Welcome Guest - Sign Up today
Welcome Guest - Sign Up today

Announcement

Collapse
No announcement yet.

Volvo Penta 5.7 GXi-C cranks but won't fire

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • Volvo Penta 5.7 GXi-C cranks but won't fire

    Good morning ... I'm hoping to receive input on this issue from the more experienced personnel within the Forum. Thank you to all in advance. I've read so many posts on various forums that simply ended without conclusion, one thing I will commit to is closing the loop on whatever the solution turns out to be.

    The engine in question is:
    Volvo Penta 5.7 GXi-C Raw Water Cooled
    Serial Number 4012062213
    Production Number 3869137
    MEFI Assembly Number 57IAFM/02HT01 3861773
    Boat - 2002 Cobalt 240

    Symptoms:
    1. DTC Code 81 is present - We don't have a scan tool. This was obtained via the paper clip and counts 1-2, then 8-1, then 1-2
    2. Cranks fine off the starter motor but will not fire
    3. Fuel Pumps do not go through their normal 2 sec prime / stop as ignition key is placed to on
    4. Fuel Pumps do not operate during cranking
    5. Will fire and idle well with an ounce or so of fuel added through throttle body
    6. Audible alarm is a persistent, non-stopping on off on off, etc. once the key is in the on position regardless of what other action is being done
    7. Boat has not run in 18 months - fuel in tank has been replaced

    Actions taken:
    1. Although batteries are 6 months old, batteries have both been recharged and read 12.6v dc
    2. Prior to my involvement, ECM's were exchanged with a supposedly good one although I wasn't around during that testing
    3. HP fuel pump has been replaced due to recommendation from a previous marine mechanic.
    4. Fuel Pressure regulator removed, screen sprayed clean with carburetor cleaner
    5. Batteries grounds all indicate less than 0.5 ohms
    6. ECM grounds from J1 connector pins 13, 28, 29 all tested good at 0.2 ohms
    7. Verified and tested all 5 15A & 20A fuses at relay terminal
    8. Verified and tested fuel pump and ignition relays - 0.2 ohms with contacts closed
    9. Continuity tested SB/Y wire from fuel pump relay terminal 85 to J1 connector pin 6 - 0.2 ohms
    10. Continuity tested Y/GN fuel pump wiring from relay contact 87 to each pump harness connector - 0.3 ohms or so
    11. Continuity tested SB fuel pump ground wiring - 0.3 ohms
    12. Added clear tygon line to pump assembly, and at fuel pump relay terminals jumpered 30 to 87. Fuel Pumps each operated continuously until jumper was removed
    13. 12v dc and a solid ground have been confirmed at both the crankshaft and camshaft sensor harnesses. Signal voltage from each sensor has not been confirmed as I did not have a sewing needle to back probe for this voltage.

    Over the last several weeks, I've been helping a friend troubleshoot several items on this engine. Although many hours have been spent trying to find something of a scenario comparable within the VP Forum, I've not quite been successful. I've been using Workshop Manual C EFI Diagnostic 2(0) for troubleshooting logic as well as the appropriate wiring diagram. I'm not a Marine Mechanic although I spent a career managing electrical power plants using aero-derivative engines as the prime mover for power production and enjoy this type of troubleshooting on EFI auto engines.

    Given the symptoms and testing described above, it's my opinion the fuel pump relay ground at J1 pin 6 is not being commanded closed to ground by the ECM. That being said, I don't know if this is because of a "problem" with the ECM or a separate permissive issue the ECM is sensing that results in the ECM electing to not complete the ground circuit for J1 pin 6 to FP Relay contact 85. I do appreciate the extra sets of eyes and knowledge. Thank you!

  • #2
    DTC 81 is for many things

    DTC 81 - Crankshaft Position (CKP) Sensor Circuit Fault .................................................. ... 300
    DTC 81 - Camshaft Position (CMP) Sensor Circuit Fault .................................................. ..... 304
    DTC 81 - Camshaft Position (CMP) Sensor Circuit Fault (cont.) ........................................... 306
    DTC 81 - Fuel Pump Relay Driver Circuit High, Low or Open ............................................... 308
    DTC 81 - Fuel Injector Driver A Circuit High, Low or Open.............................................. ...... 312
    DTC 81 - Fuel Injector Driver B Circuit High, Low or Open .................................................. . 314
    DTC 81 - 5 Volt Reference Circuit Out of Range .................................................. ................... 316
    DTC 81 - Depspower Circuit Out of Range............................................. ................................. 318

    Your on the right track. You could jump across the relay 85 to 30 and see if the motor runs. My guess is it will not, and therefore the ECM is suspect.

