HELP! CAPS issue on Cummins 8.3 ISC

[Atoyot1031]

I have a 2000 Holiday Rambler Ambassador with the Cummins 8.3 ISC. It has ~80k miles on it, and it has been great for the few years that we have owned it.

Recently, we were on a ~3k mile trip from Idaho to Mexico and back, when 4 hrs from home, we lost engine power. It acted like a fuel delivery problem. I had the coach towed to a nearby Freightliner dealer with a Cummins tech.

They performed troubleshooting and decided that the ICV was bad. Diagnostics, labor and parts were just under $4k. Ouch, but I didn't seem to have a choice.

Well, after the ICV arrived and was installed (along with the transient suppressor), the coach still would not fire. Then I was informed that further diagnostics indicate a bad distributor rotor. So they sent me an estimate for an additional ~$4.5k (now at $8.5k total). I said pump the brakes.

As I understand it, if the rotor is bad, the gear pump coupler is likely bad and a entire new CAPS would have been less than the labor and parts to continue replacing components. They quoted me ~$7k for a new CAPs installed ($10.8k total).

I ordered a replacement reman CAPs that I found online for $2k to my door which is arriving today. My plan is to go and install it this weekend, repair the one on it currently, and have an entire spare.

Here's my sticking point. Following the troubleshooting from Cummins, they arrived at the need to replace the ICV despite passing the ICV and PCV click test (steps 3I & 3J). Why replace the ICV if it passed the test? Why not continue on to 3K where you discover the bad rotor. I'm asserting that the ICV they replaced is good, and now that fuel has been pumped through the new one, it can't be returned. What are the chances that at the exact moment I was driving down the highway an electrical component (ICV) and a mechanical component (distributor rotor) failed at the same time?

I think the dealer or Cummins should eat the part and labor cost for the misdiagnosis (assuming that both parts didn't fail simultaneously). However, the Cummins manual states that if it has already passed the ICV click test and it then passes the PCV click test to replace the ICV module. Why replace if it passes both tests? The dealer is reaching out to Cummins on this question.

Anyone who has more experience or a better understanding of this, please help me out. I just want my coach back, but now that I'm doing the repairs and sourcing the parts myself, I don't see how I should be on the hook for $4k which didn't resolve anything.

Thanks in advance!
Nick

[Fffrank]

I'm actually surprised at two different parts of this:

- They were willing to replace just the ICV.
- They quoted you only $7k for a new CAPS + labor!

My quote for a CAPS was $6800 for the refurbed pump + another $3k in labor. Possible they can buy one without an ICV (which you already bought) but I've yet to see this as an option from either cummins or 3rd party rebuilders.

What I'm not surprised by? The misdiagnosis.

It sounds like they are trying to work with you. I don't think you're being unreasonable -- they told you something was bad and it turns out it wasn't bad. The return should be on them (assuming you purchased the ICV through the dealer/authorized service center.)

Curious what their next response will be. I'd at least give them a chance to take care of it before yelling too loud (not that that won't be called for in the future.....)

[Atoyot1031]

Originally Posted by Fffrank

I'm actually surprised at two different parts of this:

- They were willing to replace just the ICV.
- They quoted you only $7k for a new CAPS + labor!

My quote for a CAPS was $6800 for the refurbed pump + another $3k in labor. Possible they can buy one without an ICV (which you already bought) but I've yet to see this as an option from either cummins or 3rd party rebuilders.

What I'm not surprised by? The misdiagnosis.

It sounds like they are trying to work with you. I don't think you're being unreasonable -- they told you something was bad and it turns out it wasn't bad. The return should be on them (assuming you purchased the ICV through the dealer/authorized service center.)

Curious what their next response will be. I'd at least give them a chance to take care of it before yelling too loud (not that that won't be called for in the future.....)

Frank,
Thanks! I think they said their cost on the whole reman CAPs was $4,700, and they'd get it for me for a little over $5k. However, my delivery just showed up for (allegedly) the correct one from ebay reman'd with no core for $2k.

I've been keeeping it very friendly and letting them know I understand how we got here, just that it doesn't seem reasonable to charge me unless they can show that the ICV they removed was actually bad.

[Mile Marker 42]

Jerry, where are you? Nick, Jerry just went thru this 3 weeks ago+- in his driveway. I am sure he will reply back soon. I agree with Frank, in that a misdiagnosis is par for the course. It's really too bad that correct diagnosis's can't be way higher than it actually is. The problem is, if a mechanic spends too much time messing with your coach, he will miss out on the other repair tickets in the shop and someone else is going to get the gravy, like the brake jobs. Because of this, a quick diagnosis is given so the mechanic can move on to the next ticket. I know this because I was a wrench for almost 15 years and saw this all the time. I'd stop payment on the repair payment if need be. Unfortunately, now you are at a crossroads. You will have a brand new/rebuilt Caps pump, but how about your lift pump? That is the critical piece in the whole thing. Might as well replace that too or install a Fass or AirDog.

