LBZ: log of 600,000 mile LBZ throwing 0087s

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lotsofmiles

Father of the Van
Dec 4, 2008
3,097
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Michigan
Rodger, 86burgandyss, stopped by today to get a log of his truck throwing the 0087

the truck, iirc is
07 lbz with 600,000+ miles
bully dog tune - dont remember which
shimmed

He was getting the 0087s, replaced the 2 fuel lines at the stock filter and it helped alot he said. But he is still getting 0087s under load. He hasnt checked the rest of the fuel lines yet under the truck

Attached are a few log files. The file where it threw the code actual vs desired were about 12K apart when it threw it.

Whats next?

Check the other lines.

Could CP3 be going?

Thanks
 
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LBZ

LBZ

Super Moderator
Staff member
Jul 2, 2007
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600 000 miles. If it's a stock cp3, that is one of the things I would be leaning towards as being the problem. A tech II would be a handy tool to diagnose it's performance.
Easy and cheaper things to look at would be any of the hoses between the tank and the cp3 as they can come apart inside and start restricting flow. I'm ASSuming he changed the fuel filter already........
Does he run a lift pump??
 
Bonestock

Bonestock

Active member
Aug 9, 2010
1,358
1
38
Worland Wy
FPR? The first log is the only log I had looked @. Desired rail was 26,000+. I didnt see actual psi logged. I know the trucks used to throw the 1093 on fpr but for some reason I thought 0087 was common also. Possible Fuel PSI relief valve poping off?
 
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lotsofmiles

Father of the Van
Dec 4, 2008
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Michigan
That 1st log he was stomping the go pedal pretty good. Iirc we were up over 100 MPH.
I wasn't ready on the laptop when he stepped on it so the log starts when we were already moving pretty good.

The other logs show desired going up and down fairly normal
 
McRat

McRat

Diesel Hotrodder
Aug 2, 2006
11,249
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Norco CA
www.mcratracing.com
You need to check for vacuum at the front schrader valve. Could be poor tank venting, dirty pickup, etc.

Air leak is another.

I'd do a Bottle test also.

I'd also put a cheap lift pump on it before replacing the CP3 or regulator.

Also see what it does with stock tune.
 
z79outlaw

z79outlaw

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Apr 20, 2007
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Get whole of that rvhaulin or something like that I'm sure someone else here has to remember him 2 years or so ago he had a 300,000 miles lbs iirc and Merchant did all kinds of stuff to that truck including the CP3 and he problems had problems. I'd definitely think it'd be worthwhile to get ahead of him and Eric.
 
fishsmith

fishsmith

Active member
May 14, 2008
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We have had several of our lmm's doing the same thing. It doesn't seen to matter if it is a stock tune or not.

Sent from my DROIDX using Tapatalk
 
12secondhandshaker

12secondhandshaker

<---Stock trans
Jan 21, 2009
146
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Sparta, MI
I bet the FPRV is leaking pressure.

I had a shim kit go bad once. Replaced with a "race" valve and no more problems. I would never shim a stock cp3 truck again!
 
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86burgandyss

600,000+ miles
Apr 27, 2011
9
0
0
south east michigan
McRat said:
You need to check for vacuum at the front schrader valve. Could be poor tank venting, dirty pickup, etc.

Air leak is another.

I'd do a Bottle test also.

I'd also put a cheap lift pump on it before replacing the CP3 or regulator.

Also see what it does with stock tune.
Click to expand...

Thanks for all the input guys.
When you mentioned poor tank venting, it makes me think of when I'm fueling. I can be at a car diesel pump, have it on the slowest setting and it will still spit back out!! Big time!! I have a Titan aftermarket tank that I had a shop install. What should I look for?
 
Mike_S

Mike_S

OOPS!
Nov 18, 2009
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Idaho
86burgandyss said:
What concerns should I have with running a race valve?
Click to expand...

IIRC the race valve completely blocks the pressure relief port in the fuel system, i dont like the idea, but many many people have good success with them. Look at the other suggestions first, check the vacuum port on the front of the engine, check for degraded fuel lines, does fuel pressure follow commanded when youre not wringing the engine out? Try a return rate test, with that many miles, your CP3 could well be getting tired.
 
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lotsofmiles

Father of the Van
Dec 4, 2008
3,097
0
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Michigan
Mike_S said:
does fuel pressure follow commanded when youre not wringing the engine out? Try a return rate test, with that many miles, your CP3 could well be getting tired.
Click to expand...

From what I saw, yes desired and actual were sticking close together when normal driving. I've got one more log file I didn't post of just normal around town driving

86burgandyss said:
Thanks for all the input guys.
When you mentioned poor tank venting, it makes me think of when I'm fueling. I can be at a car diesel pump, have it on the slowest setting and it will still spit back out!! Big time!! I have a Titan aftermarket tank that I had a shop install. What should I look for?
Click to expand...

Funny that comes up. No issue with the truck, but the gasser van does the same thing at the gas pump and is very touchy on hard acceleration. I think I've got a blockage in the filler neck due to the line for the equipment in there

Is your aux tank plumbed in the same as mine with the dual barbed filler neck adapter thingy from dually depot?
 
LBZ

LBZ

Super Moderator
Staff member
Jul 2, 2007
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If you tie your sliptank into your fuel tank vent hose, it will spit back at you. It's because the barbed fitting inside the hose restricts the flow of the air trying to escape the tank when filling. Mine does the same thing and it's annoying as hell. There is a kit out there to eliminate this problem but I can't remember where I saw it.

I'm not sure how a shimmed valve can fail unless you only have one shim in it or the spring wears out which I don't think is that likely but plausible I suppose. I had a race valve at first and it leaked after 6 months (yes it was tightened by the hand of God!!) so I pulled it and replaced it with a new stock valve which I put 3 shims in and never had a problem since. Like Pat said, a bottle test is a quick test for this though.
 
8

86burgandyss

600,000+ miles
Apr 27, 2011
9
0
0
south east michigan
LBZ said:
If you tie your sliptank into your fuel tank vent hose, it will spit back at you. It's because the barbed fitting inside the hose restricts the flow of the air trying to escape the tank when filling. Mine does the same thing and it's annoying as hell. There is a kit out there to eliminate this problem but I can't remember where I saw it.

I'm not sure how a shimmed valve can fail unless you only have one shim in it or the spring wears out which I don't think is that likely but plausible I suppose. I had a race valve at first and it leaked after 6 months (yes it was tightened by the hand of God!!) so I pulled it and replaced it with a new stock valve which I put 3 shims in and never had a problem since. Like Pat said, a bottle test is a quick test for this though.
Click to expand...

any ideas on where to search for that kit?
yes I have all 3 shams and it also. thinking about replacing it just to eliminate that as an issue
 
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