I am having occasional problems with starting my 98.5 A4 1.8TQ (5-speed). The engine spins just fine, but will not "catch" and start. From observation, this only seems to happen when the car has been sitting outdoors in direct sunlight and high heat. I do not know if this has any connection to the problem. The car will generally start again after sitting for ½ to 1 hour.

I have checked the ECM fault codes and have found the following:

P1237, P1238, P1239, P1240 (All four injectors, open circuit, intermittent);

P1425 (Evap. Purge Valve, short to ground, intermittent);

P1547 (Boost Pressure Regulator Valve, short to ground, intermittent);

and P1472 (Evap. Leak Detection Pump, short to ground, intermittent).


My first step was to replace the ignition switch, which was sticking and had become difficult to turn. This was something that needed to be done, and my hope was there may have been a short in the ignition switch. A new switch was installed and no shorts discovered.


My thinking now is this is some other sort of electrical short, or a problem with the ECM. I know ECM failure is very rare, but I suppose I need to consider the possibility.

Any advice or help you may be able to give me would be greatly appreciated!

Mike

Mike