. If I could read logged event codes maybe i could be more useful.

 

[TDFDiesel]

so on this forum the hundreds of posts about that code saying the shim kit solved the problem they should not have tryed a $15 mod to try and fix the problem?

A quick data log will tell you if the problem is the FPRV, CP3 not keeping up, etc...

I personally do NOT throw parts at a problem without knowing what the problem is.

 

[danhr]

so on this forum the hundreds of posts about that code saying the shim kit solved the problem they should not have tryed a $15 mod to try and fix the problem?

most of the people who are getting that code are draining their rail due to running a fairly "hot" tune.

on a "70 hp" setting, you should be no where close to draining your rail pressure, which leads most to believe that something else is the culprit, and that your problem (even though it has the same code) is more than likely caused by something else. What the something else is can not be determined until proper diagnosing is done... which starts with monitoring the fuel rail pressure.

Here's a quick analogy for you.

Let's say that you have a problem with low tire pressure because you have a nail in your tire, and it makes your low tire pressure light come on. You search on here and find out other people installing different pressure sensors, that way they can run lower tire pressure for the drag strip and not set off the low tire pressure light. You read that everyone else is doing this and install the new sensor in your wheel, but you keep having your light go on.

The two have the same symptoms, but not the same cause.

 

[hetdiesel]

well as soon as i can moniter that i will chime in let everyone know what i come up with. no one replied that are going to the meet so we will see how long it will take if anyone can help me out. anouther thing i have in mind is the qs2 i have been looking into efi live from atp trucks i personally never liked quadzilla but it was on the truck when i bought it I did not try it yet but i wonder if i set the truck to stock or eco tune if it will still throw the code?