1990 Audi 100 2.3 NF - 2500 rpm idle! - Page 2

pimpdriver · 12-06-08, 12:33 PM

OK, the one off the 100 turbo didn't fit!!! Different plug.

I might just order one off ebay and try that.

Steve

pimpdriver · 17-06-08, 08:09 PM

Got a new ISV.

No change....

Bugger.

I will try cleaning out the throttle body again (but not tonight......)

Any other ideas?

4v6 · 17-06-08, 08:59 PM

Darn if i was closer id come get my hands dirty....

pimpdriver · 17-06-08, 09:11 PM

just been on phone to 'Manda, I'm going to replace all of the little vacuum hoses, the fabric covered ones. I might have cracked a previously perished one when I removed them.

Octanejunkie · 18-06-08, 08:03 AM

Easily done.
Had to replace a load of perished ones on my sport. Sometimes they bake hard and crack and sometimes they go all squidgy and collapse...

Make sure that ones that have lots of sucking going on through them are made of good quality stuff or they could collapse under load

Gonna replace all my hoses soon with silicon stuff. Highly resistant to all manner of under bonnet nastiness and they come in pretty colours too.

Octanejunkie · 18-06-08, 08:12 AM

Is the distributor in good condition? Do the advance mechanisms work as they should?
Does this engine have an auxillery air valve? It could be broke, letting in too much air.
The problem you're having is almost certainly too much air getting into the system and leaning it out at tickover/low revs.
Are the plugs still a nice browny colour?
Check all the cars "air" related devices.
Does this car have an ECU?
I might be able to pop over Monday or Tuesday if you're about during the day?

pimpdriver · 18-06-08, 02:43 PM

Quote:

Originally Posted by Octanejunkie

Is the distributor in good condition? Do the advance mechanisms work as they should?
Does this engine have an auxillery air valve? It could be broke, letting in too much air.
The problem you're having is almost certainly too much air getting into the system and leaning it out at tickover/low revs.
Are the plugs still a nice browny colour?
Check all the cars "air" related devices.
Does this car have an ECU?
I might be able to pop over Monday or Tuesday if you're about during the day?

Dizzy is fine (car was working fine apart from broken fuel pipe, until I took the frigging thing apart!)

It does have an ECU of sorts, being KE-JET rather than K-JET. The Aux air valve has been replaced by the ISV.

I am currently of the opinion that it is getting the correct 14:1 mixture when ticking over at 2400rpm, as it is neither leaning out, or running rich. I think that even though I checked the throttle butterflies, cleaning them out PROPERLY won't hurt.

Because it runs fine (apart from being at 2400rpm), I don't think that there is an air leak in the system, or an overfueling problem.

Quote:

Originally Posted by Octanejunkie

Easily done.
Had to replace a load of perished ones on my sport. Sometimes they bake hard and crack and sometimes they go all squidgy and collapse...

Make sure that ones that have lots of sucking going on through them are made of good quality stuff or they could collapse under load

Bought some 3.2mm fuel hose from Camberley Auto factors today. Will change hoses later.

I *MAY* be about on Monday / Tuesday if my wife has this bloody baby! SPent the morning in Bath Hospital cos she was having 3 minute contractions, lasting 1 minute.

But when we got there, they said, "yes you're having contractions, but go home until something else happens". WTF else can happen? C section booked in 2 weeks but it is torture as she has been contracting for 8 bloody days now and is knackered, but they woldn't do C section today cos they're too busy.

pimpdriver · 18-06-08, 09:01 PM

cleaned throttle body, made bugger all difference.

My latest theory is......

Engine is NF

New fuel pipes are off an NG (80/90 car) and are shorter. The pipes are a bit "stretched" but I managed to get the injectors to seat into the inserts, and the other end onto the metering head.

The injectors are held in place by a rail. However, as the pipes are a bit "stretched", some of them may be pulled over to a slight angle, and may be letting air in there.

