No Start DDEC 2/ATEC

[ArtGill]

I decided today to try to start my Eagle model 20 with a 6V92TA.  I had a check transmission light and the start button did nothing.  Upon investigation I found the little black "KNS" box wet in the rear electrical box.  I took the box apart and cleaned with Alcohol.  It on contained a diode, resistor and capacitor and all looked OK.  One of the pins in the connector looked more discolored than the rest and it was on a red wire.  So, my question is, is there a fuse somewhere that could have blown?  I could find any, but I didn't take the cover off the ATEC in the front bay.  Any suggestions will be appreciated.

Thanks,  Art

[Busted Knuckle]

Art try looking in your battery compartment for some single wires with inline fuses. I'm not sure about Eagles, but I have seen them in this location on several other brands! FWIW   BK 

[luvrbus]

Art are all the fluids up to safe start level,water,oil and granny.Don't know if the model 20 is the same but some 15s with ddec had a low voltage no start plus the low fluids no start from Eagle.Do you have the drivers manual telling you how to check the automatic shutdown they are a  timed system

[Blacksheep]

Check all your grounds! DDEC'S and such are notorius for faults leading from bad, loose or dirty grounds!
Ace

[ArtGill]

I'm thinking/hoping it is a fuse somewhere.  BK, I'll check the two fuses in the battery compartment.  I assumed they were for the DDEC.  I'll check them in the next few days.  When I turn the main switch on the "check trans" comes on and stays on.  But, I just realized the check engine doesn't even come on.  It usually come on and then goes off.  Also the shift quadrant doesn't even light up or flash "do not shift".  I'm hoping there is a hidden fuse for the ATEC.

Art

[Nick Badame Refrig/ACC]

Hi Art,

One last little thing... Make sure your trans is in Nutral.  It's happened to me

Good Luck
Nick-

[captain ron]

Is it cranking but not starting or not cranking at all? If it's not cranking at all check your fuel pressure switch down by your filters that feeds juice to your starter. I don't know if Eagles are equipped with them but my MCI is.

[NJT5047]

Not sure what chassis voltage your coach uses, but the DDEC system operates on 12V only. 
Somewhere near the front of the coach, the 12V taps off two battery sources (plus the ATEC).
If your engine harness is still intact, the DDEC leads are numbered. 
There should be a DDEC B+ fuse that's hot all the time.  I have no idea where to suggest you find the lead, however, if your coach is a 24V chassis, it's likely near the batteries.  There will be a center lead from the batteries that powers the ATEC and DDEC ECMs. 
There is also a relay near the engine that controls the 'ignition' source.   DDEC ignition lead is 439.   The B+ is 440...if the wires are OEM DD.
If your 'Check Engine Light' works, read the codes.  If not, the unit isn't powered up. 
If I recall, the engine room had an electrical fire? 
Don't take the ATEC ECM apart...it's probably not causing problems. 
You'll get a 'Check Transmission'/Do not Shift', if the DDEC isn't powered up. 
Is the dash powered up? Have you traced the DDEC ignition and B+? 
I'll bet that the DDEC is powered up, or being turned on by the ignition relay.  That's where I'd put my money...for now. 
Even with a fault sensor (low water, low oil), the engine would turn over and start.  I would shut down within a few seconds and set a CEL indicating the offending sensor.
You may want to look at www.coachinfo.com and verify that you have a DDEC II.  If so, order a DDEC II diagnostic guide.  I'd recommend not dinking too much with the DDEC system without this guide.   The guide will enably you to easily figure out what's ailing the engine.  Put 12V, or 24V on the wrong pin and you let the smoke out.  That's very bad. 
If your bus is a 12V unit, the DDEC fuses may be where the chassis fuses are located. 
If it's 24V, look a the batteries and see if a lead, is tapped into the 12V terminal of the downstream battery.   
If you have an equalizer, make that two 12V leads...?  Some MCIs have 3 leads...for the headlight backup system. 
Usually, the DDEC wiring and the chassis wiring are two separate systems.  Only the ignition control lead interfaces with the chassis system....usually.    There may be other systems that appear to interface, such as high idle, and cruise, but they don't stop the engine from running.
Keep in mind that the starter circuit is not part of the DDEC system.   You may have had a fuel pressure switch in the engine room that has been disabled.  If so, the starter won't work.  As has been stated, it won't work if the neutral selector isn't indicating neutral. 
Does your CEL function light up when the ignition is turned on?  Both the engine and trans CELs should lite...so should the cruise control if you have cruise enabled.  You have cruise but it may not be wired up.
Is your coach a 24V or 12V chassis?
Somethings to think about, JR

[RTS/Daytona]

Bet the little "KNS" box is the TPS (throttle position Sensor) interface to your ATEC - I have the details of the innards if you need them.

