Hello, Talking about between the banks. Maybe just tired & impatient, but looking for the simple logic to balance the banks. The 400i fuel injection book method didn't work for me. I tried exactly per their method, and something was lost in translation. It comes out better with a modified 2 liter coke bottle, and a Weber synchrometer (flow gage). So you need the two autonomous fuel injection systems to have equal flow at idle, and just off idle where the linkage comes in. Does it make more sense to: A) sync at 2500 - 3000 with throttle held by cable (to set linkage) first? - OR- B) Set idle, then act on linkage? Also, what's the cool tool to set the balance, and how to connect? The 400i book has you measuring manifold vacuum UPSTREAM of throttle plate (Between throttle butterfly and CIS flow plate) where vacuum is really small, and that gave me nothing. I tried DOWNSTREAM, where I was getting about half scale vacuum (~15in Hg), but way too frustrating to get a logical setting. Also, what rpm do you target? I've found it hates to be below 1000. Many Thanks!
That has to be a misprint/error. That's the correct location -- equal pressures in the two intake plenums is the goal. ~15 in. Hg vacuum is a perfectly reasonable value at sea-level warm idle -- why isn't that "logical"?
Thank you!!! Yup! That's exactly what they've got in the picture. It shows the top chamber of the WUR which "Vents" the upper chamber. I was thinking they may have meant a water manometer - but they mention using a Hg manometer. The part that was fighting me is as you open the air bleed screw, vacuum goes down ------- but rev's go up which can increase vacuum. What in the world!?!? Are you supposed to wait til it stabilizes? But again, the battle of rev's Vs air restriction makes the gauge reading about the same. Do I need to measure resolution of 1/10's of in-Hg? In which case the pulsing needle brings more joy. This can't be "that" tough?
No, it shouldn't be that hard, but you never know if someone before you wrongly messed with every adjustment screw in all random directions I don't have a copy of the 400i reference you mention, but the TR WSM (which also covers K-Jet without Lambda) might be another reference for you (and maybe the BBi throttle linkage is more similar to the TR if you are having a "equal at idle, but not equal above idle" problem). It's not 1/10 of an in. HG fussy, but the throttle plates themselves also need to be reasonable. The usual strategy is: With both air byass screws full closed = the warm idle RPM should be less than 1000 RPM (~700 in the case of the TR), with both intake plenums at the same vacuum. (This confirm if the two throttle plate adjustments are about equal.) Then the two air bypass screws are opened bringing the idle up to 1000 RPM and keeping the vacuum levels equal (although the vacuum level may be different than the prior step). One other thing to use as a sanity check is the "reasonableness" of the final amount the air bypass screws are opened -- IME, something like 0.5 turn to 1.5 turns. If one is 4 turns open, or they differ by a bunch = a sign the throttle plate mechanical positions are off. Good hunting!
Do you recall if the gages are responsive? When you open the screw, the vac decreases until the engine rev's bringing it up higher? Is this how it behaves? ie What I should look for / expect? TR workshop manual sounds like a good idea. Even the lambda part would be helpful. Now where to find one of these? Thanks!
Actually, the "base" TR WSM injection Section D covers the non-Lambda early euro version (which I believe is identical to the BBi CIS system). With ferraridatabase being no more, can only hope that someone with the TR WSM Section D in a scanned pdf form might contact you and offer to send. Opening one of the air bypass screws would lower the vacuum in that bank and increase the RPM, but don't see why this is a problem. If you got things balanced, and the RPM was too high, you would just close each air bypass screw the same amount to reduce the RPM while keeping the two banks balanced.
Thanks again. Do you have access to the TR book? Check out fig 44 on page D58. Screw 5 is the "Mixture adjustment screw"? Then what's going on in Fig 45 on pager D60? BTW: What is that "Screw 5" ?? The TR book does seem to show a good place to tap in vacuum from the WUR lower chamber (As opposed to the 400i book), See fig 43 on page D58. How we love them so! I think it makes sense that mechanically, the throttle plates must be in the exact same spot to begin with - flow wise, and angle of opening. It seems intuitive that if this is off, the progression will not be uniform, and the balance could make that transition a problem. I'm devising a way to check that.
