help rather strange problem

[ade666]

hi all. rather strange problem with my 300 tdi.the engine just  stopped this afternoon. thought i'd snapped the dreaded but a little turn of the key and it made an attempt to start. so popped the bonnet made sure everything was in its place sprayed every thing with  wd40 includine the altenator. turn the key and it started for a second or 2. so took off fan belt and it started and ran. all the pully things spin ok.  any ideas as i'm out of them. it happened on a previous engine which we found out was a siezed alt. but it spins free with the belt off


please help

[beast5680]

so it was running but stopped... now it wont start and run but if you remove the fan belt it runs?

[ade666]

yep thats it. its the strangest thing. i wondered if the tensioner has got too tight but its hard to test this out

[hobbit]

Crack the injector pipes to the injectors, see if you get a flow of spurts of fuel out of them, may be restricted flow, fuel filter, re-bleed

Fuel cut off solenoid feed wire, the list is endless

[beast5680]

tensioner shouldnt stop it running though :? something must be stopping it running, does it turn over with the belt on? not something like the steering pump seized although that only drives on the back edge of the belt does it sound like a problem where the engine is struggling to turn over or is it suddenly being cut out like with an electrical problem? or fuel problem?

[EvilEd]

Does the fan belt run the Alt on a Disco? maybe the regulator has gone on the alt and it's a safety feature to shutdown the engine rather than fry the electrics? Check the Alt output (14.4 - 14.8v roughly on most of them)

Bearings may have collapsed and only bind under pressure (Belt tension) any of the bits really. On the Alt, there's usually two bearings, front and back, if the back one has collapsed, it may not be as obvious!

EE

[ade666]

with the belt off it turns over and fires staraight away so don't think its fuel. all the pullys that the belt goes round turn fine by hand again with the belt off thats what made me think it could be the tensioner.

[bullfrog]

Check the lift pump ! Had this on my 300 . New pump all sorted ! :D

[Mace]

OK. It's 11pm and I've had a JD or two so my guess is you've got a dodgy solder joint on your impobbilizer.  :lol: No, I'm being serious. If it cut out on you for no apparent reason, started then stopped it could very well be the spider thingumy. Hick !

[ade666]

hi bullfrog would a cream crackered lift pump stop it turning over. its the belt off thing that confuses me it starts no problem at all

[forkarm]

I would agree with Mace.Removing the belt just gave the immobilizer time to cool down and start the engine again.Have you tried putting the belt back on and starting the engine ? Try putting a live feed from the battery straight to the stop selonoid on the pump and if it starts ok then it is sure to be the immobilizer(spider)
good luck  :)

[bullfrog]

Ah yes , No it would not. Check earths and relay in dash as this will "freeze" an engine one minute and free it up the next.

[ade666]

not sure if the 94 model has an immob. looks like i'll have to take my laptop and rave cd to work and try earths etc.... is there any way i can tell if the alt has a creamed bearing. thinking back to just before it died i did notice the rev counter bobbing up and down at tick over its normally rock steady

[Mace]

OK I'm sober now. I can't see how a seized alternator would stop your engine. It'll just rip the fan belt off. If the engines got enough power to get 2 tonnes up a 45 deg incline it'll not stop for a piddly alternator bearing.

Your 94 300 will have an imobilizer. It's hidden in the dash behind the Radio. When mine went all I did was take the box apart and gently resolder the pins on the circuit board. It's not stopped since.

I can give you a few pointers if your like but I'd hazzard a guess that anything to do with the belts or alternator at the front is just coincidence and you're barking up the wrong tree.

[Damonski]

This be the one: http://homepage.ntlworld.com/stage1v8/TechnicalSpider.htm

[Wanderer]

It could be that the alternator is outputting AC instead of DC and that's affecting the immobiliser circuit.

Guessing but I'd check the alternator first.

Ed

[ade666]

thanks for all the input guys. well fiddled about with it today and noticed that the cast marks on the tensioner was well past where it should be so eased it up and try starting. fired and ran straight away. when i eased it off the belt squeeled and stalled the engine, got wrong replacement belt so will have another go tommorrow

[ade666]

well got new belt on and after a quick jump start it ran, well when i say ran the alt was making a rather horrible grinding noise so 10 points to evil ed. new alt on way from paddocks and hopefully all will be well

[davidlandy]

dodgy wire to the stop solenoid ????