I know everyone has said that already, but I tried squirting WD40 around the injectors, but the manifold is in the way. I also thought that an air leak would manifest itself as lean running, and wouldn't idle very well.

HOWEVER, this car has KE-JET which has a lambda sensor which can correct an imbalance in mixture.

So if it were leaking air in, the lambda sensor would sense lean running and tell the injection system to chuck more fuel in.

My other revelation will be to squirt carb cleaner directly onto the injectors one by one, as carb cleaner sprays a jet of liquid, whereas before I was using WD40 in a mist form, or a blowlamp, and neither are very directional.

That's my thoughts on the matter.

Anybody agree or disagree on my theory?

Only thing is if I find ot the pipes are too short, I'll either have to find some off an NF engine (bloody impossible), or get some made up by goodridge supplier (merlin motorsport at Castle Combe, 10 miles from me).

More bloody cost!!!!!!

Steve

4v6 · 19-06-08, 07:54 AM

I usually use carb cleaner or better still, brake spray as it dosent damage plastics and evaporates nice and quickly.

Octanejunkie · 19-06-08, 09:04 AM

I once had a 89 BMW 535i with an erratic idle. Sometimes lumpy, sometimes fast, and sometimes it would stall.
I chased all over the engine bay looking for the fault, replacing more or less every fuel/air related ancillery to no avail.

Turned out it was the ECU. Got another from a scrap yard and it still wasn't right. In the end i bought a used one from Ebay and it sorted it out.
15-20 years in hostile conditions can play havoc with old electrics.
Don't like the sound of those fuel lines though, can't be doing the system any good. Have you had a quote for a set to be made up?
Daft question, but i suppose GSF/Euro parts etc don't have them?
If you're certain your systems are in good order, then the next logical step would be the ECU.
If you can't find another one, carefully, and i do mean carefully, take the old ones case apart and you should find an old fashioned curcuit board inside. Get a magnifying glass or some other magnifying device and check carefully over the board checking for dry joints, corrosion, signs of burning or broken tracks. Take your time about this as it can be tricky to spot. Anything that looks suspect, waft a soldering iron over it and maybe chuck a bit more solder into the joint. If you can, try and have some flux on hand to help the solder flow properly as old solder can be a bit stubborn.
This may all sound a bit extreme, but if you can't get another ECU then repair is the next best thing. I've managed to repair a couple of ECU's in this manner plus a few instrument binnacles too, so its worth a try.
Alternativly, there are companys who will test and/or repair your ECU for you. Last time i looked it was around £100 odd.

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12-06-08, 12:33 PM	#11
pimpdriver Devon Pastie Muncher Classic Audi Club Member Join Date: Jul 2007 Location: Calne Wiltshire Posts: 7,530	OK, the one off the 100 turbo didn't fit!!! Different plug. I might just order one off ebay and try that. Steve

17-06-08, 08:09 PM	#12
pimpdriver Devon Pastie Muncher Classic Audi Club Member Join Date: Jul 2007 Location: Calne Wiltshire Posts: 7,530	Got a new ISV. No change.... Bugger. I will try cleaning out the throttle body again (but not tonight......) Any other ideas?

17-06-08, 08:59 PM	#13
4v6 Ex Member Classic Audi Club Member Join Date: Dec 2007 Posts: 5,565	Darn if i was closer id come get my hands dirty....

17-06-08, 09:11 PM	#14
pimpdriver Devon Pastie Muncher Classic Audi Club Member Join Date: Jul 2007 Location: Calne Wiltshire Posts: 7,530	just been on phone to 'Manda, I'm going to replace all of the little vacuum hoses, the fabric covered ones. I might have cracked a previously perished one when I removed them.

18-06-08, 08:03 AM	#15
Octanejunkie Grown up member Join Date: Apr 2008 Location: Clevedon, North Somerset Posts: 293	Easily done. Had to replace a load of perished ones on my sport. Sometimes they bake hard and crack and sometimes they go all squidgy and collapse... Make sure that ones that have lots of sucking going on through them are made of good quality stuff or they could collapse under load Gonna replace all my hoses soon with silicon stuff. Highly resistant to all manner of under bonnet nastiness and they come in pretty colours too.

