P0087 fuel rail pressure low limp under high loads

[Kennedy]

Maybe we could get Mark Rinker to do a water mist injection on his fuel cooler and see if that helps.

[Mark Rinker]

Interesting timing on this last comment...85F day in Kentucky I75 mountains today and reset the code too many times. Filled the tank and expected it to slow down, but it remained pretty consistant.

Was thinking about a cheap experiment with doubling the fuel cooler size. Misting would also be interesting.

Coyles experience with additional filtration and high fuel capacity sure sounds encouraging, especially if the towing is heavy, hot, and uphill. Maybe he'll chime in to tell us more about what is typical loads and such are...max loads/max hills?

[More Power]

Maybe we could get Mark Rinker to do a water mist injection on his fuel cooler and see if that helps.

I don't think everyone gets the reference.... I think I still have the spray bottles I used in a TIC story a few years ago...

On a more serious note, we all know that the 6.5 community has suffered for a long-long time by dealer diagnoses that pronounced the DS4 electronic fuel injection pump as needing to be replaced for just about any sort of engine running problem. In some of those cases, it was the pump, and in many others it wasn't. Good troubleshooting eliminates the other possibilities before jumping to the most expensive solution - like changing head gaskets instead of looking for a spun impeller on a water pump.

On the other hand, if a prognosticator is so absolutely positively convinced of his diagnosis, it should come with a money back guarantee. That would be a big convincing selling point...

On another note, I saw your pic & stuff in Diesel Power mag. Good job!

Jim

[Mark Rinker]

Interesting observation from yesterday...

Loading a large boat in sweltering temps yesterday near Ackworth, GA. So hot that I left the truck running with AC on so I could take few breaks to avoid heat overload...

After I left the marina, loaded and hit I-75, immediately started getting the P00087 codes. Reset 3-4 times in the first 15 minutes and then it started slowing down in frequency...

So, under only AC accessory load idling either the high return rates heated up 3/4 of a tank of fuel (doubtful) - or high underhood temps alone are enough to cause the low fuel rail pressure code. THIS IS A VERY TELLING OBSERVATION OF THE PROBLEM, IMO.


Also it appears that the problem has not come up on LML trucks - so possibly GM changed their programming?

[Mark Rinker]

Maybe we could get Mark Rinker to do a water mist injection on his fuel cooler and see if that helps.

No, I didn't get it - but should have considering the source.

>>> After numerous calls with same issue over the years I FINALLY came across a loyal (new) customer who not only believed me, but patronized his source of free Tech advice. >>>

JK - I am not going to buy new injectors. I am not going to buy your Mega filter. I am not going to buy your vaccuum gauges, either. No cases of FPPF. It has nothing to do with believing you. Its also not because I am simple, or stubborn. It is a simple cost/benefit decision based on how I use and freqently trade my power units for my business. Period.

Over the years, I've run your LB7 and LBZ tunes with great results. I've purchased 6.5 and Duramax lift pumps, two sets of boost/EGT gauges, two sets of shocks, an EGR block-off plate, a case of FPPF and an hour of dyno tuning. This is what I can think of, off the top of my head. Q: Who is the loyal customer?



“You can make more friends in two months by becoming interested in other people than you can in two years by trying to get other people interested in you.” ― Dale Carnegie, How to Win Friends & Influence People





The same applies to sales, JK. Get interested in the P00087 limp problem programmatically and I'll be your customer...again. I have tons of real world experience that can be tapped into, if you stop selling, and start listening.

[Kennedy]

The same applies to sales, JK. Get interested in the P00087 limp problem programmatically and I'll be your customer...again. I have tons of real world experience that can be tapped into, if you stop selling, and start listening.

Someone was always going to swing by with a local load and his 2006 LBZ.
Get interested yourself and keep in mind it may take HOURS and I need to get back home. I am also a bit less optimistic abouth finding the LMM issue as readily as the LBZ based on table availability.

I listen, I sell, and more importantly I fix problems and create solutions to prevent them. Heck I called in a favor to have a used set of injectors tested and then reported my findings here.

[More Power]

On a perhaps related subject....

I spoke with a midwest fuel injection shop owner recently about "white smoke at idle". The conversation began by him asking me what I knew about using ATF as a diesel fuel treatment. I told him that I didn't have a problem with it, and that the additional lubricity should, in theory, help with longevity. I also added that every fuel injection and fuel treatment company rep I spoke with a while back condemned using ATF - for obscure and not easily understood reasons.

