Computronix Ignition

[Daniel]

this was on the website about their system.
_____________________________________________________________________________________________________

SETTING IGNITION TIMING

NOTE: A variable or “dial back” timing light can not be used unless the delay is set to ZERO and it is used
as a conventional timing light!

Start the engine. The engine is timed in the conventional manner using a conventional timing light with
an inductive pick up clamp. The inductive pick up should be clamped around the #1 spark plug wire. If
the timing light is weak, reverse the orientation of the inductive pick up on the spark plug wire. Ignition
timing should be set at maximum advance. Typical timing is 33º to 35º BTDC at maximum advance. The
engine should be running at 3,000 to 3,200 to check maximum advance.




TROUBLESHOOTING

DO NOT ATTEMPT TO SEE IF THE SYSTEM IS FIRING BY DISCONNECTING A SPARK PLUG WIRE
AND HOLDING IT NEXT TO GROUND. THE HIGH VOLTAGE CREATED BY THIS PROCEDURE
STRESSES THE INSULATION AT THE COIL AND IS VERY DANGEROUS!

Engine cranks but does not start – No spark present

Determine if the red LED light flashes on and off when the engine is cranked. If it does, the ignition
switch wire connection is good and the system is triggering correctly.

If the red LED stays off, the system is not getting 12 volts from the ignition switch wire.

Verify that there is 12 volts present at the ignition switch wire when the ignition switch is turned on.

Verify that the connectors are fully inserted and seated.

Engine starts but backfires/misfires

The spark plug wires may be connected incorrectly. Recheck that the spark plug wires are connected as
shown in Figure 1.

Make sure all rubber boots on the spark plug wires are fully seated at both the coil pack and spark plug
ends.
__________________________________________________________________________________________________

Didn't the Computronix come with instructions? or a setup sheet?

[So Cal Mark]

the system includes an instruction manual, plus the manual is available on our website

[Daniel]

ok i thought that was the case but who reads direction stuff these days

[phaetn]

Ha ha! I do, actually. And I do have a copy and read it more than once. It made more sense later than it did first time.

Sometimes -- as part of learning -- one has questions. For instance I was wondering if there were any issues with one year over another and default BTDC settings. The manual was for a Ford, so I was wondering about my application. Now I know.

Now I just have to get some free time on the weekend to actually check it out.

Cheers,
phaetn

[Daniel]

the ford and fiat units are the same except for the shaft and gear.

[aj81spider]

So I attacked the timing tonight. Previously I had followed the directions to get the Computronix set to 12 degrees (rotate motor to 12 degrees then rotate unit until light comes on). The car started and ran, but lacked a lot of power.

Tonight I printed out a degree wheel then used it to paint a line at 34 degrees. I started the car and reset the timing so it was as close to 12 degrees as possible (looking at a 10 degree mark from above and 2 feet away!). I then used the convenient manual throttle on my 74 to set the RPMs between 3000 and 3500. I then set the paint mark I made at 34 degrees so it lined up with the 0 degree mark on the timing belt cover. It seemed like the car ran even better if I advanced it a little more, but I resisted the urge and locked it down there. However when I went back to idle it looked like the engine was more than 12 degrees advanced at that point. I left it, however and went for a ride. The performance was significantly improved so it's clearly "better." Two questions however:

> Should I worry about the idle being more advanced than 12 degrees?

> Is there more to be had (i.e. it seemed to run better if I advanced it more)?

Should I just thank the Fiat gods that it's running better and leave well enough alone?

Thanks for any inputs.

[Daniel]

The engine might respond faster while parked with more advance but under load the performance will
feel different and will ping/detonate. Getting the timing dead on would be best, thanking the fiat gods
is just asking for trouble they might stick around and keep you busy working on the car so you'll call them
back over and over.

[So Cal Mark]

generally not a problem to push it to 15btdc at idle.

[aj81spider]

thanking the fiat gods is just asking for trouble they might stick around and keep you busy working on the car so you'll call them back over and over.

That explains a lot. The car has been a series of issues recently - like it doesn't want to be on the road. That's why I love this forum!

[fiat218]

I got a shock off of marks unit straight thru the body.
Turned my hair silvery gray

[majicwrench]

Now see if you still had a "weak spark" system it wouldn't have turned your hair grey.

Keith

[So Cal Mark]

gray hair is quite distinguished looking. And if you still had your stock "puny spark" system you'd still be trying to start your car

[fiat218]

I have to say that I got marks system and when you pull a plug wire while the car is running, you don't get a spark, u get one hell of a arch, it will jolt you quick, ask me!

[majicwrench]

Nah my fiat fires right up. My distinguised looking hair is from decade of working with GM's HEI system.

[So Cal Mark]

HEI, why not take it out and go back to your beloved points? Then you can remove your starter and use a hand crank along with candles in place of headlamps