Test Drive Adventure, need advice HR Ambass 36PST

[bronccat]

Hi all,

Sorry to come in hot needing help in a hurry but I guess that's this happens sometimes.

We having been working towards the purchase of a 2002 Ambassador 36PST (Cummins 300HP 6BT) for about 3 months

The unit had a leaking head gasket which the dealer finally fixed so I took it about 60 miles down the road to Cummins today to have the engine checked out.

It threw the "code of death" for the injector pump (maxed out at 250 instances in the last 120 hours) but otherwise checked out ok. I plan on requiring the dealer to have this replaced prior to delivery.

BUT.... then this happened.

I thought on the way to Cummins that the unit was struggling on the hills. I don't know the grade but I do know that the level bubble was all the way to the front. The unit lost speed and I ended up with it on the floor. It didn't seem to gear down like I would think it would and then it would surge, miss - something and the warning light would flash once each time. It did this on about every steep hill. Speed would go from 65 approaching to 45 ish at the top (depending on grade / length) - all climbs about a mile say.

Temp was about 200, oil pressure around 60, RPMS about 2000, full boost. A/C was off. RPMs also went down as I climbed.

I tried to downshift using the buttons (Allison 6 speed) but didn't seem to react as I expected so I stopped.

Is this typical behavior? I mean surely the warning light isn't, but is the power where it should be? I know it's hard to say without knowing the grade. I have video if I can post it.

Thanks in advance!

[bronccat]

That's exactly right. When I was driving that coach down the road I was thinking "hmmm, same engine as a 2500?"

[Rickieblue]

People appear to be happy with the B series Cummins, but in my book, the torque and horsepower isn't even close to what is required to move a coach efficiently. Just my 2 cents..I had a Dodge Cummins pickup at one time and the B series is great for that, but it weighed 25% of what you are looking at.

[bronccat]

I understand the logic but the RPMs were dropping to the point that I was starting to think I was going to stop if it didn't downshift lol.

[Rickieblue]

If you are expecting it to downshift when the engine is running 2000 RPM it seems unlikely. If when it downshifts, the RPM's will be over governed engine spped, it simply will not shift, even if you try and force a shift. The computer takes the worry out of an operator destroying an engine. Aren't computers wonderful??

[bronccat]

Well the dealer just called (owner's younger brother) and apologized saying "yeah it's bad, wow I don't know what to say. That thing's going to auction".

I am going to drive the other 36' for comparison and go from there....

Thanks!

[bronccat]

Thanks Bert, if it was something that simple I might take another look. I guess if could be the injector pump starting to go out as well and not getting enough fuel. They have had this unit since May and I can't believe they haven't sorted all of this out (if it is minor). The previous owner spoke highly of the coach (40,000 miles in 2 years). The trailing arm upgrade was supposed to have been done already - I should have looked yesterday but I didn't.

The PO also said that he had bought two from them but wouldn't buy a third because he doesn't feel like they inspect or fix the rigs very well. He said they were great about fixing things on return trips for free but he was 8 hours away.

[johnsonbert]

The missing and lugging on the hills before and after shifting and the warning light may be symptoms of lack of fuel from plugged fuel filters. I have experienced that before. We had a 01 Ambassador 38PBT with the Cummins 315 ISC motor in it and it did well, even in the hills. It was also a 26,000 lb unit. If that has the B motor, I did not have any experience with that.

There is also the trailing arm issue with that unit, so do not forget to check that out.

Hope this may help, Happy Trails bert

[bronccat]

I discovered last night that they have a 2006 DP, same brand, engine, slides, etc. Should be a pretty comparison.

[bronccat]

Very excellent point that I failed to mention. I have driven a semi, diesel dump trucks and drive a diesel pickup daily, but no - I have not driven a DP motor coach. I knew it would be different than the others but I didn't think this different. Yes, you said exactly what my wife did. First thing I need to do is drive another DP, preferably on that same road.

[imgoin4it]

You do not say what you are accustumed to driving or if this is the first tme you have driven a diesel motor home. The transmission not shifting down when you put the pedal to the metal as expected is not unusual to someone not familiar with how the diesel works, and sounds like my reaction the first time I drove a diesel. The warning lights, the surging and the missing are not normal so there is at least some problem with it. I suggest if you have not driven a diesel before you drive another ( or a couple ) so you have a reference to compare to.

[bronccat]

Thanks all.

26,000 lbs. 4.88 rear end. I could buy it being sluggish but not the surge and warning light.

As for downshifting, it sure didn't seem like it. I was trying to find a sweet spot by increasing RPMs to maintain speed and when I "thought" I geared down it was like nothing happened.

They did not find anything else in the scan nor anything in the online history of the ESN.

So I told them that I couldn't buy it with a clear conscience. Even if they got everything fixed I had no faith in the repairs that they had done to date considering some other issues I found.

This sucks too because I like these people I vetted them with some people who grew up with them. There aren't many decent dealers anywhere near me who have meaningful Class A inventory and so far they are pretty disappointing.

Then I look in places like TX and Fl (I am in KY) and I find SO many bad reviews of the dealers. Sigh.

I'll keep looking. Thanks again!

[Dale_Traveling]

Did Cummins find anything else? With the number of power train problems I would be having second thoughts unless the dealer was willing to discount the price, substantially. $10K might be a good no less than number.

Once you drive the coach off the lot all the risk is on you, the new owner. Unlikely the dealer will offer any type of warranty considering the age of the coach and after market policies will be cost prohibitive.

[Gjac]

What does the MH weight? It may be normal if the MH weights 28k lbs and has 300 HP to move it up a hill. Did the MH not down shift when you tried to shift it manually?

[DSDP_Don]

I'm thinking there are enough obvious issues to start looking for another coach to purchase. If a dealer was REALLY interested in your business and was trustworthy, that coach should have been running perfectly before you test drove it. The list of issues on your test drive could easily run in the thousands. Then you have to hope the thing continues to run well after you purchase it.