Bus Conversions dot Com Bulletin Board
August 01, 2014, 03:27:06 PM *
Welcome, Guest. Please login or register.

Login with username, password and session length
News: This BB is intended for the sole purpose of sharing conversion and bus related information among visitors to our web site. These rules must be followed in order for us to continue this free exchange of info. No bad mouthing of any business or individual is permitted. Absolutely no items for sale are to be posted, except in the Spare Tire board. Interested in placing a classified or web ad, please contact our advertising dept. at 714-903-1784 or e-mail to: info@busconversions.com.

   Home   Help Forum Rules Search Calendar Login Register BCM Home Page Contact BCM  
Pages: 1 [2] 3 4   Go Down
  Print  
Author Topic: 8V92 Won't Start  (Read 6850 times)
Sammy
Hero Member
*****
Offline Offline

Posts: 523




Ignore
« Reply #15 on: December 03, 2008, 03:53:11 PM »

Rob, does the "check" and "stop" engine lights light up on your dash for 5 seconds and go out, when you first turn the master switch on?
This will tell us if DDEC is powering up.
Let me know if you have trouble locating the fuses or breakers for DDEC, I have a ton of schematics.
Thanks for the kind words BK.
Yes you and I have been around these beasts for quite some time,lol.  Smiley
« Last Edit: December 03, 2008, 04:48:25 PM by Sammy » Logged
Fredward
Hero Member
*****
Offline Offline

Posts: 617


MC-5A #5401 8" roof raise 8V71 with MT647




Ignore
« Reply #16 on: December 04, 2008, 08:11:29 PM »

Ok I'm just an 8V71 mechanical guy. But even the DDEC engines have a mechanical pump between the primary and secondary filters; right? If so, I've seen the pump get air locked after changing filters or after sitting for a long time. Somtimes a combination of a little ether to make the engine go and cracking the line to the secondary filter simultaneously has worked for me to get V71 and V92 engines going. FWIW
Fred
Logged

Fred Thomson
mikelutestanski
Sr. Member
****
Offline Offline

Posts: 381


Mikes Metal Mistress




Ignore
« Reply #17 on: December 05, 2008, 05:04:15 AM »

Hello: 
    What happened to initiate the problem?   you filled the tank.  right    was the tank empty when you did that or vvery nearly empty?   If so then the problem could be an airlock and priming these beasts is a problem...
   Check the threads for priming systems and priming pump stuff; however ifthe tank was half full then the problem could be bad fuel or bad stuff in the filters..  Not knowing how you checked the filters I can only surmise what happened.


  If you checked the filters by pulling one  off or disturbed the system then you have an airlock.   
        My inclination is to say try this :
    If you pulled off a filter then take both filters off drain the fuel and refill with fresh fuel thereby eliminating the bad fuel . Then you must eliminate all the air from the system by using a priming pump to circulate the fuel betwn the filters, fuel pump and racks. once all the air is out of the system it will start if in fact the fuel system is the culprit. 
    if it runs for a short while then quits then you may have some bad fuel..

       All this is supposition from the facts given.     My advice is to check everything that you have done since the engine was running last . Somewhere in that sequence of events   is a clue to the solution 
    regards and Happy bussin   mike
   
Logged

Mike Lutestanski   Dunnellon Florida
  1972 MCI 7
  L10 Cummins  B400R  4.625R
SmoothJazz
Jr. Member
**
Offline Offline

Posts: 78




Ignore
« Reply #18 on: December 05, 2008, 06:39:47 AM »

Rob,

The DDEC engines are equipped with a low coolant sensor that will shut down the engine. It may be as simple as being low on radiator coolant or a bad low coolant sensor. This will allow it to crank over but not start. The low coolant sensor should be located in your radiator surge tank. Also check your oil pressure sender. The DDEC engines will shut down for three main reasons, low coolant, low oil pressure and hot engine.
Logged
junkman42
Sr. Member
****
Offline Offline

Posts: 450





Ignore
« Reply #19 on: December 05, 2008, 06:47:26 AM »

Rob, I know that this is far fetched, but it is not possible that gasoline was pumped rather than diesel?  I once had the good luck of having the wife pump gas into her vw diesel!  Funny enough it was not Her fault as the delivery truck had filled the underground with the wrong fuel.  You can figure out how many apology's I had to offer.  John
Logged
Skykingrob
Full Member
***
Offline Offline

Posts: 232




Ignore
« Reply #20 on: December 05, 2008, 07:19:28 PM »

Hi All
Thanks for all the ideas. Here, again, is what happened. The engine has always started within a few seconds for the past 3 years I have been working on the conversion every 2 weeks without fail. The tank was 1/2 full because every few months I would go over and get 10 gallons and put in fresh fuel. So no problems with this until, with the cheap diesel price, I filled the tank to the brim and then wallaugh, cranks like crazy with not even a sputter. It acted like a air lock or lost prime, so I dutifully shut off the fuel line valve before the primary filter thinking I would see a dry filter. What I found was a clean filter full of fuel. So then I moved on to the secondary filter, checked it, samething, full of fuel. At that point, I made sure the filters were topped up and reinstalled them. I reopened the fuel shutoff and tried again, still nothing. I may have an airlock but that would have had to present before I checked the fuel the last time.
Since the only thing I did was top the fuel tank, I thought maybe there was an overfill switch that I might have triggered by topping off the tank. So, I went to "da book" but didn't see on mentioned. Thats when i started asking you guys.
I did check for low coolant but the coolant was flushed 3 years ago and replaced with new coolant when I started working on it for the conversion. Full coolant level.
The check and stop lights come on and stay on. Normally they come on and when the engine starts, they go out. Them staying on didn't surprise me any.

