2.3 NG Starting issues

Cynical26 · 27-12-17, 11:02 AM

Hello you helpful and knowledgable people

I’m looking for some practical advice before I start randomly unplugging or replacing parts.

My coupe has a tendency to be a reluctant starter 7 times out of 10 these days. If it doesn’t catch on the first turn the second attempt to start will see it turn over for approx 10 seconds before firing up.

Once it’s does start it will either be good to go straight away or will need to sit for 30 seconds until the idle control valve kicks in. Otherwise it will miss and want to cut out when the throttle is opened. This happens from cold and once up to temperature.

Occasionally there is a smell of fuel which accompanies the 10 second startup process.

Once the car has started, and the idle levelled out, the car will run without fault.

The two things I was thinking of are the cold start valve and the warm up regulator. Neither of which are cheap.

I’ll try and get a video up once the car has defrosted. Any help, pointing the right direction, or just comic relief will be appreciated in equal measure

Gee

mikes2 · 27-12-17, 01:08 PM

are you still getting the back firing or is that fixed now ?

I'm guessing you've already swapped out the basics plugs, arm, cap air filter etc.

All breathers and air hoses all good ?

Injectors / seals - what state are they in ?

Cynical26 · 27-12-17, 03:17 PM

Arm, cap and air filter replaced. Plugs sitting in he garage ready to go in.

Only breather hose I was worried about is the big one from the Air box to the fuel manafold. I was thinking that if I had a vacuum leak the problem wouldn’t clear up and would be present constantly.

It hasn’t backfired since that time you witnessed it. Haven’t done much since then so doubt it has been fixed yet.

I haven’t looked at the injectors.

mikes2 · 27-12-17, 05:28 PM

Just throwing a few suggestions out there.

Other item worth checking is the timing. Has it always done it since you picked it up ?

If it's consistent hot and cold, it's probably not the coldstart valve unless it's leaking / dribbling fuel

Cynical26 · 27-12-17, 06:42 PM

It started without fault when I first had it. Noticed it after replacing the split intake rubber and refitted the missing metal breather pipe from the crankcase.

I’d say it’s got gradually worse since it first started doing it.

I took a video tonight, I’ll try and get the link up ASAP. It has never sounded worse on startup. Glad I got that on camera. It sounded like it was on 3 cylinders. It did catch first turn of the key though.

In the video I start it at 10 seconds in, the idle is rough until 40 seconds then the car won’t rev without hunting/ faltering until 1:10 After that I tried turning it of and restarting a few times but the problem wouldn’t repeat itself.

So:
30 seconds of really rough idle
Then another 30 seconds of level idle but won’t rev
1 minute after starting the car both the idle and running is back to normal

Unplugged the cold start valve and it kept starting first time. I’ll keep trying a combination of cold and hot starting with the plug in and out later.

Also ordered up a fuel filter. Probably Unrelated, but I haven’t done any work on the fuel system yet.

sinbin5t · 27-12-17, 06:46 PM

Wait till i try and start my NG coupe

That will be a barrel of laughs when the time comes

Cynical26 · 27-12-17, 07:37 PM

Video (hopefully):

https://www.flickr.com/x/t/0099009/p...4/25468186348/

John. · 27-12-17, 08:05 PM

Quote:

Originally Posted by Cynical26

Video (hopefully):

https://www.flickr.com/x/t/0099009/p...4/25468186348/

When it first started I thought you had a super rare NG diesel !!

Sounds like it's starting on 3 cylinders then the other 2 chime in as the air/fuel mixture sorts itself out?
Have you pulled the plugs prior to starting to see if they are wet with fuel or coolant.....this might be the worse case scenario, would be good to check and rule this out?

Cynical26 · 27-12-17, 08:42 PM

I’ve not looked at the plugs yet. I have a new set to go in, just need to find the time to do it.

Should get a chance on Friday.

Cynical26 · 27-12-17, 08:56 PM

Quote:

Originally Posted by John.

Sounds like it's starting on 3 cylinders then the other 2 chime in as the air/fuel mixture sorts itself out?

To be honest that’s the first time it has started like that. Normally it just takes longer than expected to start then idles a bit rough for a while.

I’m going to get new leads for it as well when fitting the plugs. Not sure how old the current ones are. Would be good to rule the spark out. The car can sometimes be a bit hesitant to accelerate too. Worth a punt.

27-12-17, 01:08 PM	#2
mikes2 4 ring whore! Classic Audi Club Member Join Date: Nov 2007 Location: Polmont Posts: 2,617	are you still getting the back firing or is that fixed now ? I'm guessing you've already swapped out the basics plugs, arm, cap air filter etc. All breathers and air hoses all good ? Injectors / seals - what state are they in ? __________________ 1991 90 quattro 20v sport 1991 90 quattro

27-12-17, 05:28 PM	#4
mikes2 4 ring whore! Classic Audi Club Member Join Date: Nov 2007 Location: Polmont Posts: 2,617	Just throwing a few suggestions out there. Other item worth checking is the timing. Has it always done it since you picked it up ? If it's consistent hot and cold, it's probably not the coldstart valve unless it's leaking / dribbling fuel __________________ 1991 90 quattro 20v sport 1991 90 quattro

27-12-17, 06:42 PM	#5
Cynical26 Grown up member Join Date: Dec 2016 Location: North Ayrshire Posts: 735	It started without fault when I first had it. Noticed it after replacing the split intake rubber and refitted the missing metal breather pipe from the crankcase. I’d say it’s got gradually worse since it first started doing it. I took a video tonight, I’ll try and get the link up ASAP. It has never sounded worse on startup. Glad I got that on camera. It sounded like it was on 3 cylinders. It did catch first turn of the key though. In the video I start it at 10 seconds in, the idle is rough until 40 seconds then the car won’t rev without hunting/ faltering until 1:10 After that I tried turning it of and restarting a few times but the problem wouldn’t repeat itself. So: 30 seconds of really rough idle Then another 30 seconds of level idle but won’t rev 1 minute after starting the car both the idle and running is back to normal Unplugged the cold start valve and it kept starting first time. I’ll keep trying a combination of cold and hot starting with the plug in and out later. Also ordered up a fuel filter. Probably Unrelated, but I haven’t done any work on the fuel system yet. Last edited by Cynical26; 27-12-17 at 07:00 PM.

27-12-17, 03:17 PM	#3
Cynical26 Grown up member Join Date: Dec 2016 Location: North Ayrshire Posts: 735	Arm, cap and air filter replaced. Plugs sitting in he garage ready to go in. Only breather hose I was worried about is the big one from the Air box to the fuel manafold. I was thinking that if I had a vacuum leak the problem wouldn’t clear up and would be present constantly. It hasn’t backfired since that time you witnessed it. Haven’t done much since then so doubt it has been fixed yet. I haven’t looked at the injectors.

27-12-17, 06:46 PM	#6
sinbin5t 4 ring whore! Classic Audi Club Member Join Date: Jan 2010 Location: Where a spike points skywards Posts: 12,960	Wait till i try and start my NG coupe That will be a barrel of laughs when the time comes

27-12-17, 07:37 PM	#7
Cynical26 Grown up member Join Date: Dec 2016 Location: North Ayrshire Posts: 735	Video (hopefully): https://www.flickr.com/x/t/0099009/p...4/25468186348/

27-12-17, 08:42 PM	#9
Cynical26 Grown up member Join Date: Dec 2016 Location: North Ayrshire Posts: 735	I’ve not looked at the plugs yet. I have a new set to go in, just need to find the time to do it. Should get a chance on Friday.