Upgraded Cold Start Logic HARNESS

[lpeterssen]

Dear Friends:

JUST LAUNCHED another wiring harness product that I personally consider a MUST for everyone driving a w113-230/250SL.

As you may know early MB Pagodas used a different COLD START logic than the one implemented by Mercedes in later cars with mechanical fuel injection.

They key problem on that early design was the use of two components which are NLA, and therefore market good used units asking price is ELEVATED.

I am talking about:

1.  TIMED RELAY. 

The “old can style” one second timed relay is NLA and this unit after 60 years of operation, shows in most of the cases an non consistent operation; which translates into random difficult engine starts.   Prices for this component are above 500$

2. TTS With screw terminals.

Thermo Time switch is a vital component on your MB w113 cold start logic.  This component based on the bimetallic heating principle, fatigues with time and produces therefore, erratic signals which convert into difficult engine start up.  NEW units, can be sourced for rocket high prices as 900$.  Same kind of TTS Units like the one used on Porsches or later Mercedes as W116 /126 which have solid state electronics instead are readily available through many vendors.  As offer is broader prices for new units can be as low as 85$.

This harness which I present here will allow MB w113 230/250SL owners to run their cars on the latest COLD START LOGIC which will bring to your loved Sunday drive the reliability you dream.

This is a PLUG AND PLAY solution that will allow you to use original Mercedes Benz electric components available everywhere at a much lower price point, saving you hundreds of dollars among giving you the confidence that your car will start up without hesitation every time.

Harness priced very competitive at only USD 695, which is a bargain considering the savings you will have because you will not be forced to buy specific old electric components like the 1sec relay, and  old style TTS (500+900=1,400$ in savings).

Enjoy this innovative solution and spread the word among colleagues.

Also available for free an adapter if you still want to use screw type TTS.

Best regards
Eng. Leonardo Peterssen
Www.Wiredoktor.com

[lpeterssen]

Detailed photographs here:

https://www.icloud.com/sharedalbum/#B0Q5sWRpHqZPOa

[lpeterssen]

Link to the product on my webstore:

https://wiredoktor.com/products/mb-w113-230sl-cold-start-harness-upgrade

Visit www.Wiredoktor.com

 Best regards
L.peterssen

[lpeterssen]

Dear friends

Some technical background to understand 230SL cold start logic vs. 280SL.

230SL/250
=======

The cold start aids have two points to inject more fuel during startups.  One is the CSV (Cold Start Valve) at intake manifold and the other is the Fuel Mixture selenoid at the mechanical FIP which moves the rack to RICH position when activated.

The cold start aids are activated BOTH at the same during engine cranking on the following time frames

A.) EVERY TIME for ONE SECOND, no matter if engine is cold or hot., This function is controlled by the cylindrical 1 sec timed relay.

B.) For up to 10 seconds while cranking.  IF engine temperature is lower than 35 degrees Celsius.  This function is governed by the TTS thermo time switch in conjunction with the standard rectangular relay.

So if you have difficulties starting up cold, your most probable culprit is a defective TTS.

If your starting up difficulties show only when car is hot, I will turn my head towards the TIMED 1 sec relay.

Later Mercedes changed the logic of this part of the wiring harness as is described here below:

Late 250SL/280SL
============

On these cars the cold start aids are independent.  Here the CSV At intake is controlled by one relay, as it does the ENRICHMENT selenoid which is controlled  by another separated relay.  Both of them are from the standard rectangular type (4 prongs).

TTS brings the activation negative signal ONLY to the CSV which in turn  sprays fuel during cranking for up to 10 sec as long as engine is colder than 35C.

In contrast ENRICHMENT selenoid at the FIP is activated ALWAYS during the cranking process, with no time or temperature limitation.


So……. The Harness proposed for 230SL/250SL here, mimic’s that later logic and eliminates the use of the 1sec TIMED RELAY which is very very hard to find new, and therefore expensive.   And also implements a newer solid state TTS as seen on modern Mercedes from the 90’ which is very ver reliable and can be sourced NEW for almost no money (90$ at Mercedes dealership).

So having this PATCH HARNESS on a EARLY PAGODA is in my opinion a LOGICAL and JUSTIFIED upgrade seen the difficulties in sourcing NEW ORIGINAL COMPONENTS used on the early design Cold start logic.

Best regards
Eng. Leonardo Peterssen

[lpeterssen]

Here my friends, just for reference the picture of an old style TIME RELAY used on the 230/250SL cold start logic