Rob
91 LeMirage XL
Missouri
Logged
Sammy
Hero Member
*****
Offline Offline

Posts: 523




Ignore
« Reply #21 on: December 06, 2008, 01:57:16 PM »

Rob, do you have a diagnostic request switch ??, might be near battery cut off switch on dash, next to ignition switch. IF you do, turn on ignition, press and release the rocker switch. The check and stop engine lights will blink (flash) any trouble codes. Check telltale light is for inactive codes, Stop engine light is for active codes. Let me know what you get.
Logged
Skykingrob
Full Member
***
Offline Offline

Posts: 232




Ignore
« Reply #22 on: December 07, 2008, 05:45:00 PM »

Hi Sammy
Nope, no diagnostic switch on the dash. There is a port in the rear breaker box but i don't have the unit to connect. Sorry.

Rob
91 LeMirage XL
Missouri
Logged
Sammy
Hero Member
*****
Offline Offline

Posts: 523




Ignore
« Reply #23 on: December 08, 2008, 01:58:14 PM »

Rob, take a look inside the electrical box on the streetside of your bus, just under drivers window.
Check to see if there might be a diagnostic switch in there. I know the H models have a switch on the dash, and early ones had a switch in front elec box for ATEC and DDEC. Worth a look. Cool
Logged
Skykingrob
Full Member
***
Offline Offline

Posts: 232




Ignore
« Reply #24 on: December 15, 2008, 06:46:14 PM »

Hi All
I have checked both the primary and secondary filters, both completely full of fuel, so if I understand correctly, that eliminates the fuel issue.
When I turn on the key to start there is no light up of the start and check engine light Sammy mentioned at all. The only light that lights on the dash is the low oil pressure and both low air pressure lights. I reviewed the manual at least a dozen times and there are no ATEC and DDEC switches that I can find on the coach. There is no diagnostic request switch on the dash or in the street side electrical compartment. The only thing that looks anything like what you might be mentioning is what appears to be a diagnostic port in the rear fuse box over the engine. This is a flat connector that has 7 or 8 round holes for what appears to be a dignostic machine hookup.
Full engine coolant, full oil level.
Here is where it gets confusing to me. The book, Series 92 Service Manual from Detriot, doesn't mention a DDEC but it mentions an ECM and other electrical components and yet when I compare the pics in the book to what I have in the coach they don't match, I definately have a stop fuel lever on top of a flat plate above the ECM. There is another lever on the plate also that is connected to the throttle. The stop fuel lever is in what I believe to be the start position toward the rear of the coach against an air operated plunger. I would like to believe that I have a DDEC but I am questioning that now given not all the things are there and somethings that shouldn't be there, like a fuel cutoff lever, are there. I have looked everywhere for any fuses that might be for a DDEC with no luck.
I tried the starting ether at least 4 or 5 times. The engine attempts to start but as soon as the ether runs out it quits.
I am still looking for things to check. Any more help guys? This started with topping off the tank from 1/2 tank to a full tank with diesel.

Rob
91 LeMirage XL
Missouri
Logged
Lin
Hero Member
*****
Offline Offline

Posts: 4529

1965 MC-5a




Ignore
« Reply #25 on: December 15, 2008, 07:03:51 PM »

If ether gets it going for a little, then the problem is fuel supply.  Merely because the filters are full, does not mean it is getting fuel.  It is even possible that the filters are clogged (sorry, I do not remember if you have already checked that).  There could be all sorts of things with your setup that I am not familiar with that may cut the fuel supply.  Those could be things to bypass one by one.  However, I would try to make sure that you have not somehow lost prime.  Although I have not done it, I am sure that there are those here that could tell you how to pump fuel through the system using a garden spray setup.  Another thing to be looking for is a loose fitting or a simple crack in the fuel lines.  If it sucking air from somewhere, it will not start.  The mighty DD can be laid low by little more than a pin hole.
Logged

You don't have to believe everything you think.
Blacksheep
Guest

« Reply #26 on: December 15, 2008, 07:07:39 PM »

My H model has a toggle switch for checking codes using the yellow CEL and red SEL if one doesn't have a pro-link. It is located outside, drivers side under drivers window in a compartment that also has the port for testing using the pro-link.

Now my Prevost book says, to start, you turn on ignition switch to "ON" and both CEL and SEL should light up. Stay lit for approx. 3-5 seconds which is allowing the ECM to do a self diagnostic test. When they go out, it is safe to start the engine. If you have any fault codes, the CEL (yellow) light will come back on. If you have major faults as in low coolant, low oil, or overheating, the SEL (red) will come on and about 3-5 seconds later the engine will shut down.

