BAC Forum
General Boards => Technical Support => Topic started by: Daniel McShane on May 18, 2018, 01:26:08 PM
-
Drive west on I 40 and voltage on chassis and coach batteries started fluctuating from 12 - 14 volts. Put meter on batteries and showing 15v, not good. I still have the echo charger which is under the bed in the engine compartment, I am assuming that it has failed. Any suggestions. Luckily there is a koa where I exited I 40.
-
Could this be my aternator and is my understanding correct that the echo charger charges no matter the power supply, cat, shore or genny.
-
As far as the fluctuating gauge goes, that happened to me a couple years ago. I found a loose wire on the back of the alternator. Tightened it and no problems since. So that is probably a ground issue somewhere. As far as 15 volts with engine running, that seems higher than normal 14.2 VDC. I'm not an expert but 15VDC probably won't hurt anything in the short term but may indicate a regulator problem developing. I think you are correct about the echo charger. Good luck.
Jerry
-
Thanks for the input Jerry. Just hooked up to shore power at the KOA and voltage went high again, got a reading of 14v and steadily increased to 15 and climbing when i unplugged, am i correct in thinking its the echo? Also high on genny power. Now where to get a rerplacement in the middle of oklahoma?
-
Isn't the echo charger the voltage regulator??
-
Daniel,
The echo charger is a voltage follower, not a true regulator. It does limit the output voltage to 14.4 if the input reaches that level.
When on shore power, you may see high (15+ volts) at the battery from the solar panel circuit. There is almost no currect though. Try covering the panel(s) to verify.
Jerry's comment re a loose connection is very possible. I had one in my rear electrical bay that caused voltage to fluctuate between 12 and 13.7v when driving both on alternator and generator.
Steve
-
Daniel,
Your problem is not your Echo Charger. The Echo Charger simply passes charging voltage from the house batteries to the chassis batteries only when the house batteries are being charged. It can not increase the voltage above the charging source voltage. The charging voltage for the house batteries is regulated by their charging source, either the engine alternator or the inverter.
From your description, it sounds like you had the generator running while driving and the inverter is overcharging your house batteries. If the generator was not running while you were driving, you have two charging sources that are overvoltage that probably means a connection problem. To solve the issue, you need to run a through circuit test of your charging systems, both the inverter and engine alternator. This test should be ran with the solar panels covered so that the 5 or 6 amps from the solar panels does not confuse the results.
Gerald
-
Gerald, I did find a severely corroded wire, 16-14 gauge, on the positive terminal of the chassis batteries (sense wire?). I removed the wire, replaced the connector and reconnected. Went to start and cat wont go into its normal sequence, no wait to start for warm up and what ever else it does. Checked every fuse I could find, Allison included. Not sure what else to try.
-
Daniel,
The wire that you worked on may be the one to your ECM (engine control module). Double check that it has a good connection to the battery. I am not sure where the ECM fuse is located on a 1999 Monterey, but on most SMC built coaches it is in the upper part of the battery compartment.
Normally if you work on something and something else stops working, it is caused by something that you did wrong. Double check everything that you did, and if it checks out OK, check the power circuit for your ECM.
Gerald
-
Gerald,
I agree, I have caused colateral damage over the years working on various things be it home or auto. The wire I replaced the terminal connector on was RED as is the one at the alternator, not sure which wire goes to the ECM. I called a mobil tech and after a couple hours he says he's sure the ECM is bad. He said he wasn't receiving the proper signals from the data link in the service compartment, nothing from the ECM. My production year is 98 so thats 20 years and from what I understand these ECM's do fail. I'm 65 miles west of OKC and will have to get a tow on Monday back to OKC, the tech suggested Premier Freightliner over a local Cat dealer due to Cat's high hourly rate.
-
So with power TO the ECM and no signal from the ECM would it be safe to assume that the unit has indeed failed. I've crawled all around and can't see anything obvious. It sure is a coincidence, perhaps my voltage spikes took it's toll on the ECM but not bad enough to blow a fuse. Thank you to all that contribute to this forum, I've spent countless hours reading all I can about my coach to educate myself as much as possible. It's comforting to have the Beaver Ambassador Club on the road with me, again, many thanks.
-
Daniel,
If you've got 12v at the ECM then the fuse is OK. Since the outputs are data lines and thus not fused, it would seem the ECM is faulty, unless there is a bad connector between the ECM output and the data jack.
