I have been trying to diagnose a bunch of problems with the way my car runs. Its a 1992 190e 2.3. Poor power, stumbles on acceleration, I was looking at fuel injection but thought I might have a vacuum leak so I bought a vacuum gauge. At idle the needle oscillates rapidly between 10 to 13, I think it should be over 15. It stops oscillating and goes up as you increase speed. Troubleshooting guide says its worn valve stem guides. Can anybody second this opinion, or are there other possibilities??
Thanks

Valve stem seals are a pretty easy job to do. And that would be good for a vehicle as old as yours. So even if you go that route, it's only going to be an improvement. On that vehicle you usually see a lot of blue/white smoke from the exhaust when the seals are bad. Also check the intake gasket and all those confusing vacuum lines and hoses. A quick way to do that is to remove the air cleaner box, idle the engine and spray carb/throttle body cleaner in the suspected areas. If the engine suddenly revv's up, you've found an intake leak.

I've tried to rule out any leaks in lines leaving the manifold including the brake booster. I suppose it could be intake gasket or rubber cover under airmixture control, although I had that off and it looked good, replaced all lines to idle control. I'll try the choke cleaner tomorrow. Interesting though it doesn't smoke at all. Replacing the valve guides would require me to pull the head , wouldn't it?

Thanks

yes.

and you were talking of guides not seals as was thought by the prev poster.

and yes, a vacuum guage can reveal poorly sealing valves. the fluttering is indicative of valve issues. i dont think the seals would have any effect on the vac reading.

and that engine has hydraulic adjusters so you cannot adjust them to solve the problem. i suppose loose guides may cause the valves to rattle around and not seal well.

tom w

__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Yes, thank you. I read too fast sometimes.

Considering that the valve train is prob. the hardest working part of your motor, with extream preassures, forces and high tempreatures, a poor head/head gasket & valves a overhaul would b a good way to go.... though

Suggest though you get a compression test done 1'st! This will give you a referance point to work from, and once any work has been done, you have an empherical and accurate measurement, to compare back to should other issues arrise.

Make sure you get a (cold) dry test and a (operating temp) wet test done. This eliminates the poss. of worn rings, etc, and wiil confirm any vacume readings/take the guess work out of things.

Suggest if you not a mechanical person, who has the requied knowledge AND tools, this is best left for your 'trusty' mechanic/engineering shop. It (the head) will have to go to the engineering shop in anycase, for valve guides to b pressed into the head, the head skimmed, and a good idea is 2 have it pressure & cracked tested at the same time, for not 2 many more dollars..

Have fun,

Keep 'n touch
Graham

we all do that at times.

tom w

__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

good advice. i guess down under an engineering shop is what we in the us call an automotive machine shop.

i enjoy the different usages of english. i read a couple of english car mags frequently and in the haynes repair manuals the differences in our english are there to see and appreciate. in the us we are all about saying things in the fewest words possible. we lose a lot of elegance this way.

tom w

__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Thanks to all who replied. I guess I'll be working up the ambition to pull off the head and take it to a machine shop. At least it's not a V8.