1993 300TE Engine hesitation
 

I am about to take my mercedes to remedy the problem. The car hesitates when accelerating from full stop as well as while moving. Sometimes going through the gears helps the performance. Very dangerous to merge into on-going traffic. It was recommended that I have the wiring replaced and check/replace plugs. The rubber wears out over time or so I am told. Only 38000 miles. Any thoughts or suggestions? Thanks

similar problem
 

I have a '97 E300 (non-turbo diesel) with a similar response. It doesn't happen often, but there are times when either from a stop or slow speed, there is a momentary lull in the acceleration. It doesn't last long but feels like 3 1/2 minutes when turning in front of oncoming traffic. I look forward to the input from the MB pros that know this kind of stuff.

More on 93 300TE hesitation
 

Having made a more thorough search of related postings, it seems the areas to focus on are as follows: ignition coil, distributor cap/rotor, overvoltage relay, new plugs, spark wires, fuel distributor (?), and vacuum lines. Once I am up and running, it is quite smooth. I thought it might have been some bad gas but have replaced and still have same problem. Feels as though not all the pistons are sparking together.
Hope to have some additional input from the experts. Please.

Strange, I was going to make a post here today for the same problem.....my spark plugs are recent. And for some reason I dont think the problem is coming from the dist. cap or rotor button, but it looks as though I may end-up changing them. I am looking forward to a response also!

If it were my car I would run at least one bottle of Techron or similiar quality fuel injector cleaner through the system.

My 95' 320E does this. I have found if I drive it under hard acceleration (when properly warmed up) the condition goes away.

J

Bought Techron
 

I did go out and purchase the fuel injector cleaner so will see if it makes any difference. Thanks.

Ive heard that replacing the air mass meter (mass air flow sensor?) fixes these hesitation problems.

Isn't your car prone to the infamous Wiring Harness failure!? Do a search!

I've been reading the posts and noticed the following:

1. You have the same 3.2 liter M104 engine as in Haasman's 95 E320, which is also very similar to the 2.8 liter version in Dave C Klasse's 95 C280.

2. Memphis10c has a diesel model, so there are surely no similarities with his problem and yours.

3. drbrandini has the 3.0 liter M103 engine in his car, and these engines are very different, have different fuel injection systems, etc. Your idle is controlled electronically, his is mainly mechanical with electrical help (from what I understand from Stevebfl's posts).

Do a search on M104 hestitation and see what comes up.

I know from experience with my car and reading many posts here, the obvious things to check with this problem and M104 engines are:
1. the engine wiring harness. They were bad from 93-95, and if yours hasn't been replaced, do it now.
2. spark plug wire resistor ends. On M104 engines, these are very frequent causes of idle problems, missing, and hesitation under load. The spark plug wires on these engines very very rarely go bad. It is always the end or boot of the wires. These engines use 3 coil wires and 3 spark plug wires. Each coil is responsible for two cylinders. It is usually a bad connection of the boot on a coil wire that causes the miss. If it's not your engine wiring harness, my bet is that it's this.
4. Mass airflow sensors can cause idle fluctuation problems, but my guess is it is not your problem.
5. Throttle actuators can cause this problem. The wire harnesses also go bad on these units. Stevebfl has also said the throttle actuators have potentiometers in them that also go bad or wear out. Usual signs that these are going out is your cruise control starts to go out, your idle will fluctuate up and down rapidly at idle, or under acceleration your pedal will be very sluggish. My best (uneducated) guess is that it's not your throttle actuator.
6. Your problem could also be fuel supply or fuel pressure related. Check your fuel pressure relief valve, fuel accumulator, fuel filters. You also have two fuel pumps, but they rarely go out.


Just my .02 cents. Hope it helps. The best thing about my advise is that it's free! No charge to the reader.:D ;) :cool: :)

I just also noticed that you're confusing engines again.

Your engine, 3.2 liter M104, does not have a distributor cap and rotor. I don't know the proper term, but you have what I call a 'coil pack' that controls the spark. I've never even heard that these go out.
M103 engines have a dist cap and rotor.

The following models share your engine, or a similar version of it:
93 300E / 94-95 E320 (W124 chasis)
93 300E 2.8 (W124 chasis)
96-97 E320 (W210 chasis)
93-97 C280 (W202 chasis)
92-99 S320 (W140 chasis)

follow-up on 93 300TE
 

I brought the car into a bosche authorized center and was informed that there was no distributor cap or rotor. Obviously, I am a novice at this. As you have stated, it is all electronic. It appears that he is planning to replace some wiring, the sparks have never been changed. So I should have some follow-up later today or tomorrow. Thank you all for providing your insights into my problem. This has certainly been informative.

Results of servicing
 

As you all mentioned, I asked the shop to check a number of the items, in particular the wiring harness. By the way, the engine is a 3.2 liter ohc 6-cylinder. To my delight, the wiring all checked out fine. Sparks were replaced, oil fliter, and engine tuning. That seems to have done the trick. I will drive next couple of days to see whether anything changes. Since there were no lights on indicating some failure, it appears the remedy was pretty straightforward.

Don't know if I mentioned, but the car had sat a week at local MB dealer without anyone looking at it so I pulled it out to have work done with the bosche authorized service shop. Where's that focus on service? Anyway, thanks to all. Hope I am not back for awhile.