91 U300 Bulkhead and AC Questions

Topic: 91 U300 Bulkhead and AC Questions (Read 3023 times) previous topic - next topic - Topic derived from Coach Build Numbers

Re: 91 U300 Bulkhead and AC Questions

Reply #25 – August 30, 2015, 02:43:14 pm

Thank you Pierce for those codes! Do I assume that a flash sequence of 3-1 would mean number 31? Or a 4-3 would mean number 43? If so, then I have:
code 31 (Fault on Aux circuit)
code 32 (ECM backup system fail)
code 43 (low coolant level)
code 46 ((Low battery voltage)

Now since the coolant level is up where it should be in the sight glass, I must assume that code 43 is an old code that was never cleared out? And if that is the case, then perhaps the other codes (with the exception of code 46) may be old codes as well, at least I would hope.

Code 46 does seem likely to be a current issue, since (as mentioned above in previous post) it starts fine if the battery is charged up to 100% 12.7v as indicated on the battery charger, before trying to start the engine. If the battery charge is below 90% as indicated on my battery charger it seems to trigger the check engine light and engine shut down light when I start the engine. All the Interstate batteries were new in April of this year, but the cranking battery does not hold a good charge overnight. I have switched it out with the other batteries to see if another one would hold a charge better, but no luck. There could be a draw on the cranking battery somewhere which causes it to drop voltage overnight. But I am suspecting the batteries themselves as perhaps being faulty. I have experienced issues with other Interstate batteries in RVs, and have heard first hand stories from other folks experiencing the same issues, so I am suspicious. When I bought the coach all the batteries were as dead as a rock, and they seemed to struggle to take even a 75% charge. The Interstate battery dealer told me that before I could ask for a warranty exchange, they had to have the batteries overnight to try and bring life back to them. So I let them have one battery but the dealer was only able to bring it back to about 80%. He said I needed to bring the batteries home and keep charging them at a 2 amp setting when not driving the coach, and over time this would bring them back to life. Since this is not my first rodeo, I began to suspect he just did not want to deal with me, even tho he had sold the batteries to the previous owner and had even installed them.
I just can't afford a new cranking battery right now, so I was hoping to bring this one back from death. And with the onboard battery charger off line for whatever reason I have not figured out yet, I have to put my shop battery charger on the batteries overnight, or run the gen-set which seems to charge them up, even with the onboard battery charger off line. I have not figured out all the nuances of that electrical mystery.

Does anyone have a good suggestion as to where I can buy the Pro-Link code reader mentioned by several folks on the forum?
Just a typical auto parts store like Auto Zone, NAPA etc?

Re: 91 U300 Bulkhead and AC Questions

Reply #26 – August 30, 2015, 02:55:55 pm

Look on E Bay for a Pro Link You should be able to pick one up for a few hundred bucks you will need the DDEC II cartridge and the DDECII connection plug it could be rectangle or round.

Re: 91 U300 Bulkhead and AC Questions

Reply #27 – August 30, 2015, 03:04:50 pm

It looks like the reason your charger in the battery bay was unplugged is the PO (previous owner) has installed a Xantrex Freedom modified sine inverter/charger combo - the green box in your pictures - to replace the OEM inverter. This explains why your batteries charge when the genny is running, the Xantrex switches to charger mode when there is genny or shore power available, and back to inverter mode when there is no genny or shore power.

This might also explain your issues with the front outlets. If the old inverter has been pulled, there is also an inverter transfer relay in the cubby hole under the bed that only will work with the OEM inverter. It has to be removed and the coach circuits rewired to the Xantrex which has a built-in transfer relay. This is probably why the OEM breaker for the front outlets is disconnected and wiring is removed, the Xantrex has built-in breakers. Unless the PO was a fairly good electrician, this wiring could easily be fouled up, and affect the coach circuits that were connected to the OEM transfer relay. The other possibility is the Xantrex 120 volt inverter circuits once worked, but now do not - but it appears the charger still works.