    If the tachometer shows 300 or so rpm when cranking, then the CPS is working

    Would be nice if you had another motor which you could install the ECM on to check it out. That said, yours could possibility be repaired, but your still talking some coin to do so
    94 Formula 27PC Custom 509MPI MEFI3 , B3 XR
    95 Rinker 232 w/ 7.4L Carb 0F425011 B1 0F486471
    07 Seadoo GTX
    Merc Adults Only VP Adults Only
    G-Dad always said "First Liar doesn't stand a chance"

    Comment


    • #3
      Thank you for your response. We will need to confirm the tach readings next time a start is attempted. Very good to know if we do get the rpm's then the crankshaft & camshaft sensors have been eliminated.

      I do intend to do some additional testing on the 5 Volt Reference Circuit Out of Range and the Depspower Circuit Out of Range diagnostics procedure.

      Regarding your suggestion to jump across the relay 85 & 30 to see if the motor runs, I'm not sure I understand that. I have jumped across 87 & 30 and the fuel pump motors did run. Item 12 of Actions Taken from initial post. Would you please explain a little more what you had in mind and how to execute this suggestion? I'm probably just missing something with what you're thinking.

      If I correctly understand the ECM's role in closing the ground circuit to 85 coinciding with turning the key to on, wouldn't a DMM continuity test with a probe at 85 to GND prove whether the ECM is completing the ground circuit?

      Thank you!
      Click image for larger version

Name:	Relay Panel 5.7 GXi-C.jpg
Views:	1
Size:	102.1 KB
ID:	10745113

      Comment


      • #4
        Your correct, I was thinking and didn't get my thoughts straight before posting. You should be able to use a test light and go across 85 and 86, then when the key is ON it should light. Or if using a meter, see if zero ohms show

        You have done the testing correctly (30 and 87) and mentioned in first post, so my mistake
        94 Formula 27PC Custom 509MPI MEFI3 , B3 XR
        95 Rinker 232 w/ 7.4L Carb 0F425011 B1 0F486471
        07 Seadoo GTX
        Merc Adults Only VP Adults Only
        G-Dad always said "First Liar doesn't stand a chance"

        Comment


        • #5
          Very good. I'll post those results after the next set of tests. I'm assuming there is value in going through the 5 Volt Reference Circuit Out of Range and the Depspower Circuit Out of Range diagnostics procedures for DTC 81 unless you think otherwise.

          On the very rare occasion and only after disconnecting the batteries, J1 & J2, main cannon plug at the rear and the 3 connectors at the relay terminal then reconnecting all, the fuel pumps will go through the prime cycle maybe once or twice as the key is turned on so I've not completely ruled out some kind of an intermittent trouble. Meanwhile the audible alarm never stops beeping on & off.

          That said, the ECM visually is kind of 'crusty' looking. Also wonder if there is any value in splitting the ECU case for a simple visual inspection looking for water intrusion, burning, etc. We're considering sending the ECM to OBD Diagnostics, CA for an incoming, as received test and are interested in feedback, unless it violates forum rules, regarding their performance.

          Much appreciated!

          Click image for larger version

Name:	ECM.jpg
Views:	1
Size:	538.8 KB
ID:	10745278

          Comment


          • #6
            On the very rare occasion and only after disconnecting the batteries, J1 & J2, main cannon plug at the rear and the 3 connectors at the relay terminal then reconnecting all, the fuel pumps will go through the prime cycle maybe once or twice as the key is turned on so I've not completely ruled out some kind of an intermittent trouble. Meanwhile the audible alarm never stops beeping on & off.
            This is good to know. I don't see the ECM working and then not working. Check the 12V and 5V supplies to see if one of them is falling below reference voltage. It could very well be that one of the sensors is shorting out and causing the ECM to have an issue.

            Posting test results and other such is of no concern and most all info is welcomed. More info the better, even if some does not pan out.

            You could open it, but for the most part I don't see it as helping, but won't hurt.

