PT4 as cam input but no signal

[S.Bretz]

I have pt4 hooked up as cam angle sensor #4 but I get no signal when its plugged in. With the connector unplugged the reading jumps all over the place, with it plugged in....its just reads one value (stops at a random value that comes up as the reading is jumping around unplugged).

I originally thought I had the wire crossed with something else since the signal bounces around so I did a continuity check to all the wires on the BD37 main & expansion harnesses along with power and ground to be sure...and its crossed with nothing.

I do notice that on the signal wires for cam sensors 1-3, I get a positive voltage with power on, but nothing on pt4 with power on. I'm wondering if I'm suppose to have PT4 wired into a 5v pullup like cams 1 and 2 (3 looks like it has a 10v on the signal wire that I assume trips going low).

The 5v ref and low ref ground both test out.

I have swapped sensors and even tried every wire combination on the sensor to no avail.

I can run the cam test by adjusting the duty cycle and the cam moves.... There is the notable change in tone on the engine, the EGT goes way down on the left back and the a/f gets all wonkie so I'm 100% positive the cam moves....I just don't see it moving in TS.

At this point I cracked open an Yeunglin and turn to the forums; I am at your mercy.

[Matt Cramer]

Please attach a copy of your MSQ file and a composite log; this will give me a bit more to go on.

[S.Bretz]

I attached the current msq, a log of the sensor connected and also disconnected.

Note in the log of the sensor connected, the reading stopped at whatever value it happened to be fluctuating to when I plugged it in.
If I start the log with the sensor plugged in after a restart, the reading will stay at 32degrees.

The top comp-log is with the sensor plugged in, the bottom log is with it disconnected.

[S.Bretz]

Before we get to far into this... Is the PT4 supposed to be connector to a 5v pull-up separated with a 1k ohm resistor? All of the other cam angle sensor signal circuits measure high when I unplug them and measure voltage with my DMM.

I mean, its very likely I have over looked something and messed something up.

[jsmcortina]

Before we get to far into this... Is the PT4 supposed to be connector to a 5v pull-up separated with a 1k ohm resistor? All of the other cam angle sensors measure high when I unplug them and measure voltage with my DMM.

I'm pretty sure that PT4 does indeed need a pullup if you are using an open-collector style cam sensor.

James

[S.Bretz]

Before we get to far into this... Is the PT4 supposed to be connector to a 5v pull-up separated with a 1k ohm resistor? All of the other cam angle sensors measure high when I unplug them and measure voltage with my DMM.

I'm pretty sure that PT4 does indeed need a pullup if you are using an open-collector style cam sensor.

James

Its a 3 wire gimmick.

For testing purposes, do you think would be ok to put a 1k ohm resistor between the 5v ref on the sensor connector and the signal wire to see if it starts working? And if it works, then open the MS case and make something more permanent?

[jsmcortina]

For testing purposes, do you think would be ok to put a 1k ohm resistor between the 5v ref on the sensor connector and the signal wire to see if it starts working? And if it works, then open the MS case and make something more permanent?

Yes.

James

[S.Bretz]

Thanks James.

Its getting a bit late here tonight for me to be playing around with the turd-bucket. I will report back tomorrow with my findings.

If a pull turns out to be the cause, where would be a good place on the board to hook up the 5v to connect to the PT4 circuit on the board? The proto side for the 5v is obvious....its the other end of the resistor I curious about.


PS: shouldn't you be in bed? What time is it over there? About 2am?

[S.Bretz]

The 1k ohm resistor between the 5v ref and the signal circuit did the trick.

Time to pull the case open.

[S.Bretz]

Well, I was poking around on the ms3x card to find a place to wire in the pull-up circuit and broke the .01uF cap of the baord. The solder pads pulled up. If any one has a fix for that please let me know, otherwise I will be ordering a new 3x card tomorrow.

I don't see a good place the make the pull-up on the board so I will just solder the resistor into the harness.

[S.Bretz]

New board ordered from DIY along with some 0.01 micro-farad caps that are a better fit than the huge ones I found at radio shack.
Is DIY open today; Good Friday? I'm not in a rush since I need to fix a fuel pressure leak internal to the tank.

[Matt Cramer]

Yes, we are open, although I'm afraid I didn't see this post until after our shipping cut-off time.

[S.Bretz]

Yes, we are open, although I'm afraid I didn't see this post until after our shipping cut-off time.

Matt, Seriously, I don't need it rushed, it is a few days later because you missed a post..oh well.

It will be a few weeks before I get the tank reworked with a different setup for my pumps. My buddy did this elaborate design but unfortunately is has a few flaws to it. The new version will involve some fabrication for a simpler design that will be a couple weeks at minimum before every thing is back up and running on the fuel system.

[S.Bretz]

The new expansion board showed up today....super fast shipping. I was not expecting it here until maybe tomorrow at the soonest.

Unfortunately it will need to go back already. When I got the scsi cable off I noticed the r11 was folded over. I do like the redesigned 37pin header though... It looks like I will no longer have to hold the "nut" from the back side while I screw in the screws that go threw the face of the unit.


Sadness....




Matt, I sent in an email to the sales department to get this worked out. I realized after I hit send that I neglected to provide an invoice# in the email. Just email me back or call the # I left and I can get that for you.

[piledriver]

The solder pads pulled up. If any one has a fix for that please let me know,.
.

This is quickly/cheaply fixable by anyone who does PCB repair on a regular basis,
...but you would not want to buy a cir-kit just to DIY one pad, as the cheapest complete trace repair kits cost almost as much as a MS3X.
DIYautotune can surely do it, Peter Florence can likely do it, heck, even i can do it.
It probably won't exceed their minimum, and will be far stronger than original if it can be done with a swaged eyelet.

I'm looking for a second MS3X for an MS2 project, PM if you'd just prefer to sell it.

[Matt Cramer]

No problem, our shipping department will take care of this as it looks like a shipping insurance claim. They should be in touch soon.

[S.Bretz]

Thank you Matt for forwarding me to the correct department.

[Matt Cramer]

No problem. The tech department handles most of these; the shipping department normally takes care of cases where items were damaged in transit.

[S.Bretz]

Nanette emailed me...wow. your operation goes above and beyond. Thank you.

[S.Bretz]

The new expander board came in and it looks good.

+1 for DIY's customer service!