Engine slow to pick-up

[k langdon]

I'm a newbie to the forum.

I have a 1988 (F reg) 300te 4matic. I bought it off a retired gentlemen who in recent years hasn't used it much because of his age and his wife suffering a stroke. The car's always been garaged and serviced at the right mileage intervals, but sometimes there have been long time gaps in the services because the vehicle wasn't used a great deal.

Over the past week, the car has started to become lumpy at idle and when moving off the engine is slow and hesitant to pick up. When it gets going it's fine.

The 72,000 mile service is due shortly. I'm wondering whether the car just needs a good service or if there's something else to be worried about.

Any ideas????

 

[Richard Moakes]

When was it last serviced?

If you don't have any evidence of what is wrong, concentrate on the cheap 'service' items, spark plugs, ht leads, rotor arm, distributor cap and fuel filter.

The M103 engine fitted to your car does not have a perfect smooth idle, it isn't forced and computer controlled like the later M104, so don't expect it to be completely smooth even when everything is working fine.

A real cheapskate fix would be to try some injector cleaner and take it out for a good thrashing, aka an Italian Tune-Up, you might find it helps these old engines, mine seems to really improve with Redex in the tank, but then again it might be psychological :lol:

The slow pickup is probably a fuel or ignition issue, so unless you want a mechanic to check things and diagnose the problem, I would recommend you start slow and cheap in finding what is wrong.

Good Luck and welcome to the family of Benz.

Richard

1989 W124 300E

 

[talbir]

Nice advice from Richard - give it a basic service first, i.e. plugs, air/fuel/oil filters, oil change. Then have it tuned to correct CO/timing with machine hooked up to the XII diagnostic port - this can be done at your local independant tech.

That should solve it. Otherwise it's probably further diagnosis of the fuel injection system - starting with the injectors and idle air control valve.

A few questions :

(1) What's the idle speed at operating temp ?

(2) What's it like on cold starting ? Does it take ages to start and get warmed up or is it quick fire start ?

Also agree with Richard on the injector treatment method - try something a little stronger than Redex, like STP injection system cleaner available from Halfords. IT costs about 12 pounds. Pour it into half a tank of fuel and then go for a few long drives on the motorway. These elixirs are effective - you'll see the gunge coming out of the exhaust if you rev the engine hard...lots of black soot pouring out the back. A shot of redex each time you fuel up is good too.

I have to disagree on the M103 not being smooth idle - my 300SE idles creamy smooth....JUST as smooth as the M104 in my 1997 S320.

 

[Richard Moakes]

Talibir,

Smooth is relative

I also have a rotary powered RX7, and you can balance coins on that engine :wink:

....and my father's E320 is definitely smoother, it doesn't 'fluff' every so often if you know what I mean.

Cheers,

Richard

 

[k langdon]

Thanks for the replies Richard and Talbir.

In response to both of your questions.

The car was last serviced about 5700 miles ago, but that was in 1999!!
So, I think this might be the crux of the problem.

The engine starts from cold on either the first or sometimes the second turn of the key.

When the engine's warm, it'll idle at around 6-650 rpm. This is a bit lower than other cars I've owned. Is this normal??

Looking through Yellow Pages, there doesn't appear to be much choice in the way of independent specialists.

Does anybody know of any in the Bristol area??

 

[Richard Moakes]

Sounds like it needs a good conventional service and general health check.

It would be worth booking a day trip to Birmingham and visiting Andy at www.mercedesservicing.com

Mine idles at about that speed, sometimes I think that is part of the problem, with the slightly wobbly idle, an extra 50rpm could make all the difference.

Saying all of that, mine has just had two new fuel pumps, which have made a tremendous difference to starting and idle smoothness.

Take it Andy, and let him give it a full service, it will need new brake fluid and all the other things which should be done every three years or so.

Regards,

Richard

1989 W124 300E

 

[k langdon]

Thanks Richard.

I was thinking of driving up to see Andy as this site seems to highly recommend his work. The only problem is this month I'm unable to get up to Birmingham for a whole day because of work committments.

I see from you're posting you live in Devon, do you travel up to Brum yourself and, if so, do you find it worthwhile?

 

[k langdon]

Hi Richard, thanks for the advice.

I'm thinking of driving up to Birmingham to see Andy Gale, but unfortunately work committments mean I'm unable to get there until next month.

From your posting, I see that you live in Devon. Do you travel up to Brum yourself for maintenence/servicing work and, if you do, have you been pleased with the results?

 

[Richard Moakes]

I do most of the simpler work myself, I consider myself to be a decent amateur mechanic with a fairly extensive set of tools.

Every now and again I let my local independant in Plymouth have a go at the car, perhaps because the job looks too difficult, or perhaps I am feeling lazy at the time :lol: I want to make sure he is still in business for when I REALLY need his help.

I haven't had the pleasure of visiting Andy, but the general consensus on this board is that he is the place to go, and any professional who is willing to help amateurs with questions is an ok guy by me.

Cheers,

Richard

 

[Andy]

Hi all


Thanks for the vote of confidence.

K Langdon. I would try a distributor cap. Nothing but Bosch, otherwise you will buy trouble on your self.Also replace the rubber seal around the cap. Sorry should of mentioned the rotor arm as well. If you have a ohm meter check the resistances firts. Otherwise its a trip to a specialist. Or the dreaded stealership.


Regards

Andy @ www.mercedesservicing.com