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mhaynes · 03-03-2016, **(Subject: 08 ISX Boost issue )**

A friend of mine has a 08 Peterbilt dumptruck with a ISX that has had a egr, dpf delete done for the past two years. A while back he started having a high idle issue. It would idle at 900 instead of 650. He was told that the ecm may be going bad. He had a reputable tuner in Europe hook up to it and he saw that the file that had been put in it when the delete was done shouldn't of been with that CPL number. This tuner in Europe only puts a tune in that is good for that CPL number. The file that was in it had a lot of added HP. This tuner in Europe reflashed it with one of his tunes and that cured the high idling issue but now has no power in the top gears until it hits 1500 rpm's. It seems fine at a idle and in the lower gears, but when you get in the high side it has nothing under 1500rpm's. When it finally hits 1500 the boost spikes and it pulls great. He pressure tested the whole system and found no leaks. Inspected the turbo and it seems good. While inspecting the Actuator it had a very bad grinding noise in it so he replaced it with a new one. The problem got a little bit better but its still not right. Does anyone think the ecm could be bad from the prior tune? I have never experienced anything like this.

Mr Hagg · 03-03-2016, **(Subject: 08 ISX Boost issue )**

SOunds like the low end turbo table is set to low...Im sure rawze ,unilevers can chime in on this. Also check the turbo actuator and the turbo.

preacherboy24 · 03-03-2016, **(Subject: 08 ISX Boost issue )**

Yea....we had a guy with the same problem. It was a flaw in the programming. Definately start there because I believe that is where the issue is. I am going to guess he got one of those high dollar deletes and threw his vg turbo away along with all the egr hardware....right? Just like my guy did?

mhaynes · 03-03-2016, **(Subject: 08 ISX Boost issue )**

The turbo actuator is brand new. Turbo checks out fine. The tune done two years ago was crap. It should not of been with this cpl. Tried two different files from the tuner in Europe. Second one with a little more Hp was better but still has a 3-5 second delay to get boost in the top 3 or 4 gears. Once the turbo spools up at about 1500 rpms it creates good boost and pulls great. I know a lot of people with tunes from this guy in Europe and have never had any issues with his tuning.

preacherboy24 · 03-03-2016, **(Subject: 08 ISX Boost issue )**

(03-03-2016 )mhaynes Wrote: The turbo actuator is brand new. Turbo checks out fine. The tune done two years ago was crap. It should not of been with this cpl. Tried two different files from the tuner in Europe. Second one with a little more Hp was better but still has a 3-5 second delay to get boost in the top 3 or 4 gears. Once the turbo spools up at about 1500 rpms it creates good boost and pulls great. I know a lot of people with tunes from this guy in Europe and have never had any issues with his tuning.

The tune isnt flawless. Sometimes we find out that the tune needs to be tweaked a little. It could be a silent derate. Rawze said that sometimes when people just pull the magic plug the engine runs great until the ECM decides enough is enough. I would get the guy who programed your truck to take a look because I believe something in the tune didnt kill a derate. I would still like to know what the boost and EGT numbers are....that tells a lot.

~~Cuya~~ · 03-04-2016, **(Subject: 08 ISX Boost issue )**

this guys can solve it 500%

close to atlanta - Mr. Hag < took my truck there. best thing i ever did

indianna? or canada not sure Unilevers

maryland i think Gearhead

boots769 · 03-21-2016, **(Subject: 08 ISX Boost issue )**

Gday guys .. i have a similar problem , sort of ..I have just done a {**Content removed by protection bot**} also reactivated the oil and temp shutdowns. Am now getting turbo overspeed derate at higher rpms while under load usually pulling up hill .... have already pulled the turbo min closeing tables down to 50% .. do i just need to continue dropping this table to bring turbo speed down ...or is it possible the by removeing the derates that the turbo is able to reach overspeed threshhold? have also noticed {**Content removed by protection bot**} is not enabled ( am in the possess of checking this parameter against others i have done ) could that be where my issue is coming from?? I have not seen this happen before now , has anyone else had this issue ?

Marajin · 03-21-2016, **(Subject: 08 ISX Boost issue )**

(03-21-2016 )boots769 Wrote: Gday guys .. i have a similar problem , sort of ..I have just done a {**Content removed by protection bot**} also reactivated the oil and temp shutdowns. Am now getting turbo overspeed derate at higher rpms while under load usually pulling up hill .... have already pulled the turbo min closeing tables down to 50% .. do i just need to continue dropping this table to bring turbo speed down ...or is it possible the by removeing the derates that the turbo is able to reach overspeed threshhold? have also noticed {**Content removed by protection bot**} is not enabled ( am in the possess of checking this parameter against others i have done ) could that be where my issue is coming from?? I have not seen this happen before now , has anyone else had this issue ?

I would start by verifying that you do not have the following...

* A bad turbo speed sensor.

* A leak in your CAC, EGR, exhaust manifold gaskets or mounts, turbo gasket, intake gaskets, etc.

* Good IMAP and exhaust back pressure sensors.

* The engine is in good shape and running well, and the overhead and other things have been done and are up to date.

---

Your turbo speed sensor could be reading incorrectly. I have seen some that even read 10k or 12k rpm even when the engine is not running. I have seen soot and carbon clogging in the shaft where the sensor goes make the speed sensor read high before. Some brake cleaner in the hole where the sensor goes can usually clean it. A turbo out of proper calibration can make it over-spin too.

Got new IMAP and exhaust back-pressure sensors?

What is your boost getting to?. It should not exceed 36-38 psi. That is most likely your problem if all else is good.

Make sure all else above is good, then keep lowering your adjustments until it gets back into the 36-38 psi range maximum. That is what custom tuning is all about.

It is not unusual for some trucks to need only 45% or so to get 36-38 psi.

Also, Some factory calibrations derate the engine as low as 90k rpm. The holset can go to 150k max. I have seen custom tuners set them to 115k safely to avoid derates at the upper end as they reach 40 psi on some programs.

Advice: When you do custom tuning yourself, you will need to study and understand what you are doing to a great degree. Those info's you are using are only a starting point towards whatever goal you might be seeking. Also, Rawze does not allow open detailed discussions about such things to be taking place on this forum. I hear that their mumble server is the place to discuss such detail of things.

boots769 · 03-21-2016, **(Subject: 08 ISX Boost issue )**

Thanks Marajin ,, I usually test run anything ive tuned and have found that the overlays for 550/1850 running in most chassis in Australia will run to just over 40psi when pushed hard and will cruise about 20-25 psi , usually get good mileage (2-2.4kpl) ,,just have not seen turbo overspeed derate even in 600/2050 cals that if you dont bring boost right down will blow to 45psi ,, will recal tgc min opening to 45 max and set turbo derate threshhold from 105k to 108 or 110k and test run the sucker ..all seems to go well until pulling hard at or around max power ,, I usually expect to see max boost around max torque , just seems a little strange to be overspeeding at higher rpm