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orgonomix
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Joined: Oct 17, 2012
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PostPosted: Wed Jul 02, 2014 5:04 pm Reply with quote Back to top

Please help I can't figure this one out and it's doing my head in.
Run your eyes over these symptoms and let me know what comes to mind.
Car has had recent cat. ,new oxygen sensor, HT leads, spark plugs, MFTemp. sensor and the other coolant temp. sensor.

It has been sat for best part of a year started and warmed up every now and again apart from when the keys were lost for a few months last year.

Car starts and drives reasonably well, compression is 130 odd on all five cylinders, had a recent head gasket before I bought it roughly 18 months ago. Seems to be running rich, plugs black, oxygen sensor the same when pulled out and cleaned.

Idle seems ok apart from a slight hunting up and down during warm up but settles when warmed up but when timing light shone on flywheel, the timing mark appears to wander in andv out of view and there is a periodic missing flash from the strobe light.

Was timed at 18 deg BTDC according to spec. but seems happier at something less than this which someone else marked on the flywheel, looks something like 12- 15 deg BTDC.

CO emissions were a little high but not much, but the HC was 10 times its allowed value. Seems like its overfuelling some .

I haven't been able trace the misfire even after replacing most of the ignition system, the distributor cap will be replaced tomorrow unless I decide to go for a complete distributor as I can't figure what else would make it wander like that.

Quite a bit of water dribbles out the tail pipe. I am fairly sure the Head gasket is not leaking since it was replaced so recently and compression is good, but would a lot of condensation/water in middle box/muffler give high HC reading?
The exhaust is blowing slightly from that middle box , the big rectangular heavy one.

Previously overcome problems that could have a bearing on this are a bad air leak on the inlet pipe/rubber bellows where the crankcase breather pipe union was broken. This had been bodged with silicon sealant but has now been sealed off and a crank breather filter fitted to the pipe.

Any thoughts or advice well appreciated.
 
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recurveandy
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Joined: Dec 07, 2005
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Location: Cirencester

PostPosted: Wed Jul 02, 2014 8:24 pm Reply with quote Back to top

Timing is 15 +/-1 BDTC so not far out there
Have you tried adjusting the mixture to see if it comes down, may be itís been set up rich to overcome the air leaks etc. Or possibly the cold start valve is stuck open?

Mine was high on CO, around 9-10% so I gave it a thorough going over
Intake hose was removed and repaired of leaks. Breather system was removed and flushed through, amazing how much gunk was in there, oil, plugs and filter changes etc, and is all now within spec.
Also, check the throttle idle switch is contacting when the throttle is closed, this is the one on the underside of the throttle. Not sure if you can adjust it with the throttle in situ, I had mine off to do the valve cover gaskets so wasnít a problem doing it

I think these engines need to be good and clean to have them working well

_________________
AOC#1295
1989 NG Q Pick-up (Daily)
1999 AGZ Bora (For the Doris)
1997 ACK A6 Avant Q (Under the knife)
1984 JS Coupe GT (restoring)
1983 MK1 Golf GTI Pirelli (In storage) 
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orgonomix
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Joined: Oct 17, 2012
Posts: 6

PostPosted: Tue Jul 08, 2014 8:39 am Reply with quote Back to top

Thanks for the reply . I cleaned the idle stabiliser valve and the cold start valve and removed all the relays and cleaned the contacts.

After a lot of twiddling of the fuel distributor plate pot I have managed to get the HC down to an acceptable level within limits but I cannot get the lambda reading at exhaust tail pipe down enough to get to an acceptable level for the MOT. It stays around 1.2 to 1.4 whatever I do to the fuel mixture.

The exhaust is old, probably original but I have ensured there are no leaks . It does seem like there is an unseen leak though. Any ideas?
I cannot afford to just replace the exhaust system to see if it makes a difference.

Today is the 10th working day of the period when I can taker it back for a free MOT re-test.

Any ideas would be well appreciated.
 
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recurveandy
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Joined: Dec 07, 2005
Posts: 370
Location: Cirencester

PostPosted: Tue Jul 08, 2014 2:50 pm Reply with quote Back to top

When I had a few exhaust leaks on my old V6, I went round with a cartridge of chimney flue sealant which seemed to help.
Also, I see you replaced the O2 sensor. Did you use genuine Bosch or one of the universal types? I've used the universal before with little to no success, will never put anything but Bosch in now.

Bosch catalogue here:
https://www.bosch-automotive-catalog.com/public/catalog/products

Hopefully that should come up on the correct part, if not, Bosch OE number is: 0 258 003 057

And, how hot was the motor? If it's not been driven for a while you'll really need to give it a good Italian tune-up, give it at least 15-20 miles of hard driving to clear it out and get it properly hot.

Hope this helps
Andy

_________________
AOC#1295
1989 NG Q Pick-up (Daily)
1999 AGZ Bora (For the Doris)
1997 ACK A6 Avant Q (Under the knife)
1984 JS Coupe GT (restoring)
1983 MK1 Golf GTI Pirelli (In storage) 
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orgonomix
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Joined: Oct 17, 2012
Posts: 6

PostPosted: Tue Jul 08, 2014 9:15 pm Reply with quote Back to top

Yesssss! Got the bastaad in the end . MOT retest passed right at the end of the 10th working day and in the words of Ice Cube who was playing on Radio 6 at lunchtime today, I've got to say it was a good day. I managed to get the emissions within limits with a combination of mixture twiddling, exhaust fettling, high octane fuel spunking and the enduring patience of an excellent MOT tester.
Thanks recurveandy and other bloke for tips and support also.
Hip hip Hoo-ferkin-ray ! It's summer time, I have a convertible ! Much mischief now to follow I think ... heheheheh Razz
 
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