Buy Suzuki Outboard Parts


No announcement yet.

Apparent CMP Sensor issue, Stumped!

  • Filter
  • Time
  • Show
Clear All
new posts

  • #16
    Mate 4.2 is for the crank, just make sure when you refit the sensor that you have the right gap between the reluctor and the sensor.
    If the gap is to wide the sensor will not induce enough voltage.
    Even though this has nothing to do with spark, have you checked and made sure the compression is ok seeing the engine was running when it went into the drink.


    • #17
      Thanks Redlowrey. Yep I get the codes-- and your point about the gap is well taken, but w/o a manual I won't be able to find that number. Which brings me to the other thing I wanted to ask: I'll obviously be wanting a service manual, but the links supplied on the sticky entry on this forum don't work for me-- I've tried several times on different days. Any advice there?

      Update on my (lack of) progress: the neutral switch seems to work fine; I tested it at its plug.

      I checked resistance at the stator coil connector. The three yellow wires show about half an ohm in any combination. That's a very small resistance, but I compared it with the stator on the other motor and it looked just the same.

      Put my meter on the spark-plug end of a coil and hand-cranked with the key on, saw no voltage there w/ respect to motor ground.

      I can't seem to find my compression guage, but I really doubt it's that; hand-cranking or rope-pulling, it feels like lots of compression, certainly enough for at least a kick on the motor.

      I guess I'll try swapping the rectifiers next, and the oil pressure switch too, but it's getting on evening here and it might be tomorrow b4 I get that done...

      Thanks and stay tuned!


      • #18
        I haven’t got a wiring schematic for your engine but l am thinking that your computer is deliberately not supplying spark.
        with the key on you should have battery voltage on both injector wires going into the injector and coming out.

        If you have remove an injector connector and with an led test light or multimeter connect one end to battery pos and crank the engine while probing the ground side the light should blink or meter should indicate that the computer is supplying the ground.

        For the coils with the key on there should be battery voltage on the grey wires, the black is ground and an other coloured wire for coil turn on and off.

        Remove a connector from the coils and connect the meter to battery pos and probe the other wire that is not grey or black and crank the engine same deal if the computer is turning the coils on and off the meter will switch between 0 and five volts.

        Check and make sure that the computer is receiving the start signal at the computer when the key is in the start position cranking the engine and make sure that the emergency stop plate is at 5 volts with the key on.
        You can get a workshop manual off eBay for 10$.


        • #19
          Hello everyone, and thanks again Redlowrey. I've been reading the back-and-forth between this forum and its member wellcraft34, from a post dated 2019. Wellcraft34 seems to have had almost exactly the same problem that I've got now. It's sad and disappointing to me that he didn't follow through with the thread. We don't know whether he ever solved the problem, and if so, how??; I promise I won't commit the same sin.

          Meanwhile, I'm still not feeling the love from my motor. I'll list what I've tried today, but first I'd like to ask for clarification of what you said, redlowery, a few weeks ago:

          "That ground seems high, the ecu may not be seeing that as low.
          check the ground for the cam sensor 300mv seems high l would think around 40mv."

          OK, so what could be causing that, and what might be a good way to cure it? Am I looking at a new sensor, even though the one in there now works fine in my other motor?

          So, here's what I did today:

          1. Gapped the CKP at 0.75mm. The most recent manual I could find online was from 2005, (my motor is a 2020 model) so I'm aware that number may have changed. Anyone got a comment?

          2. Checked static resistance of the CKP, unplugged: 212Ω.

          3. Checked voltages at the coil input connector, unplugged: GRY/ 12.47VDC, BLK/ 0.00VDC, Coloured/ 0.01VDC

          4. Hooked up a test light to the BLK and Coloured wires at the coil connectors, unplugged: no flashing, but see below for 2nd attempt, I may have done something wrong here.

          5. Checked AC voltages at the ECU connector, where the CKP wires (RED?BLK and BLK/WHT) enter it, while cranking: inconclusive, looked around 0.7VAC, but wasn't steady-- see below for 2nd attempt. Also checked at the CKP connector, unplugged: 0.86VAC

          6. Tried the same AC voltage checks on the "good" motor, got about the same results. One thing I noticed: The "good" motor wouldn't start as long as I had the meter probes on the CKP connectors (at the CKP or at the ECU). As soon as I removed the probes, it started right up.

          7. Checked the connections to ground at the coil connectors, all 0Ω.

          8. 2nd Attempt: Re-checked the AC voltage, while cranking, at the CKP, unplugged 3.36VAC; at the ECU connector, plugged in: 3.36VAC-- so this time working fine(!)