Post a pic of the cubby hole under the bed and we can see what the wiring looks like.

Re: 91 U300 Bulkhead and AC Questions

Reply #28 – August 30, 2015, 03:50:00 pm

Yes, you have it right.

Go to Ebay for the Pro-Link reader and correct cartridge for the DDEC II. Cartridge may be listed as DDEC I & II or DDEC II & III . Since this reader has been replace with newer models (at astronomical prices) you will have to do a search using key words like Detroit, Pro-Link 9000, Kent Moore, MPSI. All Foretravel 2 cycle Detroits are DDEC II. Many are trying to get a fortune for the used readers and cartridges but I bought a couple for less than $200 each for the reader (less than $100) and the cartridges. One came with Detroit, GM, Ford and Chrysler cartridges. The domestic car cartridges are going for about $5 each. The Detroit DDEC II cartridge should be under $100 and the CAT or Cummins quite a bit more. Domestics cars are super cheap because they made so many. Detroit DDEC engines are/were on most all buses but CAT and Cummins put computers on later so not as many on the market. Getting a reasonable deal may take a while.

The Pro-Link 9000 will read about 40 or so engine functions (total gallons used since new along with engine serial number, horsepower, rotation direction, firmware ware version, fuel mileage, trip mileage, temperature, injectors, etc, etc, etc.) and can also modify several. It will tell you the active codes as well as the stored codes and also give the dates and length of time the code was active. You can then erase any of the old ones.

ECU voltage is one of the functions so will be applicable to your code and starting problem.

Isolate (disconnect cables) each start battery and check in the morning with digital voltmeter.

I installed digital voltmeters where the Audit CRT was to constantly monitor both engine and house batteries but you can buy lighter plug digital volt meters and keep an eye on both voltages. The lighter plug in the dash is engine battery voltage, the lighter plug by the wall is house battery voltage. See my old posts.

PM with questions,

Pierce

Re: 91 U300 Bulkhead and AC Questions

Reply #29 – August 30, 2015, 04:01:23 pm

PrFleming, you are really helping me to understand what may have gone on with the PO, and what is going on now!! As I have said before, electrical issues are my weak point (among many others) and now I feel like I will be able to get some kind of a handle on what is going on, or not going on!
I found the book for the Xantrex inverter/charger and will also read that to help me understand some of the issues!

Thank you again Pierce for your help, and the info about the code reader- I will start a search on Ebay and see what I can find.

Re: 91 U300 Bulkhead and AC Questions

Reply #30 – August 30, 2015, 04:11:16 pm

Tell us what the Xantrex monitor panel (first picture in above post) does when you plug into shore power or start the generator.

Re: 91 U300 Bulkhead and AC Questions

Reply #31 – August 30, 2015, 04:19:28 pm

OEM transfer relay box is removed. Yellow romex and small metal romex strain reliefs are new, should help with tracing what was changed.

Re: 91 U300 Bulkhead and AC Questions

Reply #32 – August 30, 2015, 04:44:38 pm

Looks like some cut romex circuits here. These are probably wires that went to the old inverter, not sure why they weren't re-used with the Xantrex. Definitely need to do some circuit tracing and trouble-shooting.

BTW, earlier you mentioned connecting your shop power to the dead coach circuit and blowing the shop breaker. Really shouldn't do that...you don't know what in the coach will be getting that power... Better to switch off the main 50 amp breaker, make sure the inverter is off (disconnect it from the battery), and trouble shoot with a circuit continuity tester. Just make sure ALL 120 volt circuits are off.

Re: 91 U300 Bulkhead and AC Questions

Reply #33 – August 30, 2015, 04:57:49 pm

Brett, the inverter shows nothing with the gen-set running until you push one of the buttons at the bottom like 'share' or 'set up' and then it lights up just like in picture 1. Then it looks like that for a while and then goes 'blank' unless you push one of the bottom buttons again. Nothing shows up in the column 'invert' unless you push the button, and then only the green LED by the button lights up, but nothing in the column above it. I was away from shore power when I did this test, so had to use the gen-set.

