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BonS · 10-27-2021, 11:12 PM

My ISM 500hp Cummins gave it up today and we're stranded in a small town in Arkansas.

First some background: I've had the coach for 4.5 years. Ever since I've had it I would get an occasional variable geometry turbo (VGT) position error and it would quickly go inactive. Usually this would happen in hilly terrain and never while cruising on the Interstate. Boost would be anywhere between 37 psi and 0 depending upon the demand. No real issues in drive ability. Recently the VGT position error began to come and go more frequently. I attributed it to driving in hilly parts of Arkansas and Missouri. Well, today, I lost all boost and found myself crippled at about 1-2 mph. Luckily I was approaching a small town and found a decent place to pull over and we're now parked.

When we lost all boost there were several Silverleaf messages about the lost boost and more. Unfortunately when I turned off the Silverleaf I seemed to have lost some of the additional messages. I now have to current messages on the Silverleaf: 1) VG turbo Acutator 1/ECU and 2) VG turbo Actuator 1/mech.

This evening I pulled up the rear floor and began to investigate the turbo and actuator. There are no metal bits anywhere in the intake plumbing or air filter. All fittings look to be tight and in place. The intake compressor blades look fine and it spins easily for about 5 rotations with a quick flick. I don't know if that's good or bad. But it feels smooth and easy. I removed the VGT actuator and the actuator gear spins smoothly but the Silverleaf error codes suggest that the ECU electronics may very well be bad. I haven't gotten down to the exhaust turbo blades yet but I'm working in that direction.

I've put out some feelers about a replacement turbo. It's a Holset HE531VE turbo. Cummins doesn't have any in their system so of course I'm hoping that the turbo is okay and it's the actuator that shut us down.

I'm hoping that I can find someone that can test the actuator or that I can find one tomorrow.

Any and all suggestions are certainly welcome!

hayward3411 · 10-28-2021, 04:36 AM

Following

CountryB · 10-28-2021, 04:43 AM

Watch this video:

https://www.youtube.com/watch?v=Ja8LjVwJWHw

and

https://youtu.be/eAu4w7KXe7I

basketball · 10-28-2021, 07:44 AM

Quote:

Originally Posted by BonS

My ISM 500hp Cummins gave it up today and we're stranded in a small town in Arkansas.

First some background: I've had the coach for 4.5 years. Ever since I've had it I would get an occasional variable geometry turbo (VGT) position error and it would quickly go inactive. Usually this would happen in hilly terrain and never while cruising on the Interstate. Boost would be anywhere between 37 psi and 0 depending upon the demand. No real issues in drive ability. Recently the VGT position error began to come and go more frequently. I attributed it to driving in hilly parts of Arkansas and Missouri. Well, today, I lost all boost and found myself crippled at about 1-2 mph. Luckily I was approaching a small town and found a decent place to pull over and we're now parked.

When we lost all boost there were several Silverleaf messages about the lost boost and more. Unfortunately when I turned off the Silverleaf I seemed to have lost some of the additional messages. I now have to current messages on the Silverleaf: 1) VG turbo Acutator 1/ECU and 2) VG turbo Actuator 1/mech.

This evening I pulled up the rear floor and began to investigate the turbo and actuator. There are no metal bits anywhere in the intake plumbing or air filter. All fittings look to be tight and in place. The intake compressor blades look fine and it spins easily for about 5 rotations with a quick flick. I don't know if that's good or bad. But it feels smooth and easy. I removed the VGT actuator and the actuator gear spins smoothly but the Silverleaf error codes suggest that the ECU electronics may very well be bad. I haven't gotten down to the exhaust turbo blades yet but I'm working in that direction.

I've put out some feelers about a replacement turbo. It's a Holset HE531VE turbo. Cummins doesn't have any in their system so of course I'm hoping that the turbo is okay and it's the actuator that shut us down.

I'm hoping that I can find someone that can test the actuator or that I can find one tomorrow.

Any and all suggestions are certainly welcome!

