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[SR-71Blackbird]

Hi all,

I have a jumping rev counter on my 1998 2.5TD Auto. Mostly it is fine but sometimes it just jumps around from 0 - max etc.

Is this likely to be a crankshaft sensor failing?

Is there a way I can test this and is there a guide/images anywhere on how to replace it?

Thanks

Alex

[zirk]

Its a TD so most likely something wiring related, my first call would be to pull the Dash Clocks out, ElectroLube the main connector and firmly refit.

(Edit, if you cant get your hands on ElectroLube Spray, a good clean with some Meths and cotton buds on the connector pins and socket should suffice)

[SR-71Blackbird]

Hi all,

Getting a bit more serious now.

When the rev jumps around abit and then sits on 0 even when moving (should be around 2000rpm lets say) it causes the "Automatic Transmission Fault" check light to come on on the Display. I then stop, turn the engine off and on again and it clears but I want to get it solved.

Is it likely to be a failing crankshaft sensor? If so is there a guide or images of where this is and how to change it etc? I saw a Post where TheBoy says

http://oldsite.omegaowners.com/forum/YaBB.pl?num=1246733913


"crank sensor on TD is under starter motor. Never known one to fail.  The sensor has a connector on it, might be worth giving that a clean, as that tractor blood tends to get everywhere."

Any pics or guidance of how to replace it and where it is?

Thanks as always all.

Alex

[X30XE]

I doubt it. No feed from the CPS is an immediate engine shutdown condition in my experience. 

Dodgy rev counter and dodgy idle... These may be two seperate issues that just happen to occur together sometimes. Or a more complex wiring fault causing both.

[X30XE]

http://www.omegaowners.com/forum/index.php?topic=135078

See post from Nick W re: rev counter function...

[Kevin Wood]

I doubt it. No feed from the CPS is an immediate engine shutdown condition in my experience. 

Dodgy rev counter and dodgy idle... These may be two seperate issues that just happen to occur together sometimes. Or a more complex wiring fault causing both.

No necessarily on a TD, as the engine has a conventional mechanical injection pump, so it can run without. Given that the autobox is complaining, in addition to the rev counter, I'd tend to go with the RPM indication from the engine ECU being to pot, which might well be a crank sensor problem.

[SR-71Blackbird]

Thanks Kevin,

I have ordered another Crankshaft position sensor.

I went under the car the other day (forgot to take a picture damn) but there is a sensor that seems to be clipped to the starter motor and goes to the transmission. Is this the Crankshaft sensor and cable? I didn't take it out or disconnect as I was unsure.

Thanks very much in advance.

Alex

[TheBoy]

It sits right next to the starter motor, is about 3inches long.  Fitting lengthways, so goes through the engine casing, and presumably is picking up something on the flexplate.

Cable is a 2 pin connector, plugs straight into the sensor.

[TheBoy]

Here's a pic, sorry not overly clear, as its an old pic of swapping my engine



But you can see under starter motor

[SR-71Blackbird]

Thanks guys,

I will see what I can see when the part arrives.

Great picture btw, I think I can see the bit you mean, under the starter and then the other end of the cable must connect somewhere too but I will just follow the cable back and see.

Fingers crossed this solves it.

I will report back when I have had a go.

Thanks

Alex

[TheBoy]

Cable is part of engine loom, sensor has a socket on end, no cable

[SR-71Blackbird]

OK my sensor just arrived and it has a cable attached to it, not removable and it has a 3 pin connection. I take it this is not correct?

Thanks

[Kevin Wood]

Oh, what fun and games we had with that tractor donk!

[TheBoy]

OK my sensor just arrived and it has a cable attached to it, not removable and it has a 3 pin connection. I take it this is not correct?

Thanks

Not like that on the U25DT and X25DT engines I've seen.

[TheBoy]

Oh, what fun and games we had with that tractor donk!

Notice the fine weather in that picture, unlike "that day"