1992 300TE Replaced the alternator-cuts out

[todd]

I'm a new member so my knowledge is low!
After breaking down i had the alternator replaced. Mechanic couldn't get it to run-disabled the demobiliser and it started fine. Mechanic backed it up,forward,back - dies. Turns over first time, soon as it gets to 2000revs it dies. There's a small rattle at the same time, somewhere down in the exhaust area between engine and driver.
The garage is a small country one and they don't see many mercs.
The cars a sportline version and its done 180,000m, prior to this it ran like a dream. It had some flood damage to the electrics last year.
I need to find an answer fast as we live in the country and we need both cars to taxi the kids around! My wife drives it just now, too thirsty for my job - if it doesn't get fixed soon its got to go! help.

 

[Stevie A]

Catalytic converter broken?? So ratttles?? I have read of this but not 100% sure. Others will know.

 

[todd]

Yeah i read about that today on these pages. The mechanic says that it could be, but how much money do you want to throw at the problem.
The other thing is that i could hear the fuel pump quite clearly which made me think it could be the fuel pump relay?

 

[Stevie A]

I don't know this model - but if you can hear the fuel pump then that means the pump is working. If you hear the pump a lot on a Merc at idle then the fuel filter needs replaced.

Get your cat checked first. I don't know how to check cat??

How do you check catalytic converter - experts please help?

 

[Sprint'n'Go]

Did you have a flat battery and try to tow/bump start the car? cats can get very upset about things like that which would explain how a faulty alternator could develop into a failed cat.

 

[todd]

Exactly what happened. Alternator went and had to get it towed in.The more i read about this the more it seems like that darned cat!

 

[todd]

Ok, i've tried fuel pump relay and ovp-no go. Trouble is i don't have an excess of ££s to throw at this problem. the car just passed its mot 2 weeks ago-only needed a tyre! If i throw any more money it'll be more than i bought the car for-shame, but i think i'm about to become an ex mercman.

 

[Stevie A]

Get the catalytic converter checked then decide what to do. The fact that the car only needed a tyre for MOT is a good reason to keep it.

 

[homer dog]

bite the bullet and get a specialist to check it out. lets face it, you wouldn't get rid of it if the cat had just needed replacing, the fact that it's an unexplained prob is what's causing the sweats. besides, you love it really. don't you?

 

[Sprint'n'Go]

I have no experience when it comes to cats as luckily the few petrol cars I have owned have been ok but I would try this if it were my car.

Remove cat.
Shake/prod/probe the open ends to see what comes out(only if the insides are rattling) as there have been mentions in other threads of broken bits of cat blocking exhaust.
Put it back together and see what happens, if all is well run it to the next MOT and see what turns up in the meantime.

It may well pass the MOT without a cat as from memory, 1992 was around the deadline for cars having to have a cat. Many people have replaced cats with straight through pipes.

NICE CHEAP SOLUTION

 

[todd]

Well, tried the cat and its ok. run out of ideas. can't afford transportation to the merc specialists 100miles away...and now the end is near.. oh lord won't you buy me a mercedes benz!! indeed.

 

[jberks]

Dying at 2k sounds a lot like an ECU/sensor issue.
The only time (twice) I've seen a car die in this way it has been a leak between the MAS sensor and the air intake. Once with a loose pipe and once after an accident where the air filter box had been smashed. The car looked fine, started and idled fine but as soon as you gave it any revs, it sounded and felt like fuel starvation. The MAS has told the ECU that there is no air coming in so it doesn't supply any fuel either.

I mention this as I assume the car has been dismantled to some extent in order to fit the alternator. Its quite normal to remove the air filter to gain better access. I suspect the pipework simply hasn't been reassembled properly, perhaps a perished pipe not fitting properly or the MAS not being re-attached correctly ...

 

[Stevie A]

Todd - I agree with Jberks. Do another post describing exact symptoms and some other suggestions to help may come up from people who know this model.

 

[television]

I don't know if I can find something, your car is it after Sept 92 or before or what are the first 3 numbers after 124 on the VIN.


Malcolm

 

[todd]

Cheers guys, the 3 numbers after 124 are:090

 

[todd]

the thing that still concerns the mechanic is the rattle? he thinks its to do with the transmission. Car tries to move then stalls-restarts straight away.