If all you did was fill the tank, it kind of sounds like an air lock, OR what happened to me once was a blown fuse to the ECM. This fuse on mine is hard wired directly to the start batteries. It is a blade type fuse that actually lays on top of the batteries in a rubber housing with a cover that completely conceals the fuse. You may want to check there and see what you have if any at all! Other than that, when you say it tries to start with ether but quits, makes me think it's fuel related rather than electronic. Could the fuel pump gone bad as a coincidence?

Ace
Logged
Blacksheep
Guest

« Reply #27 on: December 15, 2008, 07:10:56 PM »

I might add too that don't rule out the possibility of a rubber fuel line collapsing. I have seen them get really soft and when you try to start the engine, the hose would actually close itself off. To look at it, you couldn't tell because it was the inside lining that was actually collapsing not the outside! That would make for fuel not going to where it was needed!

Ace
Logged
Hartley
Hero Member
*****
Offline Offline

Posts: 1217





Ignore
« Reply #28 on: December 15, 2008, 08:00:44 PM »

Ok, I will get a lot of flak over this suggestion, I know that right now..

If I had to say something dumb like there is an air bubble in the fuel pump
causing the "gear" pump to fail to start moving fuel from the primary to
secondary filters. I might have to run for cover.

However, I have been through these nightmares before... Even though you have
fuel in the lines and filters, It only takes a small air bubble to make a gear driven
detroit fuel pump to fail to move fuel.

Now.... What I did was on my MCI I have a fitting on the secondary filter. That is an old a/c fitting to which I attach a suction pump to pull fuel through the primary and pump and into the secondary filter.

( Those of you that have NJT buses probably still have those same fittings. )
( Old R-12 a/c hoses fit them. )

You have to clear the air out of the pump and primary filter "FIRST" then you should be able to get going unless something is goofed up in the computer keeping the fuel cut off.

Even those little throw away portable air pumps have sometimes a suction port on them or can be rigged up with one. You only need a vacuum enough to pull bubble-free air out of the filter and pump lines.

But then again, If that isn't the problem then keep guessing. a Detroit will run on ether and air alone no matter what the computer is saying or doing so that does not necesarily say the problem is limited to the fuel supply. eliminate that first...

Dave....
Logged

Never take a knife to a gunfight!
Busted Knuckle
Hero Member
*****
Offline Offline

Posts: 6447


6 Setras, 2 MCIs, and 1 Dina. Just buses ;D


WWW

Ignore
« Reply #29 on: December 15, 2008, 09:32:54 PM »

Hi All
I have checked both the primary and secondary filters, both completely full of fuel, so if I understand correctly, that eliminates the fuel issue.
When I turn on the key to start there is no light up of the start and check engine light Sammy mentioned at all. The only light that lights on the dash is the low oil pressure and both low air pressure lights. I reviewed the manual at least a dozen times and there are no ATEC and DDEC switches that I can find on the coach. There is no diagnostic request switch on the dash or in the street side electrical compartment. The only thing that looks anything like what you might be mentioning is what appears to be a diagnostic port in the rear fuse box over the engine. This is a flat connector that has 7 or 8 round holes for what appears to be a dignostic machine hookup.
Full engine coolant, full oil level.
Here is where it gets confusing to me. The book, Series 92 Service Manual from Detriot, doesn't mention a DDEC but it mentions an ECM and other electrical components and yet when I compare the pics in the book to what I have in the coach they don't match, I definately have a stop fuel lever on top of a flat plate above the ECM. There is another lever on the plate also that is connected to the throttle. The stop fuel lever is in what I believe to be the start position toward the rear of the coach against an air operated plunger. I would like to believe that I have a DDEC but I am questioning that now given not all the things are there and somethings that shouldn't be there, like a fuel cutoff lever, are there. I have looked everywhere for any fuses that might be for a DDEC with no luck.
I tried the starting ether at least 4 or 5 times. The engine attempts to start but as soon as the ether runs out it quits.
I am still looking for things to check. Any more help guys? This started with topping off the tank from 1/2 tank to a full tank with diesel.

Rob
91 LeMirage XL
Missouri

Rob I believe you have just led me to the problem! OK now I am not positive but I am sure I know the problem as in been there, done that and felt really silly once it was discovered what had happened! But at the same time relieved it didn't cost ANY $ to fix! I left my cell phone # in a PM for you call me and we'll have you running in the morning with in minutes! Afterwords I'll let you confirm what it wuz! (if ya wanna take the ribbing! That is! LOL! Grin)
Grin  BK  Grin
« Last Edit: December 15, 2008, 09:34:36 PM by Busted Knuckle » Logged

Busted Knuckle aka Bryce Gaston
KY Lakeside Travel's Busted Knuckle Garage
Huntingdon, TN 12 minutes N of I-40 @ exit 108
www.kylakesidetravel.net

Grin Keep SMILING it makes people wonder what yer up to! Grin (at least thats what momma always told me! Grin)
Pages: 1 [2] 3 4   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.18 | SMF © 2013, Simple Machines Valid XHTML 1.0! Valid CSS!