Skip to main content ↑ ↓
Topic: 1991 U300-- bought it! (Read 9363 times) previous topic - next topic

Re: 1991 U300-- bought it!

Reply #160 –
Your idle speed on that motor should be around 600 RPMs just a FYI good job and good luck 👍

Re: 1991 U300-- bought it!

Reply #161 –
Before you spend big bucks for an overpriced shop alternator, check ebay. They are not expensive with a new one about $250. A small electrical shop should be able to rebuild with new bearings, etc for around $100. We have a shop in the next town that rebuilds alternators for $65 unless major parts are needed. This even includes aircraft alternators. 

If you are new to RV ownership, the repair process has a lot of minefields.  Ask source questions on the forum before getting ripped off.

LEECE NEVILLE 160 AMP DUVAC ALTERNATOR MOTORHOMES RV'S 2824LC 2825LC EL-039...

All Detroit 2-cycles in Foretravels should idle almost exactly at 600 RPM as the speed is controlled by the DDEC II ECU. The same for fuel cutoff RPM at 2130 max.

Pierce

Re: 1991 U300-- bought it!

Reply #163 –
Quote from: Pierce & Gaylie Stewart –
Before you spend big bucks for an overpriced shop alternator, check ebay. They are not expensive with a new one about $250. A small electrical shop should be able to rebuild with new bearings, etc for around $100. We have a shop in the next town that rebuilds alternators for $65 unless major parts are needed. This even includes aircraft alternators. 

If you are new to RV ownership, the repair process has a lot of minefields.  Ask source questions on the forum before getting ripped off.

LEECE NEVILLE 160 AMP DUVAC ALTERNATOR MOTORHOMES RV'S 2824LC 2825LC EL-039...

All Detroit 2-cycles in Foretravels should idle almost exactly at 600 RPM as the speed is controlled by the DDEC II ECU. The same for fuel cutoff RPM at 2130 max.

Pierce

I am going to see if any shop nearby can rebuilt for less than $200. If so, I will keep the powerline alternator as back up.

As to the RPM, I have no way to verify the RPM since the Tachometer is not displaying correct value.  As I mentioned in my last post, I bought a cheap laser tachometer to measure the RPM of the wheel that powers the alternator, My reading is about 1170 RPM. Other friends mentioned that I should measure the crank shaft. Where is the crank shaft? Is it the one drives the radiator fan?

I read also, new alternator can also change the RPM reading.  Since some of the Tachometer based on alternator pulse.

Is there anyway I can read those information from the DDECII ECU directly?

Re: 1991 U300-- bought it!

Reply #164 –
Yes, buy a ProLink 9000 and your can read out about 45 different values, test injectors and change some operating parameters. But it might be better for you to buy the Bluefire adapter and use a tablet to read out the information. My first choice would be a Samsung Galaxy Tab S2 or above as they are the best tablets on the market. iPad are also excellent but more expensive for less.
BlueFire LLC

You need a list of questions and another owner looking over your shoulder. You have an excellent attitude. PM for more information.

Pierce

Re: 1991 U300-- bought it!

Reply #165 –
The tach is all electronic as is all engine controls (DDEC II) and the cruise control.  My guess is it might just be wiring in the dash area and if not, a new dash gauge should be all that is needed.  In terms of priorities, I would place fixing the tach pretty low on my list;  the engine and tranny computers take care of the RPM for you.

I too would suggest a VMSpc system over a ProLink.  The Bluefire appears to be a new competitor to VMS so I don't have an opinion on them.  The Prolink is a handheld mechanics tool.  The VMS is for a driver who wants more information while driving and it shows multiple items on a tablet simultaneously.  If I didn't already have a system I would get a setup from Roger listed in the Commercial Listing section of the forum; you will get personalized support too.  It's worth it just to have an accurate engine temperature readout.  The dash gauge is just not that accurate and backups to all the dash gauges it great to have and will save you a lot of worry.

Re: 1991 U300-- bought it!

Reply #166 –
Both VMS and BlueFire are readers, not tools. One works on almost all platforms, is wireless, costs much less and you don't have to use Windows. If you want to test injectors and have a 1000 rpm fast idle, you have the Prolink as it is a tool, not just a reader. That said, it is not nearly as convenient for driving down the road.

