My 230SL ignition/hot/cold start issues solved.

[Paul99]

My issues were around hot/cold starting as I know many people have. 

I offer my solution only as it fixed my issues, might not fix yours, then again might. Might not be "by the book" but worked for me. Hope it helps others.

Engine was "stuttering"-( new plugs and 123 ignition) at high revs -  Replaced the coil. Problem disappeared.

Cold starts fine but could be better.

Hot starts a real pain. Got to point that it WOULD NOT start when very hot.

1) Removed the wire on the back of the injection pump - which I believe was flooding the engine when hot..  - helped massively. Still took a bit too long sometimes. 
 
2) Then adjusted the" time switch " relay.  Closed the gap slightly. Seemed ok when cold but when the engine bay was hot the gap was there so didn't energise the inlet csv on cranking.

3) Also did the "fix" where I grounded the thermo time switch.

Now all issues gone. Starts hot/cold/very hot/very cold/slightly hot/slightly cold !  At last!

Hope that helps.  As i said, might not help everyone but solved my problems so happy.

[rwmastel]

Paul99,

I don't have a full understanding of these starting aids.  Because you say your solutions may not be "by the book", I hope you're setting things "right" instead of masking other things that are "wrong".

[Paul99]

Well what I mean "not by the book" is that in theory you don't need to make any adjustments at all to make our cars start and run perfectly.  If they were straight from the factory they would start perfectly every time.  It seems 60 years and 150k miles later means my car needed a bit of help/tweaking.

[lpeterssen]

Dear Paul

Interesting your comments, but many reveal that wear does not forgive even electrical parts.

1. The Timed relay (3prong) used on the cold start mechanism of 230/250SL is an aging part.  Very expensive to source new if you get lucky to find one NOS.  In my opinion, everyone having this start logic should go either : a) replace the 1sec relay off with a modern HELLA cubed relay or b) make someone like me to modify the harness to have the cold start logic of a 280SL which uses components easier to source and that has proven that its cold start logic it’s better.  You can hide the HELLA timed off relay inside the housing of the old cylinder time relay.

2. TTS, that is also an aging part. Go for a new one as used on Porsches or w126 and change terminal connections accordingly.  A Solid state part surpasses the reliability you can have from an aging bimetallic TTS, and that part from w126 can be sourced NEW.

3. Importance of grounds, also shows on your post.  The engine should be correctly grounded in order to have a working CSV ( which in some harness receives  only a positive lead , not also a ground). And same story for the TTS.  Remember that TTS is activated by the positive T50 Starter signal (rose blue cable lead) and in return gives through the rose cablea NEGATIVE triggering signal which s used by both Cold start relays.

So if the TTS lacks of good grounding it can not pass that ground signal to the cold start relays array.

Best regards
L.Peterssen