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Author Topic: Series 60 DDEC II Mystery  (Read 4760 times)
RichardEntrekin
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« on: December 31, 2009, 05:00:02 AM »

Got a little mystery that maybe one of the experts can tell me where to start looking.

The pertinent info is this. I monitor all the temps with a VMSPc so the temps I quote are coming straight from the ECM and the problem is not a gauge problem.

Sometimes my engine water temp runs right at 200 plus or minus 3, the oil temp is about 5 degrees cooler, and the tranny temp runs about 210 to 215. I can watch the temp cycle up and down like the thermostat is opening or the fan is cutting on and off.

Other times, the engine runs at 180 plus or minus 2, the oil runs at 179 plus or minus 2, and the tranny runs at 175.

I am figuring either a thermostat issue or something amiss with the circuitry that activates the hydraulic fan.

Do you guys want to venture a guess or theory about what is going on here?

One last clue. The last time it ran at 200, I pulled over. Shut the engine down at a rest stop, and when I restarted it ran at 180 for 500 miles,
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Richard Entrekin
95 Newell, Detroit S 60
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« Reply #1 on: December 31, 2009, 06:11:39 AM »

Not really a mystery! Not all detroits run the same temps such as 180. If you check with any good detroit certified mech. or a good manual you might find that the series 60 runs best at 200-210. You never said what speeds your temps are at but my 8v92 runs 200 easily while hitting 75-80 mph but at normal 180 temp at 60-65 mph. Its also a DDEC 2!
Ace ... Having a blast in Arcadia!
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Ace Rossi
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Ed Hackenbruch
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« Reply #2 on: December 31, 2009, 06:42:58 AM »

Change in ambient temperature could make a difference too.
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1968 MCI 5A with 8V71 and Allison MT644 transmission.  Western USA
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« Reply #3 on: December 31, 2009, 07:05:49 AM »

My S60 runs very consistently at 195 degrees.  It will climb close to 200 on the steepest grades out west.  BK told me a long time ago that every S60 bus he has dealt with runs between 190 and 200 consistently.  More recently he said he did some cooling system work on on one of his older Setras with S60 and it now runs under 190.

My bus has had the water pump, thermostats, and radiator replaced so I doubt anything I do will ever lower the temp.  I am happy at 195.  Before I replaced the radiator I was overheating on the slightest hill.  When I first got the bus I hit the DDEC shutdown temp on a grade in Pennsylvania.
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Brian Elfert - 1995 Dina Viaggio 1000 Series 60/B500 - 75% done but usable - Minneapolis, MN
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« Reply #4 on: December 31, 2009, 07:54:23 AM »

Do you have a fan clutch , a drop in turbo boost will add heat to a 60s, the air to air could be dirty a lot of things could cause the problem.
You take the heat out of a series 60 with turbo boost a different animal than a 2 stroke.
Do you have 11.1 engine if so they run around 195 all the time 180 is a little cold 




good luck
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RichardEntrekin
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« Reply #5 on: December 31, 2009, 11:17:57 AM »

I didn't do a good job of explaining what the issue is. SOMETHING is controlling the temp to either 180 or 200. I see no temps in between. The computer shows accurate readings coming out of the DDEC and both the oil and tranny temps follow the coolant temp, so I tend to think it's real. It doesn't change under load or between 55 and 70 mph. It is NOT a cooling system capacity or dirty radiator issue. SOMETHING is controlling the temp to either 180 or 200. The engine will hover at one of those two temps with very little fluctuation. I just wonder what it is. I would never have even wondered about this IF it didn't flip back and forth between the two. The key to the flip is ignition off and a restart. It NEVER has changed from one temp to the other while it was running. It is a mystery to me why sometimes it runs exactly 180 and sometimes it runs exactly 200, nothing in between, nothing lower, nothing higher.

Does that explain my curiosity better.

Thanks for the info on S60 temps. All along I was thinking 180 was better than 200, but apparently it's the other way round.

Thanks for all your ideas.
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Richard Entrekin
95 Newell, Detroit S 60
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« Reply #6 on: December 31, 2009, 11:42:57 AM »

Richard, if you have the hydraulic fan there is a wire from the fan clutch to the thermal valve that comes lose or the plug gets corroded. 
let us know what fan setup your Newell has 


good luck
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belfert
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« Reply #7 on: December 31, 2009, 01:01:55 PM »

Could you have a two speed fan clutch that is acting up or a faulty temp sensor?  Not sure if the DDEC II can even control a two speed clutch or not.
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Brian Elfert - 1995 Dina Viaggio 1000 Series 60/B500 - 75% done but usable - Minneapolis, MN
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« Reply #8 on: December 31, 2009, 03:11:26 PM »

Richard -

I'm not familiar with DDEC engines, but, as seems to be a common issue with all kinds of electrical gremlins, you may have a bad ground or a loose connection somewhere.