Once you remove the actuator and find the problem, Turbo or Actuator you have to have software to set up the 2 pieces. The actuator goes to the home position every time you power up. The turbo has to be set so that it is in the home position also. This will allow full boost or no boost.
Once you take off the actuator you will be able to turn the key on and see if it moves to the home position. You can also see if the turbo will move in and out.
My actuator was fine, but the turbo was in a lock position and would not move.

I took to a repair shop and had the turbo rebuilt and a rebuilt actuator (just in case it was going bad). The repair shop set up the 2 pieces and had the 2 pieces installed on coach.

If 1 person turns on the key and the other have an ear close to the actuator you will hear the actuator try and move to the home position.
I guess you could set up the turbo in middle position (pie shaped gear, this is the gear that moves the turbo back and forth) if it moves. Take to repair shop and have set up. If the actuator gear spins when key is turned on, it will set to home position.

If you take the actuator off to prove it rotates or not and it rotates actuator is working(resets to home position). Prove the turbo slides in and out, if not, turbo problem.

basketball · 10-28-2021, 07:50 AM

I am on line this morning, if more info required respond to form.
Basketball Junkie

hypoxia · 10-28-2021, 07:50 AM

https://ytsturbochargers.com/

BonS · 10-28-2021, 08:08 AM

Quote:

Originally Posted by basketball

I am on line this morning, if more info required respond to form.
Basketball Junkie

Thank you for the information. The turbo actuator arm moves easily, by hand, from stop to stop which is approximately 30 degrees of movement. I can feel and hear it reaching its limits. The actuator seeks its home position when I cycle the key as well. I can randomly spin the actuator and it always returns to the same home position when power cycled. So I'm back to being stumped. I can get an actuator overnight to me for $600 if necessary. I haven't found a turbo yet.

basketball · 10-28-2021, 08:49 AM

Have you checked the CAC hoses and clamps?

basketball · 10-28-2021, 08:50 AM

From input of cac to output of cac to turbo. Hoses, clamps?

basketball · 10-28-2021, 08:55 AM

Not sure if actuator should spin. It is on a gear setup and should only rotate on power up.

It does have to rotate when required for turbo boost. Not be your fingers and spin. Could be a gear problem under load??

basketball · 10-28-2021, 09:36 AM

Go to Turbo Actuator Repair Service / Rebuild Service

Read about test for actuator and gearbox in actuator. You may have a gearbox issue if you can spin gear.
Call them and ask about spinning gear with fingers??

basketball · 10-28-2021, 10:05 AM

Keep us posted on outcome

BonS · 10-28-2021, 10:11 AM

Quote:

Originally Posted by basketball

Go to Turbo Actuator Repair Service / Rebuild Service

Read about test for actuator and gearbox in actuator. You may have a gearbox issue if you can spin gear.
Call them and ask about spinning gear with fingers??

I was told by a turbo company that I should be able to rotate the actuator gear by hand to see if it was frozen. It does rotate but not easily as I can feel the gearing that I'm moving when I rotate it. When it does its startup routine I can add resistance to the gear and it easily overpowers my resistance.

The local truck shop told me that they're 5 weeks out for any service. Ugh.

I did button everything back up and approximated the correct gear alignment of the actuator, and started the engine for a test. I don't have any diagnostic codes showing on the Silverleaf but also have zero boost. Of course, the engine revs weakly and some smoke is seen at the exhaust.

I'll scan the entire turbo plumbing for any issues now.

BonS · 10-28-2021, 10:49 AM

I've checked out the entire turbo-CAC-intake bellows and clamps. They all look perfect. I also inspected the CAC at its inlet and outlet for obvious cracks. When the engine is running the soft bellows connections are totally soft; no pressure at all. The Silverleaf says 0.0 boost. In order to lose all boost I'd either have to have a significant crack in the CAC or a dead turbo, IMHO. I'm trying to get someone to come with a scan tool to recallibrate the actuator. Probably money down the drain but I have nothing else to do at this point.

I have a lot of hooks in the water trying to find a turbo but so far no luck.