Thanks also PrFleming, I feel like I am starting to at least get a sense of direction to go in looking for a solution! Yes, there are two cut romex wires in the corner that don't appear to be hooked up anymore to anything. When running the gen-set or hooked up to shore power they have no power in them.
I will be more careful and not apply power to anything, I will take your advice and do it the right way!!

Re: 91 U300 Bulkhead and AC Questions

Reply #34 – August 30, 2015, 05:42:29 pm

Here are a couple of schematics that show the OEM 120V circuit panel and inverter wiring, hopefully these can help you to "reverse-engineer" the state of things now.

Note that both circuits 2 (microwave) and 5 (bath and front outlets) originally were switched for the OEM inverter (because the inverter could only run the microwave alone). Does the microwave work now? This would also have been re-wired in the new setup.

Just noticed on your pic of the breaker panel labels that #2 "Microwave" is crossed out, then "Inverter" is crossed out - Hmmm...

Re: 91 U300 Bulkhead and AC Questions

Reply #35 – August 30, 2015, 06:04:37 pm

No, the microwave does not work since it is plugged into one of outlets that is in the small cabinet above it and that outlet is dead also. Like you said, I may have to reverse engineer the current set up to figure out what got cut out of the system and why. And I am going back to basics and re-reading and re-checking all aspects of the Xantrex unit to make sure there is no setting that is turned off, or something unplugged, etc.

Re: 91 U300 Bulkhead and AC Questions

Reply #36 – August 30, 2015, 06:11:25 pm

Yes, you really need to (carefully) trace it out. There should be a breaker on the main breaker box that goes to/supplies the inverter/charger with 120 VAC from either shore power or generator.

When the inverter/charger gets that 120 VAC in (and their is a breaker in/on the inverter/charger) it does two things:

1. It starts charging the batteries (the Xantrex monitor will show high amps and voltage around 14 VDC).
2. It will "pass through" the 120 VAC to all circuits downstream of it. There are likely two small breakers on the inverter/charger that you may need to reset for this.

Re: 91 U300 Bulkhead and AC Questions

Reply #37 – August 30, 2015, 08:17:48 pm

I am just arm-chair quarter-backing here, but it seems to me the best approach is to step back a few steps, get the inverter out of the circuit and get things working again, and then move forward, step by step, in this order:

- Identify the coach circuit 2 wire (I'm thinking one of the wires going into the circuit box where the OEM relay was), and wire it back directly to the circuit 2 breaker (unhook any other wires on the breaker), verify the microwave works on shore power and/or genny power.

- Identify the coach circuit 5 wire (I'm thinking one of the wires going into the circuit box where the OEM relay was), and wire it back directly to the circuit 5 breaker (replace breaker in box), and verify the front outlets work on shore power and/or genny power.

- Now, wire the Xantrex per the Xantrex manual. Depending on the Xantrex you have (i.e. if it can support dual input and dual output), for the 2 "inverter" circuits 2 and 5, I'm thinking this will require all new runs of 10 gauge romex from the circuit breaker box cubby to the Xantrex (2 to the inverter, 2 back from the inverter). The yellow is 12 gauge, not heavy enough, needs to be orange 10 gauge. From the pictures you have 2 breakers on the Xantrex, so you won't need a separate inverter sub panel with breakers.

You'll have a real nice upgrade when done.

