Wiring loom installation

[Random]

I am looking at the wiring loom for the 2b and the new loom seems to make sense. It looks like I need to take some things from the old loom so that the 2.0 pinto (carburettor) ESC module has its own circuit for the engine. I don't fully understand what this module is for other than is seems to do something with the distributor. Does anyone have a list of the stuff it must connect to for the engine to work?

Edited November 26, 2020 by Random

[richyb66]

Have a look at this but you need to identify which system you have. Everything you need to know should be there. 

https://nw.rhocar.org/Ford ignition systems.htm

[Random]

Thanks.

What is the power hold relay for? 

What does the ESC use the water temperature for? Wouldn't this sensor be needed for the temperature guage on the dash, can it be shared?

 

[IanS]

cant remember the power hold.

The temp sensor has to be 2 wire and electrically insulated  from the engine block for the ESC module.

The gauge sensor is one wire as it earths through the engine block.

So without a load of electronics the same sensor will not work for both.

[Random]

So what do people do then, fit an extra sensor, go without a temperature guage, or just not connect the ESC up to the sensor?

(I can't work out why it needs to know the temperature)

[IanS]

Ignition is retarded for a cold engine.

[Sparepart]

I have the luxury of a copy of the Haynes Service and Repair manual .... I found a copy on line some time ago... I am rebuilding using the original Sierra Gia model loom that had ALL the bells and whistles. I don't need most of the wire, but I am too cheap to just throw it away and buy a new purpose built loom. So I have been pruning literally pounds of weight out of the mass of wires, and in doing so have had to take care not to remove something I need. So to get to your questions. The manual says the Power Hold relay allows the stepper motor (it's what operates the choke) to operate for a short time after the ignition has been turned off, to ventilate the manifold and deter the engine from "running on". Running on is what it says, you turn off the ignition but the engine keeps running for a while, very annoying. As for your temperature guage question. There are two temperature sensors shown in the manual, I did not look on my engine because it's all wrapped in cling film at the moment. In Chapter 3, page 3.8 picture 16.3a shows a sensor screwed into the block just opposite the dizzy cap. This is the one that runs to the guage, in the wiring diagram it is item 30 "Coolant Temp Sensor". The other sensor, the one for the ESC module is item 58 "Engine Coolant Temp. Sensor" its located in the underside of the inlet maniford (Page 5.20, picture 19.4) it's a bigish plug just above the oil filter.

[Sparepart]

As well as retarding the ignition for a cold engine, the temperature is used to apply choke, and turn on the manifold heater. So it's pretty important.

[Random]

Thanks for the information, on closer inspection as you said the temperature sensor for the ESC does appear to be surface mount, and a separate temperature sensor is in the block for the guage. Looks like I need to wire in a power hold relay (I was asking because it seems to be missing from my loom. Great.)

[Random]

The wiring diagram is all good, but does anyone have the numbering for the ESC 2 plug so I know which one is PIN 1 and which one is PIN 25 etc?

Edited December 18, 2020 by Random

[Random]

24 minutes ago, Random said:

The wiring diagram is all good, but does anyone have the numbering for the ESC 2 plug so I know which one is PIN 1 and which one is PIN 25 etc?

Ah, it's written on the ESC unit.

[Sparepart]

Random, I am really interested to know how you have/are connecting the ESC2 into your loom and how much of the Ford donor loom you are using. Especially whether or not you are following the diagram referenced earlier in this post at:-

https://nw.rhocar.org/Ford ignition systems.htm

I am still using the whole of engine bay loom from the donor as fitted on the Sierra, and there are several more components in the original loom that do not appear in the simpler circuit shown in the diagram. Looking at the circuit diagram in the Haynes manual, there is another relay, a couple of suppressors and a connection from the power hold relay to pin 8 of the ESC2 module. I am thinking that if your simpler loom works then I might be able to remove some wires and a relay from mine.

Edited December 22, 2020 by Sparepart
Correct the embedded url link

[Random]

The loom is still a working progress. I am following the diagram posted. I will use the old engine loom as unmodified as possible to get the engine started, and once running will be removing as much as possible. 

[Sparepart]

Quite similar to what I am attempting. I have found the Haynes wiring diagrams quite hard to follow AND do not exactly match what I see in front of me. I am also using diagrams from a french persons cloud site that Google turned up. I put the link below to download the pdf. The diagrams are for all the electrics, and in there are coloured diagrams for the bits in the engine bay, they seem easier to understand and so far more accurate. (however the power input pin for the ESC2, pin 8, near the top is miss-labeled as pin 13). Anyway you might find these diagrams of some use.

http://www.jeankule.free.fr/Pinto/1982-1989.pdf

 

[Random]

Link didn't work for me, but I found the PDF after a search. Thanks for the information. Let me know how you get on.