W210 E240 Hot Starting Issue - Sort Of, Weird

[m1bnk]

Thanks to everyone who has offered advice regarding this car for me in the past - Sorry, but once I more I prostrate myself at your feet and beg further assistance.

1999 E240 2.4 V6. Had misfiring issues etc which turned out to be a oxygen sensor and MAF. Now I have a new fault which my (recommended lots on here) independent cannot find even with STAR diagnostics. It's an intermittent fault, and wouldn't you know, the car behaves itself just fine while I shell out for hour after of diagnostics. I dunno if they are too busy to stand over the car and recreate the fault or what, but while the price per visit is very reasonable, cumulative cost is becoming excessive.

If the temperature gauge is between 1/4 and 3/8 it doesn't start. Goes through the start cycle as normal, engine turns but it doesn't even try to fire. Car starts fine if the temp below 1/4 or above 3/8 (normal running is 1/2 way or a tiny bit above). Phoned the AA out the first time, felt real silly when he got in and started it right away, he took a while so engine was cold by then. The car drives fine if started outside this range, and there is no misfire or anything as it warms up.

I'm assuming that it's a sensor somewhere that's telling the ignition not to fire. Having just spent 500 quid sorting the misfire out, and several hundred more on diagnostics that revealed nothing, I can't afford to be keep spending. So, I thought that a cheap second hand laptop, with diagnostics of some description, keep it in the car, and read what codes i can next time it refuses to start. Can anyone recommend one from the bewildering array offered on eBay and elsewhere - I can't afford a STAR set of my own, but something like CarSoft seems to fit the bill here but I am not sure what I need regarding OBDII or CAN capabilities on the code reader

Any and all advice, except my mate's "apply a box of Swan Vesta's and wait twenty minutes before phoning the fire brigade", would be most welcomed.

 

[Robbo]

Crankshaft position sensor?

 

[m1bnk]

Wouldn't that have shown on the diagnostics though, or could it be that at certain temperatures it quits?

 

[momomo]

A faulty crankshaft postition sensor wont show up as a fault even though it may be faulty, when diagnostics are carried out

 

[grober]

Crankshaft position sensor?

X2 CPS definitely worth replacing---- common fault and not too expensive--possible DIY even---- Êàòàëîã--item 5 -- be careful tho since there was an engine change in 1999 and changes in the sensor also----best to check via your chassis number.

 

[m1bnk]

That engine change, was that the 2.4 to 2.6l change. If so mine is definately the 2.4l version. Can anyone give me a part number and source for the sensor, I can send me chassis number if it helps, or should I just go and buy them from the dealership?

 

[grober]

the link I gave you is for the M112.911(E240) (2.4 V6) if you look on the 2.6 engine pages the part nos are the same. There are 4 numbers which I expect refer to say Bosch and HELLA parts and to different connectors referred to as "single and double interlock " ??? Safest route is to go by your MB chassis number don't think there's much difference in price to OEM.
Bosch numbers are
BOSCH
0 261 210 141
To MY 04.00 To Eng. No. 370998

0 261 210 170
To MY 04.00 From Eng. No. 370999

 

[Dieselman]

I'd go with the crank sensor also, the output of which can be metered on Pin 13 of the 38pin diagnostic socket.

TBH, I'd just fit a new one as they are a known failure item.

 

[lynall]

Google mercedes crank sensor, loads of info, all say roughly same thing either no start full stop, or wont start when hot.



Lynall

 

[stevesey]

Ditto to CPS, your symptoms sound pretty standard - mine went within a week of purchasing the car. Initially wouldn't restart when hot, wait 20 mins all fine, garage I got the car from had sent me to an MB dealer to pick up a second key and it did it to the tech when I arrived - he stuck it on STAR and it had logged a fault (but that is unusual). Was advised to get it looked at soon.

Anyway on the way home - the car died in traffic (first time it had actually cut out) and I got delivered to the garage I got the car from on the back of a AA truck. They were a little embaressed and very apolgetic (although there was nothing they could have done to pick this up really).

Does puzzle me why they don't normally log a fault - the engine has both cam and crank sensors - if one is telling you the engine speed is different from the other you should be able to log a fault.

 

[stevesey]

...the output of which can be metered on Pin 13 of the 38pin diagnostic socket.

DM where are you getting you info from? Only page 13 here suggests pin 13 won't work for ME-SFI as fitted to the 112 engine. (But I have found several versions of the 38pin pin-out - this one works for the OBDII on pin4, but I haven't done much with the other pins so it could be wrong.)

 

[Dieselman]

DM where are you getting you info from? Only page 13 here suggests pin 13 won't work for ME-SFI as fitted to the 112 engine.

That very page you mention says...

13: TNA-signal (gasoline, LH-SFI engines)
.....TN-signal (gasoline, HFM-SFI engines)

Pin 13 definitely works on my car for a raw CKP output, all 38 pin sockets have one configuration with additions or deletions as appropriate.

 

[stevesey]

That very page you mention says...

13: TNA-signal (gasoline, LH-SFI engines)
.....TN-signal (gasoline, HFM-SFI engines)

Pin 13 definitely works on my car for a raw CKP output, all 38 pin sockets have one configuration with additions or deletions as appropriate.

After comparision with pin 4 I took that to mean - "petrol LH-SFI" and "petrol HFM-SFI" but not "petrol ME-SFI" (i.e. 240 V6).

However if it works on a diesel it seems likely it will work on all (I'm sure I saved a link to a Mercedes originated pin-out somewhere, but can't find it at present).

 

[w124coupe]

There was a bulletin for that engine re water penetration into the CPS connector - you may have corroded pins in the harness connector into the CPS. Worth a check as a new one might not fix it if the connector is dodgy.

The dealer repair was to solder on a new connector and seal with heat shrink tube.

Re the 38-pin socket, this is from WIS