Pinout Question

[Superdave]

I'm working on my ECM test bench but am having trouble finding what pins to use for an RPM input. I've tried the ref pulse pins but get nothing when i inject a square wave.

i've gotten the VSS inputs to work this way...


i know the ECM doesn't think it's in run mode, think that's the problem?


Thanks for any input.


BTW, 1227730 ECM and $A1 BFUZ code is what's on the emulator for now...

[ghrarhg]

I believe the ref wire is correct as far as where to input RPM. What is the amplitude of the signal you're using?

[Superdave]

I can range from .1 Vp-p to 10Vp-p, 20 Hz to 200Khz, sine or square wave.

i was using about a 1Vp-p signal to trigger the VSS input, tried a little more on the ref wire but still got nothing.

I'm going to work on getting all the other inputs wired up then i'll try to trick the ECM into thinking it's in run mode...

[torq455]

the ecm is less understood by most everybody. i just plugged my VSS sensor into the tranny and it all worked fine! from what you are doing Dave, Sounds lie you need a square wave generator. Digitally.

[pocket-rocket]

Maybe probe the plugs on an ICM with an oscilloscope while turning an engine over with a starter to see what kind of signal it puts out? I don't see why it wouldn't be a square wave, but for all we know, it's sine or sawtooth.

[Superdave]

Andy, it does both.. sine or square.. lol


I guess i could trace the wires back on my car since the bottom half of the dash is out. I hope to have the pigtails from a harness soon so i can hardwire in everything. I'm slowly working on a control box to simulate sensor inputs.

[pocket-rocket]

I wish I could help on this project, but as far as that goes you > me since I took 4 years of electronics in high school (many moons ago) and your a freaking electronics engineer :P It's the thought that counts though, right?

[Superdave]

lol

i might hook the scope up to it and see what's on that pin. If i get to it i'll take a snapshot of the waveform and post it up.

[pocket-rocket]

I've got a sillyscope, but it was given to me by my friends dad who I used to help repair TVs and VCRs and he had blown both inputs. I bought some of the parts to replace the blown parts (transistors and a couple ICs), but I didn't get everything so I think what I lack is what keeps it from working :/

EDIT: It's a Goldstar OS-9020A sillyscope and BK Precision 3020 Sweep/Function Generator (does sine, square and sawtooth waves).

[Superdave]

I'll post up a pic of my home bench tonight, it was set up pretty nice but i've got alot of projects going on at the same time.. lol

[ForcedFirebird]

Can't you probe the white wire from the ICM and see what's going to the ECM?

It should be the same as any aftermarket tach.

[Superdave]

I'll look at that tomorrow...

here is my home bench:



Tektronix color 2 channel 100 MHz scope, DC power supply load tester, variable DC supply, 3.5A 13.8V DC supply, 13.8V 20A DC supply, Viz generator (old school) and some other stuff.

Most of the time i build custom flashlight stuff and repair car amps at home, it's nice to start fresh with a project

[ForcedFirebird]

Is that a bag of charcoal in case you need to burn something?

[torq455]

I'll look at that tomorrow...

Most of the time i build custom flashlight stuff and repair car amps at home, it's nice to start fresh with a project

Good to know...

[pocket-rocket]

Is that a bag of charcoal in case you need to burn something?

Lol! Nice soldering iron you have there (I have the same one). I won't buy anything but Weller after using them in school. Ben even liked mine enough that when he was actually removing EPROMS and soldering in new EEPROMS that he bought a Weller as well. I like your setup