My question would be why do you feel you need to disable the cold start injector? Is it flooding the engine on occasion? What if you take the car to the mountains in the winter - you may then wish you HAD a functioning CSI.

I had a 1990 740 Regina for many years. That was the model year that had issues with flooding due to the injector staying open too long. So Volvo issued a service bulletin instructing mechanics to snip the wire coming from the ECU to the CSI and just run a jumper wire from the starter motor to the CSI. That way the injector only opened while the starter was cranking, regardless of engine temperature. The down side was that it caused the OBD to record a fault code due to the open circuit between the ECU and the CSI. So whenever you read out the fault codes, that one (I can't recall the code number) would always appear which would limit the system to displaying only two more (valid) codes as it could only retain a total of three codes total. It did NOT trigger a check engine light so it really wasn't an issue. My guess is that if you simply disconnect the plug from CSI, it will record a fault code in the same manner but do no harm.

You electrically disable the cold start injector by disconnecting the cold start injector from the wiring harness.

You then place a tolerant resistor of the same load as the cold start injector.

You do this as the cold start injector driver in the ECU expects to see load. A fault code is indicating a faulty cold start injector, otherwise.

The next and somewhat messy step is:
- At least removing the cold start injector from the fuel line, then plugging, removing or something with the fuel line.
- You then remove the cold start injector and plug the hole using the same cold start retaining hardware, a cover shaped to fit the cold start injector hole, and some gasket method, appropriate to the application.

Indeed, why in Bosch LH-Jetronic 3.1, Bosch remove the cold start injector complete. Yet you only have the Bosch LH-Jetronic 3.1, and corresponding EZK ignition, on Volvo 240s 1988 or so and newer with manual transmission and no EGR.

Others can direct you to the procedure. You may want to use Google and target brickboard.com using search terms. Include in the search field the expression, and without quotes, "site:brickboard.com" or, maybe better, "site:www.brickboard.com" The www limits the network protocol the search engine uses to search the domain of your interest, I believe.

cheers,

dud