Classic Audi Ľ Technical Ľ Mech/Tech Ľ Engine » 2.3 NG Starting issues

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Old 27-12-17, 10:00 PM   #11
msh
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There's no need to change spark plugs for no reason - if you want to rule them out, test them - leads should have nominal resistance, which I don't remember, but it's in manuals - and insulation problems could be seen in night or felt when touching wires while engine is running.
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Old 29-12-17, 11:54 PM   #12
Cynical26
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There's no need to change spark plugs for no reason - if you want to rule them out, test them - leads should have nominal resistance, which I don't remember, but it's in manuals - and insulation problems could be seen in night or felt when touching wires while engine is running.
Replaced the plugs tonight as I had them to go in anyway. No change to the start up problem (didn’t think there would be as it appears to be a fuel/ Air mixture problem).

Old plugs were in ok condition, although someone obviously didn’t realise it was a 5 cylinder at some point in the past





Four Bosch plugs and one Champion



I removed the rubber waffle pattern air duct from the fuel manafold and checked for splits. I didn’t find anything.

This is the same rubber duct that I replaced, as when I first bought the car it had been split where the metal breather pipe connects, the metal pipe removed and the hole blocked off and the breather from the crankcase lying open. I think all the starting problems started back then too, although only occasionally, and nothing like in the video.

Long story short: I removed the whole lot and blocked off the end of the metal breather pipe and left the crank breather open, just to recreate how it was when I bought it. Note the finger from a rubber glove cable tied over the pipe end



Cranked the car over it started faultlessly 5 times in a row. It’s a bit late to keep turning it over and waking the neighbours so I’ll test it again in the morning.

Now all I need to do is work out why that fixed it

Last edited by Cynical26; 30-12-17 at 02:04 AM.
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Old 30-12-17, 01:48 AM   #13
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Hi man how is it going, still problem starting the coupe, just had a quick look through your post and if I am correct you are saying if you blank off the crank case breather the car starts ok, I know zip about the NG engine and any experience that I have comes from WR or KV engines with bosh K-jetronic fuel injection, if you have a WR engine running and remove the oil filler cap in the cam box the engine will run uneven / rough and may even cut out, this due to the engine breather system being sealed type, this dose not happen with the KV engine as it is not a sealed type breather system, some of the engine have one way valves in them that may have failed letting air pass both ways or been fitted in the pasted the wrong way round,
hey just a couple of thoughts, hope it helps, anyway have a good one.
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Old 30-12-17, 08:47 AM   #14
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Sounds like you're getting somewhere Graeme.

Colin;- is the valve in the breather referred to as a "fire-trap valve"??
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Old 30-12-17, 10:00 AM   #15
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Don't know the name of it John, the one way valve in the Ur is fitted in a rubber hose that connects to the top of the cam box /cover, from looking at photos of the NG engine bay online I don't think it has one, but from what was said by Graeme after blanking of the crank case breather the car starts fine, in my mind with the breather connected the engine in starting mode it is drawing air from the crank case rather than through air meter flap in turn the flap will not rise as far as it would to let the correct amount of fuel in to the cylinders, there for run like a bag of spanners, also said if there is some sort of one way air valve it may be connected round the wrong way of not acting like a one way valve (f**k*d), they also may look like a pipe connector with different colored ends, I think I am correct in saying Graeme has had this problem from day one and it may be a very simple fix as most of these starting / running problems are.
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Old 03-01-18, 10:22 PM   #16
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Not had much time recently to look in to the issue much further.

Got an afternoon to myself today and made the temp bung over the end of the metal breather pipe a bit more robust. Left the end of the breather from the crankcase open, as it was when I bought the car.

Checked the vacuum pipes for leaks and all looked good. Need to look in to the startup procedure prior to the idle control valve kicking in. Would rather the breather pipes were fitted as intended and starting.

Car now continually starts without any issues. Took it for a 160 mile round trip to the Rest and be Thankful and back through Luss, Helensburgh and the Inverclyde coast and finally Largs before a fast drive home with a new 3 series BM in hot pursuit.

Plenty of hot starts without issue tonight. Will see how the cold starting goes over the next day or two. But itís running well and pulls like a train

Got a new fuel filter delivered today, will pick up the copper pipes for the fuel lines soon.
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Old 03-01-18, 10:31 PM   #17
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Quote:
Originally Posted by Colin Aitchison View Post
Don't know the name of it John, the one way valve in the Ur is fitted in a rubber hose that connects to the top of the cam box /cover, from looking at photos of the NG engine bay online I don't think it has one, but from what was said by Graeme after blanking of the crank case breather the car starts fine, in my mind with the breather connected the engine in starting mode it is drawing air from the crank case rather than through air meter flap in turn the flap will not rise as far as it would to let the correct amount of fuel in to the cylinders, there for run like a bag of spanners, also said if there is some sort of one way air valve it may be connected round the wrong way of not acting like a one way valve (f**k*d), they also may look like a pipe connector with different colored ends, I think I am correct in saying Graeme has had this problem from day one and it may be a very simple fix as most of these starting / running problems are.
Colin: the car has always run fine once started. When I got the car the breather pipe at the crankcase was open. I replaced the rubber inlet duct after the mastic bung that had been clumsily used to block where the metal pipe was ment to connect had blown off under heavy acceleration (causing the car to cut out).

After replacing the duct I had some starting issues, nothing major. Those eventually built in to the problem exhibited in the video.

I donít know about any one way valve, but the system is now open at the crankcase and runs, and starts, fine.

Need to find the cause though.
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Old 03-01-18, 11:50 PM   #18
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Never having or working on an NG engine I may not be the correct man to listen to, but the engine may be drawing air from the crank case rather than through the fuel injection air metering flap, this would cause lean fuel mixture, as I say I not the man to talk to on NG engines.
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Old 04-01-18, 06:21 AM   #19
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Quote:
Originally Posted by Cynical26 View Post
......the system is now open at the crankcase and runs, and starts, fine.
Making up a "catch can" type set-up wouldn't be the end of the world??......but I understand why you want it standard and as Audi made it!



....Did the BM pass you?!

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Old 04-01-18, 12:28 PM   #20
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....Did the BM pass you?!

Only after the third roundabout, by that time I was a bit worried it may be plod

After he passed me he nearly put it in a wall at the first corner. Definitely time to back off then.
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