turbo lag and variation

[Milehigh]

I have a 2008 cummins ISX that I am experiencing difficulties with. The turbo has quite a lag or hesitation when you step on the accelerator. It makes shifting smoothly almost impossible. The turbo boost is also very unpredictable. Some days I will have 41 pounds of boost and other days only 32-35. I have even noticed on some long pulls that it will fluctuate 5-7 pounds of boost back and forth while on a dead pull. Another odd problem is that often on a hard pull the turbo boost gauge will drop to zero and a check engine will flash over the screen. It will flash for a bit and then hold steady. Sometimes it only holds steady for a few seconds and then all goes back to normal. Other times it will hold the check engine code for the length of the pull or until I back off the throttle. One mechanic wondered if the band for the variable turbo was sticking. The turbo is supposedly only a year or two old. I have had the truck for 4 months. It was mandate'd before I bought it by {*** Name removed: PM for the info ***} in Colorado. It was stock a 485 with 1850 torque. I talked to the man that sent the ECM in and he says it was flashed to around 600 hp. The motor has 765000 miles on it and has not been overhauled yet. Am looking for help.

[Nilao]

First get a inline 5 adapter and insite 5 off eBay. That way you can see what is going on in your ecm and your not at the mercy of the dealership telling you only what they want you to know. There are ways to test the turbo but you need a computer to do it right.

Secondly you need get with unilevers, Mr Hagg, or gearhead to check that tune out. There is so many tunes out there that, even though the mandate is gone, they do it in such a way that allows the engine to damage itself in the process.

Third you need to check the dpf to make sure it was hollow out properly. Some places just drill holes in the filter. Also make sure your egr cooler is still there as it requires for the oil cooler coolant circuit to function.

That's about all I can think of to assist you for now. Other will chime in also.

[Unilevers]

ahh troy strikes again. the owner of elite diesel. decent guy but likes his stolen stuff from utah with a Colorado flare on it. he shoulda stayed with cats instead of venturing into cummins.

i literally have retuned and fixed about 50 of his tunes, you arnt the first and last but your symptoms sound like the others. not saying your problems are all in the tune but its a place to start.

[Milehigh]

Ok guys, I will display my ignorance. I'm seeing the inline 5 adaptor but the insite stuff says 7.62. What am I missing? I'm not very computer literate so I will need lots of help. Unilever, if you have helped retune ECMs how can I get your help here? Do I need this computer stuff for your help? Nilao, the dpf is gone. The cooler is still on motor but not sure the status of functionality.

I guess the biggest thing is I need to figure out the insite program and buy it.

[Waterloo]

Here is the Inline 5 Reader that most all of us use here, there is only one left, you better jump on this one! If you do manage to buy that one, you should have it by the end of the week. And that is a damn good price, and includes software.

http://www.ebay.com/itm/Data-Link-Adapte...SwceNZQ69I

And get with {Edited: Unilevers, Gearhead, or Mr. Hag}... 485 to 600? Dude, you will blow the head on that thing and God knows what other damage. Sorry, and I don't mean to scare you, and I understand you bought it like this, but I have been down this road, and it was not cheap. I have my factory 600hp 871 set to 485hp, it does fine, plenty of torque with the proper tune.

Also, how is the coolant level? Any signs of pressure in the coolant system? Loss of coolant? I ask because as I said, the head is the weak link on these CM-871's. They are disposable, not meant for reuse or remanufacturing. Cummins routinely runs out of them. Something to keep an eye on.

You will also need to download TeamViewer, https://www.teamviewer.com/en/download/windows/ Use this link, it is direct to the maker of the software, otherwise you will get a bunch of adware and other nasties. The FREE version is all you need. TeamViewer will allow {Edited: Unilevers or Gearhead} to use your laptop remotely, so that he can set you up on that laptop via internet and fix your motor.

You will need Windows 7 or greater and a USB connection in the laptop. {Edited: Unilevers or Gearhead} will need to know the CPL file on your truck. Look on the engine plate on your motor, the one with your engine serial number. The CPL number should be on that plate, write it down, you will need this.

Also, make sure the Delta P sensor is set up properly, and you can do this now... From the Rawze @m*m^2 package of a few years ago... This is for the CM-871 only as far as I know, which is the motor I have.

"Remove the Delta-P sensor and break away the center pin in its electrical connector, then re-install it/plug it back in. EGR delete or not, the engine will still try to protect this sensor. Removing the center pin from it ensures it reads zero all the time. This prevents silent derates that have been seen on some trucks, if the sensor itself were to go bad. The feedback from this sensor needs to be zero at all times, regardless of what type of delete you have."

