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Old 01-28-2014, 02:12 PM   #1
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Speedometer reads low

We just bought our '08 Phaeton 40QSH and on the first trip out we noticed that the speedometer and the GPS werent in agreement. We determined that the speedometer was 5 mi. low at 65. And at 70 we were about 6 mi. low. Problem is that while towing a Ford Focus with a limit of 70 we were actually doing almost 76 (actual) at 70 (gauge), thus exceeding our limit of tow and risking a possible ticket to boot. Brought it right back to Lazy Days and they/re fixing all other punch list items (we hope) but said they're not responsible for the faulty gauge, nor was it covered under my $4,000+ extended warranty. Sooooo...... where do I start? Speedometer head? Gear? Tire size is correct btw. Any ideas besides stay away from Lazy Days?
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Old 01-28-2014, 02:22 PM   #2
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Pretty sure your problem is a programming issue. If you have a Cummins engine, it has a settable parameter tech's call "revs" which tells engine something like how many tire revolutions per mile. This relates to tire diameter. My 2012 Nissan pickup is about 1.5mph high at 70mph speedo, same problem.
You can have a shop w/Cummins Insite software reset the revs to correspond to your tire size & speedo will be right on.
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Old 01-28-2014, 02:29 PM   #3
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You didn't say who made your chassis, but you have a computer problem in your chassis. They can reprogram it to correctly correct for tire size, transmission, rear end ratios and so forth to make everything run right. We had an 08 Allegro Bus and it required Freightliner just a few minutes to reprogram it correctly.
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Old 01-28-2014, 03:15 PM   #4
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Quote:
Originally Posted by NobodyJr View Post
We just bought our '08 Phaeton 40QSH and on the first trip out we noticed that the speedometer and the GPS werent in agreement. We determined that the speedometer was 5 mi. low at 65. And at 70 we were about 6 mi. low. Problem is that while towing a Ford Focus with a limit of 70 we were actually doing almost 76 (actual) at 70 (gauge), thus exceeding our limit of tow and risking a possible ticket to boot. Brought it right back to Lazy Days and they/re fixing all other punch list items (we hope) but said they're not responsible for the faulty gauge, nor was it covered under my $4,000+ extended warranty. Sooooo...... where do I start? Speedometer head? Gear? Tire size is correct btw. Any ideas besides stay away from Lazy Days?
I would say that LazyDays IS responsible for the faulty speedo. It's not a cosmetic issue, it does affect the function of the coach. Now it may be that they cannot reprogram at LazyDays, and all they know how to do is replace the parts, and they don't want to do that. And it doesn't matter that you already drove it off the lot, it's not a defect that you could identify either during delivery or on their 5 mile test drive. I'd scream a little more at them. I've had to do that at LazyDays before.
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Old 01-28-2014, 03:23 PM   #5
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Might I suggest a simple idea until you can get the programming changed. Mark your speedometer with tape or sharpie pen for the speed you do not want to exceed. Then at a glance you can be sure you are not damaging your toad, without doing mental calculations.
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Old 01-28-2014, 04:44 PM   #6
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Quote:
Originally Posted by Pigman1 View Post
You didn't say who made your chassis, but you have a computer problem in your chassis. They can reprogram it to correctly correct for tire size, transmission, rear end ratios and so forth to make everything run right. We had an 08 Allegro Bus and it required Freightliner just a few minutes to reprogram it correctly.
We're on a Freightliner chasis with a Cummins Deisel. LazyDays stated also that it might be a programming issue but didn't seem too willing to want to mess with it. Being a Tiffin dealership you would think that their mechanics would know the Freightliner Chasis and be certified. I called Tiffin and they told me to find a Freightliner service center. So, it's probably as everyon here is suggesting, a calibration issue.

Thanks to all who posted here. I'll be looking for a Freightliner service center if I can't get CrazyDays off their duffs.
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Old 01-28-2014, 05:52 PM   #7
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We're on a Freightliner chasis with a Cummins Deisel. LazyDays stated also that it might be a programming issue but didn't seem too willing to want to mess with it. Being a Tiffin dealership you would think that their mechanics would know the Freightliner Chasis and be certified. I called Tiffin and they told me to find a Freightliner service center. So, it's probably as everyon here is suggesting, a calibration issue.

Thanks to all who posted here. I'll be looking for a Freightliner service center if I can't get CrazyDays off their duffs.
I have a similar issue with my 2004 Journey on a Freightliner chassis. There is a post in the MH-General Discussions on my problem. Freightliner told me to take it to a CAT shop and they could program the ECM to correct the bad reading. They use a formula - I suspect Cummings would have the same ability.
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Old 01-28-2014, 06:05 PM   #8
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My Ford is 2 mph lower than the GPS. On another note, the 70 mph limit on the Focus should not be a problem. IMHO, that is too fast for a large RV. Slow down to 60 to 65 mph and you will get better fuel economy and enjoy the trip.
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Old 01-28-2014, 08:45 PM   #9
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I have seen, on quite a few hwys., areas where there are measured miles. Set your cruise control to 60 mph and time the distance between the beginning and the end of the measured mile. If your speedometer is correct it will take exactly one minute to travel the distance. Do the same with the gps.
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Old 01-28-2014, 10:06 PM   #10
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Quote:
Originally Posted by gruelens View Post
Might I suggest a simple idea until you can get the programming changed. Mark your speedometer with tape or sharpie pen for the speed you do not want to exceed. Then at a glance you can be sure you are not damaging your toad, without doing mental calculations.
An even simpler solution is to ignore the speedometer and drive by the GPS reading...
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