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| How Does the CRD Stop Running? http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=5&t=20914 |
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| Author: | Cowcatcher [ Mon May 21, 2007 12:13 pm ] |
| Post subject: | How Does the CRD Stop Running? |
In reading some of the recent comments in tdifferent threads on "runaway diesels" I got to thinking about how that could happen if you cut the fuel...how cna it continue to run only on air. The thought quickly turned to how does this thing turn off. Any other diesel I have run you killed the engine by killing the fuel. On my JD wheel tractor you are even cautioned to not turn the key off until after you have killed the motor. So, how do our CRD's stop? I assume there must be a fuel feed cutoff somewhere that is electrical. |
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| Author: | Jeger [ Mon May 21, 2007 12:52 pm ] |
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Looking at the parts manual: there is a valve 05159962AA right before the injectors the fuel pressure solenoid 05159964AA on the fuel rail a valve on the injector pump 05159962AA And of course the injectors could just be shut off. As well as closing the FCV. The only one I am sure of is the FCV closing, those other ones are just guesses 
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| Author: | MightyCRD [ Mon May 21, 2007 1:09 pm ] |
| Post subject: | Re: How Does the CRD Stop Running? |
Cowcatcher wrote: In reading some of the recent comments in tdifferent threads on "runaway diesels" I got to thinking about how that could happen if you cut the fuel...how cna it continue to run only on air. The thought quickly turned to how does this thing turn off.
Any other diesel I have run you killed the engine by killing the fuel. On my JD wheel tractor you are even cautioned to not turn the key off until after you have killed the motor. So, how do our CRD's stop? I assume there must be a fuel feed cutoff somewhere that is electrical. Cowcatcher - The main fuel feed cutoff on the CRD should be the injectors themselves, since they are electrically actuated. So the injectors quit providing fuel, and the FCV valve shuts off air. This valve on an older diesel was referred to an anti-shudder valve, if my memory serves me correctly .... You can get a runaway diesel IF you are introducing some sort of "fuel" into the system; it doesn't have to be diesel fuel provided thru the injectors. If, for instance, you are pulling in enough oil through the intake system, and then through the intake valve and into the combustion chamber, as the engine continues to spin & compress the air, the oil can auto-ignite, continuing the combustion process & keeping the engine running. The way the CRD shuts off *should* be a combination of 2 things; you close the FCV valve, which should starve the engine of air, and you shut off power to the injectors, which starves the engine of fuel. I would think that a runaway diesel with electronic/electric injectors AND an FCV valve would be a rarity, and pretty much ALMOST impossible. That, of course, is allowing for the FCV valve to be functioning correctly and shutting off enough air to prevent combustion ... |
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| Author: | DnA Diesel [ Mon May 21, 2007 2:08 pm ] |
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Old 1.6L NA VW Rabbit diesels in the 80's had a nasty habit of breaking their oil control rings on the piston and sucking the crankcase oil through the broken cylinder. I friend of mine had that happen to his '82 Rabbit...he had to put in the clutch and let the thing grenade itself to stop it... |
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| Author: | Bonehead [ Mon May 21, 2007 9:07 pm ] |
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I've seen 2 big truck that lost the seal/s in the turbo and pumped oil through the turbo, which caused a "runaway". The only way to shut them done was leave it in a high gear and stop without pushing in the clutch 
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| Author: | Cowcatcher [ Tue May 22, 2007 1:31 am ] |
| Post subject: | |
Interesting all. Thanks for the feed back. |
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| Author: | Joe Romas [ Tue May 22, 2007 6:24 am ] |
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DnA Diesel wrote: Old 1.6L NA VW Rabbit diesels in the 80's had a nasty habit of breaking their oil control rings on the piston and sucking the crankcase oil through the broken cylinder. I friend of mine had that happen to his '82 Rabbit...he had to put in the clutch and let the thing grenade itself to stop it...
This happened to me on a well worn 90 Jetta. A better way is to leave the clutch out and hit the brakes riding it to a stop. It easily restarted and was fine till it got t boned on the drivers side by a blazer. My wife got injured but was upset the most because she lost her jetta diesel 
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| Author: | tulsa [ Tue May 22, 2007 7:49 am ] |
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Would a CO2 fire extinguisher directed to the air intake help shut down the runaway? Runaways occasionally happen when natural gas lines are cut, happens in the oil fields. |
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| Author: | oldnavy [ Tue May 22, 2007 8:09 am ] |
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tulsa wrote: Would a CO2 fire extinguisher directed to the air intake help shut down the runaway? Runaways occasionally happen when natural gas lines are cut, happens in the oil fields. Yes and it is sometimes seen on big rigs and such, and there is often properly spaced extinguishers in diesels shops. The runaway can also happen if you hole a piston or break a ring, besides the turbo seals failure. The seal failure is not that uncommon in 100k mile range, depending on how the vehicle was serviced. Without the FCV you have no way of engine shut down on a CRD automatic and if you are in traffic it will be a real mess to say the least if no FLV gto shut engine down if turbo seal fails. You will be pushing other vehicles out of the way or headed toward 110 mph + if on the interstate before engine self destructs.
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