[Wheathead]

I have a 2005 lly that doesn't seem to want to read balance rates when warm 160+, all read 0. It also has a slight miss at idle when it wont read balance rates. If you put your foot on the brake it'll read and clear up (won't miss) but as soon as you let the brake off it goes back to missing every so often. This is all in park, in gear it reads fine and within spec as well as driving there's no problems. Replaced injectors back in march of this year (another issue). Also checked wiring going to the ficm and was fine. Replaced ficm and still no change.

It's to the point where I'm at a dead end on what to try next. I was going to try data logging the truck with an autocal to see what it might be but am unsure on what PID's to choose to help me diagnose this. I have checked FPR actual vs desired and that was within spec +/- .1 kpsi.

This doesn't seem to be a major problem just something that bothers me and I'd like to try and figure out what is causing it.

Anyone have some suggestions for PID's or answers to what may be causing my problems?

TIA

 

[ieetgluu]

Perhaps ask whomever will be looking at the datalog. Reason being I believe you can't view the datalog for locked tunes

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[Wheathead]

Sorry about the long reply. Got busy at work and didn't have time to think about it. I can view data logs on the computer with EFI live and can set my own parameters/pids but I just wasn't sure which I'd need to help diagnose this problem. I'll give my tuner a call/email to see if they can help figure out what could be wrong. Don't believe it's tuning related as I put it back to stock and still did the same thing where when it got above 160 it starts to slighty miss. I feel like it's electrical related because of this.

 

[PaLLY]

I had the same issue with my LLY. Turned out my lift pump pressure was set at 14psi. I set it at 6 psi. No problems so far.

 

[04.5LLY PA]

I have the same issue. Truck warms up and it misfires at idle. New injectors fpr thermostats and temp sensor still doing it. Before I installed the injectors it idled perfect. And after new injectors once 160+ idles like a gas misfire. Totally random and shakes truck. Any ideas?? I just joined the site and posted a LLY misfire when warm
The dealer said they didn’t know. Everything mechanically is perfect. No chaffs at alt wire harness bracket or ecm or ficm. This issue is driving me nuts!!!

 

[Wheathead]

I never have found the root cause of this rough idle problem. I’ve done similar to you check most the error prone areas, replaced several parts, reverted the truck back to stock but nothing helps or makes it worse. Sometimes when in park it idles relatively normal, put it in gear then back to park and it misses like a son of a gun. One thing I really haven’t checked sure close yet is grounds and that’s mostly due to not knowing exactly where they are. Just haven’t had time to research it yet. Only other possibility to me is corrupt ecm or internal short that only happens above 160. Don’t feel like shelling out the money though for an ecm if it doesn’t fix it.

One thing I’ll add is there are boatloads of stories that I’ve found regarding to these very same circumstances and no one has ever came up with a solution. So if you do please tell, or if I find grounds was the cause I’ll try to update this thread so someone else may get the answer.

 

[04.5LLY PA]

I had it at the dealer today and they said mechanically it’s perfect running and everything checks out good. The only thing he said was could be the ecm which was $1100 plus flash and he said it’s no guarantee. Soooo idn. PPE will Reflash ecm for $100. So I’m gonna send it to them and have them flash it and test it. But that’s gonna take atleast a week but I’ll get back to you for sure. I wanna solve this and give others a answer as well.
I start the truck up in the morning idles perfect. Then drive it 10/15 minutes and stop put in park and idles all jacked up. RPMs from 640-700ish. It’s a misfire. I’ve spent over 4 grand the past month with injectors and fpr and fuel lines and hoses and Tstats and temp sensor and nothing. Very frustrating and it’s my daily driver.

 

[Wheathead]

Besides finding the problem, I’ve thought about trying to mask the problem...160 degree thermostats if possible or fouling the computer into thinking its running below 160 to see if it still misses. I haven’t done these but just thoughts I’ve had about it.

