Hi all
Can anyone tell me what this part is and what it actually does? Can it be deleted or is it a required part for proper engine function?

What does EAC4371 do?

 

Pretty sure that that's the early version of the full load enrichment switch, which fattens the fuel mixture when manifold vacuum drops below xxx-value (about 3 inHg as I recall). it was replaced at some point with the more commonly know "blue white switch".

The engine will run fine without it...to a point, at least....but I would not recommend eliminating it. It protects the engine under heavy load

Cheers
DD

 

Thanks Doug, at present the switch is plugged in but the vacuum hoses are not. Could this cause the motor to run real crappyespecially when it's fully warmed up?
Con

 

Yep.

NO vac = contacts closed = richer mixture.

 

thanks for your answers Doug and Grant. Guess I better get that sucker reconnected.
Con

 

OK, Ive got another question, the above drawing shows the switch connected from the manifold via a 4 way connector with hoses going to the heater, the switch, the manifold and the distributor. My car has a dedicated hose for the distributor and at this stage the heater and a/c is not working and does not need to be connected. So can this switch be connected via the manifold only with no other hoses?
Con

 

I am assuming the 1/2 size engine here, not the V12??? Nothing in your profile telloing us the beast at play here.

Yes, on the V12 it is usually attached to an open vac spigot on the rear of the A Bank Inlet.

You need constant vac, as in NOT via any thermo switches etc etc. The vac holds the contacts OPEN, and this is the key.

BUT

That vac line needs to dump vac quickly as needed, so connected to other circuits that "may" run a vac reserve tank will not be good.

 

This is the wide open throttle switch

It is a vacuum-operated switch which is “normally closed” i.e. at atmospheric pressure it is closed. At low throttle, there is high vacuum pressure and so the switch is held open. At full throttle the vacuum drops to nearly nil and so the switch closes, which instructs the ECU to enrich the fuelling. The switch is set to switch states from closed to open at 4mm Hg vacuum

on USA market cars this was not used, but instead a rotary switch to sense throttle position was employed which also has a closed throttle sensor in place of the microswitch on other market cars.

This vacuum operated switch is obsolete but can be replaced by a Honeywell vacuum switch part number 76061

 

Grant, your "1/2 size engine" comment made me smile. I guess I have cylinder envy.

 

Ha, I miss my V12 fleet. So bloody simple and just unique.

I tolerate the lesser cousins now with the S and the X, and YES, I measured, the real engine will NOT fit.

ALL in jest of course, I am too old to take offence, and as I have said too many times, "If you own a V12 you MUST have a warped sense of humour".

BUT, we are going off topic, and that is not good.

 

I assumed it was a V12 !

Cheers
DD

 

Sorry about the model info, now fixed. It is indeed the half size motor (not that there's anything wrong with that).
Good info here
Thanks all!
Con

 

Just for anyone that may care. The left hand side of the switch as shown in the diagram has a metal mesh bthat I think OS where the the vaccuum is dumped from, so only one hose to the manifold is required.
Con