When was Detroit Diesel DDEC introduced?

[pickpaul]

Hi Everyone,

It's been a year or two since I last posted but the bus bug never left me and I'm now seriously looking at buying one again.

I plan on doing a vegetable oil conversion (let's skip that debate for now  ) and for that reason and just for simplicities sake I would rather avoid DDEC and get a bus that has a mechanical engine with no electronics. Can you guys explain when DD started putting them in busses? I'm looking at 80's MCI-9's and Prevosts right now.

One of the specific busses I'm looking at is a 1988 40 FT. PREVOST LEMIRAGE with a  8V92 ENGINE WITH TURBO

Also, is it simple/easy/possible to make a DDEC engine, a nn DDEC engine?

Thanks in advance guys, you have always been a great help before.

Cheers, Paul.

[RJ]

Paul -

Welcome back!

1988 is right on the cusp of the DDEC intro.  IIRC, CA engines had it, but the other 49 didn't.  Clifford or Don will know.

There are so many buses out there right now, better to buy one with the engine/transmission you want in it up front than go thru the madness of converting it to something it wasn't when it left the factory (DDEC back to MUI).

BTW, that 8V92TA is a good engine, as long as you keep it cool.  Doesn't like getting overheated at all.

Also, if that Prevost is a wide-body (102), there will be more room inside than a similar vintage MC-9.  (Technically, MC-9 production ended about 1985 w/ the intro of the "A" series, but there were a few built after that.  The MC-12s are virtually identical to a 9 - all were built for 'Hound, run hard and put away VERY wet.)

FWIW & HTH. . .

[Joe Camper]

That 88 Prevo will be a D-deck unless someone changed it.

I have an 85 it is a mechanical I am not sure if it was the last or second to last year

[robertglines1]

my 89 prevo is a ddec II

[luvrbus]

DDEC hit the market in 1985 you could order a DDEC or MUI till 1992 in a bus or truck in every state except Ca  


good luck

[HighTechRedneck]

Changing a DDEC to manual is a tough one.  Several changes to the engine, plus iirc it uses an electronic controlled transmission that also depends on signals from the DDEC.

[luvrbus]

Changing a DDEC I to MUI is not a major deal or up too about the middle of the run of the DDEC II after that it is a big deal  lol


good luck

[HighTechRedneck]

Changing a DDEC I to MUI is not a major deal or up too about the middle of the run of the DDEC II after that it is a big deal  lol


good luck

That's good info.  So the early DDEC's didn't use electronic injectors and interface with an electronic controlled transmission?  I could almost get along with a DDEC that didn't control every aspect of the bus and refuse to let it run at the slightest anomaly.

[Bill B /bus]

When I bought the 1986 MCI 102A3 it had a bad engine, 6V92TA. I found a donor bus with a 6V92TA DDEC. Bought that bus. It had been a Hertz bus at the airport. Put the two engines side by side. On the new engine: Changed bearings. Installed rebuilt mechanical injectors, 9G85. Rebuilt blower. Installed governor and racks from old engine.
Swapped accessories to the best available.
Installed and started. Worked great but it was still a 2 stroke. Pulled and sold for what I paid for the donor bus to install a Series 50.
Conversion from electronic to mechanical is no big deal you just need a parts source, ie donor engine. If you have to buy the parts then not worth the effort as just too costly.

Bill

[Don Fairchild]

Bill,

  as Clifford said if you have an early DDEC then it is no big deal, but if you have a mid production run DDEC II then there is more involved in the change over.

One other thing is the DDEC one is a two computer design and the DDEC two and forward use one computer.

Don

[HighTechRedneck]

So if a person were in the OP's situation and got a bus with an early DDEC (DDEC I or early DDEC II) and wanted to convert the bus to MUI, in general terms what would that entail?  I'm just asking because easy/difficult is relative to the skills of the person doing it.  Engine work that amounts to childs play for Clifford or Don could amount to a challenging piece of work for many of us.  So knowing what would be required might help the OP and others to judge whether it fits for them.