18-06-08, 08:12 AM	#16
Octanejunkie Grown up member Join Date: Apr 2008 Location: Clevedon, North Somerset Posts: 293	Is the distributor in good condition? Do the advance mechanisms work as they should? Does this engine have an auxillery air valve? It could be broke, letting in too much air. The problem you're having is almost certainly too much air getting into the system and leaning it out at tickover/low revs. Are the plugs still a nice browny colour? Check all the cars "air" related devices. Does this car have an ECU? I might be able to pop over Monday or Tuesday if you're about during the day?

18-06-08, 09:01 PM	#18
pimpdriver Devon Pastie Muncher Classic Audi Club Member Join Date: Jul 2007 Location: Calne Wiltshire Posts: 7,530	cleaned throttle body, made bugger all difference. My latest theory is...... Engine is NF New fuel pipes are off an NG (80/90 car) and are shorter. The pipes are a bit "stretched" but I managed to get the injectors to seat into the inserts, and the other end onto the metering head. The injectors are held in place by a rail. However, as the pipes are a bit "stretched", some of them may be pulled over to a slight angle, and may be letting air in there. I know everyone has said that already, but I tried squirting WD40 around the injectors, but the manifold is in the way. I also thought that an air leak would manifest itself as lean running, and wouldn't idle very well. HOWEVER, this car has KE-JET which has a lambda sensor which can correct an imbalance in mixture. So if it were leaking air in, the lambda sensor would sense lean running and tell the injection system to chuck more fuel in. My other revelation will be to squirt carb cleaner directly onto the injectors one by one, as carb cleaner sprays a jet of liquid, whereas before I was using WD40 in a mist form, or a blowlamp, and neither are very directional. That's my thoughts on the matter. Anybody agree or disagree on my theory? Only thing is if I find ot the pipes are too short, I'll either have to find some off an NF engine (bloody impossible), or get some made up by goodridge supplier (merlin motorsport at Castle Combe, 10 miles from me). More bloody cost!!!!!! Steve

19-06-08, 07:54 AM	#19
4v6 Ex Member Classic Audi Club Member Join Date: Dec 2007 Posts: 5,565	I usually use carb cleaner or better still, brake spray as it dosent damage plastics and evaporates nice and quickly.

19-06-08, 09:04 AM	#20
Octanejunkie Grown up member Join Date: Apr 2008 Location: Clevedon, North Somerset Posts: 293	I once had a 89 BMW 535i with an erratic idle. Sometimes lumpy, sometimes fast, and sometimes it would stall. I chased all over the engine bay looking for the fault, replacing more or less every fuel/air related ancillery to no avail. Turned out it was the ECU. Got another from a scrap yard and it still wasn't right. In the end i bought a used one from Ebay and it sorted it out. 15-20 years in hostile conditions can play havoc with old electrics. Don't like the sound of those fuel lines though, can't be doing the system any good. Have you had a quote for a set to be made up? Daft question, but i suppose GSF/Euro parts etc don't have them? If you're certain your systems are in good order, then the next logical step would be the ECU. If you can't find another one, carefully, and i do mean carefully, take the old ones case apart and you should find an old fashioned curcuit board inside. Get a magnifying glass or some other magnifying device and check carefully over the board checking for dry joints, corrosion, signs of burning or broken tracks. Take your time about this as it can be tricky to spot. Anything that looks suspect, waft a soldering iron over it and maybe chuck a bit more solder into the joint. If you can, try and have some flux on hand to help the solder flow properly as old solder can be a bit stubborn. This may all sound a bit extreme, but if you can't get another ECU then repair is the next best thing. I've managed to repair a couple of ECU's in this manner plus a few instrument binnacles too, so its worth a try. Alternativly, there are companys who will test and/or repair your ECU for you. Last time i looked it was around £100 odd.