Anybody ever seen a breakout box for the 32way PCM connector?

Hello to all,
I am wondering if anyone has ever seen a breakout box for the 32 way PCM connectors? I have searched high and low on the internet with no luck...so I can only guess that there is no demand and therefore no one makes one.
I would like to try and make my own...if anyone has a dead PCM or old wiring harness with PCM connectors that they want to donate to the cause, I will glady accept them.
My plan is to solder up a breakout box, plug it in between the PCM and one of the connectors on the PCM, and then use my oscillscope to record signal waveforms while my Jeep is running correctly and then keep them on file, for that day down the road when they will come in handy troubleshooting a no start condition or a rough running engine, etc. etc.
I would prefer to use a breakout box instead of piercing the insulation on all of the PCM input and output wires. Naturally, if it works out as planned, I would be happy to share the tool with those who donate and are in need, as it would be a useful tool even with a good Digital MultiMeter if you don't have a scope. - McQue

McQue said:

Hello to all,
I am wondering if anyone has ever seen a breakout box for the 32 way PCM connectors? I have searched high and low on the internet with no luck...so I can only guess that there is no demand and therefore no one makes one.
I would like to try and make my own...if anyone has a dead PCM or old wiring harness with PCM connectors that they want to donate to the cause, I will glady accept them.
My plan is to solder up a breakout box, plug it in between the PCM and one of the connectors on the PCM, and then use my oscillscope to record signal waveforms while my Jeep is running correctly and then keep them on file, for that day down the road when they will come in handy troubleshooting a no start condition or a rough running engine, etc. etc.
I would prefer to use a breakout box instead of piercing the insulation on all of the PCM input and output wires. Naturally, if it works out as planned, I would be happy to share the tool with those who donate and are in need, as it would be a useful tool even with a good Digital MultiMeter if you don't have a scope. - McQue

Click to expand...

I've not seen one either, and I don't have anything (material) on hand that will help you - but have you thought of backprobe pins? They're slender pins (semi-pointed) that are meant to be slipped into the connector from the back, used while the connector is still connected (to get running signals, as you're trying to do.) Fluke and AES both carry them, and I'm sure there are others out there as well (AES at www.aeswave.com)

AES also carries a bunch of other fun stuff for automotive troubleshooting - have you checked them out yet? I know they've got an OBD-II passthrough/breakout box, maybe they'll have something for ChryCo as well.

If/when you do get your waveforms, if you can take screenshots or pictures of them, I'd like to host them for you - probably at XJOG, if not at JeepPower as well.

Backprobing can also be done handily using hatpins - although I do suggest you "break" the sharp point on a whetstone before you use them (round it off slightly - you need it to guide you past insulation, not poke through it...)

Thanks for the reply 5-90...and the link to aeswav.com

I will gladly send you the pictures if/when I get the waveforms..
I have used pin type tools for electrical probing before with some success...they are just more difficult to manipulate than a good solid breakout box..the pins pop out with vibrations, and they get dropped, etc. etc. ...I am just thinking that making a breakout box/tool and creating a little reference notebook with signal levels / waveforms / notes would be a good little fall/winter project. For instance, list of signal levels of all PCM inputs and outputs with key on, engine off...then engine cranking but not running... then open loop running, then closed loop running... etc. etc... I guess if I thought about it long enough, a reference notebook could be created without a scope or meter if you study the FSM long enough...but then I kind of want to get my hands dirty, make the tool as a little hobby project just too prove to myself I can do it...if I can't get the materials together I'll probably end up using Fluke wire piercing test leads or Ferret claws like the ones at this URL:
http://www.etoolcart.com/browseproducts/Ferret-Claws-FER911.HTML

best regards - McQue

When my ECU died and I was trying to diagnose it and the condition that caused it I was in touch with a firm that programmed ECU/PCMs and such, they asked me what I had determined so far and where I had tested and did I by chance backprobe the ECU, I told them no, they told me NEVER backprobe the ECU, for the life of me I don't remember why,so I didn't back probe it, I figure 5-90 would know why they said no backprobing .

dizzymac said:

When my ECU died and I was trying to diagnose it and the condition that caused it I was in touch with a firm that programmed ECU/PCMs and such, they asked me what I had determined so far and where I had tested and did I by chance backprobe the ECU, I told them no, they told me NEVER backprobe the ECU, for the life of me I don't remember why,so I didn't back probe it, I figure 5-90 would know why they said no backprobing .

Click to expand...

I've never run into a connector that couldn't be backprobed. If you're hamhanded, I suppose you could spread out the female side of the terminals (which is why backprobe pins have rounded ends, and why I said to round off the ends of the hatpins,) but if you're careful, you'll be fine and won't damage anything. I'd be very interested in knowing why they told you not to do so...

dizzymac said:

When my ECU died and I was trying to diagnose it and the condition that caused it I was in touch with a firm that programmed ECU/PCMs and such, they asked me what I had determined so far and where I had tested and did I by chance backprobe the ECU, I told them no, they told me NEVER backprobe the ECU, for the life of me I don't remember why,so I didn't back probe it, I figure 5-90 would know why they said no backprobing .

Click to expand...

I've never run into a connector that couldn't be backprobed. If you're hamhanded, I suppose you could spread out the female side of the terminals (which is why backprobe pins have rounded ends, and why I said to round off the ends of the hatpins,) but if you're careful, you'll be fine and won't damage anything. I'd be very interested in knowing why they told you not to do so...