Why is my engine running on?

[Milhouse Junior Member Find all posts View Profile Close Milhouse]

I have a 2000 Nissan Patrol with the 4.2L turbo diesel engine. I have recently made a batch of BD entirely from Tallow and I have found it gives more power, however my engine seems to continue running for a few seconds after I turn it off. It then shudders and dies.

My mate who has the same car has this problem with BD made from oil and we cant seem to pinpoint the cause. My car runs (and stops) fine on normal BD.

Any suggestions?

Thanks
Milhouse

[Peda Senior Member Find all posts View Profile Close Peda]

Re: Why is my engine running on?

Hi, I have a 2001 Nissan 4.2 td and occassionally, say 2 out of twenty five times, mine will tend to run on roughly just a little bit longer also. I have done over 2500 klms on 100% bio and this is the only problem I have noticed with the vehicle, but I have no way of knowing if it is related to using bio or not. From research I have done, there is a solenoid operated needle valve at the injector pump and this can be sluggish closing off the fuel supply and allowing the engine to get a little flow of fuel, enough to cause a run on and rough shut down. I am filtering my fuel through a Denco filter with a glass bowl and see no deposits in there so I doubt glycerine is the problem.
The solenoid can be removed and cleaned or replaced if needed. I havent removed mine yet as the problem hasnt happened for a while now.

Does yours run on for a considerable time and you need to engage fourth gear to stall it or is it taking just a bit longer to shut down? Does it happen with the engine hot or cold and how often does it happen?
Regards
Peter

[Slippery Senior Member Find all posts View Profile Close Slippery]

Re: Why is my engine running on?

I have read somewhere that the running on could be caused by engine oil vapours escaping between the rings and igniting in the cylinder. Cannot remember where I saw that but I think there was an element of possible additional damage being caused as well.

It had nothing to do with BD but more a wear and tear matter.

[Milhouse Junior Member Find all posts View Profile Close Milhouse]

Re: Why is my engine running on?

Hi, I have a 2001 Nissan 4.2 td and occassionally, say 2 out of twenty five times, mine will tend to run on roughly just a little bit longer also. I have done over 2500 klms on 100% bio and this is the only problem I have noticed with the vehicle, but I have no way of knowing if it is related to using bio or not. From research I have done, there is a solenoid operated needle valve at the injector pump and this can be sluggish closing off the fuel supply and allowing the engine to get a little flow of fuel, enough to cause a run on and rough shut down. I am filtering my fuel through a Denco filter with a glass bowl and see no deposits in there so I doubt glycerine is the problem.
The solenoid can be removed and cleaned or replaced if needed. I havent removed mine yet as the problem hasnt happened for a while now.

Does yours run on for a considerable time and you need to engage fourth gear to stall it or is it taking just a bit longer to shut down? Does it happen with the engine hot or cold and how often does it happen?
Regards
Peter

It is generally pretty good and only runs on maybe 1 time every 15 - 20 runs. However on the tallow based bio it runs on nearly every time. I know it is a fuel issue because I tried going back to dino diesel and the car shuts down fine. It is not too big a deal and I dont need to stall the car or anything it is just a bit rough shutting off.

Thanks again

Greg

[Terry Syd Senior Member Find all posts View Profile Close Terry Syd]

Re: Why is my engine running on?

Sounds like a leaking fuel shut off valve. Perhaps with the bio the extra cetane allows the flame front to move a bit quicker with the reduced fuel and provide enough power for the continued run on.

If you replace the fuel shut off valve, I'm sure the problem will go away. No fuel, no run.

[gwalker Senior Member Find all posts View Profile Close gwalker]

Re: Why is my engine running on?

My '89 Patrol TD 4.2 doesn't do this on 100% BD bought at the last supply day.
George