crankshaft position sensor W463
Sorry but could someone post a diagram/photo showing location of CPS for a 1993 W463 300GE
She turns over but won't fire - has good spark, fuel pressure seems low (a trickle before injectors so possible fuel relay and/or pump may be required )- am hoping to have a diagnosis carried out.
All and any help appreciated.
Many thanks
David
Simplest test would be to swap in a fuel pump relay that you know works and see if that cures the problem.
Where do you live - you never know, there might be a member with the same model around the corner that would be happy to let you use their relay to check. That only takes 5 minutes.
The Crank-Position Sensor connects directly to the EZL ignition unit on the left of the engine bay (passenger side UK). Follow the wire back to the rear of the engine and you will find the sensor.
If you need to replace;
Click on ENGINE tab and then you will see the part and its part number.
Available here:
Look here on link below for a list of parts including Fuel-Pump Relay (£23) and Crankshaft Position Sensor (£22)
http://gwoa.co.uk/content/g300e-fuel-system-parts
Note that the vehicle has TWO fuel pumps, a pressure accumulator and a filter. One is located under the tank and the other is located under the rear, left, plastic wheel-arch liner. This second pump is in assembly with accumulator and fuel filter.
A leaking accumulator can also give the impression of low fuel pressure, by leaking fuel back to the tank. Also, if you fuel filter has never been changed, this might be the time to do so.
The fuel accumulator has a rubber hose on the rear, which vents back to the fuel tank. If you pinch that hose and the fuel-pressure increases, it's an indication that the diaphragm in the accumulator is perished and leaking pressure. The vent hose should normally be empty in a good accumulator, but will have fuel if the diaphragm in the accumulator is leaking.
The link in my earlier post has all the various fuel-system parts listed.
As far as diagnostics go on these engines, I'm afraid that you may find it somewhat lacking. The circular multi-pin socket in the engine-bay will allow you to diagnose the heath of the fuel-system through various % duty-cycle codes that can be read with an appropriate multimeter on two of the pins.
Here's a meter (just by example) that has a duty-cycle function https://www.clasohlson.com/uk/USB-UT61D-Multimeter-/36-4717?
I don't think a scanner would work on your model given the year; I could be wrong but OBD2 came mandatory from 1994 onwards. Best you would be able to do is look for blink codes.
Measure the resistance between the center and outer rings of the smaller round socket fitted to the ignition module. I will come back with the allowable readings you should be getting vaguely it should be something like 1.2 - 3 ohms. But I will confirm this latter.
I do have a brand new M/Benz CPS if required.
[/quote]
I will come back with the allowable readings you should be getting vaguely it should be something like 1.2 - 3 ohms. But I will confirm this latter.
I do have a brand new M/Benz CPS if required.
[/quote]
The new CPS reads 0.84 Kilo ohms ; yours should read close to this alternative test is to remove the fuel pump relay and get an assistant to crank the engine while reading between the inner rings on the smaller socket attached to the ignition module. You should be reading circa 200 mv.
Thank you all very much for the responses.
I live in Halkyn, Flintshire
I have put a new fuel relay in - not money wasted as my mechanic blew the last one when disconnecting the fuel pump but regrettably not the easy fix I had hoped for!
Pump kicks in when key is turned as usual but fuel pump pressure seems a bit low (not measured it but more like a puppy piddle than a pressured stream that one might expect from a police horse).
Accordingly i will replace the 25 year old pump. I have also ordered a new CPS (which I think/hope will actually solve the problem -many thanks for pointing me in the right direction (I could not find it on that well known web based auction site).
I trust it connects to the lower rear part of the engine -by bell housing but will follow the lead and see where it takes me.
I have also ordered a cheap diagnostic gizzmo and 9 point adaptor just to see how many error codes I get.
Once again thank you all very much