rev counter sensor

[bobngo]

my 2.5 diesel , will go a certain distance starting from cold ,then the rev counter goes to zero, then later the hold light comes on ,then even later it drops out of top gear and goes into limp home mode.

it always starts this with the rev counter dropping to zero

to cure the problem ,i park and stop the engine, for approx 2 minutes, then everything works ok( this seems to allow heat to get to a sensor somewhere)after this it will also work ok even if i leave the van parked for as much as 8 hours in the day , because the engine still has some retained heat

now the distance it travels before this happens is dependant on the ambient temperature that day , if its cold it only goes about 1 mile , but if its really hot it goes 2/3 miles.

so it would seem to be dependant on a temperature sensor somewhere , my guess is its not on the gearbox, as in either distance ,it is not far enough to have increased its temperature, so it would suggest its on the engine

so which temp sensor controls the rev counter ,and where is it ??????

should add no hills are involved , all flat flat roads, east anglia is not noted for its mountains !!!

[missfixit70]

As per the last time you asked, did you check for fault codes as per the factsheet & check the crankshaft sensor? - http://www.igmaynard.co.uk/bongo/forum/ ... or#p418336
Are you still getting the same symptoms?

AFAIK the only temp sensor that has anything to do with the ecu is the one above the starter motor (although a gearbox sensor of some sort is alluded to in the manual), shouldn't have anything to do with the rev counter.

[bobngo]

missfixit, i am only an ex aircraft engineer ,mainly working with engines, on spitfires ,lancasters ,sunderlands, meteors, vampires, hunters, lightnings , etc .

so how can you expect me to understand the in,s and outs ,of a bongo engine, and more especially how to find the fact sheets to get the fault codes , i do,nt even know where to begin ,

yes it is the same old original fault i had ages ago,and its not changed one bit. what a wonderful memory you,ve got, wish mine was as good. (ooppss who,s creeping )

so can you spell it out step by step, from the facts that i,ve given ??????

if you do there will be "crabbies" waiting for you at the next big meet !!!!

my local bongo garage has many spares ,including temp sensors, but i need to know which and where etc !!!

[Doone]

Here's A LINK that may help you. You also have a pm.

[missfixit70]

As I said I don't think it's the temp sensor, as said before it's probably the Speed/crankshaft/ne sensor, not changed one myself, but if you read through the links above, you should arrive at the info needed, if the garage are doing it, they should know what they're doing anyway
Factsheets in the members area for fault code diagnosis - http://www.igmaynard.co.uk/bongo/member ... factsheets you'll need the password & username that Ian sends you each month to access them.
I didn't remember, just did a search on "crankshaft and sensor" & there was your previous thread near the top of the list

[bobngo]

problem solved ???

after giving it alot of thought (and help from all of you ) i decided ,that the rev counter MUST take its reading from either the crankshaft or canshaft , and that it could not be a temp sensor.

finally found the NE sensor at the front of the engine on drivers side, this has two electrical connectors between the main loom and the sensor , so took them apart and gave them a liberal dose of switch cleaner, this had no effect,problem still there. *^%&*$£* or words to that effect

removed the sensor from the engine , and half of the end ,and in particular the brass sensor end, were covered in a black tar like substance, i do,nt think this runs in engine oil normally as it was only half covered, cleaned the tar off ,refitted sensor to engine , took the bongo for a run , no problems at all , no matter what i did.

so it looks as though the problem is solved, but must not get too excited, tomorrow morning,when the engine is really cold will be the proof .

will keep you posted ,and thank you very much to everyone that gave their thoughts on the problem

[behavedave]

missfixit, i am only an ex aircraft engineer ,mainly working with engines, on spitfires ,lancasters ,sunderlands, meteors, vampires, hunters, lightnings , etc .

Ooooh...... I'm dribbling...... that sounds like such an awful job!

[The Great Pretender]

missfixit, i am only an ex aircraft engineer ,mainly working with engines, on spitfires ,lancasters ,sunderlands, meteors, vampires, hunters, lightnings , etc .

Ooooh...... I'm dribbling...... that sounds like such an awful job!

Easy peasy............... You can get a Haynes manual for the Spitfire and Lancaster and, no, I'm not telling porky pies.

[bobngo]

well i tried again today and it worked perfectly, no probs at all

so it was the tarry stuff on the NE sensor (crankshaft position sensor )causing the problem

may be a good one to put in the fact sheet area ??????

perfecto mondo !!!