You can watch the EGR Tuneup videos to find that Delta-P sensor. It is on the driver side center at the head. Here is the video, go to the 3:40 spot to see the sensor. https://www.youtube.com/watch?v=FhJxpyS5MpY

Also, like Nilao stated, it might be a good idea to drop the DPF and DOC can to make sure they have been properly hollowed out. If you do drop them, and I would, trust me, you will need a new gasket kit for the cans and exhaust. Two large gaskets and one small gasket for the inlet side. I hollowed mine right out, sounds good, not obnoxiously loud either. Honestly it is not that much louder than when the cans were intact. I have a weed burner too...


It sounds like Unilever already has a grasp of your situation, listen to him, he knows his stuff. As he has helped many of us on here, myself included. Good luck.

[marek4792]

(09-05-2017 )Waterloo Wrote:  Also, make sure the Delta P sensor is set up properly, and you can do this now... From the Rawze @m*m^2 package of a few years ago... This is for the CM-871 only as far as I know, which is the motor I have.

on the CM870 the Delta P sensor with a jumper harness on it. The signal wire is pin #3 on the wiring diagram which i believe is the white wire looking at my truck. I'm not sure if it will make a difference on a demandated CM870 though as I pulled the middle pin(black wire) before looking at the wiring diagram (D'OH!) and no engine code present even when the sensor was throwing a code prior to being demandated.

[Rawze]

(09-04-2017 )Milehigh Wrote:  I have a 2008 cummins ISX that I am experiencing difficulties with. The turbo has quite a lag or hesitation when you step on the accelerator. It makes shifting smoothly almost impossible. The turbo boost is also very unpredictable. Some days I will have 41 pounds of boost and other days only 32-35. I have even noticed on some long pulls that it will fluctuate 5-7 pounds of boost back and forth while on a dead pull. Another odd problem is that often on a hard pull the turbo boost gauge will drop to zero and a check engine will flash over the screen. It will flash for a bit and then hold steady. Sometimes it only holds steady for a few seconds and then all goes back to normal. Other times it will hold the check engine code for the length of the pull or until I back off the throttle. One mechanic wondered if the band for the variable turbo was sticking. The turbo is supposedly only a year or two old. I have had the truck for 4 months. It was mandate'd before I bought it by Elite Diesel in Colorado. It was stock a 485 with 1850 torque. I talked to the man that sent the ECM in and he says it was flashed to around 600 hp. The motor has 765000 miles on it and has not been overhauled yet. Am looking for help.

Your turbo may be acting up because the VG control is damaged but you shiould not rule out bad delete. That is the more common problem ...


WELCOME TO THE BAD DELETE CLUB!!!

I have added you to the list of victims located here...
http://rawze.com/forums/showthread.php?t...5#pid13255

Max boost for the CM871 egine no matter what HP you want should be 36 - 38 psi MAXIMUM!. 800+ HP cam be made with only 39 psi of boost on that motor and that stock VG turbo. 41+ psi WILL EVENTUALLY DAMAGE THE ENGINE AND TAKE OUT THE HEAD OR A PISTON!. Any more and your pissing upstream and making too much exhaust back-pressure to get it, and causing engine damage. Personally, at 500 - 600 hp, I like to see about 36 - 37 psi on them max, 38 max being the upper side of that. Below 500hp, more like 35-36.

Is the boost gauge you have a factory boost gauge? - if so, consider getting an external one. Do you have a pyro on the outside of the manifold? - Like in my video series? -- If not,.. THEN GET ONE SO YOU CAN MONITOR THE TURBO AND EXHAUST TEMPS. Your RIGHT FOOT is now the only temperature control factor with no more EGR, and with no gauge, you have no idea how hot your getting your turbo or other components and that is bad! this may very well have been the thing that did it in if it is the turbo going bad.

Bad tuning, excess EGT's and over-spooling over-boosting turbo = EXPENSIVE REPAIRS IN A HURRY!.

Hopefully, and for your sake... you have not damaged the engine or the head yet from that bad tuning. there are more bad deletes out there than you can shake a stick at and it is downright shameful! - You end up trading DPF problems with more expensive engine and turbo failure problems from bad tuning alone and it is a rampid disease in the trucking industry, especially with cummins engines.


========

Your options are to

A) get it tuned remotely,.. I would never do this myself, too many unknowns, especially if you had a bad delete and YOU HAVE A BAD DELETE!.

B) Take it to Gearhead or Mr. Hag's shop and have them go over the work that has already been done. Also go through the engine to replace mis-reading sensors, verify the exhaust flow, quality of the block-plates, and to ensure your turbo is actually still good or if you have damaged it from that bad programming.

If anyone is in the area and wants me to look at (CM871, CM2250, CM2350 engines) and go through the programming they have, I will always do so for free with them. I have always offered that and am unbiased about it. It is used this to track what others do and the quality of their work. For me it is to genuinely helping others, as I am not a repair shop. I like to call it "The second professional opinion" as there is nothing about what someone else might have done that cannot be answered or accounted for in a genuine way.


