EFI ITB Install Progress Update

[KMoore68]

Hi,

I have completed the installation of the ITBs and I have run the fuel lines including through an FPR and back to the tank.

I am waiting on a couple of nut extenders to install the vacuum manifold and then i'll be tackling the wiring.

A couple of questions:

1. On the picture, I've attached, there is a hose on the left side of the engine that seems to lead back towards the front of the car, I can't seem to figure out what it is for, any ideas?
2. I'm guessing that I need to hook-up a vacuum for the distributor, can I just "T" it into the input going into the vacuum manifold for the ITBs?
3. I am running a Megasquirt (typo not microsquirt) V2 357C and with respect to wiring, I think I have a good plan however I am a bit confused about the tach input. I believe I have to route it into pin #24, is that correct?

My plan is to pin the loom and engine components into a Deutch connector for easier engine drop in the future.

[Showdown]

The hose the left looks like the brake booster hose- that needs to be connected to a manifold that collects the vacuum from the ITBs and also feeds the MAP sensor (not included and has to be purchased separate with microsquirt) which connects to pin 24. Best practice is to collect all the vacuum ports from the ITBs into one manifold which helps reduce noise and fluctuations from the 6 throttle bodies and that is where you connect the MAP sensor and the brake booster hose (make sure it has a check valve inline - usually where the hose changes from cloth wrapped to rubber)

The tach output looks to be pin 35 with microsquirt and that *should* connect to the two-prong “T” connector (usually white or off white) just below the regulator panel and electronics on the left side of the engine bay, but I don’t have any experience with microsquirt so take it with a grain of sand. Each megasquirt product differs slightly so be sure to read the manuals.


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[KMoore68]

Oops, typo, I have a Megasquirt ECU

[Showdown]

What else do you have in your setup- what’s your ignition setup - that can have en effect on wiring


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[KMoore68]

I'm planning on running the stock distributor for now and just controlling fuel via the ECU.

[rwest]

If you are using MAP to control your fueling, I think hooking the distributer vacuum line on the manifold might cause problems. maybe it could be done on the brake booster line? hopefully someone else can add to these thoughts.

[dannichols1474]

My MegaSquirt2 ECU has the MAP sensor in the ECU enclosure so I ran a 1/8 inch ID vacuum line from the intake vacuum plenum to the MegaSquirt. The vacuum plenum is connected to the vacuum line from each ITB so you have a more steady vacuum signal.

The distributor vacuum diaphragm on my 75 911 was an 11 deg timing retard when throttle was closed hence 5 deg ATDC at idle with vac line connected becomes 6 deg BTDC at idle with vac line disconnected. Anyway, I eliminated the vacuum line to the distributor and just set idle timing to 6 deg BTDC with a stock 2.7L CIS engine.