The ATEC needs to know throttle position- Pull up your diagnostic switch for the tranny - bet you have a "21" TPS error

BUT THAT should not stop you From starting to engine

Trouble shoot the "no DDEC check engine light" not blinking once when you turn the key on - that's very important
or
trouble shoot why no DDEC diagnostics when you hit the switch

I have the manuals DDEC-II manual on C/D - it's too big to email - let me know and I'll send you my copy

Pete

[ArtGill]

Update.  I've had time to check the two main DDEC fuses at the battery and they both are good.  I have a DDEC II manual and have been following the "NO check Engine" light.  So, far I 've been able to confirm the bulb is good by swapping the bulbs.  So, my next step is disconnect the DDEC and insert a jumper and then check the "ignition" line to the DDEC.  It has a 5 amp fuse and I suspect it maybe blown, but I can't find it. Does anyone have a wiring diagram for a NJT model 20?

I took the "KNS" box cover off and all it had was one diode, one cap and one resistor. It was connected with four wires.  Can anyone tell me what those four wires connect to.  My box got wet and may have shorted and killed something down the line.  Does the red wire from my KNS have voltage on it and a fuse downline?

I hope I haven't blown my DDEC.  I've already replaced it once.

Thanks everyone for your help.
                                             Art

[RTS/Daytona]

Art
ART

That little KMS box is the interface box between the Dec's TPS (throttle position sensor) and the ATEC computer - The ATEC needs to know the Throttle position for shifting

I have the diagram of the KMS with the voltages for Idle and Full throttle marked on them - unfortunately the PDF file is 250K and this site will only allow me to to post 128k files - I'll email to your address

If your KMS box is all screwed up - I would think you would get DDEC error #21  and/or ATEC error #21 or #22  (all TPS errors)

But I believe those errors will not stop you from starting the engine

call me if you need to ask question ...386..672..0571.

Pete RTS/Daytona   (sitting in the EYE OF THE STORM for the last 12 hours)

[NJT 5573]

The DDEC on my 20 pulls power from the shut down switch. Clean the terminals and check for a broken wire, wiggle the wires with the switch on and listen for the low air buzzer to come on. Repeatedly throw the on/off back and forth about 20 times. Throw the main disconnect several times too. The DDEC fuse is inside the big box and is a regular inline fuse thats wire runs across the box. Mine is on a red wire.

Take the drivers side electrical panel off and check everything out.

Did any liquid spill on the keypad? My roof leaked onto the keypad and I had your problem. Now I have a protective cover over the pad all the time.

My 20 is notorious for glitches like yours. Turning off the computer emergency shutdown has made it driveable but it still codes out for no reason about once a thousand miles. If you can't figure it out, call Randy in Hibbing.

I have the original set of shop manuals that Eagle furnished NJT in 1989. I'm burried for about the next 2 days but can look some stuff up or give you the codes you need after that.

[Busted Knuckle]

I hope I haven't blown my DDEC.  I've already replaced it once.

Thanks everyone for your help.
                                             Art

Art,
I hope you haven't hurt the DDEC also. But I did find this http://cgi.ebay.com/ebaymotors/DETROIT-DIESEL-SERIES-60-ECM-DDEC-II-no-reserve_W0QQitemZ220268920081QQihZ012QQcategoryZ50466QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
on ebay if you have to replace it!

[ArtGill]

BK  Thanks for the link for the DDEC.  I assume ( yea I know) that I could take the prom out of mine and put it in the DDEC from a 60 engine and it would work??!?

NJT5573 My "KNS" ATEC interface box in the rear electrical box got wet from water in the bottom of the box.  I have no idea how the water got in the NEMA 4 box inside the battery compartment.  I do have the buzzer when I turn on the master switch.  Thanks for the location of the DDEC Ing fuse I'll try to find it this weekend.

Thanks everyone,
                            Art

[Busted Knuckle]

BK  Thanks for the link for the DDEC.  I assume ( yea I know) that I could take the prom out of mine and put it in the DDEC from a 60 engine and it would work??!?

Art,
Ahhh, all I can say is oopps! I musta been tired or having a brain fart or something! I didn't even realize those were for the 60 Series units! I just saw DDEC II and yes I just @$# U ME D it would be what ya needed. I sometimes slip like that! Sorry again!     BK