LLY: Why use a RACE FUEL VALVE

[Chevy1925]

I think it's funny when people try a race valve to help low rail without doing the super simple bottle test.

Difference between a mechanic and a parts replacer lol

 

[henery97]

I've seen a couple LLYs with bad stock fprvs. I've also had bad race plugs too. If your not having rail pressure problems, probably not worth it unless you are planning a cp3 upgrade.

 

[LBZ]

Most guys throw them on hoping it fixes a rail issue caused by bad injectors. Usually start with rail plug. Then lift pump the trucks for sale. I have only had 1 test out bad in the last 4 years. Then fought getting race plug to seal.

That was my problem the one time I bought a race valve. I think they probably work fine in the ppe fuel rail they were designed for but mixed results in stock rails in my experience.

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[LBZ]

Yep. I have seen a bunch of true LLY trucks pop them, but when they upped the max rail pressure with the LBZ, they also raised the pop pressure on the relief valve. The only time I have ever seen an LBZ or LMM pop a relief valve is on a truck running a dual CP3 setup. Most people usually install a race valve on an LBZ or LMM because they think or they heard it is a problem. Unless you have verified your valve is leaking or you have an 04.5-05 LLY, you are most likely wasting your time by shimming or installing a race valve.

The race valve I installed was on my lly because the stock one wouldn't stop opening with my tow tune towing my camper. It came out when I couldn't get it to seal and I shimmed a new lbz one and it was good after that.

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[WolfLMM]

Kinda like the lb7. They don't pop but once they do (if ever), they damn near never seal again

Honestly, I wish the made set pressure ones like the cummins boys can get. Shimming it doesn't do a thing to tell you where it will pop and most guys set it to the point of spring bind or just before so it won't ever open. Or maybe they do and I just ain't looked yet

Exactly, when you shim the valve you have no idea where the new pop off pressure is set. Could be 80,000psi for all you know. So that kinda throws the whole "I like safety backup" argument out the window.

 

[zf>allison]

Exactly, when you shim the valve you have no idea where the new pop off pressure is set. Could be 80,000psi for all you know. So that kinda throws the whole "I like safety backup" argument out the window.

That's why I just plugged mine, either way damage can occur more than likely plugged or shimmed. Guess that's why it's a race plug not a safety plug lol.

 

[joecool752]

Doesn't sound like an issue or at least not long enough of a test. Are these the same conditions as before?

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What's the trick

I totally agree with this statement, however, I honestly don't believe that the pump is capable of making enough pressure to burst anything.

I've tried my share of stupid things, and had some problems over the years on various trucks that caused some wicked high rail pressures, but have never broke anything on an LLY and newer fuel system from to much pressure.

I install a ton of race valves. Never once had an issue. But there is a trick to installing them.


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[ikeG]

Most guys throw them on hoping it fixes a rail issue caused by bad injectors. Usually start with rail plug. Then lift pump the trucks for sale. I have only had 1 test out bad in the last 4 years. Then fought getting race plug to seal.

That has been my experience

 

[BoiseRob]

Yep. I have seen a bunch of true LLY trucks pop them, but when they upped the max rail pressure with the LBZ, they also raised the pop pressure on the relief valve. The only time I have ever seen an LBZ or LMM pop a relief valve is on a truck running a dual CP3 setup. Most people usually install a race valve on an LBZ or LMM because they think or they heard it is a problem. Unless you have verified your valve is leaking or you have an 04.5-05 LLY, you are most likely wasting your time by shimming or installing a race valve.

This past Friday we were driving on the interstate with the cruise set at 70mph towing our TT when I heard a muffled "pop" and the check engine light came on. Engine wouldn't go above 2000 rpm. Got to our campspot and went into town and the local NAPA pulled a P0087 code. Stock LBZ running an IdahoRob tow tune.
Air temp was 106 degrees. My friends 6.0 Ford engine light came on 15 minutes before mine. We did not fuel up at the same station but we did leave our trucks idling for 20+ minutes while we shopped for groceries (wives & dogs in the trucks).
This was the first time the P0087 code has happened. Truck is a 2007 LT1 Classic with 72k miles and has run the same IdahoRob tune since it was 6 months old in April of 2007.

Does high ambient air temp have an affect on the fuel or fprv valve?

 

[NC-smokinlmm]

Google. It's your friend. This subject has been thoroughly covered multiple times...

 

[NC-smokinlmm]

This past Friday we were driving on the interstate with the cruise set at 70mph towing our TT when I heard a muffled "pop" and the check engine light came on. Engine wouldn't go above 2000 rpm. Got to our campspot and went into town and the local NAPA pulled a P0087 code. Stock LBZ running an IdahoRob tow tune.
Air temp was 106 degrees. My friends 6.0 Ford engine light came on 15 minutes before mine. We did not fuel up at the same station but we did leave our trucks idling for 20+ minutes while we shopped for groceries (wives & dogs in the trucks).
This was the first time the P0087 code has happened. Truck is a 2007 LT1 Classic with 72k miles and has run the same IdahoRob tune since it was 6 months old in April of 2007.

Does high ambient air temp have an affect on the fuel or fprv valve?

Probably high fuel temps set it off...

 

[SoCalMike]

This past Friday we were driving on the interstate with the cruise set at 70mph towing our TT when I heard a muffled "pop" and the check engine light came on. Engine wouldn't go above 2000 rpm. Got to our campspot and went into town and the local NAPA pulled a P0087 code. Stock LBZ running an IdahoRob tow tune.
Air temp was 106 degrees. My friends 6.0 Ford engine light came on 15 minutes before mine. We did not fuel up at the same station but we did leave our trucks idling for 20+ minutes while we shopped for groceries (wives & dogs in the trucks).
This was the first time the P0087 code has happened. Truck is a 2007 LT1 Classic with 72k miles and has run the same IdahoRob tune since it was 6 months old in April of 2007.

