Apparent CMP Sensor issue, Stumped!

[redlowrey]

That is right, first sign of exhaust gas leaking under the cowl is a loss of power, map sensor code because of high map signal voltage from low manifold vacuum. If your engine was running good before this happened I would think something has shorted to ground in the ecu and damaged it. Having a fail safe operation for the crank and cam is not going to help if something has been fried in the wiring loom .

Big phils engine does not have fail safe for the crank and cam, and it is coil on plug not waste spark like yours, you need to do some voltage drop testing at the computer and check your inputs and outputs.

[Vanisle]

I just got off the phone with the mechanic at the local Suzuki dealer. After going over everything I have done he feels it is most likely an ecu problem and to try ordering a used one off of eBay. If that doesn’t work he will take a closer look

[redlowrey]

@RedLowrey-- I'm very sorry to have disappointed you, you've been nothing but helpful and I'm very grateful. I will absolutely report any results as soon as I get them. The problem is, there haven't been any results, just the same questions again and again and again, and it gets very frustrating.

The whole project is on ice right now. I'll take it up again in bits and pieces, but for right now money has to flow in the other direction for a while, which will mean devoting my time to earning it, not spending it.

Thanks again, more later.

Mate when you decide to have another crack check the 5 volt circuitry, something is pulling it low from the emergency stop plate.

[BigPill]

Hello all, I'm back after almost a year. Sorry for the delay. Here's a quick recap:
My 2020 DF50 got dunked briefly under water. When it came out, I got a CMP warning signal. Since then, I feel like I've tried everything to get the motor started, to no avail. The warning persists, no matter what I do. I took the motor to a local dealer, who, in 6 weeks, also couldn't find the issue. Pressing him a bit, he did admit he'd seen a similar problem before and was not able to solve it. I'll spare you any discussion on my personal feelings about this.

I happen to have a week's time right now to work on this problem; after that I'll have to stop again, but if this problem can be solved, I intend to solve it this summer. I have a very difficult time believing that a €6000-plus motor, brand new, is nothing more than a door-stopper.

Here's my current question:
I've now removed the entire main wiring harness, which was a PIFTA, I can tell you, and I'm checking it for continuity and shorts. So far nothing. What I'm wondering is whether it might be possible that although that CMP sensor voltage does test correctly while hand cranking, its current is not sufficient. Is there a current limiting device somewhere that is simply not allowing enough amperage through?

Second question:
I still haven't found a service manual for a model so new; the one I bought goes up to 2010, and quite a lot has changed since then, including this: I can't find an ECM main relay. There is a black, sealed monolithic block sitting in a rubberized holder just to the left of the ECM, with 4 wires that are permanently attached to the wiring loom. It measures around 2x3x8cm. What is that?

Thank you again!

[BigPill]

Oops I meant PITFA...

[redlowrey]

I wrecken it will be a capacitor for the main control relay, what color are the wires, pull the computer out the way and you see the main control relay and the starter relay beside each other. Even though 300mv seems high for the ground, don't forget your checking that voltage at the sensor try checking at the computer it may be higher, suzuki say 5 volts high 300mv low, you have swapped cam sensors from the good engine no change. I have no information on your engine at all.

Even though I would like to see no more than 40 mv on that ground, what voltages do you get with the plug disconnected key on.

[BigPill]

Hi and thanks for this. Sorry for the delay (again), I didn't get the memo that you had answered. Quick update: I checked out the wiring harness-- no issues. Put it back together and I still have the exact same problem, as seen by the beep code and also the PowerSports/USB program hookup: CMP Sensor error, check sensor. Which is not very helpful.

I'm under pressure again, but I'll try to get a reading on that voltage tomorrow.

What more information on my motor would you like to have? I'll be glad to give it to you!

