Fleemer

Had to do a recent engine swap on my car (old engine spat out my apex seals after stopping at the post office.. hurray)

87 n/a.

Got pretty minty engine (pushes 120psi front and rear :O) And just swapped it in. During swap, battery (old dead one) was put in backwards. METER and LAMP fuse blew (the 7.5A ones)

Replaced, car started first few cranks and then idled super high, but I couldn't tell because the tach was mia.

Tach not working was traced to what I beleive to be a faulty trailing ignitor (used to work before, could have been damaged during noob battery incident)

Disconnected it tested coils etc, coils seemed fine. Plugged just the 4 prong connector back in and tach worked, plugged the power for the coil connect in and the tach dissapeared.

Moving the coilpack and ignitor around as the car is running shows the tach to bounce all over or just read idle as ~100rpm :P ((sounds like 700-900))

Been driving it around with no trailing coil, took it out. Backfires like crazy.

Idle has a slight lope to it, pretty sure its the TPS (had to swap from old motor)

When the idle used to be very high until I unplugged the BAC connector. I checked it and it seems to always give ~12v. Idle seems to be like 2krpm when the bac is turned on. Bac also reads ~13.5ohm.. don't know if its super accurate, book says its no good. Between 10-12.5omh O.o

Was wondering if anyone can give me any insight into what the voltage to the BAC is supposed to be when car is just idling. I know its supposed to go on when the clutch is depressed or if accessories are on (to stop the car form stalling under high load)

The constant ~12v to the BAC concerns me as I think it shouldn't be on all the time.

Going to swap in another trailing coil plus ignitor sometime soon to see if that cures my tach problem

HAILERS2

The BAC is on more or less all the time. It has a duty cycle of approx 120hz or so controlled by the ECU pulsing a gnd to it. The black/white wire should have batt/alt voltage on it all the time if the key is ON. BAC also go full open if the key is HELD to START. Aids starting.

Remove the BAC and leave its plug on. See/feel if it is vibrating or not. Should be vibrating/pulsing if the key is ON. I wouldn't worry about the thirteen ohms bit. Never pry on the diapharm that vibrates. Clean its internals by spraying cleaner into it as it vibrates and dumping the cleaner out. Carb cleaner.

I've a question. You pulled one of the two plugs off the trail coil assy and the tach worked but when both were connected up it did not work??????

Fleemer

Correct.

The prong to the ignitor mad eit owrk momentaraly. Anyway,
I'm gong to get a new ignitor/coil pack fora friend and see if my tach starts working. According to the FSM, the BAC's duty cycle is dependant also on the RPMs. I'm guessing its reading 0 because the tach isn't working thus its trying to keep it form stalling.

I'l get my trailing coil working first before i start plugging the BAC back in :P. I also need to adjust my TPS since it came form another car and it gives me a lopey idle hehe.

HAILERS2

Your headed for a disappointment. I just went out and pulled both white plugs off my Trail coil assy and started the car. The BAC works as long as the rpm are under approx 850rpm.

The rpm signaln to the ECU is from the CAS. The tach signal is from the trail coil assy.