ford transit

Take off the rocker cover and make sure there's no damage to the valvetrain. MY mate lost a cylinder on his S reg 2.5D about the same mileage and it was a snapped camshaft...had only gone on the very last lobe.

Is the misfire constant, or just when revved/under load? And do you know what cylinder it is?

As Conor has mentioned, check the camshaft. It's not unknown on these engines for the cam shaft to snap. If it snaps at the rear, the engine will still run (the fuel lift pump is driven by a lobe before the last two valve lobes).

Another common problem on these is for the front injector to airlock. With the engine running, crack open the front injection pipe for a few seconds, then tighten it again. If the misfire goes away for a brief period, then the engine needs the leak-off pipe mod (the leak-off pipe return for the injectors gets altered so the return line goes from the front injector instead of the rear injector).

Also at that mileage it could be a valve clearance problem, espcially if the van has done a lot of motorway work. When you've got the rocker cover off, check the valve clearances. However, setting the clearances has to be done a set way on these engines (on the rock, and rule of 9 doesn't work properly). From memory (the pairs may not be right), the valves are numbered 1to8 from front to back. The pairs are - 1+7, 2+3 (definately right), 4+6, and 5+8(definately right). Turn the engine until you see what valves opening, and what ones closing. For each pair, you want to get them so that one of the pair has almost finished closing,and the other is just starting to open. You then find what pair are fully closed, and adjust them. You then turn the engine until you get the next pair off valves with one just finishing closing, and the other starting to open, and repeat until all 8 valves are set.

I'm not entirely sure, but I think 2+3 and 5+8 are complementary pairs, so

Failing that, it is always worth checking the timing belt, to make sure it hasn't jumped.

I suspect that a broken cam may just have shown up on the compression test.

When you changed the injector, are you sure you got all of it out of the hole? if the white plastic seal stayed in the injector hole, then the injector will not seat fully down, and the nozzle will not be protruding into the combustion chamber, causing the misfire.

What was the original fault before you changed the injector?

What do you mean exploded? Did the tip come of it?

If it did, then it's most likely a damaged piston, and/or a bent valve causing the misfire now.

that not cause a lack of pressure when i did the compresion test? Do you know how to advance the timeing on the fuel pump as i have been told that this might be the cause of the misfire.

When the tip comes off, it damages the top of the piston and the cylinder head, as there is very little clearance. You may also find the injector tip is still embedded in the top of the piston.

Depending on what's been damaged, will depend on if the cylinder will still have compression. How did the compression test compare with the other cylinders?

But, in all honesty, you're as well removing the cylinder head to see what damage there is now, rather than wasting time chasing highly unlikely possibilities. If the piston is damaged, there is a high chance that it will be likely to fail, with resulting catastrophic engine failure (conrod through the side if the block). I've seen two engines with split injector tips, one got a new engine (was still under warranty), and the other needed new valves.

The fuel pump timing will not make any difference to a misfire (and on the bosch pumps, it's bench set anyway).

To be honest the tip will now be long gone out through the exhaust valve.

I'd like to know on exactly what this misfire is like. Is an occasional misfire? Is it one pot not firing at all?

I would have thought a compression test would show if there were any valve seating issues and the good compression tests imply that all is well with no bent valves.

Hi yes done a compression test and all cylinders all the same at 320. The misfire is constant as it puffs out smoke under all running types as in tick over/ exceleration and constant speed.

Not always. It could quite easily still be embedded in the piston crown.

That would be good to know.

I've seen these engines have a slightly bent valve, which lets the engine idle fine, but as soon as you rev it/put it under load it'll start missing. Normally caused by the valve sticking slightly in the guide (at anything above idle, the valve doesn't snap shut quite as quick as it should) There's also the possibility the tip has mushroomed the head of the piston, which can cause strange problems.

A compression test does not guarantee the condition of the engine, and if it's idling reasonably well, there is no reason it wouldn't show as having good compression on a compression test. I've seen one of these engines have near perfect compression, but still fail to start every morning because of low compression (timing belt had jumped quite a few teeth, meaning the engine hadn't been running well for quite some time, and the engine had slowy coked up and jammed the piston rings). I've worked on these engines for far too many years now, and there's not much I havn't seen go wrong. For the amount of time it takes to remove the cylinder head, and the cost of a head gasket, it won't take long to find out what's damaged.

If the timing was ok before why would it have gone out now?

I just had a thought about this. You did fit the right injector? These engines had differently calibrated injectors fitted, depending on spec.

It's something that never affected me at work, as we always bought new injectors from ford, but if you didn't get the injector from ford, then it could very well be the wrong one. I've seen an engine fitted with the wrong injectors, and it took us a while to figure out why it wouldn't run (somebody had done it for a mate, and we only seen it after it had had numerous parts fitted, before the guy gave up and towed it in. One set of injectors later, and it was running perfectly), so one wrong injector would give you a misfire.

Yes fitted fords own injectors.

to be working ok. The compression was ok at 320 as it says it should be according to the book. The engine starts ok and dosent use water or oil any other suggestions appart from taking the head off.Thanks agin