However, what's intriguing is that apparently, with whatever temp is showing, it doesn't fluctuate.  If I'm reading your message accurately.

When it comes on and says 180, it stays at 180, regardless of driving conditions.  Ditto with the 200 reading.  Is this right?

If that's the case, I'm wondering if maybe it might be a temp sensor that's dying.

FWIW & HTH. . .

 Wink
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RJ Long
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RichardEntrekin
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« Reply #9 on: December 31, 2009, 06:25:35 PM »

I do have a hydraulic fan, so fan clutches are out.

It can't be a dying temp sensor because both the oil temp and tranny temp track exactly the two different coolant temps.

SOMETHING is controlling the temp either at 180 or 200 without fluctuation. The question is WHAT?

I am thinking something in the DDEC that controls the fan, and here is why. The tranny temp tracks the temp in the engine. However, the only place the tranny fluid and the engine coolant are in  proximity is the radiator. When the engine temp is running at 180, the tranny temp will run anywhere from 150 to 180 depending on ambient, when the engine temp is running at 200 the tranny temp will run 200 to 215. Curious that when the engine temp is running at the 180 setpoint the tranny runs at that temp OR COOLER, and when the engine is running at the 200 setpoint, the tranny runs at THAT temp OR HOTTER.

Does anyone know if the DDEC turns the hydraulic fan off and on, or better yet runs the fan at different speeds?

Thanks again.
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Richard Entrekin
95 Newell, Detroit S 60
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« Reply #10 on: December 31, 2009, 07:09:52 PM »

Richard, the DDEC doesn't control the fan speed if you are positive you do not have a 2 speed fan clutch and some hydraulic systems do.
Then you have a thermostatic valve somewhere in the cooling system that tells the switching valve how much oil to flow for fan speed. 
Check and see if you have a thermostatic unit it will look like a sender somewhere in the piping for cooling or could be on the engine even on the side of the radiator tank.
It will have a hose about 3/8 of an inch in dia (or it could be electric controlled) going to the switching valve close to the fan.


good luck
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RichardEntrekin
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« Reply #11 on: January 01, 2010, 05:39:09 AM »

I am not positive at all about the two speed fan. That makes the most sense of anything. I will check the connections to the "box" that controls the hydraulic flow to the fan.

Thanks to all of you for your help.
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Richard Entrekin
95 Newell, Detroit S 60
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« Reply #12 on: January 01, 2010, 08:41:42 AM »

Richard, building on Clifford's comments,  I am pretty sure that the Series 60 DDEC system would not control the hydraulic fan system.  It does have the ability to control an air type fan clutch on trucks, but nothing specifically for a hydraulic fan.  I guess someone could have gotten cleaver and used the air clutch signal to do something with the hydraulic system (shift speeds).

I bring this up, as it would let you focus on just the hydraulic system and not have to deal with the DDEC system.

I would think the Newell folks could give you the details of the hydraulic fan design.  I would also suspect that there are forums specific to Newells that might also help.

It has been said already, but none of the information you have given us would be cause for concern.  I suspect you are asking from an academic standpoint.

Jim
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Jim Shepherd
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RichardEntrekin
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« Reply #13 on: January 01, 2010, 07:00:24 PM »

There is a control box that the hydraulics pass through on their way to the fan. It is getting a 12V signal, but I do not know how it is supposed to function. I'll give Newell a call on Monday.

I am guessing the solenoid on the control box changes speeds on the fan, and the solenoid is not working properly or perhaps working sporadically.

The fan speed did not change when I unplugged the voltage to the solenoid, so that was a clue.
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Richard Entrekin
95 Newell, Detroit S 60
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« Reply #14 on: January 02, 2010, 06:59:34 AM »

Nothing but a wild a** guess...

By your test, the fan fails safe by running when the controls fail (by taking the wire off and fan runs)

If we assume for the minute the fan has some sort of set point, or points in a multi speed fan control, there would be set points for engaging each speed...

Could there be an intermittent fan control glitch, so that sometimes the fan runs flat out (broken), taking the temp down to the thermostats, and sometimes it works right, letting the temp run up at the higher temp?