            OBD is a good place, and Bob is tops. I bought the MEFI burn software from him, and have a copy of my bin file. So if mine ever goes out, I can re-flash the new ECM
            94 Formula 27PC Custom 509MPI MEFI3 , B3 XR
            95 Rinker 232 w/ 7.4L Carb 0F425011 B1 0F486471
            07 Seadoo GTX
            Merc Adults Only VP Adults Only
            G-Dad always said "First Liar doesn't stand a chance"

            Comment


            • #7
              Excellent! Bob and I have exchanged a couple of emails. It's a scorcher here in the Pensacola area with little shade at the boat so it might be a few days before I have any new information to share. In the meantime, Happy Memorial Day to all. Thanks AllDodge for your interest.

              Comment


              • #8
                Just me trying to keep it simple but are you getting fuel at the test nipple when ignition is turned on ? When you say you don’t get the usual pump priming, you mean it doesn’t come on at all ?

                Comment


                • #9
                  So, as a follow up to earlier action items, here are a few updates from some addition testing today:

                  1.) Tachometer read 100-150 rpm's while cranking

                  2.) Resistance measured from the fuel pump relay terminal #85 to ground was a.) infinite with key off and b.) 0.420 megohms with key on. I find this interesting that even though the resistance did not go to zero, the ECM was 'attempting' to close to ground given the reading change. Under initial actions #9, continuity tested SB/Y wire from fuel pump relay terminal 85 to J1 connector pin 6 found as 0.2 ohms

                  3.) With J2 connector removed and Ignition On Engine Off, confirmed 12.68 V at J2-1

                  4.) Performed DTC 81-5 V Reference Circuit Out of Range. Step 2 measured 0.14 V at J2-2 which did not exceed the 5.1 V limit. Is 0.14 V a typically expected value or is anything less than 5.1 V an acceptable reading?? Step 3 did not find any resistance measurements between 0-2 ohms during continuity checks between J2-2 and all other circuits of the ECM J2 connector. This all results in replacing the ECM via step 9 DTC 81-5 V Reference Circuit Out of Range 05.28.19.pdf

                  5.) Performed DTC 81-Depspower Circuit Out of Range. Step 2 measured 0.42 V at J2-17 which did not exceed the 5.1 V limit. Is 0.42 V a typically expected value or is anything less than 5.1 V an acceptable reading?? Step 3 did not find any resistance measurements between 0-2 ohms during continuity checks between J2-17 and all other circuits of the ECM J2 connector. Again, this all results in replacing the ECM via step 9 DTC 81-Depspower Circuit Out of Range 05.28.19.pdf

                  Another observation was that after reconnecting the J2 harness to the ECM, the fuel pumps attempted to prime only one time. Key was turned on and off a handful of times yet the pumps never ran again.

                  I'm not really sure of the proper next step. Cranking speed was less than the expected 300 rpm and the voltages measured at J2-2 and J2-17, although lower than 5.1 were a lot lower. Whether that's acceptable or not, I don't know.

                  Any feedback is appreciated. Thank you!

                  Comment


                  • #10
                    To QBhoy, yes that is basically correct. Under a normal lineup, the ECM is not closing to ground the J1-6 to fuel pump relay terminal 85 circuit.

                    Comment


                    • #11
                      Sorry if I missed you saying. Possible the fuel pressure regulator is at fault ? Sorry if I’m still keeping it too simple.

                      Comment


                      • #12
                        Sorry. Just saw you had it out. Would still be maybe suspecting that perhaps. Especially now that the pump has once tried to run ?

                        Comment


                        • #13
                          Thanks. It's not been eliminated, however, being downstream of the fuel pumps, I don't believe the fuel pressure regulator is really in play at this point in the troubleshooting.

                          Comment


                          • #14
                            Originally posted by PcolaBeach View Post
                            Thanks. It's not been eliminated, however, being downstream of the fuel pumps, I don't believe the fuel pressure regulator is really in play at this point in the troubleshooting.
                            You’ll likely know better than I but I assumed that the fuel pump and when and how it runs on a common rail system...must have a means of control on the discharge or pressure side of the pump.

                            Comment


                            • #15
                              Sign up today
                              Both J2-2 (5V ref) and J2-17 (Depspower) should read 5V the way I read/understand the guide. Getting less the 5V reference can cause the ECM to do all kinds of strange things and throw codes. This is why they want all the 5V sensors/fuses disconnected to see if power comes back up, if it doesn't then its inside the ECM
                              94 Formula 27PC Custom 509MPI MEFI3 , B3 XR
                              95 Rinker 232 w/ 7.4L Carb 0F425011 B1 0F486471
                              07 Seadoo GTX
                              Merc Adults Only VP Adults Only
                              G-Dad always said "First Liar doesn't stand a chance"

                              Comment

                              Working...
                              X