Coupe quattro starting probs.

[splitpin]

My 2.3 (NG) engine is difficult to start from cold. Once it is warm, it is on the button. Also, as soon as the engine is started, even from cold, the Low Coolant Level/High Coolant Temperature symbol flashes on the Autocheck system. I have checked the level and that is ok. According to both oil and water temp gauges the engine is not overheating. I have been told that the same sender is used for both Cold Starting and Autocheck. Is this correct? Has anyone else had this problem, and how was it resolved?




Cheers,
Graham.

[scotty33]

Hi

There is a sensor with gauge feed and overtemp warning, the multi function temp sender, but this does not control the Cold fuelling.

see this link for more info:

http://www.sjmautotechnik.com/troubl...ing.html#gauge
Audi Parts Specialist, SJM Autotechnik 503-244-2834, Audi Quattro Parts, VW Parts

As far as I can tell, the MFTS should be mounted on a pipe off the side of the head that the top hose connects to. The other sensor on that pipe should be the ecu temp sender for cold starting.

[splitpin]

Cheers for that info.
Will have to dig out my fluke (dmm) and bell it out.
Graham.

[splitpin]

I have sorted out the Low Coolant/High Temp warning.
I'm still having problems with cold starting.
I managed to interrogate the ECM using a LED and all it flashed was 4444. No Fault Found.
I have since removed the Cold Start Valve and turned engine over (when it was cold). The Cold Start Valve did not operate. I unplugged it and put 12V direct from the battery across it. It sprayed fuel OK.
Does anyone have a copy of the correct pin Numbers on ECM and which components are connected to it? Or even the current flow diagram for a 1990 Coupe quattro 2.3 10V (NG)?
Cheers,
Graham.

[splitpin]

HELP!!! I'm getting desperate now.
I have checked every connection on the ECU. Everything belled out OK except that I had no earth on Pin 34. Found it disconnected under the dash. Bolted to the earth on side of footwell. Thought this might have been the switched earth for Cold Start Valve.
Still problems Starting?
Has anyone got any ideas?
Cheers,
Graham.

[scotty33]

Hi Graham,

Try this link for more info on testing your KE III jetronic system:

http://www.sjmautotechnik.com/troubl...g/100ecuf.html

In particular, 2312 may be of interest:

• 2312 Coolant sensor Open or short circuit, Defective sensor or wiring Symptom: Cold starting difficulties at low temperatures, Poor idle and acceleration during warm up

n.b. you can have a situation where the sender is 'out of spec' but NOT open circuit or shorted so it does not throw a fault code - it is possible your sensor is telling the ECU the engine is warm when it is stone cold?

[splitpin]

Hi Scotty33,
I replaced the Coolant Temp Sensor for a new one from Audi (Main Dealer Part Only). It still wouldn't start from cold.
The only other thing I could think of, is if there is a break in the wire that makes when little or no current is sent down it, but as soon as you try to fire the Cold Start Valve it breaks the connection. To check this theory, I connected a wire to the CSV Earth and ran it into the car. I turned the engine over, and while cranking, earthed the wire. Hey presto engine started immediately.
As weather has started to get too wet and cold, I fitted a switch under the Dash that I just push while I start engine.
Will get to bottom of problem in new year.
Many Thanks,
Graham.

[scotty33]

Sorry to labour this point, I may well be barking up the wrong tree! Have you changed the Mfts to cure the autocheck overtemp alarm?
Have you changed the other coolant temp sender which controls cold enrichment only?

[splitpin]

Hi, I changed the MFTS a while ago. The Temp gauge is now working correctly. The autocheck was still showing overtemp/low coolant. I found that the low coolant sensor was closed circuit. I have unplugged this now and everything is working fine. How do you change the low coolant sensor in the header tank?
So answer to you question, yes I have changed both senders.
Cheers,
Graham.