And yet again, the cruise control fast idle that works on some coaches does NOT work on a Detroit U300. You have to DIY the wiring or use a ProLink.

Pierce

Re: 1991 U300-- bought it!

Reply #167 –
The posted eBay LN alternator does not have the adjustable voltage regulator of the oem one. .2 volts too high on my particular coach and install.  May reinstall my rebuilt oem one.  Mine needed one diode and the bearings which were not an easy install per the Marine company I used.  $300 in Costa Mesa in Orange County, ca. 

Re: 1991 U300-- bought it!

Reply #168 –
Quote from: Pierce & Gaylie Stewart –
Yes, buy a ProLink 9000 and your can read out about 45 different values, test injectors and change some operating parameters. But it might be better for you to buy the Bluefire adapter and use a tablet to read out the information. My first choice would be a Samsung Galaxy Tab S2 or above as they are the best tablets on the market. iPad are also excellent but more expensive for less.
BlueFire LLC

You need a list of questions and another owner looking over your shoulder. You have an excellent attitude. PM for more information.

Pierce



I have @stump looking over my shoulder ;D  and all you guys.

Re: 1991 U300-- bought it!

Reply #169 –
Quote from: JohnFitz –
The tach is all electronic as is all engine controls (DDEC II) and the cruise control.  My guess is it might just be wiring in the dash area and if not, a new dash gauge should be all that is needed.  In terms of priorities, I would place fixing the tach pretty low on my list;  the engine and tranny computers take care of the RPM for you.

I too would suggest a VMSpc system over a ProLink.  The Bluefire appears to be a new competitor to VMS so I don't have an opinion on them.  The Prolink is a handheld mechanics tool.  The VMS is for a driver who wants more information while driving and it shows multiple items on a tablet simultaneously.  If I didn't already have a system I would get a setup from Roger listed in the Commercial Listing section of the forum; you will get personalized support too.  It's worth it just to have an accurate engine temperature readout.  The dash gauge is just not that accurate and backups to all the dash gauges it great to have and will save you a lot of worry.



I thought VMSpec is for newer coach like 2000+. Never thought it can be installed on a 91 coach.

Re: 1991 U300-- bought it!

Reply #170 –
Quote from: Caflashbob –
The posted eBay LN alternator does not have the adjustable voltage regulator of the oem one. .2 volts too high on my particular coach and install.  May reinstall my rebuilt oem one.  Mine needed one diode and the bearings which were not an easy install per the Marine company I used.  $300 in Costa Mesa in Orange County, ca. 

Is it really necessary to have adjustable voltage regulator?

The old alternator (Powerline 25-15) only have three wires, Positive, Negative and Sense wire. The new alternator (Carquest 28SI) has many more terminals. But I just use the Positive Negative and Sense wire. I don't see how the DUVAC in play with just three wires. I guess time will tell.

Re: 1991 U300-- bought it!

Reply #171 –
Quote from: jiaxinxi –
1.  Is it really necessary to have adjustable voltage regulator?
2.  I don't see how the DUVAC in play with just three wires.
1.  No  (My opinion only)
2.  DUVAC will work fine with just the three wires you connected IF the small SENSE wire is connected properly to START battery B+ post.

Re: 1991 U300-- bought it!

Reply #172 –
The adjustable voltage allows some compensation in the charging voltage if desired for temp and battery types.

Starting in mid 97 the standard heart freedoms inverter chargers had the ability to adjust the voltage for temperature.

The alternator side normally does not have temp compensation.  Unless you have a marine external voltage regulator.

So the adjustable units allow you to turn down the max voltages. 

Brett mentioned the same number as Foretravel used in production as being 13.6 volts at the battery as a compromise. 

Automotive alternators made for valve regulated lead acid are set for 14.1 or so at the batteries.

My understanding is in later model nice cars like a BMW that are equipped with AGM batteries that the voltage is set lower 13.9? 

Given the multiple reports of over 10 years service life of the Unicoaches oem mk gels and optima red tops the 13.6 seems to be a workable number.

Hot summer the correct voltage might be in the low 13's float.  Deep winter the 14 is more correct.

