blue

I got an SSI-4 box to match TPS and RPM to my AFR signal and output it to a data file to use in tuning. Innovate's instructions, however, stink. They talk a bunch about different RPM signals on different cars but then don't tell you how to hook up your box. Does it need to see one pulse per rotation? One for every two rotations? Can it take a 0-5V signal to convert to RPM? Not a word about it in the manual for either the SSI-4, or in the LM programmer software manual.
I just called Innovate (after they ignored an email I sent asking about it and pointing out the omissions in their manual) and the guy gave me a big time attitude and talked to me like I was stupid. I took it for a little bit and didn't blow up, then told him I didn't like his attitude and I thought I could figure it out on my own, then hung up without getting much for an answer. This was the rudest person I've talked to on the phone, or in person, for a long time--years. I should have gotten his name but I hung up instead.
So, does anyone know if the SSI-4 has to have a pulsed signal as RPM input? Also, does anyone know if the signal to our cars' tach gauge is pulsed? The little guy at Innovate said it was pulsed, but I don't see how when it's an analogue gauge. And that's about when I hung up. I would rather not start cutting wires and pulling stuff apart before finding out.

Kevin Blown 95 TA

Do you have an ignition amp or multispark? If so, then it is as simple as hooking SSI-4 channel 1 +/- up to the tach output and box ground. Otherwise, I believe they use the PCM A13 wire on the red connector which is a tach output. You have to use the LM Programmer software to configure the SSI-4 Input 1 for rpm and try a couple settings if the number is off. It's been so long since I've done it that I can't remember exactly.

blue

It's a '96 SS. When you say tach output, do you mean the signal going to the tachometer in the instrument cluster next to the speedometer?
And then I just jump the channel 1 negative to the box ground? Thanks.

I have a Crane Fireball on the car also that has a tach output that was going to an aftermarket RPM gauge; also analog. But the SSI-4 manual implies that channel 1 has to see a pulsed signal. I haven't hooked a voltmeter up to various outputs, but how can a signal to a tachometer be pulsed unless the tach display is digital? I guess a pulsed signal could deflect an analog needle proportional to the number of pulses, but what I have always seen is that a pulsed signal requires a processor of some kind to read it.

Kevin Blown 95 TA

Hook it up to the crane output. That's what I did.

blue

Sweet. That will make it easy. I won't have to run one wire. The Crane TRC-2 retard switch in the car wasn't working (or at least, the light wasn't coming on) and I never used it, so I got the TPS and air intake temp hooked up already, courtesy of those wires.

Injuneer

Electronic tachs have always run off a pulsed signal, at least from my experience. In "ye olde days", we just hooked them up to the coil primary. Typically, the internals of the tach include a frequency to current converter. The current output drives the needle.

blue

Aha. Thanks for that answer. I would have hooked the wire up, but with an unsettled feeling not knowing what was actually happening.

I've thought about getting an oscilloscope now and then to look at some of these signals. I had a '99 Corvette a while ago and the body control module broke down. That car has the resistance value in the key that the BCM wants to see, but then the PCM also wants to see a pulsed signal from the BCM before it will deliver fuel. It took ten hours of looking on the internet to find out what that signal was, but with an o-scope it would have taken about one hour total. There was even a circuit somebody had figured out that you could build for about $20 in parts from radio shack to send that signal to the PCM.

Injuneer

All you need is a frequency meter, included in many relatively cheap multi-meters.

blue

Did you just hook it up and have it work right? Mine reads 2000 or so even at idle. I've monkeyed with the program in every way I can think of for calibration, and I can get the idle matched up, but everything else is off for RPM.
I had an aftermarket tach hooked up to the Crane output before, and it worked fine. So I don't know what the problem is, and I've found Innovate's customer service to be more likely to insult you than to help.

If you don't have any simple instruction, I suppose I'm going to go ahead and hook it up to the wires feeding the ignition coil and see if that works.

Kevin Blown 95 TA

I'd go in and see what the config is but it won't run unless it is hooked up to the car and I am in the middle of working on the blower stuff, so it is not convenient for me to check it. I don't remember having any issues at all getting it to work. Maybe you can check and see if your ground is at the ignition box ground and not at the chassis ground. That might be the problem if you haven't already checked it.