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Author Topic: Love my Bus but...  (Read 23592 times)
bobofthenorth
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« Reply #105 on: January 17, 2009, 06:21:28 AM »

Congrat's Ace and you could have your own lifetime channel movie from this Wink Cheesy

If it was me I'd be really nice to Susan from now on.  It sounds like payback for the WallyMart plastic tub incident.
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R.J.(Bob) Evans
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« Reply #106 on: January 17, 2009, 10:40:25 AM »

See!!  Wink I knew it would be something simple, I just didn't know what it was. Huh
Congrats for not kicking anything too hard ( I broke a bone in my foot once when I was good and frustrated). (oh yeah, and in my hand before that, that's why I changed to kicking). Now I just scream into pillows.
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JohnEd
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« Reply #107 on: January 17, 2009, 01:42:49 PM »

Ace and Blue_Goose,

Blue Goose seemed to have had you test the input power to the ECM.  That should have identified this problem on page two instead of page 8.  As I read his post he called out two different pins for the 12 volt input power than Pappas had you check.  Why the discrepancy in pin numbers or was it not read properly.  I would wonder that others haven't had this question.

At the conclusion of each troubleshooting experience I had my men go back over every test they made and what conclusion they had drawn from each.  Sort of a debrief among themselves.  They ALL profited from this and in a short while they were drawing precious few wrong conclusions and getting gear up and recovered quickly and often without a single needles test.  I would suggest doing that here.  A lot of people were suggesting fuel problems and no test was ever made that would put that one to bed.  Wrong conclusions ALWAYS delay results....at least positive ones.  How could we have tested the fuel theory conclusively?  We should have been able to test the inputs to the ECM to eliminate those as the problem.....even 12 volt inputs.  I think we could have even tested the outputs of the ECM but I think that was our weak point.  This is a really great opportunity to make this a learning experience for all.  How could we have gotten there sooner and with less false steps?  I think Ed Rolle set us up to march down the path of "eliminate probable causes decisively, one at a time".   Lots of really solid advice was given.  I think Ed gave us the process and Blue came the closest but Pappas gets the star.  Maybe that is because we ignored the first two.  Those that ignore history are doomed to repeat it, sort of thing.

What do you say, Ace?  Can we make this a point in history that we never have to repeat?  You certainly have the support to do this considering that 8 pages worth of people have fallen out on your behalf.  You must be one heck of a Banjo Plucker to have this many concerned friends.

Now for the finale: WHAT BLEW THE FUSE?  Carrying spare fuses is not the answer.  If the cause isn't eliminated you have no guarantee that a fuse will recover you in subsequent failures.  Sometimes you can't reach a conclusive fault ID.  Most times you can.  Considering the fuses are in the bat tray that was suspect early on, I wonder that a harness hasn't been impinged or chaffed.  That the fuse separated in any place other than the visible section would seem to indicate that the fuse was defective in some way but not necessarily that it blew at less than its rated current.

This was a long drawn out event that even led to threats of "selling this POC".  May we never repeat it but if we do I hope all will receive the support that you did.

John

Where did Pappas get the drawings/schematics he used?  How can those be made available to all?  Were they different than those used by Blue?  It seems that Pappas left the path of the troubleshooting guide with an epiphany moment after hearing about exhaust manifold temp differentials.  Then we had your Eureka moment.  You know what they say about the job not being done till the paperwork is complete. 
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« Reply #108 on: January 17, 2009, 02:21:31 PM »

John, here's the schematic I was using from Prevost. All Prevost diagrams are VIN number specific.
This choice was made on Ace's VIN - N-1232.

http://prevostparts.volvo.com/technicalpublications/pdf/d060688p2e.pdf

The only other source of info I use is a DDEC 2 wiring diagram - from Detroit Diesel.
I never looked at mine based on info that was posted already - as you mentioned.
DDEC wiring from DD is very similar, if not the same for many applications. OEM wiring from different manufacturers will vary with connectors and of course any options.
Happy to hear Ace has his coach running again.

Hope this may help.
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NJT 5573
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« Reply #109 on: January 17, 2009, 02:28:34 PM »

John,

If you want drawings and schematics, the basics are all available for everyone at "DDEC Motherload" that was posted for everyone to use as needed and reposted for Ace to look at. Its probably a few pages down now but it is available at this site. The DDEC info starts about half way down the first page and goes on forever.

We have to remember not everyone is able to do their own troubleshooting or even give us good information but once a mechanic was on the scene it was repaired quickly.

