I'm at a total loss here, I've read at least a hundred "wont start" type threads and I'm still at a loss. Here is a rundown...

1984 240D 4spd, ODO says 170k (but it feels like more to me?) uncle bought it 3 years ago so no history beyond that. I converted it to WVO 2 years ago and it has only had about 15,000 miles total driven on WVO maximum. So I feel WVO is unlikely to be a big culprit this early in the game.

It won't start, not even with a wiff of ether into the intake PRE-air filter. The only way I can get it to start is to pop the clutch in 2nd rolling down hill. The not-starting issue started to rear its head 3-4 months ago but it was manageable with a few glowing cycles before starting.

It started to have this issue when starting that baffled me. Sometimes when it would start it would have no power. Not even enough to drive. If I turned it off and glowed it a few times it would start instantly and have full power and be fine until I turned it off again. Then it would start doing this even after the motor was hot. Eventually to the point a couple weeks ago where even if it had been running for an hour if I shut it off (even for 5 seconds) it would need re-glowed several times before starting. I don't think the glow plugs would even matter when the engine is at full temp???

A few days before I made the time to tear into it since I wanted to do some pre-winter maintenance it died while at ilde when I was parking it at my place. It has essentially been dead since then.

I have the ability to pressurize the fuel system under veggie and that seems to have some positive effect when trying to get it to idle after I bump start but it does not help with starting at all.

I noticed the idle is much rougher now and after exhausting everything easy I pulled in the injectors and they looked pretty bad. I really believe this car may have more than 170k miles on it as the injectors had alot of build up. (or they are original) MUCH more than my 84 300D that I put nearly 100k on veggie before I replaced the injector nozzles.

I pulled four old but working injectors off my 81 240d and it seemed to give the car a little more power and smoothed the idle, but had no effect on the starting issue.

So I have purchased 4 new Monark injector nozzles and a compression tester, I may have it tomorrow so I can run a compression test as I suspect the compression is pretty poor. The oil cap rattles pretty bad from blow-by.

I'm pretty desperate. I start a new job in a week and I really need my car back. I know I should have made the time to dig into this earlier but I have been busy.

I'll try anything at this point!


Thanks so much!

 

Fuel filters. ?

 

Try the glow plugs man. They are super easy on that car.
I'm pretty sure a vegi company called Esbit sells glow plugs that stay on longer, or so they say.

 

Veggie works fine, I always start and stop on 100% diesel, I've put more than 100k through a 300d (one that actually works fine! but unfortunately is being used by my better half ) But I think there are definitely bad ways of doing it. Hot,clean oil through a Hot engine only. I don't want to get into defending veggie fuels here. But suffice to say if wvo kills one of my cars entirely no matter what the repair it was paid for a long time ago. Wvo has saved me more in fuel costs than all my cars + conversions + maintenance combined. Its really amazing. But I go to great lengths to do it right and it does suck up a lot of my time sometimes.

I tried fuel filters, thats the first thing I do. I'm suspecting that the compression is just terrible, but It surprises me that it got so bad so fast. I really don't understand it. I should get my tester today and the new nozzles. I also bought a glow-plug reamer to inspect the coke in the pre-chamber.

@chrisarnt I think thats a good idea I've considered wiring up a extra switch to allow me to control the glow plugs manually.

 

All the normal no Veggie use stuff should be checked like the Glow Plugs and the Filter Change.
If you remove and replace any Glow Plugs you should ream or other wise clean the Carbon out of the Glow Plug Holes. If not your new Glow Plugs will not last long.

I believe Carbon Build up conducts heat into the Cylinder Head instead of heating the Air in the Prechamber like they are supposed to.

Other no start issues can be caused if your Starter is not turning the Engine over fast enough. This can be a weak Battery/Poor Battery connection Issue or a tired Starter Issue.

I would expect that you Veggie use has over time caused sticking Piston Rings and that is reducing your compression.

You will know when you have done your compression check.

I would do some research regarding dumping some Marvel Mystery Oil into your Cylinders and letting it soak as many days as you can before doing an Oil Change and running the Car again.

It freed up some Sticky Rings in my Volvo Diesel. However I am no veggie user.

Ounce you get the car going you need to run it on Diesel so it will get you to your Job. After that you can go back to veggie later if you want.