- Unilevers is a good option to get it remotely tuned. He knows his stuff and has contributed greatly towards helping people without gouging them for it. I know he also has helped countless with setting up software and things of that nature too, will look at what you already have, etc. most of the time without even charging any money. He does charge money for engine tuning, that is what he does for a living.

Unilevers does a lot of stuff with power tuning (above factory HP) but for most highway trucks, the shortened lifespan that comes with this, I personally would not recommend, as I am all about fuel mileage and long term profit. An ISX with 600 HP in it averages 650k miles before the head comes off vs 900+k miles, simply because people that feel they need that much power all the time also like to push the bigger HP engines harder. Maybe 500~ish seems to be the break-over point for this. - Personally, I would recommend leaving an engine at stock power. It is hard to teach an older motor new things without some damaging consequences sometimes. Engines with age on them do not like suddenly having to work harder. You can always have the power adjusted later down the road. My own CM871 is at 450hp and I think that is just fine for making a living with.

- Gearhead knows his stuff too. He has a shop in MD, and also does remote stuff too when needed. Great guy who knows every single detail of how that engine is made, built, tuned, and programmed. Like myself, there is no question he does not know the answer to when it comes to tuning that engine. He takes his work seriously, and is the kind of guy who will loose sleep if he thinks something is not done to perfection.

- Lastly there is Mr. Hag down in Atlanta. He does not do remote tuning, only tuning with the truck in hand. He also has the advantage of having me down the street / come over to visit if there are any questions, concerns, with a setting, mod, or just about any type of thing in question ( Believe me when I say I am on the guys side who owns the truck). His shop is down the street from me and he knows I am the pickiest "you had better make it 110% right or I will shout it on my forum" bastard on the Internet. He is picky as hell about making sure things are 100% right both with the programming and the mechanical stuff like I am. It is of the mindset that every truck should be looked at and gone through thoroughly BEFORE the tuning is done so that no stone is left unturned. Because of this, he has a set way of going about it without compromise. He includes installing new boost and pyro gauges, cam inspoection, fuel pump inspection on 2250/2350's, overhead valves re-adjusted, sensors replaced, top quality plates, making the cans 100% hollow and not just drilled through, test drives it + load tests, fine tunes the turbo and other things, and a lot more. The mindset is to establish a repeatable, predictable result + verified to perfection BEFORE the job is completed. This way there is no question to what you have as a result.

- Those are your choices. There are a lot of other places who claim they do this type of work but they always result in a horror story just like yours. This is why those places are not on my forum. I will not allow them to advertise or incite/drum up work from this forum until they have proven themselves 110%,.. and THE REST ARE ARROGANT, BLIND FOOLS WHO TAKE PEOPLE'S MONEY AND LEAVE THEM WITH AN ENGINE THAT IS HELL BENT ON DESTROYING ITSELF AND/OR ITS TURBOCHARGER -- Or worse yet,.. hell bent on removing the most efficient VG turbo ever designed for that engine and putting on something that is inherently LESS EFFICIENT!.

This is why it only comes down to a few people ever being recommended. I do all of my own work on my own equipment and help people for free when I am not busy. I cannot always have people over here, it is merely a hobby for me. I do help people look at their programming with them and explain what someone has done and its consequences, good, bad, or otherwise, so they know what they have and its quality. THOSE PEOPLE DOING THAT KIND OF WORK THAT CAN POTENTIALLY BE DAMAGING need some kind of unbiased accountability. I have no trouble providing that when needed and I am not busy doing other things.

=============
- Personally, I am not a fan of remote engine tuning as any kind of first choice. ?I know there are people who only go regional or local who have no choice, but personally, I would drive 3,000+ miles on my own dime to get one right after seeing what I have seen. An ISX costs $36,000, just saying. The ability to test and load test the engine and truck, inspect the work that has already been done to verify it is correct, get that cam insopected, gauges installed, some test driving, and a second set of eyes on the truck is worth every mile for such drastic changes. I want to do something ONCE, not 6 times because something got overlooked, missed, or was giving bad feedback when it was done the first time. Some people just can't get to one of the 2 shops I mentioned above, and drive locally, or only have day-cabs and cannot leave the state with their vehicle. Some people just don't want someone to go through their truck to ensure everything is 100% right, but I think those people are simply short sighted as hell and must not care about their equipment enough to give a damn... but then again that is just my own opinion.

=============

[ZeroNthedark]

(09-05-2017 )Waterloo Wrote:  Here is the Inline 5 Reader that most all of us use here, there is only one left, you better jump on this one! If you do manage to buy that one, you should have it by the end of the week. And that is a damn good price, and includes software.

http://www.ebay.com/itm/Data-Link-Adapte...SwceNZQ69I

I can vouch for this listing. Same people and price as the one I got a couple months ago. Doing the Insite setup is a little wonky, but it definitely works.

[Unilevers]

thx rawze. i dont always do power, just it seems thats what 75% of people who come to me want these days. Power finds the weak spots, remember that its fun until it lifts/cracks a head.