Hard to do temp compensation on the alternator side as the engine batteries being in the engine bay on the Unicoaches get much hotter and drop the charging voltages excessively.

The unihomes were made for flooded cell batteries in a vented box and can take the higher voltages.

They require more care and feeding and have much shorter lives.

We used to turn up the alternators for a long drive to equalize worn flooded cells.  Helped but not very accurate.




Re: 1991 U300-- bought it!

Reply #173 –
Quote from: jiaxinxi –
I thought VMSpec is for newer coach like 2000+. Never thought it can be installed on a 91 coach.
For '91 U300, the VMS only talks to the engine computer; not the transmission.  VMS only started talking the the transmission with the introduction of the "World Transmission" series (i.e 6 speeds).  There are also quite few VMS functions that don't work on the DDEC II (at least for the '91 year): trip MPG and horsepower to name a couple.  But all the real important ones like oil pressure, oil temperature, engine temp, boost pressure and battery voltage are there along with other "interesting" things like throttle position, cruise control speed set, fuel temperature, rolling MPG, instantaneous MPG, fuel burn in gallons per hour and others.  The setting for the VMS list engines to choose from.  There is no DD 6V92, but there is the 8V92 500hp which is what mine is set; so the HP reading is off by that factor.

VMS will also read all the fault codes on the engine.  You can actually do that without any VMS or other reader by using the switch under the dash and reading the "check engine light" flashes.  That process and the definition of each code is in your users manual for the coach.

Re: 1991 U300-- bought it!

Reply #174 –
It has been a while because the coach was in the shop for the whole time.

I was testing driving the coach few weeks ago. I was trying to find if the gear can be shifted to the 4th gear. approximately 65 mile/hour. According to @stump this is the best speed for the coach. My speedometer and tachometer is not working properly. The readings are way above real value. For example, when the real speed is 30 MPH, speedo shows 75 Mph. Tacho shows over 2500 RPM. Following @stump suggestion, I used a GPS speedometer on my phone, it display the speed properly. I can confirm that the gear was shifted to the 4th position. Otherwise, the transmission is bad and it is going to cost a fortune to fix transmission. In that scenario, the best solution is just to sell the coach again. I really can't handle it anymore. Luckily the transmission seems fine. In fact, I have watched so many "Can you start" video on youtube about 30~50 years old diesel truck. I never see the host worried about transmission. As long as the engine starts, they just start driving. Nobody seems to worried about transmission. I guess most truck transmissions are super reliable. Rarely become an issue.

Again, it is super lucky for me to return to the storage facility safely. While I was driving, I can hear grinding noise come from the front axle. It is pretty loud under the driver side. Air suspension is supposed to be quiet and smooth. The noise form front axle is definitely not normal. I took the hub cover off, there is no oil in the hub at all. Only water inside. The coach was parked in a place where the front AC condensation water drop right pass the front axle. For the 15 years it parked there, water has come into the hub through the pressure release hole. Talked to @stump, he give me direction on how to change the front axle bearing. It is not easy job, but definitely doable, at least for @stump . Also I read on the forum, Ron the Red Tractor was able to fix somebody's front axle within 3 hour including a trip to the part store. So I thought it is not that big of deal, I might be able to DIY.

I bought box jack, impact socket to try to take off the front wheel. But the wheel nut was fastened using 1 inch air gun by the tire guys. It is way over torqued. My little Milwaukee mid torque impact wrench with 650 lb-ft torque can't take the nuts off. Not even close. The manual ask for 450 lb-ft. I guess those tire guys way over torqued the lug nuts. Consulted with @stump, he think it is better to send to a shop to do it. Since rebuilding front axle is a pretty standard job for any decent heavy duty truck shop. it won't cost too much.


Luckily there is a diesel mechanic shop 15 minutes away from the storage facility. I added some more water to the hub and drive very slowly to the shop. According to the mechanic, as long as the hub is not over heated, water is fine. 20MPH So 15 minutes turn into 30 minutes drive. 

Before I drop the coach to the shop, the shop manager promise me everything I asked. I want to read the DDEC computer, he said no problem. I want them to check the generator, he said no problem. I want them to change the coolant hose, he said no problem. I guess, he probably will say no problem to covert the 6V92 to a Tesla. Of course he can't do everything he promised. He just try to get me in the shop.