I know what you mean about spending money and another problem arises. When injectors were going bad I replaced them hoping to fix it only to have more problems when done

 

[rta1197]

I am very interested in what you find out.
Just in the last week, my LLY started running rough and had a loss of power. Had some white smoke that, to me, did not initially smell like diesel. I ended up getting two codes, P0046 & P0307. I replaced the solenoid for the vanes but both codes returned. Yesterday I got the balance rates checked and found the #7 was dead in the water, #2 was pretty close to .0 and the other 6 were about a -3.0. I'm leaning towards the #7 could possibly lead to the P0046 code if the ECM could not decide where the vanes needed to be. IDK.
Anyway, gonna replace the injectors with S&S and see what happens.

 

[04.5LLY PA]

Besides finding the problem, I’ve thought about trying to mask the problem...160 degree thermostats if possible or fouling the computer into thinking its running below 160 to see if it still misses. I haven’t done these but just thoughts I’ve had about it.

I know what you mean about spending money and another problem arises. When injectors were going bad I replaced them hoping to fix it only to have more problems when done

I’m thinking of replacing pigtails 2&7 since there the ones that fail anyway and see if that helps.

Also what you said about fooling the temperature by lowering the temp stats idn maybe a good idea to unplug the temperature sensor and maybe that will stop the computer from reading the actual temperature. I’m sure it will throw a code so maybe not a good idea if you don’t have a edge or something to reset the code. I mean you can always unplug both batteries for 20 minutes. Should reset the ecm.

 

[04.5LLY PA]

I am very interested in what you find out.
Just in the last week, my LLY started running rough and had a loss of power. Had some white smoke that, to me, did not initially smell like diesel. I ended up getting two codes, P0046 & P0307. I replaced the solenoid for the vanes but both codes returned. Yesterday I got the balance rates checked and found the #7 was dead in the water, #2 was pretty close to .0 and the other 6 were about a -3.0. I'm leaning towards the #7 could possibly lead to the P0046 code if the ECM could not decide where the vanes needed to be. IDK.
Anyway, gonna replace the injectors with S&S and see what happens.

Try wiggling the #7 pigtail. The # 2 and #7 are prone to fail. They have a upgraded kit it’s like $250 for the kit but you can buy pigtails for $20 a pop. Just idea

 

[rta1197]

Try wiggling the #7 pigtail. The # 2 and #7 are prone to fail. They have a upgraded kit it’s like $250 for the kit but you can buy pigtails for $20 a pop. Just idea

I've done a lot of wiggling ... hoping it was not the injectors. I ice picked #7 to.

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[04.5LLY PA]

What

Besides finding the problem, I’ve thought about trying to mask the problem...160 degree thermostats if possible or fouling the computer into thinking its running below 160 to see if it still misses. I haven’t done these but just thoughts I’ve had about it.

I know what you mean about spending money and another problem arises. When injectors were going bad I replaced them hoping to fix it only to have more problems when done

Have you replaced your ficm or had the exam reflashed?
What issues are happing and when did they start to happen?

 

[Wheathead]

I have swapped the ficm with another working unit. It didn’t solve anything. Also inspected wiring to and from ficm. I haven’t reflashed the ecm yet, as it’s hard to find time to take truck to dealer since I’m >30 miles from one but I feel that that could be a likely problem, mostly because I’ve tried most other things.

The problems I’m having are that once up to operating temp the truck lopes/misses at idle in park/neutral. It all started when I replaced the injectors with brand new Bosch from LDS.

The idea about masking the problem was just thinking out loud. I prefer to find the problem if possible.

 

[04.5LLY PA]

Wow so you tried swapping the ficm. And nothing. Well the same exact problem your having mines doing the same thing. Installed 8 brand new Bosch injectors from injectorsdirect.com and then once the truck warms up to temperature it starts to lope/misfire in park or neutral. The balance rates read all 0s on my edge as well.
So my trucks at a shop now. I’m getting a new ficm and reflashing the ecm and it’s $2500 including the couple hrs of diagnostics that’s leading to the tech to believe it’s ither the ecm or ficm. So the fact that you swapped your ficm out and nothing changed has we VERY worried I’m about to waste $2500!!! So I’m definitely worried!!!! Cuz after replacing all injectors I’ve also replaced fpr and the fprv with a plug. I also replaced the filter housing with new unit I did Tstats and temp sensor and all the fuel lines high pressure and low pressure. And nothingns changed. Even bought new batteries. So now I’m worried!!!!
How long have you been driving with your truck with this issue. When did this start?

