300d 1996 cranks won't start :-/

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myoldmerc

Member
Joined
Nov 11, 2015
Messages
31
Car
W201
Hello Peeps

Maybe this won't be a mystery to you bright sparks... but... my 96 300D was getting a bit grumpy upon start up. Upon advice I asked my local mechanic to fit new glow plugs while I was away on holiday. This he did. However the car cranks but simply will not start. It won't even try to cough and splutter, no smoke from the exhaust so I'm thinking no fuel is getting through. I changed the main fuel filter [which was full of clean fuel and filled the new one before fitting it]. No change... The mechanic is puzzled as started the car when he collected it and said it started as it should with the new glowplugs before he drove it back. Apart from the lazy starting the car was fine until this. It's done 125,000 miles.

By coincidence the remote has failed, I changed the batteries and still it won't lock or unlock the car. The remote doesn't seem to be transmitting anything [if I aim it at a digital camera no light can be seen when pressing the button]. I'm not overly bothered by this as long as that might not be the culprit...

If it is does anyone know whether the fuel cut off is pneumatic like older models or might this be electronic? I'm thinking a simple ON / Off switch might be a cheap solution if electrically switched....
Any advice greatly appreciated!
 
These have the push fit fuel pipes with O rings that age and let in air.

The shut off is electronic, although the O ring seal on this fails too.
Bit fiddly but take off the 2 torx set screws, pull it forward and you can replace the O ring.
 
Thank you for your response, I've had drain-back with other motors when parked on a hill, however the old girl is perfectly level. Good call re Easy-start, I might try shooting some WD40 down her, reckon it does less damage! Thanks again, much appreciated
 
Thank you for your response. Although I've not loosened an injector pipe I'm convinced there's absolutely zero juice getting through. She got a new battery, spins over nice and quick and usually starts firing immediately. Now not even a hint of a cough and no smoke from the exhaust......

You're right though, that is a sensible thing to do and I will when this damn rain stops!

if it's got **** or wheels.....
 
Thank you for your response. My other motor is an old 190D, none of this push-fit pipe and electronic nonsense....

OK, so she has an electronic fuel valve... is that an easy thing to identify would you know please or simply the only thing held on the pump by 2 x torx? Noted too regarding O rings. Thanks again!
 
OK, so she has an electronic fuel valve... is that an easy thing to identify would you know please or simply the only thing held on the pump by 2 x torx? Noted too regarding O rings. Thanks again!

Your engine still has the old style vacuum stop valve, it's fed by the brown plastic vac line coming from the passengers side inner wing.
 
Thank you for your response. Although I've not loosened an injector pipe I'm convinced there's absolutely zero juice getting through. She got a new battery, spins over nice and quick and usually starts firing immediately. Now not even a hint of a cough and no smoke from the exhaust......

You're right though, that is a sensible thing to do and I will when this damn rain stops!

if it's got **** or wheels.....

Do you have fuel in the clear plastic lines?

Loosen all 6 injector lines at the injector end and crank her over, crank for 30 secs then let the starter cool. Repeat till you have fuel at all 6, then she should start.

Once it's running see if the air bubbles in the clear plastic lines around the pump and fuel filter clear, and check if the top of the injection pump is damp with fuel.
 
Your engine still has the old style vacuum stop valve, it's fed by the brown plastic vac line coming from the passengers side inner wing.

Ah, thank you, when it stops tipping down with rain I'll have it to bits... So, [like the older models] is there a manual STOP lever on the pump too?

Thanks again!
 
Ah, thank you, when it stops tipping down with rain I'll have it to bits... So, [like the older models] is there a manual STOP lever on the pump too?

Thanks again!

No, they removed that. You should have a screw type shutoff valve on top of the fuel filter housing.
 
Thank you, much appreciated.... still raining... but eager to sort this out! Will post the result!
 
So far...

Inbetween downpours...

Loosened the injectors, cranked away for all too long and zero fuel at the unions. So removed inlet manifold for bette access to the pump. Now please bear in mind a few points chaps.

I have no option other to be a tight-fisted bodger so going to a Main Stealer alas just won't happen. Key fob has decided to not work, tried new batteries, nothing shows if viewed via digital camera and I have no intention of forking out bundles on a new un.

Looking through MB forums it seems that a few of these motors will turn over but not start perhaps due to key-fob / immobiliser probs. When I tried earlier, [and for the first time during this fault] the light on the mirror were flashing like mad.