Re: 91 U300 Bulkhead and AC Questions

Reply #38 – August 30, 2015, 11:12:46 pm

Thanks again PrFleming, you have a good plan it appears. At least I now have a better direction and a real plan of attack instead of chasing my tail! I checked the Xantrex unit, it was operating properly, the green LEDs were working on the base unit it's self as the installation manual said they should, it had not tripped it's breakers, so it seems to be functional. The remote control unit in the kitchen lights up the way it is supposed to when following instructions, according to it all systems work. So why no power to those pesky kitchen and front plugs? If they had a short in the circuit it appears they would have thrown the circuit breakers on the main Xantrex unit in the basement, but they did not, so perhaps there is a wire that has come loose somewhere? So as PrFleming suggests, go back to square one and start over again and 'rebuild the system' so to speak. That will be the plan of attack after the upcoming weekend holiday. We are going to take the coach for a short 125 mile trip to a flea market in NE Oregon, it's just a short trip to see what other things might 'shake out or show up' so I will know what other things I might need to address. I will keep the forum posted on what I find out, in case it might help someone else facing some of the same electrical issues and gremlins.
In the meantime, if anyone else has any other ideas or suggestions, don't be shy about sharing them with me please!

Re: 91 U300 Bulkhead and AC Questions

Reply #39 – August 31, 2015, 03:28:39 am

On my 91 I have a panel in my kitchen on it is a switch for the invertor and a small rfed reset button It allows ,e to select between the putlet and the microwave. Of you have that panel maybe try turning it on and pushing thye reset button and see what it does

Re: 91 U300 Bulkhead and AC Questions

Reply #40 – August 31, 2015, 08:52:47 am

stump:

Yes, I have the same panel for the stock inverter. But, we have determined that dburt's stock inverter has been removed. If this original switch panel is still there, it won't do anything now...

Re: 91 U300 Bulkhead and AC Questions

Reply #41 – September 07, 2015, 11:48:23 pm

After a weekend camping in the coach, and dealing with the issue of the 'stop engine' and 'check engine' light coming on and shutting the engine down after about 30 seconds of running when cold, I was perplexed. After 4-8 times of re-starting the engine, and when it was warmed up somewhat from the starting and running for 30 seconds so many times, the lights would stay off and the coach would run fine when warmed up.
After getting back home last night and going to bed annoyed, I woke up this morning fuming and mulling over the issue and thought I would have a 'talk' with the good Lord about my frustration when a thought went thru my noggin that I should check the coolant level again when the engine was cold. Now I was irritated by that thought, since I had checked the coolant level already and it was good before the problem started showing up. But since the thought might have some merit, I went and checked the coolant level and what do you know- the coolant level was down below the sensor level! I must have checked the coolant level originally when the engine was warm. I added some anti-freeze and started the engine and no lights, and no issues! Wow, what a simple fix- which proves the point that a person should always check and double check the basics first.

As a side note, I weighed the coach with full diesel fuel tank, full fresh water, all our gear, and two of us onboard, and we weighed in at 22,300 lbs. Before we left, I filled the tank up with fuel on flat level ground (halfway up the small slanted filler neck) and then drove from the Ontario, Oregon area over to Baker City, Oregon on I-84. Those of you who are familiar with that route know the long grades you have to pull headed NW. In fact local lore says if we were to level the road down flat, instead of 75 miles of long grades and a climb in elevation from around 2,200 feet above sea level to nearly 3,500 feet elevation at Baker City, we would have nearly 150 miles of flat level highway.

Anyway, with about a 15 mph headwind I just knew my mileage would be way down in the basement, but filling up again in Baker City I was surprised to see my mileage at 9.6 mpg. Now I always fill my own fuel tanks, and always at the same level on flat ground. I am somewhat OCD about such things, not sure why but I like to know the precise mpg ability of my vehicles. I only drove 60 mph top speed, and did not tow anything. I used the cruise control when I could on the flats, and never on the uphill grades. The engine/transmission retarder was great on the long downgrades, much better then riding the brakes. Coming back last night, the long 6-7% 3 mile long uphill grade climbing out of Farewell Bend on I-84 dropped my speed down to 42 mph at the top. Now I may have been able to drop down to 2nd gear and run the engine up against the redline for a little more top speed, but I am not inclined to abuse an engine when there is no real need to.

All in all, it was an interesting weekend with a good ending for problem solving.

