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Perfect Pass GURUS! HELP!


85 Barefoot

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Crew,

Had many perfect pass boats but this problem is a headscratcher for me and perfect pass.

Boat is an LCR response.  RPM signal was "dropping" (to 0) and/or reading erroneously causing wild speed swings when in GPS slalom mode.  If you've opened this thread you know that it's not a pure GPS system like zero off.  Thus, RPM signal is needed for correct operation, speed, and times. 

Got with perfect pass.  I bypassed the factory perfect pass harness and wires straight to the RPM wire and grounded to grounding block.  Same results.  Then at their suggestion put ground wire to the boat's RPM wire (gray, as I recall).  Same results.  I sent my master module to them to bench test.  Tested OK.  They sent me a module to try.  Immediately the boat was "perfect".  Consistent correct RPM readings.  Baselines all reset, course mapped, and boat was perfect for about 15 hours.  Then...

it happened again and now is reading all over the place about 50% of the time, rendering it useless for slalom.

It has been suggested that I may need to run a wire straight to the ECM but thus far, I don't know what wire to splice to.  Anyone have an ECM schematic for LCR ECMs? 

Anyone have any suggestions, ideas, or thoughts?  Case of beer for whoever solves this :lol:

Unfortunately I do not have an extra tach to test if whether the dash is getting a dirty RPM signal.  Yes the boat runs fine in trick and wakeboarding as those are "pure" GPS modes.

Thanks!

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1 hour ago, Woodski said:

Try running the PP wire directly to the coil and as you noted make sure ground is good.  Also, are your plug wires good, PP is sensitive to EMI so you need good resistor plug wires and plugs.

Wood, Thanks.  Which wire?  12V or rpm? 

  I'm splicing into the rpm signal wire at helm.  Per my understanding of my convos w PPass, I do not have a voltage issue, only rpm signal issue.  Are you saying dirty RPM signal can be caused by interference on the 12V "side" of things?

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1 hour ago, 85 Barefoot said:

I do not have a voltage issue...

I'd be willing to bet that you have a cruddy connection somewhere.  It could be 12v or ground to mess up the tach signal.  I would start with a thorough cleaning of the electrical connectors under the dash and the grounds at the engine.

A definitive test would be to find an oscilloscope and check the tach signal to see if it looks OK.

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RPM wire directly to the coil, your tach may be a noisy source.  Concurring also with 'justgary' that a poor signal is your issue.  Sounds like the RPM signal but could be any of the three options.  Good luck, keeping those pesky electrons in the wires can be like herding cats.

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19 hours ago, justgary said:

I'd be willing to bet that you have a cruddy connection somewhere.  It could be 12v or ground to mess up the tach signal.  I would start with a thorough cleaning of the electrical connectors under the dash and the grounds at the engine.

A definitive test would be to find an oscilloscope and check the tach signal to see if it looks OK.

Just to be sure I'm following, you're saying a dirty 12 v connection(which has now been run straight to my key btw) is causing an intermittent, erroneous tach signal?

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10 minutes ago, 85 Barefoot said:

Just to be sure I'm following, you're saying a dirty 12 v connection(which has now been run straight to my key btw) is causing an intermittent, erroneous tach signal?

I'm saying that you are dealing with an electrical circuit.  Every electrical circuit needs to actually be a *circuit* to work correctly.  In your case, the power to the PP system and the engine ECM both have to have the same input power (12v) and voltage reference (this is commonly called a ground).  The pulse signal from the engine will not look correct to PP if the voltage and reference are not the same.  Cruddy connections can behave in very strange ways.  Just because the systems power up and appear to operate does not mean that they have the correct voltage available.  You have a signal from one system that needs to get to another system, and they are powered by different harnesses.

It will be less frustrating for you if you clean every connection under the dash and at the engine.  Personally, I would include the starter, alternator, cannon plug, ground lugs at the back of the heads, and I would even break, inspect (looking for pushed, bent, or dirty pins/sockets), and re-mate the ECM connectors and the distributor connector.  Then I would clean every terminal connection under the dash.  I would also spray every one of these connections with light oil to keep air away.  If the problem didn't go away after that, I would then start more drastic troubleshooting measures.

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58 minutes ago, justgary said:

I'm saying that you are dealing with an electrical circuit.  Every electrical circuit needs to actually be a *circuit* to work correctly.  In your case, the power to the PP system and the engine ECM both have to have the same input power (12v) and voltage reference (this is commonly called a ground).  The pulse signal from the engine will not look correct to PP if the voltage and reference are not the same.  Cruddy connections can behave in very strange ways.  Just because the systems power up and appear to operate does not mean that they have the correct voltage available.  You have a signal from one system that needs to get to another system, and they are powered by different harnesses.

It will be less frustrating for you if you clean every connection under the dash and at the engine.  Personally, I would include the starter, alternator, cannon plug, ground lugs at the back of the heads, and I would even break, inspect (looking for pushed, bent, or dirty pins/sockets), and re-mate the ECM connectors and the distributor connector.  Then I would clean every terminal connection under the dash.  I would also spray every one of these connections with light oil to keep air away.  If the problem didn't go away after that, I would then start more drastic troubleshooting measures.

sounds good, I'll get after it. 

 

Also just ordered diacom to see what RPM reading (and how stable) it stays.  Good idea?  Thought being if ECM signal is stable and correct, issue is "forward" of the ECM?

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1 hour ago, 85 Barefoot said:

sounds good, I'll get after it. 

 

Also just ordered diacom to see what RPM reading (and how stable) it stays.  Good idea?  Thought being if ECM signal is stable and correct, issue is "forward" of the ECM?

I guarantee the ecm knows rpm correctly if the engine runs ok.  PP is reading the spark pulse from the distributor module. 

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