[BigPill]

So... I measured the voltage at the CMP connector, unplugged with key on. On the BLK/BLU wire I got 11.52VDC with respect to ground (which is at the BLK/WHT wire)-- no surprise considering my battery is a bit run down. On the YEL/BLU wire, which is the pulse signal wire, I got 0.00VDC, which is of course to be expected-- the sensor was disconnected. I then repeated the same test I tried last year: I threaded a single strand of copper wire into the connector at the sensor end, to test the pulse signal voltage while hand cranking. I got +5.01VDC, toggling to 0.30 or 0.31VDC while cranking. That is exactly the same result I got last year.

While falling asleep last night I got to thinking about that apparent capacitor which sits next to the ECU. It has 4 wires leading to it. The whole thing is potted in plastic, so sealed. That to me suggests a triple capacitor-- one ground wire and 3 separate + poles. The wire colors are BLK/BLU, BLK/GRN, BLK, and WHT. The BLK/BLU corresponds to the +12v wire at the CMP sensor, which comes from a little sort of junction box, where 4 BLK/BLU wires are connected together, including the one going to the sensor, and the one going to the capacitor, if that's what it is (it surely looks like one). So I'm wondering whether it could be that the capacitor has gone open, and so is not filtering the 12V supply voltage to the sensor, thus providing the sensor with junk electricity, affecting its performance? Yes, it seems to toggle blissfully while hand cranking, but in the real world, at speed, can it be that a capacitor failure would cause a problem like the one I've got? In a world that seems absurd, this is the first thing that seems to make a little bit of sense.

So-- it would be great to know the values of those capacitors. It's permanently mounted to the whole wiring harness, which costs a ridiculous €700 tor a new one, but a capacitor is a capacitor, so this might be a bodgeable job...

[redlowrey]

I have a gut feeling that Y/BL should have five volts on it with the key on, check with your good engine.

[BigPill]

OK will do tomorrow. But I don't see where those 5V should be coming from, unless the sensor is plugged in. My understanding is that the sensor itself generates that 5V pulse, and sends it to the ECM. In fact, I'm not sure about this, but I'm pretty sure when the sensor is connected, the 5V do show up immediately, unless the camshaft is in position for the "Lo" voltage. Default seems to be "Hi," which is to say we're seeing the 5V except at the moment the little nibs on the camshaft are passing by the sensor.

[redlowrey]

I know what you are saying, some systems send out a five volt bias voltage on the cam sensor line and the cam sensor pulls the bias voltage high and low. I know for a fact that the 2010 DF 60 has a 5 volt bias voltage on the cam sensor signal line y/bl coming from the computer, and the cam sensor is pulling the bias voltage high and low. If that is the case, your cam sensor triggering will be arse about.

The Capacitor is a dual functioning capacitor with a diode included, if it was shorted it would blow the 30 amp fuse, if open it won't crank, if it didn't suppress noise, you could have interference on the sds, or noise on the cam supply voltage, seeing you have identical motors unplug the cam sensor turn the ignition on and see if it has 5 volts coming from the computer.

[BigPill]

Unfortunately I'll have to go back out on the road now for a few weeks, so today's results will be the last for a while. Here's what I learned: Yes, redlowrey, you were right: There is 5V on that wire as soon as the key is switched on, whether it's connected to the sensor or not. Yes I measured no volts that time before, but I'm putting that down to my own error for now-- I think I must have had my tester probe badly connected or something. I know it's always a bit ominous when you're not sure about these things, but I was expecting 0 volts, so when I saw 0 volts, I think my confirmation bias must have kicked in, because today I saw a definite bias voltage on that wire.

I tested the healthy motor, too. Yes there is 5.01 volts on that wire there, too, so I took the opportunity and tested further. With the connector connected, hand cranking, I got 5.01V HI and 0.31V LO, the exact same values as I get while hand cranking the sick motor. I was hoping the plot might have thickened a bit with this last round of tests, but I find myself back where I started, namely, nowhere. GRRRR...

[redlowrey]

I was pretty confident you were going to see 5 volts coming from the computer to the cam sensor, that is a pull down circuit. when you come back we will go through the circuits one by one, it is going to be something simple that you have over looked. start with the main control relay then the five fuses that power up various circuits around the computer.