Re: 91 U300 Bulkhead and AC Questions

Reply #42 – September 08, 2015, 01:49:59 am

@dburt

Quote

Coming back last night, the long 6-7% 3 mile uphill climb out of Farewell Bend on I-84 dropped my speed down to 42 mph at the top. Now I may have been able to drop down to 2nd gear and run the engine up against the redline for a little more top speed, but I am not inclined to abuse an engine when there is no real need to.

You won't be hurting the engine. It is governed to 2,200 rpm. Plenty of 4 strokes go to 4,000rpm without problems. Your 6v92 can handle the 2,200 rpm no problem. It will also benefit from more air flow, coolant, oil, and fuel circulating.

When I was having cooling fan speed problems an old 6v92 mechanic had me floor the throttle in neutral so he could check the maximum fan speed. He even said that if it was overheating climbing a hill to pull over go to neutral and floor it for a while until the temps come down! Which I've done several times without issue.

see ya
ken

Re: 91 U300 Bulkhead and AC Questions

Reply #43 – September 08, 2015, 10:46:52 am

DBurt,

The 6V-92TA was the first HD diesel engine to get electronic controls and is bullet proof if you don't use the override control when you lose the hydraulic pump belt and overheat it. It will go into a 30 shutdown mode for a lot of reasons as you found out. It, along with other premium diesels, have wet liners. They are more expensive to manufacturer but much easier to overhaul. The wet liners have sealing rings toward the top and bottom and a little more care in monitoring the coolant temperature is needed but should you exceed about 220 degrees, the DDEC will go into shutdown mode.

Downgrade, I usually let the rpm build to about 2000, use the brakes to 1700 or so, let it build again and repeat the process. I would let it go higher but I once spaced out and when I looked down, I was at 2400 rpm. The engine is glass smooth from idle to past fuel cutoff so you do have to pay attention. Fire departments go up to 2400 with a higher HP rating so 2200 is good for all day.

9.6 mpg/60 mph in mild hilly country is about what to expect. We get up to 12 mpg at the same speed on the flat but half that in the mountains. Just got back from about a 800 mile trip through the Sierras and averaged 8.0 mpg with lots of high altitude grades. Hills, headwind and speed make a big difference. Outside temps make quite a difference in engine temps and power.

Anytime the engine shuts down for an unknown reason, pop the dash top up, flip the engine switch to the on position up at the back in front of the driver and with the "ignition" switch in the on position, you can count the number and sequence of flashes out of the little bulb and then compare to the fault codes to see the problem. With a Pro-Link, you can see the fault codes and the date along with the duration. Nice!

You will have lots of fault codes stored in the DDEC memory now.

Pierce

Re: 91 U300 Bulkhead and AC Questions

Reply #44 – September 08, 2015, 01:14:50 pm

Quote from: dburt – September 07, 2015, 11:48:23 pm

... I added some anti-freeze and started the engine and no lights, and no issues! Wow, what a simple fix- which proves the point that a person should always check and double check the basics first.

You maybe already checked this, does the radiator overflow tank have enough fluid? Your engine should draw some antifreeze from the overflow tank if needed when cooling down. Sounds like yours possibly wasn't able to draw fluid and air got in. Also make sure the hose from the radiator to the tank is solid. When I got our '91 I had to replace the overflow tank and hose.

Re: 91 U300 Bulkhead and AC Questions

Reply #45 – September 08, 2015, 02:05:35 pm

I'd love to see 8 mpg this trip pretty much flat towing a 11 ford fusion 7.25 63mph best I've gotten was 7.5 towing bikes on tlr 70mph

Re: 91 U300 Bulkhead and AC Questions

Reply #46 – September 08, 2015, 04:18:13 pm

Stump,

Here is the "independent third party", no BS total fuel used/mileage, gallons, etc fuel mileage off of the DDEC with the Pro-Link 9000. First owner towed a long construction trailer and we live in the Sierras with nothing but steep hills. More miles now but same fuel mileage.