I think finding out would be prudent, so you may ignore it with confidence, or take action to prevent further deterioration.

happy coaching!
buswarrior

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RichardEntrekin
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« Reply #15 on: January 02, 2010, 07:59:41 AM »

I was thinking just like that. When I removed the signal and nothing changed on the fan, it seems like the faill safe mode is HIGH fan speed. That would make a lot of sense.

I am going to remove the solenoid powered by the 12v signal and apply 12V to it on the bench to see if it is working. I now suspect this is the problem.
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Richard Entrekin
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« Reply #16 on: January 02, 2010, 08:02:29 AM »

And check to see what the source of the 12 volt signal/feed for the system is?

Perhaps some solid state thingy in between here and there having a fit?

happy coaching!
buswarrior
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« Reply #17 on: January 02, 2010, 10:23:28 AM »

BW, I like your thinking, sounds reasonable anyway. And if it doesn't work that way IT SHOULD!
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Don Fairchild
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« Reply #18 on: January 02, 2010, 10:35:07 AM »

If your Newell is any thing like my Gillig then you have a (4) four wire sender in the lower thermostat housing on the right side of the engine looking from the back forward, it controls the fan. Mine is a 185/215 Deg. sender. On the side of the control box priority valve where the wire comes out it has a bolt head and you can adjust the on off temp some what. I have mine turned all the way in. Mine has a single speed fan on it how ever it will turn at all times, just not at speed when it does not need cooling.

Hope that wasn't to foggy

Don
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belfert
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« Reply #19 on: January 02, 2010, 10:59:37 AM »

I think my fan clutch is single speed.  The wierd thing is the fan clutch locks up as soon as the ignition is turned on without the engine even running.  I am pretty sure something is wrong, but no idea what might be wrong.

I pored over my wiring diagrams for a while the other day and could not even find a circuit to the fan clutch.  There are 48 pages of diagrams and I was mostly looking at the DDEC page although I looked at some other pages too.
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Brian Elfert - 1995 Dina Viaggio 1000 Series 60/B500 - 75% done but usable - Minneapolis, MN
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« Reply #20 on: January 02, 2010, 11:05:16 AM »

Belfert, it could be the design. It is as posted above, a "fail safe" thing. There are usually two different ways to wire something, one is NO for normally open (either an electric circuit or air on/off) and NC for normally closed (same deal, only the circuit either air or electric is off or closed). This is so that if a wire or air plumbing or whatever fails during operation, the fan goes into a fail safe mode, which in this case is that it stays on.
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Don Fairchild
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« Reply #21 on: January 02, 2010, 11:44:56 AM »

Brian;

you probably have a Horton eddy current two speed fan clutch. You can go on line to Horton and find the wiring diagram.

Don
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RichardEntrekin
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« Reply #22 on: January 04, 2010, 07:24:31 AM »

Ok, here is an update, and what I have learned.

One, it is typical design of two speed or proportional hydraulic fan controllers to fail in the wide open mode. I learned that from the Eaton and Bosch sites. Also, there is a manual adjustment on the controller to control the max fan speed.

Two, the design specs on the Series 60 Tstats are: start to open at 183 and wide open at 207. As others have stated 190 is the target operating temp.

Three, the coil that actuates the proportioning valve on the hydraulic fan controller was OPEN when I ohm'd it. So it was bad.

Newell is sending a new coil for 30.00, cool that I didn't have to buy a new valve. I probably could have sourced it locally, but the numbers on it were long faded away.

I'll update on the temps when I get the new coil installed and it warms up enough to go out for a spin.

Thanks for all your help in getting me started on figuring this one out.
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Richard Entrekin
95 Newell, Detroit S 60
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« Reply #23 on: January 04, 2010, 07:33:54 AM »

Thanks for reporting back!

Excellent sleuthing!

happy coaching!
buswarrior

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RichardEntrekin
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« Reply #24 on: January 10, 2010, 06:28:31 PM »

Here is the update. As discussed earlier the failsafe mode for the hydraulic fan is to run at max speed. The coil on the solenoid that controls the flow to the fan motor was bad. When a new coil was installed the fan started to function as normal, in that it was no longer running when the engine was below temp.

It had been running all the time before the discovery of the faulty coil. Newell had a new coil in my hands the next day after calling. I do like it that they do not gouge you on spare parts  :-)  I also found the part locally after the new one with legible part numbers got here. I didn't mind paying 4 extra dollars to Newell to get the right part the first time.

I went for a short drive to confirm temps, but dang it was in the 20's here in Fort Worth this morning, and I'm not sure that is a good test of where the engine temps will settle out now.

Thanks again for your help.
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Richard Entrekin
95 Newell, Detroit S 60
Subaru Outback toad
Huntington WV

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