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I decided to re-gap the sensors. When I took out the speed sensor, um, I was a little surprised to see this:
I pulled the reference sensor; as before, it looks fine.
This makes little sense, seeing as the Speed signal is showing very fine on the scope.
I guess my homemade tool, using the old sensor, is a little off. I did try to measure it and it looked same as the new one, but, at less than a millimetre, let's just say I don't have machinist-grade measuring tools.
I'm going to glue another washer on the like-new ref sensor and re-gap the bracket. I don't know what kind of glue to use, since I'll have to 'unglue' the washer after; I'll just use the same Krazy Glue but only a drop or two.
I will also try to put the speed sensor back as is. Cleaned, it looks like it might still work; only 1/2 the surface is scratched and the magnet is still strong. Might as well try.
Ok, so the sensors were too close. I hope this makes the difference........
Posts crossed. I think you're in the home stretch.
I re-gapped and ran the scope + LED on coil. No LED lights, and here's the scope screenshot. It's pretty similar to before the re-gap:
Next, I switched the sensors, putting the D into the B and vice-versa. Guess what? Pretty much same result:
For Reference, here is the original set-up:
Compared to the original setup, the speed signal is slightly less strong, though still well over the minimum. Funny how in all three tests and switching the sensors, the reference signal remains pretty much exactly the same.
Of course, the speed sensor did not show any additional sign of too-close gap; the re-gap was done with a washer glued to the new sensor (the ref / non-marked one).
At this point, I do believe it's back to square one, as in Post #1.
Back to the DME I guess.
Last edited by Dan Martinic; 04-02-2018 at 05:11 PM.
Reason: Added original test result pre- re-gap
That test description is a bit confusing ... You absolutely must remove the green wire in step 4! Otherwise, you will be making a direct short in the DME
Thank for this. I suspected as much, but wasn't sure. I didn't try any of this today, and frankly, until I get tach bounce and/or something flashing at the coil from the DME, there's no point.
Unless the coil itself is shorting the DME (that negative ohms reading?)
You say above you replicated my KLR pin 9 test, but I don't see that in your videos? Did you post that one? If you have a pulse train like mine on that pin, then your tach should bounce and it means your DME is making an ignition pulse (i.e., that it's getting a speed and ref pulse, that the S100 is conditioning it, and that the processor generating an ignition pulse). You sure about the KLR9 test? Everyone has to start somewhere, so more power to you, but it's hard to have confidence in the scope and multimeter tests since you are learning to use them on the fly. Also, your motor sounds like it is firing a little in one of those videos. Can you post a video of your tach when you crank it? Tach bounce is really more of a twitch, and I'm wondering it you are missing it?
I replicated your KLR pin 9 test (and pin 24) in post #132. I did it two times: once with trigger on (absolutely nothing appears on the screen) and once with trigger off (again, nothing, except a very strange "jump" of the trace signal -- visible at idle since trigger is off -- when I move the ignition key.
And.... a shot of the engine compartment... after weeks of troubleshooting... it's beauty hiding the resistance within......
When I was done the clutch job, which included removing, fixing, and replacing the rad, in anticipation of a routine startup, I filled the coolant. There's a little blue paper towel by the bleed screw, waiting for the car to start so I can bleed the coolant.
I replicated your KLR pin 9 test (and pin 24) in post #132. I did it two times: once with trigger on (absolutely nothing appears on the screen) and once with trigger off (again, nothing, except a very strange "jump" of the trace signal -- visible at idle since trigger is off -- when I move the ignition key.
I'll go out and make a tach video now....
If it's easier on you, use the LED. Positive to +12V and negative to KLR #9.
Oh, sorry, I misunderstood. I thought you meant you replicated my results and saw an ignition pulse on KLR 9. But now understand you mean you tried my settings and got nothing. And, right, no tach bounce in the video. Still looks like somethings up with the ref sensor side to me. 12 volts is pin 6 on the KLR, conveniently marked "U (sheet)" under some West German witness protection program...(or just string a wire from the battery). You could also test with one LED leg to KLR9 and the other to ground. Might start by confirming the LED lights up when you apply power to it directly from the battery.
NOTE: in the second test, the LED stays on the entire time
PS: I also disconnected the Reference sensor plug and ran the continuity test at the harness pins. No sound or ohms reading (no shorts then in the wiring)
Well, both tests suggest KLR9/DME21 is remaining high and not pulsing, which was a near-certainty since the tach is driven off that signal and is not bouncing. The only thing that I can't say for sure is whether your LED would react fast enough for the pulse to be visible. Most LEDs would, but that's not universally true with those LEDs that have built-in circuitry like that. But since you have no tach bounce, and didn't find otherwise with the LED, it's fairly safe to assume the DME is not creating an ignition pulse (absent some one in-a-million thing like a malfunctioning tach pulling that signal high). The odds point to bad speed/ref signals, since you tried a separate DME, and since you can't seem to get a sine wave on the ref scope, and since they look like a dog's breakfast.... If you want to continue on in your journey of electronic discovery, you might want to get a cheap logic probe like the one linked below. They are way easier to use than a scope and are perfect for things like KLR9 (and, gulp, the innards of the DME).
Getting a rebuilt DME, new sensor wiring harness, and ignition coil would be great steps.. but spare funds a little tight for all three now.
I'm going to make some calls and see if any (somewhat) local P-car shops are willing to test my DME by installing in a car and see if it runs it; ideally, the odds of "reference sensors" would be correct and I can get the harness .. and a coil.
Since those two look like they will need replacing anyway, might as well get them now. The ECU Doctors DME comes to about 500 in our plastic money
You really should be replacing the engine harness for the sensors. Your pics in post 43. I have rebuilt 3 engine harnesses now and the reference sensor lines looked better on the ones I did than yours in post 43. Two of the three I did have issues.
Until it arrives, I have to ask: how do you install this thing?
The place I ordered from -- chosen because they offer USPS which saves us Canucks big customs "processing" fees, aprox. 45US+ per item -- has these images that suggest you install the other end into the DME harness. But, my harness looks to be a solid piece of plastic?
Until it arrives, I have to ask: how do you install this thing?
The place I ordered from -- chosen because they offer USPS which saves us Canucks big customs "processing" fees, aprox. 45US+ per item -- has these images that suggest you install the other end into the DME harness. But, my harness looks to be a solid piece of plastic?
You can disassemble the DME plug very easily - instructions with pics here.
I have only skimmed the thread up to this point so I don't know if you are using brand new sensors or not. But bear in mind that you can totally get a bad sensor out of the box. I'd suggest reading the thread entitled 'No Start After Clutch Job' from a few years back. That guy was in a very similar situation to yours, and he went through everything more than once, and iirc that's what it turned out to be in the end.
04-02-2018, 01:14 PM
