1.9 XUD9TE idle, starting and smoke problems

[Flynn2]

Hi gents, got a 1.9 turbocharged XUD lump here. Never had any problems, always used to run without any smoke, etc, etc. It now runs like in the video below:



At first I thought it was a mangled copper washer causing the problem, which I subsequently got out. When I removed the copper washer I noticed the injector was wet up to the threads, so obviously some of the diesel vapour was blowing by back up to there.

I replaced the washer, cleaned the carbon off the injector seat and nozzle, ran the engine and removed the injector to inspect it again. There was no more blow by the copper washer but the whole nozzle was coated in fuel. I noticed that after cleaning the injector, the engine ran well for a few seconds without pulses of smoke before going back to it's old tricks again. A couple of days later I went to get some fire seals and when I pulled the injector to fit a new fireseal (to stop the fuel blowing by the nozzle) I found the whole nozzle was coated in carbon.

I cleaned the nozzle and put the new fireseal in and now it seems to run slightly better (easier to "revive" with the throttle pedal when it starts hunting up and down the rev range) but it is still producing pulses of smoke and down on power.

Before I forget to mention, I have tried different injectors (the old Lucas units) and they seem to have the same problem, so it can't be the injectors that are at fault. I am running and have been running on veg for awhile, I have read on other forum topics about the piston rings becoming "sticky" with veg residue, but I have run diesel through every now and then and still had the same problem.

[Peter.N.]

Could be that you have an air leak in the fuel system but have just noticed you are running on veggie oil that's a new ball game to me. Does it miss or hesitate when driving? If not I wouldn't worry about it. Have you changed the fuel filter recently?

Peter

[Flynn2]

That video does not illustrate the full extend of the problem. It will not idle under 1100 RPM and if the revs go too low when driving the whole car will shake violently. In addition to pumping out plumes of unburnt diesel. I have tried running it from a bottle of fuel-no difference, so that rules out an air leak.

[Peter.N.]

I would think then it has to be low compression on one cylinder, the only way to be sure is a compression test. Could be rings or valve clearances.

Peter

[Flynn2]

I'm away from my Haynes book at the moment, can you describe what checking the valve clearances would involve?

[Peter.N.]

Not to difficult to check, just remove the camshaft cover and use feeler gauges but adjusting them entails removing the camshaft and having a supply of various thickness shims and a micrometer. You can have a 'wet and dry' compression test which will determine whether the peoblem is due to valve leakage or bore/piston wear.

How many miles has the engine done?

Peter

[Flynn2]

150k. But this is severe, it doesn't idle properly and it chugs plumes of smoke out. I'll check the valve clearances then. Just looking at feeler gauges on eBay, is this one alright:

http://www.ebay.co.uk/itm/Feeler-Gauge- ... 20c627c01e" onclick="window.open(this.href);return false;

I don't know how to tell whether it has the right range of increments or not.

[Xaccers]

Lucas pump and running on veg? Are you running a dual fuel tank?
Lucas pumps and veg generally don't go well together unless you dual tank it and switch over to veg when it's hot enough.
The fuel is used as lubrication inside the pump and veg is too thick to do the job properly unless it is heated up to 80C+

Bosch pumps on the other hand just love veg

[Peter.N.]

They look OK pretty standard set. I agree with Xac regarding the pumps although even Bosch ones can suffer seal failure.

Peter

[Flynn2]

It's not a Lucas pump, it is a Bosch pump. The injectors I referred to where a spare set of old Lucas injectors I had left over from when I changed it to a Bosch pump, not ideal, but usable as a spare set when diagnosing issues.

[spider]

I'm starting to wonder if you've got a leaking injector, or one that's weakened in some way. Wonder if its worth obtaining another and trying it...

[Flynn2]

Well, I've tried the old set of Lucas injectors which had the same fault. I doubt both sets are faulty. Can someone confirm whether or not fuel is supposed to coat the nozzle of the injector? Or is it just supposed to be present on the part left exposed by the fire washer? Each time I've pulled the injectors the whole nozzle has seemed to have fuel on it.

[Peter.N.]

Do you mean actual wet fuel or soot?

[Flynn2]

On one injector there was carbon (soot) on the other ones they were just wet, but clean.

[Peter.N.]

Sounds strange, they shouldn't be wet with fuel unless its run down the outside when you removed them, but if its firing on all cylinders the sealing must be OK. I think you need a compression test before you do anything else.

Peter

http://www.ebay.co.uk/itm/NEW-COMPRESSI ... 3f1a14c54e" onclick="window.open(this.href);return false;