Please help with HPDI issues

S

Stilletto

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Jul 14, 2025
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Got it in today, haven't had a chance to install it yet. If it doesn't solve the issue, the same seller has tons of mint parts that I may need also.
Very impressed.1000018355.jpg1000018356.jpg
 
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Stilletto

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Didn't work.....runs the same exact crappy way.
I noticed that when I pull several spark plug wires, there isn't much/and effect on the way it runs even in gear
 
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99yam40

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those motors limit RPM in neutral by cutting off more cylinders that just the 2 it drops in neutral
make sure the motor knows when you put it into gear.
it may not be getting the signal it is in gear
 
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Stilletto

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I'll check that in YDS for sure. I ordered 6 coils and 6 new plugs.
After those things, i'll be at a loss.
 
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Stilletto

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I also noticed that if I pull each injector wire (one at a time) the rpm picks up and smooths a little. This suggests to me a global over fueling situation, or inconsistent spark.
 
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99yam40

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what tells the ECU the motor is getting proper fuel on these motors?
does it have an O2 senser?
maybe nothing.
it depends on the High pressure pump regulator to have the correct pressure.
did you make sure the ECU knows when it is in gear yet?
 
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Stilletto

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It does have an O2 sensor. It tests OK and I cleaned the "sniffer tube". It was quite nasty. I will check the neutral switch operation thursday in YDS. I did have a problem with it before but I had it working last time I checked.
 
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Stilletto

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It reports voltage in YDS as within spec but you never know I guess.
I got the coils today, spark plugs tomorrow.
 
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Stilletto

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Bought a new battery, coils and spark plugs installed. No change. I went out yesterday and idled around the river. Smelt really strong, not a raw fuel but like a 1969 Nova with no catalytic converter.......never went above 1000rpm.

I also bought a spark tester to see how strong the spark is. Comes tomorrow. I am wondering now about the stator, pulser coil etc.
 
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Stilletto

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Spark looks orange and not very impressive from all 6 coils. I am suspecting the stator now. Anyone had experience with a weak stator?
 
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99yam40

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the stator has the charge coils, pulsar coils and lighting coils.
your service manual should give you the minimum peak voltage readings for each going to the CDI.
I am thinking this is a CDI controlled motor
 
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