CAT 3126 Engine Brake - HELP

Blkbart · 08-31-2019, 09:56 AM

Hello all,
I'm in serious need of advice or solutions to my predicament. I recently purchased a 2003 Itasca 34HD coach with the 62,000 miles on it. It has the 3126E 330hp engine with the 6 speed Allison transmission on a Freightliner chassis. Soon after owning it I realized the dash/chassis AC was not functioning effectively. I pulled all of the engine top access panels off and decided to rinse the engine off. I used Simple Green with a spray bottle and then rinsed it with another spray bottle, then I used several cups of water to rinse over the top of the engine. I knew better than pressure washing the engine. Upon rinsing/cleaning the engine I went to start it, just my luck it wouldn't start. I had several diesel mechanics come over to check it out. One felt it might be the ECM so he pulled it for me. I took the ECM down to reputable truck dealership in San Diego CA. They bench tested it twice for me just to make sure for no charge and found it defective. They offered some suggestions to fixing it which the minimum options were in the $3+K area. They were very helpful and mentioned that being a CAT it should be taken to the CAT dealership because of CATs proprietary issues. Well I got home with the ECM knowing it was faulty and hit Google. I found a business that sold rebuilt ECMs which had lifetime warranties. I called to ask some questions and went ahead and purchased one. Once I received it I returned the original one to them for a core. I had my mechanic install the rebuilt ECM and wouldn’t you know it NO start. In total exasperation I called the CAT dealer and had it towed (thanks for my Good Sam Roadside Assistance) to them. CAT called me the next working day and told me the rebuilt ECM was for a 300hp engine and a manual transmission. I immediately called the ECM rebuilder and told them of the discrepancies in the ECM they sent me, they were not helpful at all but did offer a refund. I told CAT much to my dismay to get the coach running. They put in their own ECM which was programmed for the engine/coach and got it running. The service writer went on to tell me that the engine brake was not functioning with the switch on the dash. He told me the engine brake itself was operational but would not work suggesting that was a coach wiring issue. I’m pretty savvy on mechanical issues and have done my share of repairs through the years. So what I need to know is: Does the ECM control/activate the engine brake or is it a separate solenoid? The engine brake worked fine before the ECM issue. CAT told me they would need a wiring schematic for the coach to fix it which was beyond their scope of repairs. I really can’t accept this, I’m to pay $5+K to get it out of the shop and leave with an inoperable engine brake! Why can’t they make the engine brake functional but not able to turn off? I’m actually afraid to drive it without the engine brake. I’m am just sick about this situation. PLEASE offer any experience, suggestions, etc. on this situation. I would sincerely appreciate them. Thinking I just made the biggest mistake in my life purchasing this coach, very depressed.
Thanks,
Bart

Cooperhawk · 08-31-2019, 01:16 PM

The engine brake is separate and the mechanism sometimes gets corroded and freezes in place. Get under there with some break free and spray it good. Work on it until you're sure it's working freely. Then check by having someone turn it on and off at the dash while you use a test light to see if voltage is coming through. If not it may be a popped breaker or broken wire.

If the regular brakes are good you can easily drive it without the engine brake. Just take your time and gear down on large hills.

I do use our but I do not leave it on full time. I apply it as I need it. If you leave it on every time you want to coast it will kick in. Even on long grades I seldom use it. I just gear down and let the engine do the work while I apply the air brakes as needed.

cbeierl · 08-31-2019, 02:36 PM

Just to keep the terminology straight what you have is an 'Exhaust Brake', which closes off the exhaust to provide back pressure for braking. It should be physically located right next to the turbo. Other larger engines may have an 'Engine Brake' which actually operates the valves on the engine to provide braking force.

