Bosch - cold start?

[ColinJack]

Probably one of those 'everybody knows that!' questions - sorry

I am changing my EPIC for a Bosch pump. The pump I am fitting has a unit with bellows and a connector on the side



I presume this is a cold start assist? What does it connect to and how does it work?

Many thanks

[ColinJack]

Ahaaa ... bit if googling found this



Where is it connected to? Has an electrical connection on the back - thermostat somewhere?

[MinorMatt]

I know what it is

And yes its a cold start solenoid fitted from ~94-96.

It connected to a switch which screwed in to the side of the block below the fuel filter.

You wont have the provision for the switch in the block, so you could connect a choke cable to the lever

[ColinJack]

I know what it is

And yes its a cold start solenoid fitted from ~94-96.

It connected to a switch which screwed in to the side of the block below the fuel filter.

You wont have the provision for the switch in the block, so you could connect a choke cable to the lever

Thanks Matt,

Won't have anything suitable in the 2000 block then.

Oh well - just have get the fuelling right then ....

[MinorMatt]

It increases the amount of diesel injected... so if you have it on a cable inside the dash you can control the amount of smoke on the move...

Im not sure how well the low pressure (early) pump will work with the later high pressure injectors though

[ColinJack]

It increases the amount of diesel injected... so if you have it on a cable inside the dash you can control the amount of smoke on the move...

Im not sure how well the low pressure (early) pump will work with the later high pressure injectors though

Like James Bond - can drop a smoke screen

This is a 108 pump which Tim reckons should be okay. Am I right in saying that it is relatively easy to turn the pressure up?

Not sure if you saw this thread viewtopic.php?f=4&t=129480

[MinorMatt]

A 108 is exactly what was originally fitted to my 95 190 LWB 76PS And they were fitted AFAIK until late 1995 not 1997 as you suggest in the other thread...

You can't get torque sleeves for them (well I couldn't 5 years ago) so bear that in mind.

[ColinJack]

A 108 is exactly what was originally fitted to my 95 190 LWB 76PS And they were fitted AFAIK until late 1995 not 1997 as you suggest in the other thread...

You can't get torque sleeves for them (well I couldn't 5 years ago) so bear that in mind.

Ooh errr ... may need to have a word with my supplier (dieselhead123).
Only got the date of 1997 off a supplier website, so can't be sure.

Thanks Matt

[ColinJack]

Just thinking about it - if that is just a solenoid then I could just fit a 'cold start switch' and whack 12v to it when required?

Found this on tinternet:

Method of operation

Automatically and manually operated cold-start accelerators (KSB) differ only with regard to their external advance mechanisms. The method of operation is identical. With the bowden cable not pulled, the coil spring pushes the stop lever up against the stop. Ball pin and roller ring are in their initial position. The force applied by the bowden cable causes the stop lever, the shaft, the inner lever and the ball pin, to swivel and change the roller ring’s setting so that the start of delivery is advanced. The ball pin engages in a slot in the roller ring, which means that the timing-device piston cannot rotate the roller ring any further in the “advance” direction until a given engine speed has been exceeded. In those cases in which the KSB is triggered by the driver from the cab(timing-device KSB), independent of the advance defined by the timing device (a),an advance of approx. 2.5°camshaft is maintained (b), as shown in Fig. 13. With the automatically operated KSB, this advance depends upon the engine temperature or ambient temperature.The automatic advance mechanism uses a control device in which a temperature-sensitive expansion element converts the engine temperature into a stroke movement. The advantage of this method is that for a given temperature, the optimum start of delivery (or start of injection) is always selected.There are a number of different lever configurations and operating mechanisms in use depending upon the direction of rotation, and on which side the KSB is mounted.

[MinorMatt]

yes... if it still works (easy enough to check).

But put a choke cable on it... that way you can control your power on the move

[andypdq]

The main point about this device is that it advances the timing, which helps cold starting. This is most effective on indirect injection engines, which run noticeably smoother on cold start up with a bit more advance, Di engines don't really need it as much, especially with the temperatures normally encountered in the UK. They didn't bother with them on later models.

[MinorMatt]

No... those devices increase the fuelling.

Increasing the advance is apparently done within the pump and is on all bosch pumps...

[ColinJack]

This says it does both

Bosch VE Pumps

[andypdq]

Sorry Matt, the primary function of the cold start device is to slightly advance the timing. When the lever is pulled, an eccentric rotates the roller carrier slightly and gives a bit more advance, they do also open the throttle a bit to give a faster idle.

The main advance system is housed under the main body of the pump. The internal pump pressure, generated by the vane pump at the input shaft end of the unit, rises relative to pump rpm. This forces the advance piston to move against its opposing spring. The piston is connected via a large peg to the roller carrier, The further the piston travels, as the internal pump pressure builds, the more it rotates the roller carrier relative to the camplate, thus advancing the timing.

Pull one to pieces and have a look, there really isn't that much to them.

Regards Andy.