SL280 Cold start issues

[Ksprul]

Hi,
I'm new to the group and new to Pagoda ownership having picked up my SL280 only last weekend.  I have a 1968 model which has been well looked after but has starting problems when cold. 

I tested the CSV with a meter and found that it's not getting power when the ignition is set to crank.  I then connected the CSV solenoid to positive battery terminal and heard it operate and if i do that whilst cranking and cold it has the desired effect of increasing the idle so I think everything is ok with the CSV.

I then downloaded the wiring diagram and traced out items 21, 31, 32 and 47 to see if i could understand what's going on. 

If I understand it correctly moving the ignition to position 2 provides power to the starter relay switch terminal  and then further turning the ignition to  crank energizes the relay coil, operating the CSV.  I tested this with a meeter and it all looks correct.  However as soon as the ignition falls back to position 2 (post cranking) the relay unenergized (which also looks correct from the circuit diagram to my eyes).   From my limited understanding of the TTS i assumed it would be driven from the engaged relay until the water is up to temperature or until 12 seconds elapses. 

Not sure if I understand this correctly but should the TTS or the relay latch in someway so that the TTS receives power post cranking.

Any help in understanding how this works would be much appreciated and apologies in advance if I used the wrong words/terminology. 
Karl

[Pawel66]

Karl,

You are a Full Member - did you have a chance to take a look at Engine Starting Aid chapter in the Tech Manual? I think rather than me writing it here again, you may want to take a look there, where it is described and explained.

TTS is not getting power after cranking.

Simplest test of your TTS is to check if you have ground on W connector when the engine is cold. If you do not, TTS is most likely bad.

[wwheeler]

Karl,

Yes, Pawell has the best suggestion and that is to study all that relates to the cold starting system on this site. It is very complex and not easy to grasp at first. Take your time and absorb it. Both the Cold Start valve and starting solenoid (if equipped) only function while cranking. Once the engine is running, these no longer function. The Warm Running Device (WRD) functions after cranking and until the engine warms up.

Congrats on becoming a full member! This is the best site I found to help on these cars.

[Pawel66]

Congrats on becoming a full member! This is the best site I found to help on these cars.

For me it is also one of the best investments I have ever made .

[Ksprul]

Thanks for the feedback.  I'd not become a full time member when I posted and so had not seen the engine starting aid.  I've read through it a few times and I'm ready to dive back into trouble shooting this weekend with a clearer understanding.  Thanks for suggestions and warm welcome.
Karl

[Ksprul]

Ok so it turns out the CSV relay had tarnished contacts.  After taking it apart and cleaning i now have both the CSV and injection pump solenoids energized when cranking.

The car now fires and runs on the first crank however it slowly losses rpm's and then dies over a period of about 6-8 seconds.  If I repeats the process a couple of times on the third or forth time something changes and it idles a little higher and does'nt die.

Any suggestions of where to look next would be appreciated.  What i've read so far points to the warm running device?

[Pawel66]

Congratulations on the cold start! Feels good to crack it? 

I have not experienced similar issue, so as for spot-on solutions, perhaps someone who did will bring more value.

In general what I could say here is that:
1. My observaiton was that it took some driven kilometers for the changes in the idle settings to take effect and stabilize. I ended up driving with a set of tools to make adjustments and always made 15-20km before next step. Bad thing about it is that when you stop to do adjustments you usually get a crowd of advisors and helpers around... do not stop at shopping malls parking lots.
2. I think it is correct for idle to go down slowly from cold start, obviously stalling is unwanted here.
3. Could be WRD closing off too late or too soon - at what temperature does the engine die?
4. But I would start from more basic stuff in case you have not done that yet
- condition of spark plugs and wires, how good spark is; when engine dies and you remove spark plug - how does it look?
- how long ago did you look at the air filter?
- ignition timing/dwell
- idle running condition - regular and warm up - is it too rich?
- linkage tour and idle setting