If you haven't experienced the joys of DDEC you are lucky. If you can stay on the mechanical side vrs. the computer side, you will never be sorry. The reality is it may go for months with out expensive needs or it may die anyday anywhere. The marvels of emissions!
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« Reply #110 on: January 17, 2009, 03:33:16 PM »

Ace, Are you also going to pull the fuses to the DDEC for a couple minutes? Are there 2 10 amp fuses? Good Luck  Tom Y

I think that this may have been the best answer all along. FUSES !!! Roll Eyes Roll Eyes

Ace,
You almost let the bus gremlin get the best of you .. (again?)..

I always replace any fuses in circuits that are critical to stuff working.
I find lots of shorts that way. If it blows then something is wrong...

Sorry that it had to be in the last place you looked though...

A test light or LED with gator clips is a handy thing to have sometimes.

Glad you figured it out finally... Just look at all the things you found to fix now... Grin Grin

Dave..
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« Reply #111 on: January 17, 2009, 03:36:11 PM »

I picked up a DDEC II service manual on Ebay and even came with notes and cheat sheets the technician that had owned it took in school.  I don't leave town without it.

Art
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« Reply #112 on: January 17, 2009, 04:09:05 PM »

 Wink  did any one check the fuses in the bays, pass side?
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« Reply #113 on: January 17, 2009, 04:20:44 PM »

Sammy JOHNED  (sorry Sammy )

#1 - I prefer Pete - not Pappas  (actually it's Papas)

#2 - Blue Goose posted --> (...All it takes to make the ecm work is the power harness must have Pins E, B, and D grounded .  Pins A and C must have 12 or 24 volts
                                        depending on your ecm. The vehicle harness must have ground on pin A1 and ignition plus on pin B3....)
      A. - actually Blue Goose had it Close but not quite correct -->
           <> Pins A,B,E,F  need Power  (+12 volts)
           <> Pins C&D need ground
           <> Pin A1 is Engine Brake ??  and yes B3 is Ignition

#3 - I would GUESS that the reason the fuse went is because changing out the bad R3 relay PEGGED HIS METERS (I guessed about 18volts on the 12 volt side) when
       the bus was runnig -  he only had 15 amp fuses in the lines - my DDEC book calls for 20 amp - so he was MARGINIAL at best - raising the voltage to one and half
       times normal - also raises the current one and a half times (ohms law - the resistance stayed the same / the voltage went up / then so does the current )

#4 - I was using my DDEC-2 trouble shooting guide - available on the "tpub" site if you search using DDEC - you'll find the Army DDEC-II and DDEC-IV manuals - I paid 
       The small fee to get a clean copy - but ANYONE can look thru the FREE version on TPUB site - The downloaded file is to big to send via my email service

#5 - Putting the fuel pressure gauge on the secondary filter & seeing 40 psi at idle proved we didn't have a fuel problem - or bad qill shaft / spring pack - cause the fuel pump is at the end of blower drive

Pete RTS/Daytona
« Last Edit: January 18, 2009, 06:25:13 AM by RTS/Daytona » Logged

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« Reply #114 on: January 17, 2009, 05:28:25 PM »

John to be very honest with you AND everyone else, electronics are not my bag if you know what I mean! They scare me to heck and back and I guess when the question came up about being a fuel problem, which to me at the time seemed easy to diagnose, I went for it! The bus is here with me and nobody else and in the past when either my own or a friends bus sounded the way mine did and ran the way mine did, it sounded and reacted as if it WAS a fuel problem. It was easy to see if I had a fuel problem or not by installing a pressure gauge. It took me a couple of days (with working, cold weather and darkness) to finally get it installed. Once done, it quickly told me to look elsewhere. Even though I may have had the help from people here to look at the electronics, I admit, I did not due to ME thinking it was related to fuel. Once it was established that the fuel was ok, I had no other choice bus as I said, electronics scare me. If you ever had the opportunity to see the inside of my H3 front or rear junction box, you would probably run too!