Pierce

Re: 91 U300 Bulkhead and AC Questions

Reply #47 – September 08, 2015, 06:43:08 pm

DBert,
22,300 lbs. seems far too low for a U300.
I have an RV Rating Book (from RV.org) that lists a 1991, U300, 40 ft, SBID floorplan with a curb weight of 25,368 lbs. which is considered very good since that gives a payload of 4632 lbs.
They define curb weight as full of fuel, propane and fresh water. Grey and black tanks empty. No passengers or personal supplies on board. The listing for a 36 footer is 24,331 lbs.

When I weighted our '91, U300, 40 footer, with fuel, fresh water, us and all our stuff we came in at 27,600 lbs. We were full timing then so plenty of stuff in it, so the RV Rating Books seemed to be about right as far as I can tell. If you can it's a good idea to weight each of the four corners separately - it gives you a good idea if you need to redistribute your cargo. The natural distribution of weight on Foretravels is typically very good.

Re: 91 U300 Bulkhead and AC Questions

Reply #48 – September 08, 2015, 07:51:36 pm

Quote from: dburt – September 07, 2015, 11:48:23 pm

Coming back last night, the long 6-7% 3 mile uphill climb out of Farewell Bend on I-84 dropped my speed down to 42 mph at the top. Now I may have been able to drop down to 2nd gear and run the engine up against the redline for a little more top speed, but I am not inclined to abuse an engine when there is no real need to.

You will want to let the 6V92 rev, it is made to do this, and as others have stated, will run cooler and happier. In marine applications I have read about DDEC 6V92s tuned to 550 HP, cruising at 1900 rpm for hours at a time.

Re: 91 U300 Bulkhead and AC Questions

Reply #49 – September 08, 2015, 08:15:49 pm

JohnFitz, my first thought going over the scale was the same as yours, I figured it had to weigh more then it was showing! It is the same scale that ODOT uses to officially weigh commercial trucks, and was 'zeroed out' at 000000 lbs before I went over the scale. Front axle was 7,600 lbs and the rear axle was 14,650 lbs. Strange indeed! If I get a chance, I am going to go over a different scale just to see what that will show!

PRFleming- I thought the same thing about the overflow tank hose, so I am going watch it. It had about half a tank of anti-freeze when I checked it before adding coolant, so I am going to watch it and make sure I am not dumping coolant out somehow. I checked the oil and the exhaust for any smell of coolant going out those ways, and was relieved to find zero evidence of that!

Pierce- I'm keeping my eyes open for an affordable Pro-Link scan tool, I'd like to have that feature of erasing old codes, and checking for overall mileage, etc. It appeals to my OC nature! (I used to fly a lot when younger, so the old habits of wanting to know fuel flow, how much fuel I have used, temps, and altitude seem to have never left me. My kids think I have a personality disorder) I sure like the sound of 12mpg on the flats with no head wind, but around here there aren't many long flat expanses of highway unless we head south towards Nevada. I am quite pleased with the mileage since for some reason I was expecting a lot less, so even 9.6 was pretty good!

Ken and prFleming- the next time I come to a long uphill grade I will just keep my foot in it and see when and how it downshifts, and run it up to 2,200 rpm just to see how she runs. I used to have a screamin' Jimmy 4-71 in a road grader of mine, you just ran it full throttle and went to work, but it was hard to get used to that high sounding RPM. This 6V92 seems to run very well and sounds good, but I am just used to watching my old 6.9/7.3L IH engines in my Ford pickups I have had over the years so that I would not over-rev them when towing a heavy load going down hill. Now I have a Dodge 6.7L Cummins that I can put in tow/haul mode and let the exhaust brake do it's thing when going down long steep grades when towing a heavy load so I am not worried about a run away. But I will watch that 2,200 redline on the 6V92 when going up or down hills, and just let it run like it is supposed to!

prFleming- I like the brush/deer guard on the front of your coach! I built a similar unit for a Bounder MH we owned, since we have so many deer/vehicle 'interfaces' out in this neck of the woods. When I got the Foretravel, I was pleased to see I could just build the basic guard and use the towing adapters for the structure to sit in.

Dennis

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