280SE - Fires up great but then dies...

[shaggy]

Thanks Ken.

The screw adjuster and bracket on the air-flap is just my crude device to get the engine running. As you say, I appear to have the basis of a healthy engine and the issues are almost certainly vacuum related.

Inadvertently, I ran the engine with the towel I use to stop crud getting into the admission still in place. It was half sucked in and trying to strangle the air flow but, lo and behold, the engine revved on the throttle! In my mind, this just confirms the air leak / ever-enriching cycle.

Best course of action is now to wait until a window opens when the weather is set fair and I've some time ahead of me, remove the inlet manifold to access the vacuum piping, AAV and WUM and go through the lot, having pre-ordered a gasket, injector seals, vacuum tubing and anything else that springs to mind.

Do you have anything to add, Ken?

Regards,
Mick.

[polymathman]

It really sounds like you have a handle on what could be wrong - it's just going to take some staring at it and some figuring, and in the end you generally find that what's wrong isn't what you thought it would be. So it goes.

I am just finishing up rebuilding my cylinder head. Started 1 Jan and took my time in a heated (hellva a winter here in West Virginia), well lit garage with all the manuals and years and years of experience. I gotta say it's about the most fun I've had in quite a while (without taking my clothes off).

Since I have the entire K-Jetronic out, I am going to make a video on Bench Testing the Bosch K-Jetronic. Probably shoot it this weekend. I want to get it back on the car and get the old girl running.

I will post a link when it is ready.

[gerry l]

Where is the best place to take a vacuum reading?  Are all of the vacuum systems connected i.e. if I have a leak at a door lock, will it affect engine vacuum?
I do not seem to have any vacuum at the fuel damper, is this right?  Thanks for any assistance.

[shaggy]

Ken, That would be great if you could post a link.

Good luck by the way with the head; tackling a mechanical enterprise in uncompromised circumstances is both cerebral and noble.

Here's where I am at - engine runs great under 'towel induction' (I could patent an after-market kit!).  Rorty performance up and down the lane where I live in spite of 4 sticking brake calipers, gearbox changes up and down as it should and suspension/handling feel fine so I now know enough to justify expenditure on the parts I'll need. By the way, the brisk performance for such a small engined, big car comes as no surprise as a few years ago I had a w126 300SE and this too was by no stretch of the imagination under-powered.

I'm now de-seizing the brakes and whilst the front is raised I shall fully inspect the fuel injection from underneath.

Gerry, I don't know where to hook-up a vacuum gauge but I doubt a leaking door lock pipe will adversely affect the engine as there is most likely a non-return valve somewhere. Though I may be wrong.

Regards,
Mick.

[koan]

Where is the best place to take a vacuum reading?  Are all of the vacuum systems connected i.e. if I have a leak at a door lock, will it affect engine vacuum?
I do not seem to have any vacuum at the fuel damper, is this right?  Thanks for any assistance.

Any vacuum leak anywhere is going to affect the engine to some extent as it results in air entering engine that is not measured by the flap.

From memory the fuel damper leak line connects to the inlet system before the throttle plate so no vacuum there would be correct.

Measure vacuum anywhere convenient but avoid lines connected to the distributor advance diaphragm as they are not manifold vacuum, one is throttle venturi vacuum, the other (if you have two) is controlled by a solenoid valve and may or may not be present.

[shaggy]

Just thought I'd do a little progress report on my 350€ 'barn-find'.

Previously, I'd managed to get it running, but only by blocking open the air-flap, or, alternatively, by strangling it with a towel.

I made a breakthrough a couple of days ago, simply by richening up the mixture by two turns of the allen screw. The engine now fires up, fast idles  (subsequently slows as the engine  warms). Drives ok but the brakes were seriously binding and I had to lubricate and wiggle the pistons in their caliper housings and bleed the system a couple of times before real forward motion could be achieved. Then the exhaust back box fell off and the gearchanges were slurring. I put a bit of ATF into the box and things improved, but I need to buy a couple of litres as it's still not registering fluid on the dip-stick.
Pneumatic central locking works as do lights, wipers, heater, but the rev. counter and clock don't. Cant tell if the fuel gauge works as I've been putting fuel in via a can in 5 litre dribs and drabs!

So, I'm slowly coaxing this old beast out of 10 years slumber. Expenditure so far is ZERO (unless you count a few litres of lead-free) - but I am compiling a list of parts and consumables that will need changing.

And I know that the engine only runs approximately and that if it's to run as the designers intended, the injection system will need going through from top to bottom. Even so, I'm glad there are no serious issues with this car. As so often is the case, it appea simply laid up

[shaggy]

(Oops)...it appears to have been simply laid up for a minor (but expensive?) problem. I also anticipate having some fun with this engine, as it's definately happy to rev!

Mick.

[shaggy]

Thought I'd update the thread as this car is now up and running.

It didn't take much in the end, just careful bringing back to life after a long lay-up. The biggest single improvement, surprisingly, was a new set of plugs!
Anyway, I drained the fuel tank, new filter(s), dismantled the k-jet components, cleaned and reassembled, went through the ignition (new plugs, leads), procured a second hand exhaust back-box, welded up the front and rear sills, left side and did a cheap and cheerful paint job (partial, and now I regret not going that bit extra because the non-painted panels are darker, but hey...) fitted a new water pump and sourced a few bits and pieces that were missing.

On top of the 350€ purchase price, I've not spent more than 500€, 200€ of which was spent on paints. A very good source for consumables are "OSCARO", France's main on-line parts supplier, and very reasonably priced too (23€ for The water pump, including delivery!). I purchased an under-bonnet foam insulation from Mercedes in the mistaken hope it'd quieten down somewhat the valve chatter. Oh, and an oil and filter change for the auto-box. Engine is now running on 20/50 and quieter for it.

So how does it go?

Very well on the whole and I love it - but I can't get to grips with the contrast between engine and car, it's such an anachronism. On the one hand, the car is so solid and voluptuous, dripping with chrome, well engineered and heavy looking, yet the engine is relatively unrefined, quite noisy, 'busy' from the valve train, and has a power band quite high up the rev. range (though when there, it really flies). Plus the car feels quite under-geared as if an extra gear would be welcome. By way of comparison, the w126 300SE I had a few years ago had creamy and linear power and would cruise in silence at 100 MPH. On the handling front, things are better and with a new set of 205/70/14 tyres in place of the 185 Michelins (which are too old and cracked to be safe), the ride should inspire confidence, if a little harsh over potholes. However, my last car was a Jaguar XJ6 series 3 and nothing comes close to the dynamic prowess of that particular chassis.

I suspect, however, that I shall need to get a fair few more miles under my belt and then report back as I'm sure it's going to grow on me...

[shaggy]

PICCY...

[w116john]

amazing value for money.. many years ago i had a 280se and found it a really good drive a little underpowered to 40-50mph but when you were bossed it a bit it was great fun, i think the engine is meant to be revved and before you know it you are at 80mph.

enjoy