Hi, I have an '82 528e with consistent cold start issues - over the summer, the car would start okay but not so great when warm...and was inconsistent sometimes it would fire up sometimes not. I narrowed it down to the cold start circuit. Either the CSV was not working or working when it wasn't supposed to - I replaced with a good used and all was okay then that stopped working! I'm going nuts with this at this point...
I then tested and replaced the TTS and the cold start valve and all was fine, then all of a sudden - it's not working again...I do understand that the TTS provides the gnd to the CSV...but the CSV is not getting any power at all now. I can't seem to see where the CSV get's it's power. I have the troubleshooting guide but can't quiet decipher it - Does the unloader relay shoot power to it? I get the function of the unloader relay but it did look like power goes to the CSV from there. Or does power go through the ECU during the starting process?
thanks for any insights. Chuck
Cold start valve issues
Re: Cold start valve issues
Chuck,
The TTS gets power from Ignition Switch Terminal 50. This is the start position that energizes the starter solenoid. Black and yellow wire.
You will only find power at the TTS while cranking.
This signal goes to the unloader relay and de-energizes it, turns it off. The unloader relay shuts down power consumers that are not needed to start the engine, allowing more battery to operate the starter.
Hope that helps you locate your issue, don't forget to look for poor contacts with all these components!!
Jeff
The TTS gets power from Ignition Switch Terminal 50. This is the start position that energizes the starter solenoid. Black and yellow wire.
You will only find power at the TTS while cranking.
This signal goes to the unloader relay and de-energizes it, turns it off. The unloader relay shuts down power consumers that are not needed to start the engine, allowing more battery to operate the starter.
Hope that helps you locate your issue, don't forget to look for poor contacts with all these components!!
Jeff
Re: Cold start valve issues
Hi Jeff, thank you for the clarity.
I found a wiring diagram that shows the blk/yellow wire (that connects the TTS and the CSV) connecting to terminal 50 and to the starter. According to the Bentley I should get battery voltage at the TTS connector and the CSV (thru the blk/yellow wire). i am getting power at the CSV but not at the TTS...so it's not firing...somewhere the blk/yellow wire TO the TTS is broken I think
Regards,
Chuck
I found a wiring diagram that shows the blk/yellow wire (that connects the TTS and the CSV) connecting to terminal 50 and to the starter. According to the Bentley I should get battery voltage at the TTS connector and the CSV (thru the blk/yellow wire). i am getting power at the CSV but not at the TTS...so it's not firing...somewhere the blk/yellow wire TO the TTS is broken I think
Regards,
Chuck
Re: Cold start valve issues
That suggests something other than the CSV. Granted on M30 cars, not M20, but I ran mine for testing for a while with the CSV unplugged. Down to the high 20s temp wise. And I was unable to notice any difference in starting with it connected. There is considerable cold start enrichment thru the start function anyway, aside from the CSV, and others have had similar experiences with it. Now, after all that I'm not sure where your problem is, but I don't think it's the CSV or that circuit.over the summer, the car would start okay but not so great when warm...and was inconsistent sometimes it would fire up sometimes not.
Additionally, you said you replaced the TTS, what did you replace it with? The new version is electronic not a heater circuit like the originals and some have had nothing but problems with them, they don't seem to function like the originals. But you shouldn't need the CSV in anything besides cold winter days at most.
Re: Cold start valve issues
Hi Mike thanks for the response - I replaced the TTS with a new 'original' equipment version, it functions like the original and looks just like it. On my particular car - if I don't have the CSV operating - the car is very hard to start. And I've tested this in warm, chilly and cold temps by unplugging the TTS and it's almost impossible to start - but plug it in, and it fires right up...according to the Bentley manual too, they mention that a non-functioning M20 CSV or TTS circuit would cause a non-start. That may not be everyones M20 experience, just mine. And my car runs like new car on a normal day full of power and coolness.
I had this issue for months and months and through trial and error and testing just about everything, it came down to the cold start circuit...I think I did find the culprit in the non-functioning TTS, the connector had a frayed blk/yellow wire...making a dubious connection. Checking the BACK of the connector (removing the boot) showed that it had power on cranking...but not from the connector itself...I'll fix that and see where it goes.
Now on to my other issue: a frustrating intermittent miss...it's always something.
thank you for all the responses.
Chuck
I had this issue for months and months and through trial and error and testing just about everything, it came down to the cold start circuit...I think I did find the culprit in the non-functioning TTS, the connector had a frayed blk/yellow wire...making a dubious connection. Checking the BACK of the connector (removing the boot) showed that it had power on cranking...but not from the connector itself...I'll fix that and see where it goes.
Now on to my other issue: a frustrating intermittent miss...it's always something.
thank you for all the responses.
Chuck
Re: Cold start valve issues
Hi, I just saw this post and I know it’s over a month old but thought I would chime in. I have your exact same ‘82 528e. The issue with our cars is the TTS only works if the temperature of the coolant is 15 degrees C or below. The newer TTS are rated at 35 degrees C which will definitely make cold starting much faster. Hope this helps?