[Atoyot1031]

Originally Posted by Mile Marker 42

Jerry, where are you? Nick, Jerry just went thru this 3 weeks ago+- in his driveway. I am sure he will reply back soon. I agree with Frank, in that a misdiagnosis is par for the course. It's really too bad that correct diagnosis's can't be way higher than it actually is. The problem is, if a mechanic spends too much time messing with your coach, he will miss out on the other repair tickets in the shop and someone else is going to get the gravy, like the brake jobs. Because of this, a quick diagnosis is given so the mechanic can move on to the next ticket. I know this because I was a wrench for almost 15 years and saw this all the time. I'd stop payment on the repair payment if need be. Unfortunately, now you are at a crossroads. You will have a brand new/rebuilt Caps pump, but how about your lift pump? That is the critical piece in the whole thing. Might as well replace that too or install a Fass or AirDog.

Thanks Mile Marker!
Yeah, the lift pump tested good, but I've read up on them and will be installing a Fass or AirDog.

I still don't understand the misdiagnosis though. The manual states to replace the ICV even though it passes both the ICV and PCV click test. Seems like Cummins might have a mistake in their literature.

[JerryLook]

Which fault code did you have that they were troubleshooting from?

This troubleshooting chart shows if the ICV passes the click test to do more troubleshooting, and if the PCV passes the click test then replace the ICV. Were they just using this troubleshooting and not following a code?

https://www.thoroughbreddiesel.com/a...oting-tree.pdf

[Atoyot1031]

Originally Posted by JerryLook

Which fault code did you have that they were troubleshooting from?

This troubleshooting chart shows if the ICV passes the click test to do more troubleshooting, and if the PCV passes the click test then replace the ICV. Were they just using this troubleshooting and not following a code?

https://www.thoroughbreddiesel.com/a...oting-tree.pdf

Jerry, that is my understanding. They followed the troubleshooting guide. I went through their notes with them and that is how they justified the diagnosis and replacement of the ICV.

I don't know what code they got. I'll ask them tomorrow.

[Ray,IN]

The Cummins injector pump's fuel distributor module operates from 12VDC, a bad transient suppressor diode will cause that failure. Mine failed last July, Cummins Great Plains replaced both fuel distributor module and transient suppressor, $5,000. Four months prior to that the lift pump failed, probably due to failing transient suppressor diode that went unnoticed, that bill was $3,000 at a local diesel shop.
Most injector pump sales will not provide a warranty unless transient suppressor diode is replaced at the same time.
Transient suppressor description: "The Transient Suppressor absorbs the extra current created when the Injection Control Valve closes after an injection event. Without the transient suppressor, high voltage would be transmitted back into the ECM damaging the pump driver circuits and possibly the Injection Control Valve".

[Lowflyer1]

Originally Posted by Ray,IN

The Cummins injector pump's fuel distributor module operates from 12VDC, a bad transient suppressor diode will cause that failure. Mine failed last July, Cummins Great Plains replaced both fuel distributor module and transient suppressor, $5,000. Four months prior to that the lift pump failed, probably due to failing transient suppressor diode that went unnoticed, that bill was $3,000 at a local diesel shop.
Most injector pump sales will not provide a warranty unless transient suppressor diode is replaced at the same time.
Transient suppressor description: "The Transient Suppressor absorbs the extra current created when the Injection Control Valve closes after an injection event. Without the transient suppressor, high voltage would be transmitted back into the ECM damaging the pump driver circuits and possibly the Injection Control Valve".

Wow. Are there any warning signs for the transient suppressor diode failure to look for?

[Fefanatic]

Does anyone know where the transient suppressor is located? I'm thinking of purchasing a spare or just replace before something goes awry...

[rag_ftw]

Originally Posted by Fefanatic

Does anyone know where the transient suppressor is located? I'm thinking of purchasing a spare or just replace before something goes awry...

Here's what cummins says: The transient suppressor extends from the trunk of the engine harness and is mounted with a p-clip to the engine block. It is a small copper colored cylinder with a red and black wire extending from one end. It is located just below where the injection lines connect to the fuel pump.

It is kinda hid beneath a wire bundle but the red and black wires make it easy to identify. It is about 4" long and 3/8" in diameter. On my ISC when I open the engine access door in the bedroom and lay down on the floor it is visible and accessible, if you have long arms!

[Ray,IN]

Originally Posted by Lowflyer1

Wow. Are there any warning signs for the transient suppressor diode failure to look for?

The Cummins insite diagnostic program can make that determination; otherwise not to my knowledge.

[rag_ftw]

Originally Posted by Lowflyer1

Wow. Are there any warning signs for the transient suppressor diode failure to look for?

My 2002 ISC 350 with CAPS turned on the yellow check engine light and derated the engine to 3/4 power.

It also threw an 18 11 Scan Gage code which equates to a 539 Cummins code.

[Atoyot1031]

My son & I went to the dealership 4hrs away with the pump I ordered over the weekend. We swapped it out and drove it home. Since I now have the coach and haven't paid anything yet, I guess the bargaining chips are on my side of the table.

Thx all!