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lockmup68

Cummins ISX no power in mountains

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So headed out west and lost power along the way. In CO, pulling the grades at 15 mph. Turbo boost is barely 10 psi. Not burning oil, not blowing smoke, no check engine light. 

Take it into shop and they say it has an EGR code and a Turbo code. EGR is stuck open and won't shut. Replace EGR and no other codes. Today pulled all the way from SLC to Farmington, getting bursts up to 20 psi on the turbo, but still down on power. Not burning oil, not blowing any smoke, no check engine light, Taking the hills about 25-30 mph, so better than it was, but not like it used to be. Once we hit the flat, cruise all day long at 70. 761k on ISX. 

Another symptom, 3 stage jake used to about throw you through the windshield, now on stage 3, not really holding back at all. Compression issue? 

Anything to check? How to diagnose? is this a compression check, dyno? Time for turbo? or inframe? 

Good news, AC is working great, generator is working great, air bags all fixed. transmission is shifiting great, front steers riding nice, and new lock on the fridge keeps the door shut and stuff inside the fridge. (gotta look at the bright side). We are getting there, just slow in the mountains. 

Thanks,

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Ever watch Rawze's series of videos on maintaining the ISX? Lots of things could cause your problems.....most likely sensor related if you haven't changed them in a while. Soot is not your friend.....

 

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I agree with the sensor guess. I had the same symptoms years ago with my 12 liter volvo engine. On the volvo there is a sensor that controlled the turbo. Mine was an easy DIY job and that corrected the problem. I'll try to find the proper name for it.

 

Brad

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9 minutes ago, Brad & Jacolyn said:

I agree with the sensor guess. I had the same symptoms years ago with my 12 liter volvo engine. On the volvo there is a sensor that controlled the turbo. Mine was an easy DIY job and that corrected the problem. I'll try to find the proper name for it.

 

Brad

The sensor on the Volvo is called a boost sensor. You must have something like that but I have no idea where to find it on your engine. Mine it right on top on the drivers side. I changed in about an hour. mine was 2 bolts, about 6 screws to get behind a plastic plate, 3 zip ties and an electrical plug.

Good luck.

Brad

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Since we are on the road, no time to pull and clean whole system. Since my ISX is old, I tried the “magic plug”’ trick. For testing purposes, I unplugged the EGR valve sensor. Today pulling from Farmington, NM to TX, didn’t drop below 50 on any hill. Night and day difference. Looks like 20psi max on turbo, so still low, but so much better than the 10mph on the pulls the day before. 

Still very little jake braking. Is this compression driven?

When I have a few days sitting still, I will take the EGR system apart and clean it all out and replace the sensors. 

Good news is the check engine light works now came on when I was testing the EGR sensor plug.

 

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You might also check the turbo actuator to see if you have full movement. Might explain low turbo boost pressure. Could be why your Jake isn’t working properly. What where your EGT’s with boost at 20 psi when pulling those hills?

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No EGT on the truck. Shouldn’t that be a stock item? 

Water temp and oil temp normal. 

What oil pressure should I have? 35-40 I believe. Will check today to verify. 

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8 hour drive yesterday TX, started in Amarillo

external temp was 108 for last 5 hours of trip

oil pressure 40psi all day

water temp steady at 180 all day

oil temp 225 all day

magic plug unplugged still

on cruise at 70mph, 10psi boost, 15-18psi on pulls, never dropped below 55, trans didn’t downshift today,  it lugged it in 12th (which it wouldn’t do before) freedomline trans. 

Good news is AC is working like a champ! I also mounted a $5 fan behind driver’s seat above my head blowing down on neck/back. Big help. I will upgrade to variable speed and higher quality fan now that I know it helps. Figured $5 was good experiment money spent. Now will get a good fan. 

Edited by lockmup68

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46 minutes ago, podwerkz said:

Check/replace fuel filters.

all fuel filters are new, davco is at very bottom of gauge as it is when new. 

I'm planning on doing rawse's EGR cleanout when I have a few days and it's not 108 heat index and 200% humidity. 

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I have a 2004 ISX 500/1650.  Your boost is really low.  Mine will hit 35psi when climbing hills at max loads.  30psi is very common even on gradual inclines.  Oil pressure sounds good, mine hovers around 40 psi.  I did Rawze's EGR tuneup.  Definitely worth doing, but all the sensors are close to $700 from Cummins.  If you can get to the Atlanta area, take it to Haggai Automotive and truck repair.  The owner is a close friend of Rawze and one of the best ISX mechanics in the United States.  I just recently had my EGR cooler and oil cooler replaced there.  

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On 8/8/2019 at 11:11 AM, lockmup68 said:

Where is the turbo actuator and how do I check it? Searching on YouTube. 

The arm with a round section that has a bolt on the center of it.  On the side of the turbo facing your front passenger steer tire, between the intake side and exhaust side of the turbo.  Basically, if the turbo has any oil anywhere on it's housing, that is a bad sign.

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On 8/22/2019 at 12:10 AM, Jeff.Sloan said:

The arm with a round section that has a bolt on the center of it.  On the side of the turbo facing your front passenger steer tire, between the intake side and exhaust side of the turbo.  Basically, if the turbo has any oil anywhere on it's housing, that is a bad sign.

No oil on turbo. 

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On 8/22/2019 at 1:07 AM, Jeff.Sloan said:

I have a 2004 ISX 500/1650.  Your boost is really low.  Mine will hit 35psi when climbing hills at max loads.  30psi is very common even on gradual inclines.  Oil pressure sounds good, mine hovers around 40 psi.  I did Rawze's EGR tuneup.  Definitely worth doing, but all the sensors are close to $700 from Cummins.  If you can get to the Atlanta area, take it to Haggai Automotive and truck repair.  The owner is a close friend of Rawze and one of the best ISX mechanics in the United States.  I just recently had my EGR cooler and oil cooler replaced there.  

closing the loop on this. Spent a couple days with the folks at Haggai. Had me fixed up in 48 hours. Amazingly enough, the intake was clean. the VGT on the turbo was hosed and the actuator/air control valve on the firewall was bad. They think the air control valve/actuator died and then the VGT kind of welded itself shut since it wasn't being activated. New turbo, actuator, air control valve, etc., stayed at 70 whole way home, even on the climbs around Chattanooga. It might have been fixable if the shop I immediately took the truck to would have checked things over vs. just replacing the EGR valve, clearing the rest of the codes and calling it good. 

I also had them run the exhaust out the side vs. just dump underneath the bed. Always heated up the ramps and I'm sure the generator breathing that exhaust was not good. Nice to hear the turbo whine now. 

Burned HALF the fuel coming back vs going down. 

BIG thumbs up to Haggai Automotive & Diesel in Griffin, GA. He also knows the freedomline transmissions well, has all the software, etc. 

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Thanks for the update, i always wonder what the cause was when someone posts an issue like that.

glad to hear you’re back up and running 

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Crazy thing was a brand new turbo from Cummins was only $300 more than local rebuild/reman. 
 

I need a new boost gauge now. Mine maxes out at 30 and it is going 32-35 (guesstimate). 

Edited by lockmup68

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1 hour ago, Darryl&Rita said:

Don't forget, more boost means more fuel per mile. More fun, too, but definitely drops mileage. 

My mileage went up big time. I filled all the way up on way down, filled up before coming back. Burned a little over half the amount after the turbo fix. Cruise on 70 both ways. On way back was uphill too. Weird. 

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