LBZ: New cp3,still p0087!?!

[Devon]

Going to do a bottle test once I'm off work,not doubting anyone telling me to do a bottle test but how could it leak past the race plug? Isn't that the purpose of the plug,to block off all fuel from returning to tank and prevent any leaks?


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[Chevy1925]

Going to do a bottle test once I'm off work,not doubting anyone telling me to do a bottle test but how could it leak past the race plug? Isn't that the purpose of the plug,to block off all fuel from returning to tank and prevent any leaks?


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All PPE's FPRV is a stock FPRV shimmed for higher pressures. this doesnt mean it will hold higher pressures. Sometimes they hold and sometimes they dont. Unless you actually have a solid plug in that threaded opening or welded it shut, its possible to have the FPRV pop open and drop fuel pressure. IF you have a new CP3 and balance rates on the injectors look good, then this is the next logical/easy thing to check in the sequence of diagnosis.

 

[x MadMAX DIESEL]

When they leak with a race valve they seep past the threads. Its happened before..

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[juddski88]

All PPE's FPRV is a stock FPRV shimmed for higher pressures. this doesnt mean it will hold higher pressures. Sometimes they hold and sometimes they dont. Unless you actually have a solid plug in that threaded opening or welded it shut, its possible to have the FPRV pop open and drop fuel pressure. IF you have a new CP3 and balance rates on the injectors look good, then this is the next logical/easy thing to check in the sequence of diagnosis.

that's not true, PPE's race plug is solid. I have one. it could be a couple of things, and I would look at them in this order: check for kinks or restrictions in the bypass line that was made to delete factory filter, if none are found, measure low pressure feed PSI, if it doesn't drop much at WOT, then do a bottle test.

 

[x MadMAX DIESEL]

He has a race valve not there shim kit. What you have is a gold plated plug like a bolt, nothing like a spring or anything in it. I've heard from someone else that he's had customers with the hold flaking off and hurting injectors. Another story... just bottle test it its real easy, just be sure to block off the return side too or you'll have a big ol mess. Kinda common sense I guess but I forgot to once

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[juddski88]

He has a race valve not there shim kit. What you have is a gold plated plug like a bolt, nothing like a spring or anything in it. I've heard from someone else that he's had customers with the hold flaking off and hurting injectors. Another story... just bottle test it its real easy, just be sure to block off the return side too or you'll have a big ol mess. Kinda common sense I guess but I forgot to once

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What??

He has a race valve, exactly like mine, no shims, no confusion that I am aware of....

There is no gold-plating on my race valve.

And by bottle testing, I mean I am going to take the return line that goes to the cooler off, and see how much fuel I get in, say, 10 seconds. It wont be too messy.

 

[Chevy1925]

that's not true, PPE's race plug is solid. I have one. it could be a couple of things, and I would look at them in this order: check for kinks or restrictions in the bypass line that was made to delete factory filter, if none are found, measure low pressure feed PSI, if it doesn't drop much at WOT, then do a bottle test.

ah yes, i forgot about that. i kept thinkin his was shimmed with the PPE shim kit. my bad

 

[x MadMAX DIESEL]

What??

He has a race valve, exactly like mine, no shims, no confusion that I am aware of....

There is no gold-plating on my race valve.

And by bottle testing, I mean I am going to take the return line that goes to the cooler off, and see how much fuel I get in, say, 10 seconds. It wont be too messy.

What? How is anything I wrote any different than what you said? You just typed/read faster. I was saying that maybe the other guy was mistaken and thought he had ppes shin kit. I know what the race valve is, its like a bolt/plug. Maybe the new ones don't have plating anymore but they used to afaik. Also go take that return " u shaped" line off and cruise around for abit and hammer down... you WILL have fuel pour out on your test drive if it is not plugged on the return side. Idk what your talking about 10 seconds wise? Maybe using dvt to bring up rail pressure for the bottle test?? I do mine with real world driving... doesn't the dvt only bring rail psi to 160? You probably won't get much of a spike using the dvt function.