Does high ambient air temp have an affect on the fuel or fprv valve?

Could also be a collapsed fuel line.

I don't think you can hear the frpv pop open.

 

[Ne-max]

P0087 is the toughest code to diagnose in my opinion. Could be a supply issue, Injectors, cp3, or fprv.

 

[whitetrash21]

I was running through this a couple weeks ago. Towed the camper to Oregon and back from Vegas. Had the truck the 0087 on 8 different occasions between here and Reno. Ambient temps ranged from 100-118*. I watched fuel temps climb to 230+ on a couple different occasions. Stayed in Reno for the night and went the rest of the way in the morning.....didn't get the code at all after that. Fuel temps never broke 175 and ambient temps were under a 100*

Coming home was the same story. Less than a 100* of ambient temp through Oregon and Cali and no issues......south of Reno and temps get up to 110+ and fuel temp starts climbing again. Got the 0087 3 times on the way back, every single time was under a good load, ie passing semis or climbing grades. Didn't log it, but was watching the commanded vs actual rail and they were pretty much on par with each other.


Issue seems to happen when fuel temps climb but I'm not sure if that the reason or if something else is going on.

Btw, truck never got under ½ tank....tried to keep it as full as I could so it would maybe help keep those temps in check.

 

[Ne-max]

I was running through this a couple weeks ago. Towed the camper to Oregon and back from Vegas. Had the truck the 0087 on 8 different occasions between here and Reno. Ambient temps ranged from 100-118*. I watched fuel temps climb to 230+ on a couple different occasions. Stayed in Reno for the night and went the rest of the way in the morning.....didn't get the code at all after that. Fuel temps never broke 175 and ambient temps were under a 100*

Coming home was the same story. Less than a 100* of ambient temp through Oregon and Cali and no issues......south of Reno and temps get up to 110+ and fuel temp starts climbing again. Got the 0087 3 times on the way back, every single time was under a good load, ie passing semis or climbing grades. Didn't log it, but was watching the commanded vs actual rail and they were pretty much on par with each other.


Issue seems to happen when fuel temps climb but I'm not sure if that the reason or if something else is going on.

Btw, truck never got under ½ tank....tried to keep it as full as I could so it would maybe help keep those temps in check.

I would test return rates. Hotter the fuel the thinner it gets.

 

[BoiseRob]

I was running through this a couple weeks ago. Towed the camper to Oregon and back from Vegas. Had the truck the 0087 on 8 different occasions between here and Reno. Ambient temps ranged from 100-118*. I watched fuel temps climb to 230+ on a couple different occasions. Stayed in Reno for the night and went the rest of the way in the morning.....didn't get the code at all after that. Fuel temps never broke 175 and ambient temps were under a 100*

Coming home was the same story. Less than a 100* of ambient temp through Oregon and Cali and no issues......south of Reno and temps get up to 110+ and fuel temp starts climbing again. Got the 0087 3 times on the way back, every single time was under a good load, ie passing semis or climbing grades. Didn't log it, but was watching the commanded vs actual rail and they were pretty much on par with each other.


Issue seems to happen when fuel temps climb but I'm not sure if that the reason or if something else is going on.

Btw, truck never got under ½ tank....tried to keep it as full as I could so it would maybe help keep those temps in check.

Sounds like what happened to me. Drove home without issue but it was under 90 degrees.Truck was 3/4+ full when it limped.
Made an appointment with ATP to install the shim kit next week... :thumb:

 

[Chevy1925]

I was running through this a couple weeks ago. Towed the camper to Oregon and back from Vegas. Had the truck the 0087 on 8 different occasions between here and Reno. Ambient temps ranged from 100-118*. I watched fuel temps climb to 230+ on a couple different occasions. Stayed in Reno for the night and went the rest of the way in the morning.....didn't get the code at all after that. Fuel temps never broke 175 and ambient temps were under a 100*

Coming home was the same story. Less than a 100* of ambient temp through Oregon and Cali and no issues......south of Reno and temps get up to 110+ and fuel temp starts climbing again. Got the 0087 3 times on the way back, every single time was under a good load, ie passing semis or climbing grades. Didn't log it, but was watching the commanded vs actual rail and they were pretty much on par with each other.


Issue seems to happen when fuel temps climb but I'm not sure if that the reason or if something else is going on.

Btw, truck never got under ½ tank....tried to keep it as full as I could so it would maybe help keep those temps in check.

high fuel temps are nothing new in them temps buddy. you should see what they look like with dual fuelers and high rail pressure in those temps :roflmao:

so when the code was popping up, was actual rail dropping well below desired or was it still running with commanded?

i run a B&M stacked plate cooler and a cheapo jegs 1000cfm fan for a return fuel cooler (ditched the crappy stock one). ALL my return fuel runs through it including the air dog. it makes a significant difference in fuel temps and mpg. under the same temps as you pulling grades with a full tank, i could see 230-240* temps. with the cooler, i hover around 200*. yours ought to see even more of a drop since you dont have as much crap as me heating up the fuel.

 

[PureHybrid]

Desired might match actual pressure, but it's probably still dropping desired with those temps unless Rob maxed out the temp limiter table. Do you remember what the desired pressure was?

 

[Chevy1925]

Desired might match actual pressure, but it's probably still dropping desired with those temps unless Rob maxed out the temp limiter table. Do you remember what the desired pressure was?

IIRC, the only reason the P0087 sets is due to differential pressure between actual and desired rail pressure. not if the tune is pulling back rail pressure as actual should still match commanded.

id be more inclined to say the FPRV is popping

 

[PureHybrid]

He just made it sound like it was low on power, not in limp mode or anything.