Hello Christian and Joe,
Who said old cars are like the other half of the human race, unpredictable, sometimes annoying, but immensely desirable and ultimately irreplaceable? Or maybe it is the other way around: desirable and irreplaceable, but also unpredictable and sometimes annoying?
Anyway, I tried a variation on Christian's suggestion this morning, ie hooking a test lamp (rather than a volt meter) to the CSV, removing the fuse for the fuel pump and the high voltage wire from the coil to the distributor, and cranking the engine during a cold start. I've done this several times already, in the course of my previous cold start investigations, albeit without the fuel pump fuse removal part. I reasoned that cutting the fuel pump off during the TTS/CSV test might give me new information (even if partial and imperfect) on the status of the injectors (not flooding the cylinders during the dry run test and seeing how the engine started during the actual start after).
The test lamp lit up for approximately 7-8 secs during the dry run (outside temperature was around 5-6°C), meaning the CSV was receiving current for the same amount of time. This confirms my previous tests and conclusion, that the relay and TTS are working more or less as they should (more about the TTS later).
After taking 5mns to put the fuel pump back on line and the high voltage wire in place (coil to distributor), I cranked the engine again for a 'live' cold start (I had left the test lamp in place). This time the engine started literally instantaneously, like in a dream, while the lamp lit up (so TTS and CSV were activated). I then took the car for a short drive around until it had reached its normal working temperature. So I got to enjoy the desirable and irreplaceable parts once again, justifying the small irritations...
All in all, a perfect cold start, after 'dry cranking' for a few seconds (probably not completely dry, I imagine, as there must be some residual pressure in the fuel system, even after a 24hr rest since the last run yesterday?).
This afternoon, after the car had rested for about 3 hours and largely cooled down, I tried to restart it. Same cold start woes as before: about 5-7secs of continuous cranking until the engine finally caught, then normal warm up routine (elevated RPMs, WRD sucking air, then gradually returning to normal idle a the engine gets warmer; this part leads me to believe the WRD is working right too).
Unpredictable? Well, maybe not. After all, except for this morning, the cold start is consistently difficult, yet never impossible. I must not be doing the right thing, that's all (isn't this always the case?).
However, I don't know what to think, and what more to do (isn't this always the case too?). Not ready to give up, but at a loss for the moment...
I have, I believe, explored, tested and eliminated every conceivable malfunction of the cold start system (fuel supply, TTS, CSV, CSS, relays, wiring, fuses), concluding that everything is working as it should. I'm hitting a wall, maybe for lack of knowledge about the injection pump and injectors?
Somebody told me that if the WRD is sucking air forcefully (as mine is), then it is working (ie also sliding the rack in the injection pump). I believe that hearing higher revs (and seeing the RPM counter move up to about 1100) during warmup, followed by a gradual return to normal regime means the WRD is indeed working as it should. Is this purely logical reasoning correct?
I have also been told that if the CSS is activated and working (which it is, as I have tested too), then the injection pump 'choke' mode is activated on cold start. However, I don't know how to test that effectively?
Finally, Christian, could you explain what the mark 36/2/9 (or 36/2/13) on the TTS means? And do you think, from the info I gave here above, that the specs of the TTS on my car are correct for the usage?
With many thanks,
François