Steve
-
Daniel,
I personally would feel better about a diagnoses of a bad ECM from a Cat dealer than from a mobile tech or a Freightliner dealer because a Cat ECM can be expensive. However, if it is a large Freightliner dealer that has been around a long time, their techs should be proficient with Caterpillar ECM diagnostic procedures since Freightliner used to use a lot of Cat engines. Caterpillar has not built a diesel engine for highway use in over 8 years, so the expertise that is necessary to properly a Cat ECM failure is not at every truck shop.
Gerald
-
The journey continues.....Oklahoma City Caterpillar no longer works on motorhomes (coaches).
-
Same with Rush Truck Center.
-
The journey continues.....Oklahoma City Caterpillar no longer works on motorhomes (coaches).
I ran in to the same problem coming out of Florida a couple of springs ago. The sensor for the boost on the turbo went bad and produced a check engine light. It happened once before, so I knew I could drive okay, just needed to get the sensor replaced. Drove from Jacksonville to Perry, GA trying to find a CAT dealer. There was one outside of Perry, GA, but when I arrived they said they could not diagnose my engine. Had to go to Chattanooga to find one that could connect to the diagnostic port.
-
Update.
I met a guy who stooped to use the dump station who lives nearby. He knew a guy who works on everything. So I got a hold of this guy named John who said he doesn't work on motorhomes. I told him I have plenty of room in mine as I can sit on the engine unlike most diesel pushers. He still was very reluctant, again saying he doesn't work on motorhomes. Again, I told him of the ease of working on mine. He was still trying in a very kind way to say no. I then told him of the other facilities refusing me and practically begging he said he would try and stop by later today. Well about 2 hours later he showed up, I walked him through my situation then he went to his truck, grabbed some tools and went to work. He performed a couple test the other tech did but took some readings at the ECM wire clusters for 2 voltage sources and 2 grounds, not sure which pin numbers. 1 ground seemed curious and led him to believe that the ECM is bad. But now he went a step further, he has several ECM's in his truck. He had one that wasn't exact but when we tried it the CAT data ports wnet hot. BINGO bad ECM. He ordered a new one from his supplier in OKC who also "flashes" then with the correct data. I told him I had nothing else to do and if needed I could drive wherever needed, I'd even get him lunch. So now just waiting to hear.
This guy doesn't advertise or selicit work, he doesn't work on motorhomes, has more work than he can handle ( his son gave him a hard time for coming ), and yet he came to help me. Someone is watching out for me today, Thankyou!!
Hopefully my next post will be on the road.
-
Daniel,
I have a 2000 Monterrey, same engine, similar issues. I would be tickled to know if the ECM fixes your problem. Please let me know.
-
UPDATE.....Finally back in Tennessee after a few weeks in the Sierra's!! ECM was replaced and coach fired right up but voltage was still high. Replaced alternator and ALL was good. The mechanic asked if I recently had service at a Cat dealer which I did before I left because they downloaded all the necessary info to load into the new ECM. He also noted that the original ECM had been replaced because the existing one was not Cat yellow. Quite an experience and very thankful to all your suggestions and comments and especially John the mechanic who doesn't work on motor homes.
-
Drove from Jacksonville to Perry, GA trying to find a CAT dealer. There was one outside of Perry, GA, but when I arrived they said they could not diagnose my engine. Had to go to Chattanooga to find one that could connect to the diagnostic port.
Why couldn't the CAT shop in Perry diagnose? Was it just that they didn't want to work on an RV - or is there some technical reason why they could not hook up to your diagnostic port? Surely any CAT "dealer/repair shop" has the equipment to connect to the diagnostic port. It's the same port whetehr located in a truck or RV engine.
-
Gentleman,
In most cases there should be one engine diagnostic plug in front and one in the back of the motorhome or in a compartment on passenger side. What I find in many cases is one of the diagnostic plugs will not work and not allow the technician to connect the Cat ET or Cummins InSite to read diagnostic codes. There are also non-OEM code readers that cannot access the system. Many times the technician will stop if he cannot get a reading from rear diagnostic plug. There is what called a break-out box that connects directly into the J-1 data port on the engine ECM and will override controls in front. It provides a readout the engine ECM data and also will start and run engine to determine if any problem are present. Many engine ECMs are replaced that do not need to be replaced if the tech cannot get a readout from the front or rear ports, without trying the break-out box to determine or verify condition of the ECM. Last point is that low/intermittent voltage can impact the diagnostic codes because many sensors and regulators have a tolerance/margin of only 1/2 volt plus or minus. What happens next is that sensors and regulators that read out of correct operation range are replaced. Problem is often caused by the ground strap on engine ECM not making a good connection.
Dave Atherton Retired Cat Mechanic