Foretravel Owners' Forum

Foretravel Motorhome Forums => Foretravel Tech Talk => Topic started by: Darenlaur on September 23, 2023, 06:55:53 pm

Title: ISX 15 Turbo boost drops
Post by: Darenlaur on September 23, 2023, 06:55:53 pm
I have a 2010 Phenix with the 650 hp ISX 15.  When I purchased the RV, the original owner replaced the turbo but not the turbo actuator.  I have since replaced the turbo actuator.

My problem is on long uphill grades, my turbo is boosting well, but out of the blue it drops all boost.  After the boost is dropped, it takes about 3 minutes and the turbo slowly begins to boost back up to normal.  It never happens on flat ground, even if it was a long passing spot.
It doesn't happen on all big climbs. Boost doesn't go over 44 lbs.
With its random happenings, I can't pin point why. 

I'm about to give up and put a none variable turbo on.
Title: Re: ISX 15 Turbo boost drops
Post by: Pamela & Mike on September 23, 2023, 08:13:16 pm
With your description and with that engine it may just be the ECM shedding some of the load due to the exhaust gas running too high. You may just need to be proactive and manually downshift the trans. (before it decides to down shift) and (in old horse terms ) give it's head.

Mike
Title: Re: ISX 15 Turbo boost drops
Post by: Darenlaur on September 23, 2023, 09:38:58 pm
Interesting, I will look into a bluetooth pyrometer gauge or see if its on my glass dash board.
Thank you, I'll look into it.
Title: Re: ISX 15 Turbo boost drops
Post by: turbojack on September 23, 2023, 11:30:48 pm
In my coach there is almost always boost, even at idle. When this happens on the climb and you lose all boost do you just stop dead in your tracks?

I have 600 hp and never seen more than 39 psi.

Mike's answer sounds very reasonable.
Title: Re: ISX 15 Turbo boost drops
Post by: Darenlaur on September 24, 2023, 02:52:47 pm
On a long hill, when the boost gets dropped, the boost goes to 0.  The RV then gets down to 20-30 mph for 2-4 minutes then slowly builds boost back up.  It will take about 1-2 minutes to get back to full boost. I've tried to drive with less than 40 lbs of boost and that doesn't seem to help much.
Title: Re: ISX 15 Turbo boost drops
Post by: chris von ravensberg on September 24, 2023, 09:54:37 pm
Are there any DTC's? 
Title: Re: ISX 15 Turbo boost drops
Post by: turbojack on September 25, 2023, 06:43:35 am

I'm disappointed I didn't ask that question earlier. Your Silverleaf Dash should be able to show any, even if they cleaned