AHU problem + Performance advise.

[Jewlls]

Hi,
New to forums so don't rush to judge,
I got a VW passat AHU engine, Recently changed head, as the old one was dameged and exhaust gas was going in to coolant, the replacement head was of a AFN engine(with injectors,and nozles(p520)) since the i have this weired problem, after the I start a car i puts ALOT of white/blueish smoke out, I asume it's burning oil, but it only takes about 5-10 mins of driving and its all gone, it only does that after being parked for a few hours, not if i stop it and then star it again.

Now performance advise, As i mentioned it's AHU engine, so I was wondering, is it worth of upgrading Boost/vac system + ecu, or just sell it and buy AFN one? which works cheaper and easier?

P.s: car is hard to start in the morning, I'll Have glowplugs changed tomorrow, and report back if it's improoved.

Thanks for any advise

Sorry for my spelling, english is my second language

[Keithuk]

Welcome to the forum.

Blue smoke is usually engine oil burning white smoke is combustion temperature isn't high enough.

Does the glow plug light show when you turn the ignition on?

You could disconnect the coolant temperature sensor then see if it starts any easier that full force the glow plugs to be powered for 20 seconds. If it starts quicker then you need to investigate if the glow plugs are being powered from the glow plug relay and check the resistance of each glow plug they should be around 0.5-1.0 ohms each so you would need to invest in a multimeter if you don't have one.

[Jewlls]

Thanks,

Yes it does, for about 3-5 secs,

I'll do that and report back.

[Jewlls]

No luck, done both, (disconnected the temp sensors, replaced glow plugs) still same hard to start in the morning AND REALLY SMOKY. Any other ideas?

[Jewlls]

Can it by any chance be an EGR valve?

[thomasyelland]

Blue smoke after sitting normaly indicates valve stem seals leaking although im not familiar with this engine and if its common. This wouldnt explain the hard starting though.