Car bother

Anyone know what might cause a diesel engine to exhibit intermittent misfire?

@fat controller , @longk perhaps?

If it had been petrol, I'd say it was ignition related because it's either fine or bad, no in between, no smoke, loss of performance, worsening fuel economy, nothing like that. Runs fine, then intermittently hesitates now and again.

 

Where do you want to start?

What car is it?

 

Mitsubishi carisma. 1.9 DID, which must differ ever so slightly from the related 1.9TD because that variant also exists, though I don't know what the difference is because mine also is diesel and has a turbo.

I'm told its the exact same engine as they put in the Volvo S40 and V40 diesels of the same era (2003) In fact they shared the factory in Holland.

 

Mostly misfire, although there seems to be little consistency as to when you feel the turbo waking up. At about half throttle, the car normally really wakes up around 2500 rpm, then you can feeling significant boost. Sometimes though, not always, it doesn't wake up until over 3000 rpm.

There's no sinister noise or smoke that would implicate a (second) turbo failure. In fact the misfire is usually at the lower end of the revs where the turbo does very little.

 

Would my car have a diesel particulate filter? It's quite old, 53 plate.

 

Usually and injector failure causes white smoke out of the back, though I am talking ten years back

Jack McH

 

As FC says you will need it plugged in before you even start. There are a few basic checks you could do first though;

• check all vacuum pipes for deterioration. These (if fitted) will control EGR and turbo boost function.
• Replace the fuel and air filters.
• Check for perished fuel pipes that may allow air ingress.
• Check any earth points in the engine bay for good continuity.
• Check for leakage on the turbo boost pipes.

It could be a simple fix but it may also be a real barsteward to track down.
If you are going to keep this car (personally I wouldn't) then it may be worth investing in one of these at this price.................

Leak off test kit

Pretty good for checking injectors. Check if it is compatible first though.

 

Blocked egr,
failing injector,
blocked fuel filter,
dodgy maf ?
Get a code reader off ebay for a few quid and get the code read or take it to a garage where they will charge you 50 quid for the same thing.
Id buy the code reader,replace fuel filter and some injector cleaner (forte) and take it from there.

 

Thanks all. I think it's just snot build-up. I normally drive in the highest gear she'll comfortably pull in. I've read that's not good formodern diesels, so today I drove to work in lower gears . Same home again. It's too early to tell, but when I finally got to the one good road in my journey, I gave her some welly and she didn't half pull nicely.

 

I'm pretty sure that the Carisma was never fitted with one. I may be wrong.