1.8t 4x4 estate - overfueling?

[gpwatson]

I have been through the mill with this car!

There is another thread at http://www.briskoda.net/forums/octavia/octavia-1-8t-4x4-lpg-idle-problem/81951/3/, but I've been down so many blind alleys, I thought it best to close that one and start a new one with the exact known problems today.

Car is a 2002 1.8t 4x4 estate with the ARX engine. It has a Landi LPG kit, but we have it disconnected at the moment as we know it works perfectly and is not related to this problem.

We have carried out a full top end rebuild following a broken valve and worn out valve seats (thanks to the lpg).

Before attempting to restart it, we have checked the timing was set correctly 4 times.

On trying to restart it, the engine turns over and tries to start, sometimes running very lumpy for a few seconds before cutting out.

We were at the car for 2 hours last night with VAG COM, and must have ran the engine fault codes at least 10 times, mostly with no codes coming up at all. Only twice did we have a code:

16705 - P0321 – Ign./Distributer Eng. Speed Inp.Circ range/performance.

We also ran measuring blocks and noted that the on group 2, the only two obvious settings that were way out of range when trying to start it were:

• Engine load at idle was 100%, when it should have been 700-820rpm.

· Injector period, which should have been 2.0 – 4.0m/s, fluctuated between a worrying 6.5m/s and a frankly frightening 15.8m/s.

All the other blocks I could access on my lowly 409-1 vag-com appeared within the ranges given.

Please note that we did not touch the throttle when doing any of these checks.

Would I be correct in thinking this is a timing issue? Even though we have checked it several times?

Is the VVT stuck closed, like it would be at high revs, forcing too much fuel in at start up and choking the engine?

I know it's not the petrol as we have recently added some super unleaded to reinvigorate the petrol that was lying in the tank for months.

I'm open to suggestions... this car has now been off the road since 11th July!

[KenONeill]

Well, presuming that injector period is proportional to fuel injected, it's definitely over-fuelling.

Have you done a throttle alignment since the rebuild?

[gpwatson]

Thanks.

Battery has been flat for a couple of months, so TBA is probably quite necessary.

We will try this. And will also take it off for a good clean as well.

Update soon.

Car has done 98k, so

[gpwatson]

Bought the full VAG-com licence and performed a throttle body alignment after having cleaned out the throttle body, which was minging, so would have needed doing anyway.

Car now starts on nearly every first turn of the key, but quickly splutters and dies.

Must have started it and then ran fault codes about 12-15 times and it only ever threw up one code on around the 2nd or third time. It was

16705 - Engine Speed Sensor (G28): Implausible Signal P0321.

Not sure if this is a red herring or not?

Running the measuring blocks, I noted that the fuelling was again way out, but the more times I started it the less it was injecting. Apart from that, everything else was within the parameters set.

The longest the engine would run was around 30s before cutting out. At least that gave me the chance to get round the front and listen to the engine before it stopped.

As far as I can tell, it appears to be trying to draw air in from somewhere it shouldn't be. Listening in at the cam chain side of the engine, it sounds like it's gasping for more and more air from one of the many pipes down there, before it finally cuts out because that area has been exhausted of air. When it does cut out, there is a whistle as air is being drawn back into the pipe. Almost like it's refilling a vacuum. It will only start again one the whistling noise ends. Therefore, suggesting the air is back in that area again, but then the whole thing starts around again.

I’m open to suggestions, but am also going to speak to the local non-franchised VAG specialist and see what they think.

[Glider]

Have you checked the fuel pump is ok, also check the fuel filter.

[KenONeill]

Try searching for PCB or possibly Breather hose leaks.

[gpwatson]

Time for an update. Again.
Collected the car from mechanic who was unable to get the car running. Towed it 40 miles to an independent VAG specialist near Aberdeen. Not much fun with ice on the inside of the screen and no engine running.
Specialist has had a listen to it and decided that the cylinder head needs to come off again. God knows how much this will cost? T
he only bit of good news is that I made a small profit on the car I had bought to run arounjd in over the last couple of months. So all that cash is now in the octavia fund.
I live in hope. It beats the hell out of living here.

[Glider]

Ask them to compression and leak test first before the lift the head (just by listening ??) Also a sniff test on the coolant.
Another train of thought is the immobiliser chip in the key faulty and the engine cutting out due to this.

[G-slave]

gpwatson, any new updates since november?

[gpwatson]

Final post. The end? Hope to God it is.

Many thanks to the Volks Centre at Kingswells, near Aberdeen. They diagnosed a completely fecked cylinder head and sourced replacement from an Audi TT 225 for me.

A couple of weeks later, and another few bits and pieces and we are back on the road with a full MOT

The short of it all is that the re-seating work carried out on the original head was so bad, it couldn't be repaired.

The moral of the tail is that we should trust our mates to do good work for us as a homer. But never trust a mate's mate. You don't know him. He doesn't know you, etc, etc.

Hopefully now, I can drive off into the sunset, and back again, powered by daisy friendly, cheap as chips lpg.

Many thanks for all the suggestions. The good, the bad and the downright daft.

[fatty5000]

Hey success then


well done glad your happy got there in the end

[redbaron]

so this LPG has been costeffective then?

[gpwatson]

So far getting 25 in town and 30 on a run with LPG.

At 47.9ppl for LPG against 99.9ppl for unleaded that the equivlant of 52mpg in town and 62mpg on a run. Dial in less than £5 a week on unleaded until the engine heats up to switch over to gas, that's still more economical than a diesel.

[redbaron]

assuming the cost of the conversion and the repairs was zero...

given i could get 45+ from my vRS im not sure how cost/economical it would be?