So after few weeks and about 1.3 CB( Couch Buck=$1000,right?), I got the following done.
    • Coollant flush. Per @stump suggestion, the coolant was changed from Green to Red. Red is the better version of green
    • Grease the chassis. Not the brake caliper
    • Overall inspection of the airline, brake and other components. Overall seems good
    • Rebuild front axle. new inner outer bearing. Reused the hub cover
    • Replace 5 rusted wheel studs. Those studs are expensive. Around $50 each.
    • Change Engine oil using the Delco 100 straight 40 and filter I provided
    • Change primary fuel filter
    • No engine computer reading

The parts really doesn't cost that much. Most of cost are labor. After watching the mechanic doing it, I think the money is well spent. There is no way I can rebuild the front hub by myself under the Texas summer heat. Some time I have to let the professional do it. And also @stump said the front is the steering axle. It is super important to get it working properly otherwise, bad thing will happen. The mechanic showed me the old racer, due to the age and long parking, there are dents on the racer. The bearing is slightly deformed. That is probably the cause of the noise.

I took a test drive after everything is done. The grinding noise is gone. Still not very smooth, but I don't expect that for a 30 year old coach. I think with this, most of the chassis related work is done. Needs to start work on house related issue. Generator first.

With the expense in the diesel shop, I am close to 10 CB now. Just as I predicted in my previous post. I don't know if tires are counted as coach bucks or not. I think CB are for repairs, not maintenance. Tire are maintenance item. They needs to be changed regardless of the coach condition. I know I am just try to find excuse to justify my purchase of the cheap coach. As @stump said, I still haven't spend the $7K asked by the mobile mechanic to replace air suspension bag.

Thanks for you time! Have a great day!


Re: 1991 U300-- bought it!

Reply #175 –
Also, while driving on the road, the coach tends to get people's attention. While waiting on the traffic light, a guy beside the coach seems really excited to see the coach. Chat with him a little bit.  He can't believe the coach is 1991.

I am pretty sure you guy's coach will get way many attention. What do you do?

Re: 1991 U300-- bought it!

Reply #176 –
We politely answer as many questions as we have time.

Re: 1991 U300-- bought it!

Reply #177 –
Quote from: Running Odometer –
Thanks for your quick response.

The challenge right now it that the RV can't move. It has to be serviced on the spot. This limit the choice.
What is the typical cost to change air bag, change engine oil?

I can tell you the cheapest I have found Rotella T1 straight 40W is at tractor supply. $14.99 per gallon. I have to feed 2 8V71's in my Hatteras 45C so I stay with the Rotella as it is about 10 bucks a gallon cheaper than Delo.  The Chevron has a bit lower ash content than the Shell but not enough difference for me to justify the difference in price.
And as you mentioned there is no more beautiful sound than a running Detroit unless it's 2 Detroit's on my boat.

Re: 1991 U300-- bought it!

Reply #178 –
Quote from: MikeMcK –
And as you mentioned there is no more beautiful sound than a running Detroit unless it's 2 Detroit's on my boat.
Sound Bite!  We need a sound bite!  Preferably with video.  Boats with big engines sound cool.  ^.^d

Re: 1991 U300-- bought it!

Reply #179 –
Quote from: MikeMcK –
I can tell you the cheapest I have found Rotella T1 straight 40W is at tractor supply. $14.99 per gallon. I have to feed 2 8V71's in my Hatteras 45C so I stay with the Rotella as it is about 10 bucks a gallon cheaper than Delo.  The Chevron has a bit lower ash content than the Shell but not enough difference for me to justify the difference in price.
And as you mentioned there is no more beautiful sound than a running Detroit unless it's 2 Detroit's on my boat.
I buy 7 gallons of Delo 100 #40 for the 5.5 gallon change from the Chevron distributor here in our small town. It costs $96 out the door so about $13.70/gal. Your supplier is sticking it to the rich boat owners. If they are out of stock, they will bring it up the hill from Sacramento.

But Rotella is good stuff too and the Delo's lower ash probably won't make a difference.

I can resist finding a tunnel and winding it up and then using the Jake. If recorded it would easily win a Grammy Award. Old Ferrari V12 would be a close second.

Pierce