AMF misfire

Often, the early sign of a failing crankshaft sensor is for the engine to shut down when the sensor gets hot, then restart when the sensor has cooled down a bit

Cheers Spike
 
spike said:
Often, the early sign of a failing crankshaft sensor is for the engine to shut down when the sensor gets hot, then restart when the sensor has cooled down a bit

Cheers Spike
Click to expand...
That’s exactly what I experienced with a Merc crank sensor failure. The engine stopped when hot then started again when cold.
The A2 failed differently in that it started instantly and ran reliably but with a misfire.
 
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philward said:
That’s exactly what I experienced with a Merc crank sensor failure. The engine stopped when hot then started again when cold.
The A2 failed differently in that it started instantly and ran reliably but with a misfire.
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Exactly that happened to my CLK, so the Crank sensor in this case maybe ruled out.
 
I'm waiting for the weather to improve before starting this repair. I say repair, the cause of the misfire is a best guess but I was confident enough to commit £84 for a replacement part.

IMG_0095.jpg


I've got a bit of time on my hands so I'm going to use it to have a right good moan on my own thread. Firstly the part I've bought; £84 for four bits of wire some connectors, terminals and a bit of trunking. That is £21 per wire, where do the prices come from?
Next this may be incorrect but I suspect this part is NLA at Audi. Add cooling hoses, gear selector cables, engine mounts, hand brake cables, all NLA and my faithful daily motor of 18 years has suddenly become a liability for daily use.
The thing that really gets to me about that is the car is far from finished, with access to parts I could keep it going for many years.

InkedIMG_5632_LI.jpg


No need then, if I could maintain it, to incur responsibility for all the carbon emissions associated with producing my new car!
Rant over, under these circumstances I'm sure I'm not looking at a future classic, but the car is too good to part with, so I'm likely to find space in my lockup and get him out for towing duties. Shame and shame for the environment when I buy a replacement.
 
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philward said:
Add cooling hoses, gear selector cables, engine mounts, hand brake cables, all NLA and my faithful daily motor of 18 years has suddenly become a liability for daily use.
The thing that really gets to me about that is the car is far from finished, with access to parts I could keep it going for many years.
Click to expand...
I've got most of the TDI coolant hoses in stock, have gear selector cables regularly, TDI engine mounts in stock, handbrake cables are still available new. Don't give up just yet, its just a matter of keeping a few of the perishable on the shelf just incase.
 
philward said:
I'm waiting for the weather to improve before starting this repair. I say repair, the cause of the misfire is a best guess but I was confident enough to commit £84 for a replacement part.

View attachment 90856

I've got a bit of time on my hands so I'm going to use it to have a right good moan on my own thread. Firstly the part I've bought; £84 for four bits of wire some connectors, terminals and a bit of trunking. That is £21 per wire, where do the prices come from?
Next this may be incorrect but I suspect this part is NLA at Audi. Add cooling hoses, gear selector cables, engine mounts, hand brake cables, all NLA and my faithful daily motor of 18 years has suddenly become a liability for daily use.
The thing that really gets to me about that is the car is far from finished, with access to parts I could keep it going for many years.

View attachment 90857

No need then, if I could maintain it, to incur responsibility for all the carbon emissions associated with producing my new car!
Rant over, under these circumstances I'm sure I'm not looking at a future classic, but the car is too good to part with, so I'm likely to find space in my lockup and get him out for towing duties. Shame and shame for the environment when I buy a replacement.
Click to expand...
Before you just replace the injector harness take a look at the connectors to each of the injectors as when I had a misfire on injector two that got progressively worse, I found that it was simply down to one of the spade connections on cylinder 2 having worn itself loose over 18 years or so, probably due to more engine movement over time (and one connector on another injector was a little loose too although not yet causing a problem) so I simply removed and pinched the connectors to get a tighter fit on the spades which solved the problem and the car has run perfectly ever since and the fault has not returned, now many months later.

The rocker cover on my car had never been removed before and the loom looked perfectly intact.

Good luck and I hope you get your problem resolved quickly?
 
@A2Z the new harness will be fitted but the old one I'm going to keep, inspect and repair. If it is a simple matter of the connectors springing due to engine vibration then, as you say, that is an easy repair.
 
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The injector harness is easy to check using the procedure below. Not much to go wrong apart from maybe the crimp. I bought a new one but never needed it; it was a poor connection at the ECU.

RAB


Injector Check.JPG
 
A2Z said:
Before you just replace the injector harness take a look at the connectors to each of the injectors as when I had a misfire on injector two that got progressively worse, I found that it was simply down to one of the spade connections on cylinder 2 having worn itself loose over 18 years or so, probably due to more engine movement over time (and one connector on another injector was a little loose too although not yet causing a problem) so I simply removed and pinched the connectors to get a tighter fit on the spades which solved the problem and the car has run perfectly ever since and the fault has not returned, now many months later.

The rocker cover on my car had never been removed before and the loom looked perfectly intact.

Good luck and I hope you get your problem resolved quickly?
Click to expand...
Exactly, no need for new harness! I had misfiring issue on my former 1.9TDI AUY (Sharan) and the only thing I did was disconnecting the harness little bit squeezed all the connectors, sprayed "connector spray" on all the injector connections and reconnected. Misfire never occured again in 3 years I had the car ;)
 
Old loom, checked it with the large twist on connector disconnected.
TDi 75 so I assumed the turbo would be bomb proof.
Injectors? No fault codes so I assumed not.
 
Just because the resistance was the same cold does not mean the loom is good. Once the oil and engine are warm that is when the values could be different. If intermittent then could read the same most of the time anyway...

Not to say the problem is not in the "car" side of the wiring or even cleared while disconnecting the knurled nut.
 
I've bought a new harness so I'm going to replace it. The old one is leaking oil quite badly so that's my justification if nothing changes running wise. Will report when reassembled. If there is no change then I'll probably help somebody else save £84.
@A2Z just this minute pulled them off. They all took a bit of pulling to get them off.
 
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philward said:
I've bought a new harness so I'm going to replace it. The old one is leaking oil quite badly so that's my justification if nothing changes running wise. Will report when reassembled. If there is no change then I'll probably help somebody else save £84.
@A2Z just this minute pulled them off. They all took a bit of pulling to get them off.
Click to expand...
Where did you purchase the harness? Going to see if they do the petrol variety.
 
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