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munkymush
06-07-2013, 11:47 AM
hi, ive got a predator engine that runs purely on lpg ...im looking at checking the ignition timing, but when I put the jumper in the 2 pins on diagnostin socket to put it in service mode it obviously wont lift the throttle to 1000rpm as it has no fuel control ie throttle position sensor or iac? ...can anyone clarify the correct way to check this timing? do I still need the jumper in or do open the throttle manually to 1000rpm or whats recommended ?
thanks ..

PureInboards
06-07-2013, 06:23 PM
I don't understand the ??? (i.e. have you actually tried it?) all the 2 pins do is cause the ECU to raise the rpm by opening the IAC a bit and the fuel mixture is pretty much irrelevant at that speed/engine load combo. If you have tried it what happens?

munkymush
06-08-2013, 11:26 AM
hi , I thought that the 2pins connected actually locked the ecu as far as timing was concerned? maybe im wrong .if not what does "in service mode" mean when its got the pins jumped? if its purely a case of the iac lifting revs to a 1000rpm surely its a waste of time as you can do that by the throttle?

CantRepeat
06-08-2013, 11:39 AM
hi , I thought that the 2pins connected actually locked the ecu as far as timing was concerned? maybe im wrong .if not what does "in service mode" mean when its got the pins jumped? if its purely a case of the iac lifting revs to a 1000rpm surely its a waste of time as you can do that by the throttle?

In service mode also removes the advance from the ECM so you can time it correctly. It sets the RPMs to the correct RPM to set the timing as well. Are you sure you are jumping the correct pins?

munkymush
06-08-2013, 12:17 PM
hi thanks for confirming it also does something with the advance, I thought it ought to . I just read the procedure for setting timing and I may not have done it in the correct order as it mentions also switching engine off and leaving for 15 seconds.

JimN
06-08-2013, 12:30 PM
hi, ive got a predator engine that runs purely on lpg ...im looking at checking the ignition timing, but when I put the jumper in the 2 pins on diagnostin socket to put it in service mode it obviously wont lift the throttle to 1000rpm as it has no fuel control ie throttle position sensor or iac? ...can anyone clarify the correct way to check this timing? do I still need the jumper in or do open the throttle manually to 1000rpm or whats recommended ?
thanks ..

In Diagnostic Mode, the ECM removes Spark Stabilization- it has no control over base timing advance and this is the reason that has to be verified/set when the boat is new. The engine speed, however, will drop and you'll have to raise it to 1000RPM manually, or it probably won't keep running. Fuel control, TPS and the rest of the sensors still operate normally. If you don't use the jumper, Scan tool with diagnostic mode or a diagnostic computer with this function, you can't disable Spark Stabilization and it's absolutely a requirement that you do this. If Spark Stabilization hasn't been disabled, there's no way to see the exact spark advance because the timing mark will be jumping all over the place. Once it has been disabled, the timing mark should be rock steady. If it's still jumping, either the jumper isn't doing its job or the distributor shaft bushing may be worn.

munkymush
06-08-2013, 02:14 PM
thanks jim ..

PureInboards
06-08-2013, 08:10 PM
Sorry for the confusion I assumed that you knew it locked the timing as that is the whole point of the exercise as said the ECU raises the RPM so that the engine doesn't stall, on the carb versions with the same distributor you sometimes need to use the throttle to achieve the same result