I give up ! - PeachParts Mercedes-Benz Forum

drbrandini · #1 10-07-2002, 07:57 PM

I have tried everything I know and Sadie is still lacking power. When starting from a stop I can floor it and she barely moves sometimes I have to hit the kickdown switch just to get it going as to keep-up with traffic. Once I get going she seems fine. Every now and then I have a hesitation when starting off, but usually she is just lacking power. I have replaced: spark plugs with bosch non-resister type (cant remeber part#), Dist. cap, rotor button, and fuel filter. If there were a trust worthy mechanic in town I will be willing to take her in. I guess I am gonna start looking for one, or pay the price at the local dealership. Any Ideas?

P.S. Remeber I am a broke college Kid (this isn't helping the matter either).

Cap'n Carageous · #2 10-07-2002, 08:34 PM

Is it starting off in the right gear? When my 300 trans was working correctly it felt like it had way more horses than it was rated, and when I made it start in first gear it would snap your neck!

drbrandini · #3 10-07-2002, 08:50 PM

captain,

Thanks for the reply,
I thought of that too, I tried starting in 2 gear the other day. It was noticeably different.. Any other Ideas? you had a hesitation problem not long ago... What did the culprit turn out to be?

Thanks,

Gilly · #4 10-07-2002, 09:05 PM

Sounds like possibly the throttle valve cable (the one from the throttle linkage that goes to the right side of the transmission) is either disconnected or misadjusted.

Gilly

drbrandini · #5 10-07-2002, 09:12 PM

Gilly,
Thanks I will check it out in the A.M., I'll let you guys no what I find.

Thanks again

PS How can I tell if it is misadjusted?

Gilly · #6 10-07-2002, 09:22 PM

First see if it's disconnected. Can you take off the aircleaner assembly (not the filter element, the whole thing)?
The caple has like an orange rubber corrugated covering that keeps out water and dirt. There is a rounded socket on the end of the cable, it snaps onto a steel ball that's on the throttle pivot.
It should fit onto the ball without tension, that's how you know if the basic adjustment is correct. Minor adjustments are OK to make. If it's connected, you can try tightening up slightly by backing off the adjuster a turn or two using a 13mm open end wrench.
If it isn't connected (I've seen this a couple of times) snap the socket back on to the ball, you may be able to do this by hand.

Gilly

drbrandini · #7 10-07-2002, 09:32 PM

Quote:

Can you take off the aircleaner assembly (not the filter element, the whole thing)?

Most definately, I will check that out.. Thanks

I think I will try to test the O2 sensor also, just realized I have never replaced it in the 40,000 miles that I have owned the car. There's no telling how old it is!

Thanks again,

#8 10-07-2002, 10:09 PM

Roy Fields mercedes up here in MD would save you money as upposed to the dealer. You may be able to work something out with them. The have expert mb techs no doubt. Call 1st, 410-527-1010 tell um Keith with the mb diesel sent you.

drbrandini · #9 10-09-2002, 07:49 AM

Tank,
Thanks for the help.

Gilly,
I inspected the throttle valve cable and appears to be connected and functioning properly. Upon a more thorough investingation yesterday, it seems as though the problem is only present in the lower gears. as the speed gets up the power kinda pops in and out by way of hesitation until I reach my cruising speed. Some times the problem is more immanent than other times. The car really doesn't filling like it is missing it feels more like it is gasping for fuel.

Thanks again,

jsmith · #10 10-09-2002, 09:46 AM

how does it feel when you shift it manually? that should give you a better feel on whether the tranny is acting up or if it's really an engine problem....

pentoman · #11 10-09-2002, 10:16 AM

This might've been suggested before in another of your threads, but perhaps your overrun shutoff switch is sticking. It's the switch that's activated when the throttle is completely released, and will limit the amount of fuel you're getting like you say.

Put a meter on it and test it's output as you switch it if you can. I believe it gives infinite resistance and no resistance, or therabouts.

Only takes 5 minutes to do, and nice to know if it's working - it helps fuel consumption.

later!

drbrandini · #12 10-09-2002, 10:43 AM

jssmith,

Been there done that it is deffinately an engine problem

Pentoman,

Thanks that helps I will test that asap. Can I test it with a regular voltmeter? Could you go into more detail on how to test?

Thanks again guys

#13 10-09-2002, 03:08 PM

If the overrun protection switch is bad wouldn't this happen regardless of whether the car is in gear? Sorry if this has already been addressed but what happens in neutral throughout the engine rpms? Is it only when the trans is engaged. How about under load or no load- uphill/downhill?

drbrandini · #14 10-09-2002, 03:19 PM

Tank,
Thanks for your reply.I have noticed a small hesitation when in park, but it is more noticeable under driving conditions. I know that my car will need a valve job in the near future. I have a valve tic at low oil pressure and sometimes far a few moments after starting off at high oil pressure. Could this be my problem? Is it time to suck-it up and have the valve job done? I hope not .......sigh

Thanks to all for the help

#15 10-09-2002, 04:11 PM

Brandon;
Your post said power seemed normal at higher R.P.M.s and that the trans is starting off in first gear.
An often overlooked cause for poor take off is the torque converter,on take off the stator turns and the converter acts as a torque converter acts as a torque multiplier,as engine speed and input shaft speeds equalize the stator locks up on a one way roller and the converter acts as a hydraulic coupling.
A bad torque converter will cause poor take off acceleration but will drive normally .
Have a good trans. tech. road test the car!
M.F.