Now as far as the schematics are concerned? I bought a ddec 2 diagnostic book on ebay a while back when I was trying to find a shut down problem that was intermittent. It took thru various steps which was very helpful but it did NOT solve the mystery problem which turned out to be a loose screw (no not me) on the circuit breaker that is for the low coolant sensor. Had the screw eventually fallen out, it would have been an easy find but as it was, just loose, it was hard to find.
Getting back to the book on ddec's, when Pete called and asked me to go to page such and such, I told him I didn't have that page as it appeared we had the same information in front of us, just different books! He advised me to look for the wiring schematic specifically for the ecm control harness for an 8v92. He said it would be a page that un folds. When I found it, he walked me thru each wire, each connector and told me how to test each one physically ON the coach. When I did, I called him and told him my results. It was then he said there is two 20 amp fuses somewhere between the batteries and the ecm. It was then that I knew of two 15 amp fuses hard wired into one of the batteries. He said to look that them and see if they looked ok. I did, and they did look ok but he said to now check them with my volt meter. I did and one of them had no current from one side to the other and one did! I changed BOTH fuses and the problem was solved.
The 15 amp fuse that blew, and LOOKED ok because they normally blow at the top of the little hump connector. This one blew at the very bottom edge going to one of the legs. Even now it very hard to see it is broken.
Now you ask WHY did it blow to begin with? What we think happened is, when I installed the new relay which in turn made the voltage regulator work the way it was designed to work, it sent a high surge of voltage or a spike as some call it and the 15 amp fuse did what it was designed to do and that was to protect an expensive ecm! Oh and you might ask WHY did it get a high surge of voltage? Well only thing I can think of is that before we bought the bus, it must have had a charging problem of some sort because we have always doubted the charging system due to dim headlights and batteries always going down. The owners before us must have not diagnosed the problem and only figured they could get a higher charge rate if they adjusted the regulator to the max, which it was when I found that it pegged the gauges after the relay change. After I adjusted the regulator BACK to where it needed to be according to the book, it was then that I developed a flat sounding engine that would not accelerate or idle above 300-600 rpm.

The lesson I learned from this was a little more knowledge of how my DDEC works and what it controls such as, this large metal box with 5 connectors mean more to me than just that! I NOW know what all those wires do and where they go, again, thanks to Pete and him taking the time to explain it to me! The top outside connectors on my ECM control the injectors on the engine. One for the left bank and one for the right bank. The top center is the power plug that feeds the voltage TO the ecm for each bank of injectors and the bottom two large connectors are the connectors that connect to the many sensors, switches, and senders. At least this is MY understanding but to many electronic guru's it may mean something different!

I didn't even know that I could unplug one of the top connectors that feeds the injectors to see if it was firing on that bank! Why? All those wires and ecm are intimidating to someone like me that knows nothing about electronics but now with a little more knowledge, I have much better feeling!

Ace
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Sojourner
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« Reply #115 on: January 17, 2009, 08:52:05 PM »

Aces …thank you for the update. I read every bit of it like I was there.

Very well explained.

Thank you.

Sojourn for Christ, Gerald
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« Reply #116 on: January 17, 2009, 10:22:00 PM »

I'm glad to see that you stuck with it to the end, Ace.

Tom Caffrey
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Sammy
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« Reply #117 on: January 18, 2009, 05:39:25 AM »

John, here's the schematic I was using from Prevost. All Prevost diagrams are VIN number specific.
This choice was made on Ace's VIN - N-1232.

http://http://prevostparts.volvo.com/technicalpublications/pdf/d060688p2e.pdf

The only other source of info I use is a DDEC 2 wiring diagram - from Detroit Diesel.
I never looked at mine based on info that was posted already - as you mentioned.
DDEC wiring from DD is very similar, if not the same for many applications. OEM wiring from different manufacturers will vary with connectors and of course any options.
Happy to hear Ace has his coach running again.

Hope this may help.



Pete, I mean no disrespect as I type this but you have my post mixed up with JohnEd's. Smiley
I too believe the fuse could have blown after relay was replaced. Charging rate was set too high at that moment. I'm sure we'll all agree that this particular type of troubleshooting is unique,especially over the internet.We all have different opinions based on what we read and how we interpet it,that is what makes this board so very interesting and a fantastic source of info - all kinds of information.Happy to be a part of it. Cool
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RTS/Daytona
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« Reply #118 on: January 18, 2009, 05:52:16 AM »

Thanks SAMMY - Your VERY right - Thanks For pointing out my error - I'm very sorry

I corrected the post -

It should have said JOHNED  not you

Pete RTS/Daytona
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« Reply #119 on: January 18, 2009, 05:58:55 AM »

Ace, this is called experience and there is only one way to acquire it, unfortunately. I'm sure you won't forget it, these types of topics however unfortunate for the person having the problem, help us all learn about buses and their problems!  Trouble shooting electric, electronic problems stump the best technicians don't feel bad or unqualified!   Over current devices are there to protect wiring, devices and ultimately protect you the owner!  I've seen people put larger and larger fuses to "fix" a problem, it might do so temporarily, but in the long run, you can cause more drastic results!  I like the overcurrent or spike possibilities as the root cause of the problem!  I'm glad you have a great friend like Pete to help find the problem! 
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