So I bought a 1991 190E 2.6 with 151,000 miles and it was overheating. I put a new head gasket in and got the head shaved. I got it all back together today and now it has the hardest time starting cold! And then once its running and warmed up it seems to limp along. Doesn't run smooth, seems weak, poor throttle control. The good news is that the overheating seems to have stopped. Also since putting it all back together the ABS light is on AND my new stereo no longer works. My main concern is the hard starting and poor running. Any ideas?

 

Since the head was shaved apparently the overheating was consistent enough and extreme enough to warp the head. Simple conclusion: block is also warped.

I think ABS and radio are unrelated. Probably a fuse. Replace the fuses for $2 a set and check. Also give all leads, hoses and fittings under the bonnet the tug and look test.
If you want to go through all the cheaper alternatives before committing to a block shaving or engine change, check plugs, spark leads, rotor, dist., replace fuses as mentioned.
Timing chain could be slipped during head reinstallation, it might need retorquing, they could've knocked a connection loose or dirtied the engine earth lead, or left it loose.
You can check with the same mechanics for the possibility of human error, they should be cool with taking their time to help a customer understand the problem. If in doubt get a second opinion on their work.

 

a big thing to check is the throttle linkage. i just did my intake manifold gasket and i was having the EXACT same problem. (first start of the day i would have to turn the key a second time but once it was warm i could stop and it would start as normal) things to check would be the ground connection for the ignition coil pack (located on the driver side fender, covered with a black plastic shell, the lead will be attached to the bolt that bolts it to the fender closest to the headlight. be carrrrreful though as the ignition coil can give a nasssty shock!), throttle linkage to make sure its opening correctly and wide enough, then the battery terminals.

 

thanks for the replies guys. The throttle linkage seems fine. Rotor and plugs seems fine. I think it is a tooth out of time I am going to check later today and I will report back in this thread sometime tonight or tomorrow. The car is pretty old and the vacuum system could have problems, does anyone know of an excellent guide for inspecting the system on this car?

A short was created at one point when the battery was being installed. At least enough voltage got through to fry my stereo (hopefully just the fuse). Could an electrical problem be causing the engine symptoms? Could the computer be damaged?

 

They don't really use a computer as such, just a mapped spark controller. The rest of the K-jetronic system is automechanical (kommandogeraet), meaning an old school "mechanical computer" using vacuum and electrical senders and slide valves and that sort of thing, it just responds to conditional changes mechanically by responding directly to sensor input. There's no computerised engine management, not even a knock sensor (there's a temp sensor that retards spark when overheating to help prevent immediate damage, that's about it).
An allegorical example of the kind of "computer" this engine uses is the kickdown lever for the auto, it's a cable on the throttle linkage. Push the pedal far enough physically and the auto kick down lever gets pushed. It's not assessing whether a lower gear is needed for the driving conditions, it's just doing it because the kick down got pushed.
It's a computer in the same way an abacus is a pocket calculator.

A battery short can still do damage, to the loom and spark controller. There are pins for electrical tests but you'll have to take it to a Mercedes specialist for troubleshooting and it can get expensive since they don't leave any stone unturned.
If the main earths were damaged you should be able to see it, check them.

When was the battery shorted, when the head gasket work was being done?
Definitely replace all the fuses, you should do this first since it costs nothing. Check if that fixed the radio and ABS light.

A slipped timing chain, a warped block, bad spark earth, or damaged/shorted spark controller, these could all do what you describe.
When they shaved the head they probably would've mentioned the block could be warped too but it's a bridge to cross when you get there. That could be it.

I mean overheating damage could damage a lot of things. Many more things could be causing the trouble. You're just going to have to bite the bullet and pick some things to start replacing/testing and get them replaced/tested. Smart play is always start with the cheapest things and move upwards to the more expensive, and try to replace things that could use replacing anyway.

But before you do any of it, you might want to take it back to the same mechanics with the complaint, so they can, a) check for human error in the work done, like a slipped timing chain or untorqued head, or electrical damage if they shorted the battery,
b) they can check the block for warping, can just do a compression test for that no need to pull it out. It shouldn't be hard or expensive, just bolts into the spark tap and reports leakage.

You'll be wasting money if the block is warped. Otherwise you might have to start spending some money.

 

http://www.startekinfo.com/StarTek/o...tedDocId=11832

good place to see how things work on the engine.

 

The fuse on the OVP was blown. Replaced it and the car started right up. Thanks guys!