Hoping for some pointers with this van, it is a 2004 1.9 with 160k on the clock.

It starts and idles fine, if you gently rev it there is no smoke and sounds OK untill it hits about 2800 rpm, then lots of light coloured smoke and misfire, will continue to rev beyond 3k but same rough running and lots of smoke.

If giving it more load it will start producing the symptoms much lower in the rev range.

The only code present on my solus is 1826 — glow plug circuit.

I have checked voltage at each glow plug koeo and they are all receiving voltage, once started power is cut to them and the negative sign appears on my meter, like the polarity has changed?

Checked resistance of each plug: 1/120/130/3500 ohms

I would say that 3 need changing, but Haynes says replace if infinite resistance.

Also my understanding was on common rail diesels the glow plug continued to function whilst engine running to aid combustion, but Haynes says only used while coolant temp is under 20 degrees?

So not sure if in the absence of any other codes that it could be something to do with this side of things?

Other things I've done :

New fuel filter - old one looked clean and no metal particles that I could see.

New air filter

Spun egr 180

Injector leak off test

Unplugged maf - engine only revs to around 2k

Checked pipe from map to inlet manifold is not blocked

Checked for leaks on map pipe & both pipes going to boost sensor.

Any ideas welcome, thanks.