Ignition ECU waveforms

the wave form has to be equal and square, so no sine wave

 

That was more a stylized representation easier to draw At low RPM, I think it might be sort of trapezoidal with round corners and maybe looking more sine wavish at higher RPM - but I've not looked at that (or can't remember doing it ) Here are the 4 pages of Diagnosis sheet No. 1? Is the amplitude in spec?

By "ignition trigger signals" do you mean the signals going from the MicroPlex ECU to the coil power modules (i.e., test #11 and #12)?

 

Yes, the physical spacing is important -- do you have access to the WSM figure showing the dimension needed?

Eek -- not a good sign as they should be similar. You are at a deeper level if you are looking at time-based waveforms (whereas, Diagnosis Sh. No. 1 just uses VAC and VDC multimeter measurements), but that doesn't change that they should be similar. Do you have a copy of the TR wiring diagram book for your version TR available?

 

I just remove the RPM sensor and then use a (depth) caliper to measure from the sensor mounting surface on the bell hosing down to the top of the ring gear teeth. Then measure the distance on the sensor from the mounting surface to the end -- and subtract. (But I would only mess with this if the functional amplitude measurement was way low -- I futzed around removing some material (~0.1mm?) from the mounting boss on the bell housing which raised the signal amplitude from 1.8V to 2.4V IIRC, but that didn't make any difference for the problem that I was having -- i.e., being a little below the 2V (IIRC) spec didn't seem to be trouble).

You can get a copy of the 459/86 TR wiring diagram here (for the late euro F113B engine):

https://www.dropbox.com/s/ox8kxpyzlsid9jn/Wiring%20Diagrams%20TR%20459_86%20from%20Ben.pdf?dl=0

For the ignition system, I thinks it's the same for all version TR (except for the harness grounding to select the internal advance map), but I'll get a copy of the 509/88 US TR wiring diagram up on Dropbox tonight and post that link.

There's only one TDC sensor, and you're giving too much "intelligence" to the MicroPlex ECU . Each bank fires three cylinders per crankshaft revolution (hence the pattern of 3 notches), and it's the distributor's job on each bank to send the spark to the correct cylinder. To interleave the two banks, the ECU must be doing some electrical gymnastics for that.

 

[QUOTE="Steve Magnusson, post: 145772045, member: 260" To interleave the two banks, the ECU must be doing some electrical gymnastics for that.[/QUOTE]

nice word creation: electrical gymnastics

 

Link to copy of US version TR wiring diagram 509/88:

https://www.dropbox.com/s/gne5xw608ba818b/509_88%20US%20TR%20Wiring%20Diagram%20Book.PDF?dl=0

 

strange, there is no primary and no secondary signal even the TDC signal exist.
every how many RPM or every how many signals it is so? always constant and the same missing signal?
but when you have a closer look at the TDC signal, it is also strange. on the scope you see 8 signals. the 1st, 5th and the 8th are the lowest, the 7th is a little higher followed by the 4th, 3rd and 2nd. the 6 th I can not see right because of the scale at the screen. normaly those signals have to be all equal.

so I would try now first to check again the connection from this sensor and if ok then use an other TDC sensor only to eliminate this sensor. even I think that this sensor still is ok.

I wonder a little about the adjustment: channel 5 ( blue ) is adjusted to 50.0 mV ( milli Volt ). normaly you use MV ( mega volt ). or does this lower case letter m means MEGA, so kapital letter?

what kind ( manufacturer and type ) of scope you use?

 

Are you saying that the resistance from pin 11 to chassis ground (Test #3) measures 0.3 Ohms rather than being less than 0.2 Ohms (when ECU unplugged), or the voltage between pin 11 to chassis ground is 0.1 VDC (ECU plugged in with the engine running)? I'd measure both ways (I had some problems with the grounding of my injection ECUs as there are a bunch of buried "crimps" in the US harness for the ground path so I had to add a wire to provide a good ground more directly to those ECUs).

And the RPM sensor signal looked good too?

I hate it when we get here (multi-K$ decision). This is where an F dealer would just swap the ignition ECUs between two TR to quickly rule it in or out. Any chance you can hook up with another TR/412 Owner? Is this "dropout" in the primary firing only happening on one bank or both? If only one bank, I'd swap the ignition coils with their power modules to see if the problem moves or stays before buying a new ECU.

 

this also has to be a clear signal, not a second one put together
could you please post a photo also?

 

I remember the RPM signal being much more "square-wave" than "triangle-wave" at idle (and that sure looks "noisy" at the higher RPM - are you "aliasing" with the scope sampling rate?). Have you unplugged/inspect/cleaned/reseated the round 4-pin connector under the coolant tank that conveys the TDC and RPM signals to the ignition ECU (or stated differently - if you measure the resistance of the unplugged RPM sensor connector, is it the same as the resistance of the RPM sensor measured at the unplugged 25-pin ignition ECU harness connector when the RPM sensor is plugged in)?

 

where you have connected the scope?
all at the 25 pin connector? or nearer to the sensors?
I would try both things to eliminate bad wire connections.
but as I see it your ECU not work rigth anymore now. you have good ground for this ECU?

 

good, so you really elimanate connection problems
then as steve already mentioned: try to borrow an other ECU from an other owner to try - easiest way

 

so the TDC sensor has been to near to the flywheel? you put spacers on, so the distance is getting more.
never heard that if the distance is too short that this could cause trouble. only if the distance is too long
so you are sure??? may be that during your checking there also have been somewhere bad connection?