So... if it seems like the fuel isn't being allowed to pass due to said immobiliser my only hope is to re-plumb and or bypass and or separately energise the fuel solenoid and or fit a remote one. That's right up my street if I knew what was what on this [for me] late and complicated motor]!

Hopefully the image I've attached will show up.

Would some knowledgeable kind reader please tell me which pipe is juice into the pump, [ A or B], whether [C] is the fuel solenoid. For what it's worth with the ignition on the most voltage I could get out of plug [D] was 2.3 from one pair and 5 volts from another.

Happy daze..... and thank you
 

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Inbetween downpours...

Loosened the injectors, cranked away for all too long and zero fuel at the unions. So removed inlet manifold for bette access to the pump. Now please bear in mind a few points chaps.

I have no option other to be a tight-fisted bodger so going to a Main Stealer alas just won't happen. Key fob has decided to not work, tried new batteries, nothing shows if viewed via digital camera and I have no intention of forking out bundles on a new un.

Looking through MB forums it seems that a few of these motors will turn over but not start perhaps due to key-fob / immobiliser probs. When I tried earlier, [and for the first time during this fault] the light on the mirror were flashing like mad.

So... if it seems like the fuel isn't being allowed to pass due to said immobiliser my only hope is to re-plumb and or bypass and or separately energise the fuel solenoid and or fit a remote one. That's right up my street if I knew what was what on this [for me] late and complicated motor]!

Hopefully the image I've attached will show up.

Would some knowledgeable kind reader please tell me which pipe is juice into the pump, [ A or B], whether [C] is the fuel solenoid. For what it's worth with the ignition on the most voltage I could get out of plug [D] was 2.3 from one pair and 5 volts from another.

Happy daze..... and thank you

Ok now I'm confused, do you have a w124 or a w210? The picture you've posted is from a w210 but your asking about a 300d?
 
Ok now I'm confused, do you have a w124 or a w210? The picture you've posted is from a w210 but your asking about a 300d?

Sorry, this is 'er indoors' car and hitherto all I've done is change oil and filters not taking much notice of it always driving vans myself. 6 cylinder diesel 1996, - that's for sure... Apologies for being more daft than you'd perhaps expect...
 

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Sorted... but don't ask me how...

OK so we had no fuel at the pump and after a strange red / green lightshow finale, new batteries in the key fob [that still isn't transmitting] we had a non-starting e300d facing the scrappers as it was looking like an unfathomable [to me] immobiliser problem...

With the ignition on I had no power to fuel cut off although she'd turn over. Removed the manifolds and the fuel cut off and flashed a weak 12 volt battery across the pins until I found a pair that made it click so knew it worked. I checked all of the fuses I could find and then found there was power to the fuel shut off. Still wouldn't start.... cracked open fuel pipe unions and eventually got fuel up and eventually she started.

Whilst at it [having seen the large amount of gunk in the manifolds] I removed and blanked off the egr and spent many many hours de-gunking. Car now running nicely. According to some threads I should have got some ECU problems with the egr gone but no, [well not after a quick blast round after putting it all back together]. So as I speak 'er indoors' is a happy bunny with her car back and I'm off the hook.....
 
hope you cleaned the pre-filter out too aswell as the intank strainer.

you need to make sure there is no air in the fuel lines and draw back to the tank

replace the orings on the clear pipes; there is a kit on eBay

your picture also shows a very wet pump. suggest your delivery valve seals are shot.
 
Sorted

hope you cleaned the pre-filter out too aswell as the intank strainer.

you need to make sure there is no air in the fuel lines and draw back to the tank

replace the orings on the clear pipes; there is a kit on eBay

your picture also shows a very wet pump. suggest your delivery valve seals are shot.

Your suggestions are very wise and I'm grateful for them. I've not done those things as I endured days in pouring rain sorting this out and need to not see a spanner or be wet through for a wee while! I have seen what can only be described as grease in a Merc tank strainer so when I can get the car under cover I'll go through your list. Drove some 30 miles today and the car is starting and driving very well, - oh that heater, so damn good compared to my vans....


'Er indoors' has yet to show her appreciation to have her car up and running again although and perhaps I should be grateful for the cessation of nagging....

So thank you all for your sound advice and pointers, it's nice to have support out there.
 

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