          9. 2nd Attempt: Re-checked DC voltages at the CMP sensor: B+ was 11.72VDC, control was 5.0VDC

          10. 2nd Attempt: Hand-cranking, re-checked toggling of the CMP sensor: HI: 5.02VDC, LO: 0.31VDC-- so, also working, but is that LO voltage too high?

          BTW, I also have the exact same run-on of the starter motor that wellcraft34 had back in 2019. But we've decided that's not a problem, right?

          That was it for today. I was too busy trying out the advice from 2019 to try checking the start signal at the ECU, and also the emergency stop plate. I'll try those things tomorrow.

          I've got an appointment at the Suzuki dealer on Friday, which I'd hoped to be able to cancel, but now I'm doubting I'll be able to avoid it. Still, any tips wildly appreciated!


          • #20
            What was the start problem in 2019 l can’t remember it seems like you have the inputs going in but nothing coming out.
            The only thing l didn’t like was the high ground but checking specs that is ok with Suzuki, do the ground again this time with the engine cranking and see if it is higher.
            As l said before l think the computer is blocking the inputs for a reason, like a problem with the emergency stop circuit or when in neutral it does not see the start signal at the ecu when the key is in the start position.
            Buy your self a cd on eBay for 10$ you have an understanding electrical circuits. If l had a wiring diagram on your engine it would help, for instance there are three different voltage inputs for various models for the neutral switch alone with out other changes, so it is important to have a wiring schematic.
            I think from memory wellcraft had the same problem as you, changed the crank sensor several times and in the end said it was the crank sensor, l think that he over looked the emergency stop plate and did not want to say anything.
            What type of multimeter are you using l was going to say to you try checking the crank sensor disconnected from the ecu that way you will get a higher out good call.
            Do you see how insignificant the the amount current that your meter draws was enough to change the output of the driver in the ecu and not start.
            If you are using a digital meter there should be 20,000,000, million ohms per volt it should not be able to interfere with the signal.


            • #21
              I know you checked the neutral switch, this is how it works, when you turn the key to the start position, battery voltage will flow through both neutral switches to the starter relay then to the starter. Also in the loom is a splice where it goes to the ecu, this is where it knows what position the gear shift is in.

              Say for instance an early df four cyl on pin 5 on the ecu there would be 0 volts in neutral 2.5 volts in gear and between 6 and ten cranking and if the ecu doesn’t see those voltages it won’t turn on coils or injectors.
              same deal for the emergency stop plate between 0 and 5 volts depending on the position of the plate.

              Just think of the knowledge that you have gained in having a play my motto is, if you don’t play you don’t learn.
              Buy the CD for your engine off eBay and you will never have to go to the dealer for an electrical problem.


              • #22
                Hi Redlowery and thanks yet again! Yes, I'm definitely enjoying learning this stuff, and I've got a few sayings up my sleeve about the value of knowledge, too. I did a few last tests today, but unfortunately I was ultimately unsuccessful; I'll schlepp the motor to the dealer's on Friday with fingers crossed that he's competent and won't rip me off. It's not so much the corporate structure that scares me (although I admit...), but more the local traditions.

                BTW, I'm using a fairly decent name-brand DMM that's always worked fine, and yes, it surprised me too that it interfered with the start signal on the "good" motor, but there it is... interesting. I've got a few other meters, so maybe I'll try them too, but for the moment I just can't afford to spend more time on this.

                Oh yes I'd be delighted to shell out a few bucks for the correct manual for my motor, but I didn't find it, neither on EBay in my home country, nor on EBay in the USA. I'm thinking the motor is just too new. I wound up getting an outdated manual that doesn't help me much, but at least it gives me a basic overview. Eyes peeled for a current version.

                I will definitely post whatever results I get from the dealer, and thanks again!


                • #23
                  Just a thought did you let the check engine light run it’s course, just in case there was more than one code.


                  • #24
                    Well yes, I did. I mean I'm not exactly sure what kind of time frame we're talking about here, but I definitely let the beeping go on for ten or fifteen minutes, at least, on multiple occasions. The only variation on the 4/2 pattern was an occasional 2/4 pattern, but as I've understood it, the CMP and CKP codes are pretty much interchangeable anyway, and I tested both.

                    The motor is in the shop right now, I hope they are better able to diagnose it than I was, otherwise I've got a very expensive door stopper. I'll be in another country for a couple of weeks, so they've got plenty of time. Fingers crossed, and as always, thank you!