 

[Wheathead]

Bout 1 1/2 years. I just live with it mostly. Don’t think it hurts anything just sounds like crap at idle sometimes . If I don’t want people to notice it I’ll shut off in gear and then put in park. I don’t do this very often. I couldn’t tell you if the ficm will fix it or not. It didn’t for me but you don’t have my truck. I would guess between the ficm and reflash it should fix it

 

[04.5LLY PA]

Thanks for the reply. So a year and half you haven’t found a answer. Wow that’s crazy!!! Blows my mind that all these people have this issue and no one has a answer.
So the new ficm and reflash I Hope is the answer for me and others. Im waiting for my truck now. Should be a couple days. I’ll post back ASAP.

 

[ArizonaDieselClub]

Looks like a n old post with no recent updates but I'm experiencing a problem where the ECM doesn't sample or report any injector data at all. Doesn't matter if I have the truck in neutral or brake depressed at idle. My 2018 L5P is running rough and went into limp mode over a bad injector on cyl7 but I wanted to check balance rates to get some insight into the other cylinders but there is no data whether I use my cts3 or zurich pro scan tool. Maybe there is a condition so far out of spec it causes the ECM to not report the data which is insight into a larger problem?

Just a thought on the phantom rough idle issue. IS it possible engine hours and mileage could lead to loss compression in the cylinders that the ECM doesn't account for, thus causing a rough idle condition?

 

[jeamn]

Just a thought on the phantom rough idle issue. IS it possible engine hours and mileage could lead to loss compression in the cylinders that the ECM doesn't account for, thus causing a rough idle condition?

I think you are right.

This might not be much help unless you have EFI, but I was having the same issue with my truck, lots of parts replaced, stock or modified tuning, same problem throughout. High mileage engine.

Data logging showed a slight wiggle in commanded mm3 for both pilot and main injections at idle once the engine was warm and idling. Basically, the ECM kept making as small of an adjustment that it could to maintain a steady idle but kept overshooting, so it kept trying to compensate and you end up with an idle that varies more than it should. You end up with a tiny lope. Really annoying if you have to sit in the truck with it idling. I was just keeping my foot on the brake just to keep it smooth.

In EFI Live, I tried adjusting the idle fuel values in the calibration tables, but that didn't seem to help. I eventually stumbled on B0937, which is a pilot injection timing table, which is keyed on ECT. At idle fuel values, it reduces pilot injection timing once the engine is up to operating temps. I bumped this back up to it' slightly cooler values and the idle smoothed right out.

When idling, pilot injection is actually a large percentage of the main injection. I wonder if the worn engine or maybe a slightly worn injector need a little bit more timing for the pilot injection when operating at the very low values when idling. Otherwise the pilot blends into the main injection and causes a light lope.

 

[ZiGBlazer]

Has anyone found a fix for this yet? I just bought an LLY a month ago, did a lot of much needed maintenance on it including FPR and FPRV. Finally got it in use and have found it has a rough idle when warm. Only in park or neutral. Once in gear it smooths out. Checking balance rates show 0.0 on all when in park, but they actually start giving expected readings when I put it in gear. Main injection pulse is jumping all over from 0.0mm3 to 4mm3 when in park, but steady at 3.8mm3 when in gear. I'd love to find a solution to this, otherwise the truck is now in pretty good shape for having 280,000 miles.

I should note, that I lowered the idle timing rpm in b0940 to 500 with no change. Also tried changing the b0937 table so that 176degrees and 198 degrees matched what was there for 154 degrees like suggested above without success.