Blkbart · 08-31-2019, 06:10 PM

Thanks for both of you responding to my concerns. I can comprehend the exhaust brake better now. It's not tied into the ECM and sounds to be a solenoid operated item. I will certainly check the fuses/breakers to see that it is getting the voltage to its operation. I also appreciate the clarity between the engine brake vs. exhaust brake. I’ve been checking out a lot of other articles on the exhaust brake systems and have learned of some other issues that may be involved. Sure hoping it’s just a fuse or breaker.
Thanks again,
Bart

Blkbart · 09-06-2019, 09:15 AM

Just wanted to follow up with those of you who helped me out and others who may have similar issues. The ECM was indeed bad, take heed in the fact that you should not rinse your engine off. As I had stated earlier, I didn't power wash it but merely sprayed it with a bottle of Simple Green and rinsed it off with a couple cups of water from the top (engine panels removed). The total bill at the CAT dealer was dollars short of $5K

While I was picking it up, the service writer was telling me the expense incurred on several coaches in the lot. One had a $50K bill (engine & trans removed from coach) and the 1998 coach next to mine was $40K

Thinking I may have got in over my head

As I drove out thinking my next headache was getting the exhaust brake to work, it was functional

Hoping to now enjoy the coach. I sincerely appreciate the responses and advice. One last inquiry, can any of you recommend or suggest a warranty plan I might be able to purchase. I do realize the odds of a warranty plan for a 2003 is perhaps not a reality

Thanks,
Bart

Evie · 09-08-2019, 04:57 PM

Hey blkbart, We have a 2003 Journey and on our maiden voyage with the coach we observed that the dash AC wasn’t working. The coach subsequently died and was towed. We are curious after reading of your issues, did the replacement of your ECM correct your dash AC issue? We still don’t have our coach back yet. ECM was tested, and they say it’s not the ECM, it’s a grounding issue, so now they are hunting for a damaged wire. Like you, we are thinking we must have made the biggest mistake of our lives!

RV735 · 09-08-2019, 05:43 PM

Blkbart, I had a problem with my exhaust brake suddenly not working on my 04 Meridian. I removed the dash cover on the instrument panel and found the wire connecting to the on/off switch had pulled out of the switch. Apparently the wire out of the switch had tension on it when it was installed and had pulled out over time. I stretched the the wire to remove the tension reattached it to the switch and it has functioned properly since. I don't know if this might be typical assembly problem that has occurred on other MH.

Safe Travels and THE JOY IS IN THE RIDE

Blkbart · 09-08-2019, 08:18 PM

The ECM was found faulty and a new one programmed and installed... Nearly $5K! The dash air is a completely separate issue. We cleaned the rear condenser (very dirty) and replaced the two electric fans, this didn't make much of a difference. The R 134 was checked for the proper pressures which they were. At this point I'll be replacing the compressor on the engine, receiver dryer, and expansion valve. While these AC parts/components are relative inexpensive, the labor is not...

Blkbart · 09-08-2019, 08:22 PM

Yes, sometimes the most simple issues like the switch leads are knocked loose. These days I look at all of the ridiculously simple issues/problems and often find them the culprit. Glad you found this was your issue!

Blkbart · 09-08-2019, 08:50 PM

My previous vehicle was a 2011 GMC Denali 2500HD and I towed a 26' Weekend Warrior toyhauler. What simplicity that was, the diesel pushers are very tempting, air ride chassis, power awnings and levelers. The ability to use the restroom while on the road or slap a sandwich together. I guess what I have realized is that the maintenance and sheer size of the pushers really doesn't allow for much driveway repair or maintenance. The cost of the maintenance is EXPENSIVE!

Don G · 09-09-2019, 05:39 AM

If your a/c pressures are normal you don't need to replace these parts. The problem is somewhere else. You need to have a/c shop diagnose problem.

Don G · 09-09-2019, 05:47 AM

I know that the exhaust brake is more than just on/off switch. There are some computer controls that allow for not braking if your cruise control is turned on and also controls transmission down shifting to assist the braking. They should be able to simulate the switch and get the brake to operate to test the function.