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I think I've gone Crazy... 97 Cummins?

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Old 12-18-2004, 10:34 PM
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I think I've gone Crazy... 97 Cummins?

POST EDITED BY MODERATOR..................


OK, before we start, I want to assure everyone that I am not having a Nutty, and I really did think more than twice about posting this because I wouldn't believe it if it didn't happen today...

I stopped at 7-11 this morning, it was cold, so I turned the BD Exhaust brake on while I ran in...

I came out, put the truck in reverse, and went to back up... (this is when the psychotic episode begins...)

Let the clutch out, and the truck backs up slightly but the engine comes to a shuddering halt like I've got the ebrake on and almost stalls, so I quickly put the clutch in, as the engine is almost stalling out... and turn off the exhaust brake.

Think I release the ebrake, but can't be sure if it was even on because of the engine noise, and let the clutch out... AND GO FORWARD... .... BUT I'M STILL IN REVERSE....

Clutch back in, put the tranny (NV4500) in 2nd, and the truck goes backwards... !!!!!!!

I'm now in the middle of the parking lot, and I am trying to get out of the way of the traffic, so I continue backwards and notice SMOKE starting to come from the intake... Powersteering is not hardly working at all...

Get it backed up and shut if off....

Elapsed time, about 20 seconds.

So:

Reverse goes forward
2nd goes reverse
Smoke from the intake
No Powersteering.

Can't tell you what the Pyro, boost or oil pressure was doing because I was too busy freaking out that eveything was backwards...

Opened the hood, still some wisps of smoke coming from the intake... Let it sit for a couple minutes while I looked around to see If I was still on the right planet...

Started it up... Ran perfectly.. Proper oil pressure, EGT everything. Drove it home.

So... What Happened?

Did my engine start running backwards, and if it did, Why did it?

It's the only logical thing I can think of... or should I check myself in to the nut farm...
Old 12-18-2004, 11:50 PM
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yes, you were running backwards! never heard of it happen on a cummins... the old 2 stroke detroits were notorious for it

Forrest
Old 12-19-2004, 07:56 AM
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Just a freak ocurrence. The engine was bogging from the e-brake, there was a lot of backpressure. When you let the clutch out the engine actually did stop, but I guess the backpressure pushed it around backwards hard enough that it relit in reverse rotation. Intake through the tailpipe, exhaust through the air filter. You shut off the e-brake, which helped keep 'er running.

Oil pressure was zilch, but you were basically idling so no harm done. Probably had some boost showing because the air filter was restricting exhaust flow, and the pyro reading was cooling rapidly. Check the air filter carefully to make sure it has not been damaged. Other than that, I'm sure no harm has been done.
Old 12-19-2004, 08:40 AM
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I had an old Mack B61 do that to me one time when I left the clutch out with a big load on, I left off the hammer before I pushed the clutch all the way in. Just the weight of the front end coming back down was enough to stall the engine and rotate it backwards enough to start it. Smoke was coming out the old intake filter so I knew immediately what I had done.
Old 12-19-2004, 04:56 PM
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I have never even heard of this happening before, it's not that funny to you, but I laughed for 10 minutes

Moral of the story: WHEN I finally put on my exhaust brake, don't stall the motor in reverse

Chris
Old 12-19-2004, 10:04 PM
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My dad had an old 79 GMC semi truck with a detroit and he made it run backward and one of his hands made it run backward once by having in forward gear and it rolled backward on a hill. Said it was exhausting out the intake and sucking from the exhaust. Turn off and on and ok again.... bad thing to think about would be the lack of oil.....
Old 12-19-2004, 10:08 PM
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Kind of unrelated but I know some golf-carts use this as a way of running in forward and reverse. They start the engine in the opposite direction for reverse, so it is possible.
Old 12-19-2004, 10:53 PM
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Thanks for confirming.

I can see a 50 year old two stroke diesel, but a 12V?

I really think it did run backwards because all the symptoms make sense.

But what kind of freakish combination of variables needed to happen to make it do this...

I'm scared to go to 7-11 now.

Old 12-20-2004, 07:19 AM
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To bad it didnt happen at work , as then maybee you would be afraid to go their and then maybee you could plead insanity and get comp. or something..


But in reality the chances of it happening again are probably less than you buying the winning loto ticket at 7-11. justmy.002
Old 12-20-2004, 07:58 AM
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Originally posted by wolf359
I'm scared to go to 7-11 now.

I've seen videos of you wheeling... You're not scared of anything...
Old 12-20-2004, 08:21 AM
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Couldn't you MAKE the old '71 Detroits run backwards? Just change a few things and they would run backwards for running boats in twin engine configurations?

Chris
Old 12-20-2004, 08:29 AM
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the detroits run backward in the old greyhounds.
Old 12-20-2004, 11:41 AM
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Yeah, it's not too tough to get one of those 2 stroke detroits to run backwards
actually 2 strokes in general.......just look at ski doo's reverse system for their sleds - it stops the motor and fires it backwards to give the sled a reverse gear!......and it works perfectly!.......I would have thought the cam would not allow the motor to fire backwards on a 4 stroke.......apparently I'm wrong! ...........Oh well, not to worry......I'm sure the motor is fine as long as it wasn't running too long with the oil pump spinning backwards..........
Old 12-20-2004, 12:46 PM
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Sounds like it really did run in reverse. It's rare and the conditions have to be just perfect for it to happen. As long as you don't run it long that way it usually doesn't hurt it. Make sure you check the air filter now.
I don't think it's 7-11, but maybe Christine is taking over????
Old 12-20-2004, 12:54 PM
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Originally posted by Eskimo
I've seen videos of you wheeling... You're not scared of anything...
This is different.. Usually up and down don't change halfway through...

I took the air cleaner off, it was fine inside. No problems since, I drove it a couple hundred K on the weekend.. everything seems fine...


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