He (Matthew) told me that their shop had changed quite a few Duramax injector sets through the years for the white smoke problem. Since they also rebuild the injectors, their shop guy started looking at the parts, and noticed nearly all of the injectors removed for a white smoke problem contained a residue buildup inside the nozzle tip. There was no particular wear or other problem with the injector, just a buildup of residue that affected the nozzle sealing.

The ATF question arose because the shop has a few customers who routinely add ATF to their fuel. One of them had to have a set of injectors replaced for a different reason, and their tech guy found no such residue inside the nozzles. The only difference was the use of ATF as a fuel treatment. Apparently, ATF in the fuel keeps the injectors clean.

I asked Matthew if the traditional fuel treatments are keeping the injectors nozzles clean, and he told me that they're not seeing a difference. Interestingly, I spoke with Mark Rinker recently about a concentrated fuel system cleaning procedure some dealers have begun using at dealerships, to help solve some of the problems experienced by Duramax owners.

Food for thought....

Jim

[cabletech]

I don't know how smart, safe or good for the engine this would be!!!!

There is a limp mode torque limiting table that can be changed with EFILive. It limits torque above 2000 rpm. Changing it would not stop the CEL or fix the problem, but may stop you from having to clear codes all the time.

Food for thought.

Jay

[Kennedy]

Without going into great detail, when the LBZ injectors that I mentoned previously were being tested it was discovered that they got worse when cleaned of varnish or with a new nozzle installed.


I prefer to fix the problem not hide it by circumventing safety limits. Also there are undoubtedly many tables not present in the EFI tool making it difficult to find all paths to this particular limp mode.

[More Power]

Without going into great detail, when the LBZ injectors that I mentoned previously were being tested it was discovered that they got worse when cleaned of varnish or with a new nozzle installed.


I prefer to fix the problem not hide it by circumventing safety limits. Also there are undoubtedly many tables not present in the EFI tool making it difficult to find all paths to this particular limp mode.

Can the cause of high fuel return be identified? Do you know what component parts are the cause? Thanks,

Jim

[Mark Rinker]

I don't know how smart, safe or good for the engine this would be!!!!

There is a limp mode torque limiting table that can be changed with EFILive. It limits torque above 2000 rpm. Changing it would not stop the CEL or fix the problem, but may stop you from having to clear codes all the time.

Food for thought.

Jay

Sounds like an interesting idea. I am willing to test it and pay for the development time necessary. My goal is simple...swap ECMs until I get to the end of the road (tip/nozzle problems) on this set. Past experience says this will be about 40k miles down the road. I have a core ECM from my 2006.

[Mark Rinker]

Someone was always going to swing by with a local load and his 2006 LBZ.
Get interested yourself and keep in mind it may take HOURS and I need to get back home. I am also a bit less optimistic abouth finding the LMM issue as readily as the LBZ based on table availability.

I listen, I sell, and more importantly I fix problems and create solutions to prevent them. Heck I called in a favor to have a used set of injectors tested and then reported my findings here.

JK - Thanks for making yourself available this week for me to swing by. As fate would have it, there was a lengthy delay at the marina, followed by a low hanging telephone wire about two miles down the road that wasted alot of time in my day.

On the way home across WI, I only had two codes set, even though the temperatures were in the 90s. Both were shortly after getting underway, after sitting still and idling.

Heat soak and hot fuel is my hypothesis.


We'll keep trying to connect and test this thing!

[Kennedy]

Still testing here. Tune 3 reportedly went all day yesterday without tripping. I told tester that I'd like to have him try (within reason) to get this code to set so we'll see what happens.

Too early to tell, too many variables so we need to keep on testing.

How high were/are your fuel temps reaching?

Thinking we may try twin lift pump setup to help the CP3 and potentially increase circulation to potentially help with pump temps

[Kennedy]

More testing/validation required, but it appears as though tune #3 is doing what it is supposed to. Rail psi's were holding at or near desired and no P0087. Fuel temp pushed up even higher as I had expected.

We need to get lift pumps on this truck to see what impact we can have on fuel temps.

[Mark Rinker]

Any chance of making this programming available via the Diablosport/Predator handheld as a custom tune?

If no - is there any way to reflash the stock ECM with this fix and a mild tow/economy bump.

Reason for asking is this truck is probably going down the road this fall, as part my my relocation to Seattle. I'd like to sell it with a solution for the P00087, that doesn't require or assume much knowledge of the end buyer - i.e. whomever gets it at the auto auction after its traded in.