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[juddski88]

What? How is anything I wrote any different than what you said? You just typed/read faster. I was saying that maybe the other guy was mistaken and thought he had ppes shin kit. I know what the race valve is, its like a bolt/plug. Maybe the new ones don't have plating anymore but they used to afaik. Also go take that return " u shaped" line off and cruise around for abit and hammer down... you WILL have fuel pour out on your test drive if it is not plugged on the return side. Idk what your talking about 10 seconds wise? Maybe using dvt to bring up rail pressure for the bottle test?? I do mine with real world driving... doesn't the dvt only bring rail psi to 160? You probably won't get much of a spike using the dvt function.

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i saw afterwards that you were just answering the both of us but not separately.

A bottle test is done to compare an acceptable rate of return to the GM spec. the gm spec is given in Ml/sec or L/sec or whatever. so in order to get any good data from a bottle test, you must be consistent and know how long you tested for.

I have never done a bottle test at full rail at idle but I can't imagine it being very fun.

 

[x MadMAX DIESEL]

Sorry if I came across a dick.. didn't mean to if I did. But Fwiw you shouldnt be returning any fuel with a race valve, or any shimmed valve.. if you are, tighten the race plug, or add another washer to the shin kit

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[juddski88]

The factory valve only pops after 24k psi or thereabouts, so a stock valve shouldn't allow any return fuel? The injectors and the cp3 return through a separate line, so it is very possibly to return fuel with a race valve

 

[dmaxfireman]

I'm pretty sure that the return on the rail is not affected by the cp3 return at least on an lbz.

you take the hose off the back of the drivers side rail and plug it, then put a longer hose on the rail and put the other end into a bottle, you should get no fuel out of it if you have a race valve and minimal fuel with a shimmed valve after a WOT run

 

[ripmf666]

I'm pretty sure that the return on the rail is not affected by the cp3 return at least on an lbz.

The cp3 and all the injectors return on the same fuel line. Just giving the guy a pic off what it looks like with everything off lol.

 

[dmaxfireman]

i understand that henry, but if he puts a plug in the hose coming off the rail and then puts a longer hose into a bottle off the rail only he will know if the race valve is doing its job correct?

 

[ripmf666]

i understand that henry, but if he puts a plug in the hose coming off the rail and then puts a longer hose into a bottle off the rail only he will know if the race valve is doing its job correct?

Yes plug the top side of the return of the little horse shoe hose or the return fuel from the cp3 and other injectors will make a mess. I just worded it wrong while posting the pic of the general area of the fuel lines. And after pluging the little line run line off rail to bottle and tape it inside the bottle well and take for a ride and see if it has fuel or raise rail pressure with efi live or tech2.

 

[juddski88]

Raising rail with dvt function would be the way I was going to go about it...but...we didn't get past the boost leak last night. My own fault. Fixed it but as I was putting the last bolt on the lower tab of the egr pipe, the horn off the Y-bridge cracked at the flange

 

[McRat]

Thoughts:

P1093 is the normal code you see with PRV problems on LLY's.

Race valves don't always seat as well as OEM valves do. I don't recommend them anymore.

There is a tutorial for the Shim Mod and the Bottle Test IIRC (this is like 6-7 years old?).

GM now sells the PRV separately. They used to just sell the whole rail.

Like above, 3' hose to the nipple on the driver's side rail (rear) then to a bottle, U-shaped hose should be plugged (low pressure).

A bad race valve leaks at it's seat, so it leaks under normal engine output (stock tune). However a bad factory PRV only leaks at a pressure spike. To test OEM valve, put in big tune, hammer it, then chop the throttle suddenly at full output.

 

[juddski88]

Raising rail with dvt function would be the way I was going to go about it...but...we didn't get past the boost leak last night. My own fault. Fixed it but as I was putting the last bolt on the lower tab of the egr pipe, the horn off the Y-bridge cracked at the flange

 

[Devon]

Yea, what a night lol.I'll do the bottle test, if that comes up ok then I'm going to get ahold of airdog and see if I can get a new pump.


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[x MadMAX DIESEL]

Yea, what a night lol.I'll do the bottle test, if that comes up ok then I'm going to get ahold of airdog and see if I can get a new pump.


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Have you watched the lift pump pressure drop to nothing?

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