Can an M103 Jump time?
 

I have a weird situation. I have an 87 260E with about (odo broke) 330,000 miles. I have owned it since 140K and have done very little to her with the exception of a cam (soft cam model) and injectors 10 years ago and an ETA (I think. The electronic module on the back of the throttle body) and fuel pump last year. Amazing car, still runs real strong, looks great, gets 24MPG and is a reliable daily for my 112 mi round trip commute. All she asks for is a quart of oil per 800 miles.

Last week I shut off the car and she would not start. I got her running by jumping out the fuel pump relay. Since she restarted the valves are making noise, singing. I pulled the valve cover and the injectors are all pumping up it has great oil flow and everything looks good. The only thing I did besides jumping the fuel pump relay was mess with the air/fuel.

It kind of sounds like I jumped time. Do you think this is possible with this engine? Funny thing is I drove it home 60 miles and it runs incredibly well, better than before. I am almost temped to use it.

Any Ideas/thoughts/suggestions appreciated.

Thanks

I don't think anyone has ever had a m103 jump timing. If it did, it would run terrible, if at all. Not to say you could be the first, but that would be the last place I would check. When was the last tune up?

No. With cam lobes for 6 cylinders all on the one shaft, there is always a valve opening as one is closing. The result is a relatively even drag on the timing chain. The likelyhood of it jumping is nil.

The chain is also too short to really allow enough slack to jump time. I have never heard of a M103 needing a timing chain or having any issues with it unless it was messed with. I have asked many Mercedes mechanics who have been in the business for 30+ years about it and none of them have done a chain job or knew anyone who did unless it was a "while I'm in there" type deal.

My car had the chain replaced by a shop before I bought it. They just scammed the PO telling him it needed something it didn't need. Now I have chain slap because of the crappy aftermarket tensioner they put on it. I am swapping engines to the 3.0 from the 2.6 so I am not going to worry about changing the tensioner unless I try to sell my engine, which while at 205K now doesn't burn or leak an appreciable amount of oil between each 5000 mile oil change.

Thanks

Thanks!

Is it possible? Yes it could happen but I really doubt it. Its likely a fueling issue of some sort.

Good to know. I've thought about the timing chain from time to time and I am aware it's pretty short. My '88 300CE (with 144 k miles) won't need one in this lifetime then. (Mine I'm speaking of :o)

I've been through most of the mid life crises (the M103's that is;) ). Maybe a fuel pump or FPR lurking over the horizon.

Thanks. You think the noise could be a fueling issue?