skipton01

Hello all,

First post, so be gentle with me!!

Just bought a year 2000 A6 C5 1.8T in Ming Blue with 89000 miles and a full service history for £400 (around $650)!!!

The last owner had fallen on hard times and needed quick cash. Although the car had been stood for around 2 years (!!), a VCDS scan showed no errors, although the ABS unit is not visible to VCDS and there is a random sticking of the drivers door lock.

I just fitted a new battery and did an oil/filter/plug change and put some gas in the tank. It took a lot of cranking before the fuel was through to the head and then it fired up, only to stutter and die after about 5 seconds.

Thinking it just needed more, I kept on turning off and restarting, but it's gotten no better (I was running a jump boost battery from the my A2).

I've carried out a throttle body reset, but no improvement. Sometimes it'll run for 5 seconds, stumble, catch itself again and then die. If you press the gas pedal, it'll rev up and then die immediately.

I suppose that it's too much to ask for a car that's been stood for 2 years to run smooth straight away, but anyone any ideas?

The old plugs were pretty dirty, with oily deposits, so I suspect that there's a fair amount of oil getting into the intake system, which probably needs a strip and clean.

Any help gratefully received.

Cheers,

Mike

Redneck Truck

I would have been glad to help, but for your mention of what you paid for it. :-)

Just kidding. You've already done a lot of what I would have checked. Maybe remove the air filter to rule that out, do a compression check to rule that out, make sure the turbo isn't frozen solid (not sure why it would be, but that would make it mighty hard for air to get to the engine). Is it possible the fuel sat in the injectors, pump, filter, lines long enough that just changing the fuel won't clean off the deposits they leave?

skipton01

I've checked the air filter - a little dirty, but not blocked (how tricky is the air filter to remove!!!).

I suppose that is it possible that varnish type deposits are in the system after all this time, but then I'd expect it not to start at all.

I've seen comments from elsewhere about coolant temperature sensors (there is movement at the instrument dial) and vacuum leaks, so I'll check these out too. Hoping it's not a crank sensor, as a new one of these is going to be about 1/4 of the cars price!!

Cheers

Mike

A6Gary

You might try adding a fuel additive, such as BG 44K (if available in the UK), to help clean the fuel system and the cylinder chambers.

skipton01

Thanks for the recommendation - it's not a product that is really seen over here, but it is available.

In the UK, fuel additives are generally rubbished by press and public alike.

As this product can only clean the injectors and a very short length of the inlet tract, as well as the piston crowns, I'll do a manual clean of the system first from the turbo and search for vacuum leaks whilst I'm at it.

The car's done 89,000 miles and judging by the build up visible through the plug holes, there might be a leaking turbo seal that is letting oil into the system.

Cheers,

Mike

Edd W

Do you know why it was stood for 2 years - was this the problem that took it off the road?

I will have a think but it sounds like fuel meetering to me - maybe a massive inlet leak letting it fire up on the starting control which must inject fuel while it is cranking but then no more fuel is being dispensed by the injectors. Maybe the MAF has failed completely so I would start checking there - run through the MAF diagnostics - check resistance etc....

skipton01

Many thanks Edd - any suggestions gratefully accepted. This is my first petrol car - I'm more clued up on oil burners, so any pointers from those of you more experienced 1.8T owners is great.

I was told that it was putting out a large amount of white smoke at higher revs, which to me suggests turbo seals, as opposed to a head gasket.

There was no smell of fuel in the oil I changed and there was no water either (no sludge or mayo).

There's no fault codes showing either which is weird. If the MAF was shot, surely it'd revert to basic settings or at least 'limp home' mode? I'll have a hunt around for vacuum pipes that are loose, split, torn or blown off and take it from there.

Cheers,

Mike

2.7Lturbo

white smoke is usually coolant, although the previous owner may not know the difference between white and slightly blue tinged.... oil in the intake tract is not a good indicator of turbo healt, the PCV system puts a lot of oil vapor in ther unfortunately, i would check the shaft for play at the compressor housing... also a quick compression test wil help you eliminate head gasket, as bad compression will cause the car not to start... compression tester is like 20 bucks

skipton01

Thanks for this input.

Yes, a compression test is next on the list, to rule out head gasket, but surely it wouldn't run at all if the compression was down? When it does fire up (and it does every time now without fail), it runs smooth, with no uneveness or lumpiness and then after around 5 seconds (just when you think it's going to carry on), it stumbles and dies!

I'll carry on looking around and generally testing things out and cleaning as I go.

Cheers,

Mike

2.7Lturbo

bad compression wont nessicarliy cause a car to not start at all, i had an old honda motorcycle that had two bad cylinders but ran no problem... as long as you didnt rev to high or let the idle drop too low.