Hi all,


I recently started using my 1990 Mercedes Benz 300E w/89K. I
purchased it 7 years ago because it was in mint shape and was a good deal.
The car had basically been in storage for the last 7 years. I used it for
an average 100 miles per year bring it in and out of the garage a only few
times a year. I changed the oil yearly and kept the gas fresh too. It was in mint shape when I bought it.....the previous owner was very meticulous.


The car ran great for about 2 thousand miles but last week I noticed
the transmission is occasionally revving before shifting in the upper
gears. I changed the transmission filter and fluid but the issue still
exists. I also changed the fuel filter. Any suggestions, I was going to take it to my local transmission shop for an evaluation so I wanted any thoughts on the problem. Are there any simple adjustments on this transmission?

The car did have the head gasket changed by Mercedes along with a
conversion to R134 air conditioning. Other than that it had regular
maintenance.

Any other thoughts on what to look out for this model and year would
be greatly appreciated.

Another issue that leads me away from the transmission and toward vacuum fuel issue is:

When I first start the car cold it idles fine. After it gets hot and I attempt
to start it up again the idle pulsates very high to very low rpms (1200 to 400)
before it settles within a minute to the normal 600 rpms. Hopefully someone
recognizes that symptom too!!!

If it turns out that the automatic transmission needs replacing, what
is the price range I should be looking to pay, I live in the suburbs of New
York City where the cost of living is pretty high.


Thanks


Bob

Hi diesel 1,
You need to drive that car like you stole it.Mercedes cars were not designed to be pampered,they were made to be driven.I have a 190 2.6 and I drove the hell out of it on a 300 mile trip and she never missed a beat. Just find a highway that you can run at least 70mph for about two hrs non stop and that shoud clear out all the cobwebs out of the car.

Funny that you say that. On my most recent thread titled 2 valve bodies, I explain that I took a valve body from a 300E and put it in my 190E. I experienced the same exact problems as OP and I ended up needing to take a trip and dodd 70-75mph and the symptom cleared up. However it returned the next start up :-( Keep us posted on this issue.

__________________

1990 190E 3.0L

I gave the vehicle a good 500 mile highway trip to Vermont at 75-85 miles per hour prior to my post. The problem was still there.

The variable idle does point towards vacuum. Need to check the modulator for leakage. if it is leaking, it can cause the extremely soft shifts.

1st Modulator
2nd cracked and leaking vacuum connectors (from the sitting)
3rd k1 and k2 spring kits (firm up the shifts) You could also get the superior shift kit with tons of springs
4th Internal tranny issues

This is the order in which I would work on slipping 2-3 3-4

At that mileage I doubt your clutches have worn out, slipping due to other issues will speed up the wear and fill your fluid with clutch material which is hard on seals, clog the filter ect.

__________________

77' 300D, "Cartman" SOLD @ 150K (didn't know what I had)
83' 300SD, "The Superdon" 325k+ @ 28mpg
95 E320 wagon, "Millennium Falcon" 231k+ @ 24 Mpg
95 E300D, "Sherley" 308k @ 33.69 Mpg, currently anticipating a head
99 Suzuki Intruder "Trudy" @ 45 mpg

Hi Guys,

Just a follow up on my progress so far on my acceleration issue. It turns out that the transmission is good. I went to a reputable transmission shop and he said the transmission was fine and it was probably a fuel or vacuum issue. There is fuel startvation at times during acceleration, mostly hard acceleration. I press the accelerator and there is a sort of "dead period" when here is no response then suddenly it lurches forward sort of a "kick down" response.

I was unable to find a vacuum leak, so far I replaced the following parts and the problem still exists:

- fuel filter
- 2 fuel pumps
- coolant temperature sensor
- O2 sensor

The plugs, distributor cap, wires and rotor were previously changes last year.

I know I am just throwing parts at the problem but hopefully the next step changing the fuel injectors or fuel distributor will solve the problem.

Any new thoughts while I await the order of new parts to arrive!


Bob

I'm having the same issue with a190e 2.6. On a cold start idle is fine. If I stop and restart when warm, idle bobs up and down from 400-1200 rpm. Ocassionally no response from the gas pedal, always when warm. I have to floor it a.d it sorta slowly catches.

Haven't figured it out yet.

If it is a fuel issue and assuming your vacuum lines are OK or replaced & vacuum modulator is ok. You need to check & adjust or replace your e.h.a

I had many issues similar to yours on my 300sel even after driving hard and using fuel additives. I ended up adjusting the E.H.A and lambda (very delicate procedure). I adjusted it because I did not have $300 at the time and it was not leaking either (they usually leak somehow eventually)

__________________
2001 E55

2001 E320 Sedan

2001 Subaru Legacy

2006 SLK280

2016 Subaru Outback 3.6

I replaced my eha with a new (used) one that isn't leaking. The car starts easier now and runs a little smoother, but the other issues didn't go away. I have not rechecked the lambda after changing the eha.

I've been doing some research and I'm suspecting the fuel pressure regulator. I'm going to test as described here:

Pelican Technical Article: Mercedes Benz - Fuel Pressure Regulator Replacement

I just picked up a master fuel injection test kit from hf. Hoping I can get to this on the weekend. I'll take pics of the testing when I get there. I'm planning to test inline with the fuel filter to get pre-fpr. Then another test on the fuel distributer to get post fpr pressure.

I'd just throw the part at it, but not with a $250+ part.

Hi Guys,

I still have an issue with rough idle and hesitation during acceleration on my 1990 300E w/90K that I haven't been able to fix. So far I replaced the fuel filter, fuel pumps, oxygen sensor, coolant temperature sensor,and EHA valve.......problem still there!

My latest part swap is a rebuilt fuel distributor. After installing it a few hours ago the car now runs very rough and stalls (worse than before). I read that there are some adjustments that have to be done on fuel distributors. I don't have any special tools so I might have to take the car to a shop that deals in older Mercedes. I can't seem to get it to run enough to get it to the shop.

Does anyone know how to jump or bridge the relay to adjust the fuel flow to the fuel distributor? Books say to jump pins #7 & 8 on the fuel pump relay but this car does not have one, it has a MAS relay.

Any help or suggestions to get the car going would be greatly appreciated. I would hate to put back the old distributor to get it to a shop.

Thanks,

Bob

I haven't had a chance to test the fuel system because I found a more pressing issue. I noticed coolant and oil mixed in the breather tube that goes from the valve cover to air box. I've been focusing on a head rebuild.

I cleaned/lubed the linkage which did fix some of the high idle problems, and it has stayed fixed. I used crc-26 on the linkage, and cleaned up the microswitch with electronic cleaner spray. I replaced the coil with a tpi coil, and replaced the spark plugs with non-resistor plugs. This has helped with the hesitation, but it still has some bogging issue when taking off from a stop. It is not as pronounced as it was, but the issue is still there.

I assume if you replaced the FD you readjusted the air/fuel mix?

You make no mention about your fuel injectors. Have they been cleaned or replaced?

__________________
Eugene

10 E63 AMG
93 300te 4matic
07 BMW X3
14 Ford F-150 Fx2

I was able to start the car this morning and let it run for 10 minutes hoping that would get some air out of the fuel system. That was a suggestion in the instructions from the fuel distributor rebuilder.

After a few minutes I saw there was an excessive amount of unburnt gas coming out of the exhaust and under the exhaust itself. When I tried to accelerate it immediately stalled out. Being a safety issue are there any adjustments to correct that or should I have to get it towed to a shop? The gas did a job on my new sealed driveway in a short period of time.....it was that much getting through.



Bob