Cylinder 6 Misfire

[92snowmachine]

from the info i have (shopkey) the ecu uses the crank angle sensor to fire the coils.

[Ironhydroxide]

So, crank angle tone wheel then.... I'll check it out... I just replaced (well, sorta) the Crank angle sensor.

I used an EJ22 Sensor instead of our EXTREMELY pricey EG33 Sensor. Depth is the same, plug is the same, readings are the same. mount point and plug direction is different.

[oab_au]

The spark and injection timing, is controlled by all the crank and cam sensors together. The No.1 sends a pulse every 30*. No.2 sends a 1,2,3, pulse to tell which set of cylinders are at TDC.The cam sensor tells which of two cylinders at TDC is on compression.
So they all play their part in the firing. don't think this would have a bearing on your trouble.

Harvey.

[Ironhydroxide]

UPDATES

Well, I've run EVERY option I can think of on this.

I got a hold of an oscilloscope and checked BEFORE the ignitor for ground signall.. EVERY wire had a Pulsed ground signal when cranking EXCEPT the ground (middle of the 7 pin connector) and the #6 Coil (Far to right, Blue green wire)

I checked the Crank angle, and BOTH cam angle sensors AT the ECU for signal.. CLEAN signal pulsed on all...

STILL misfire ONLY Cylinder 6. NO SPARK at all... I traced wires in the engine, checked for continuity (and maybe shorted) All wires were within 1 ohm and had NO connection to other wires.

I am totally at a loss here...

it almost HAS to be mechanical... BUT WHAT???

the only interface between mechanical and electrical is the Crank and Cam angle sensors... I would think if one is going bad, the miss would alternate cylinders, but my problem is ALWAYS the #6 ALWAYS...

I've even used feeler gauges to check distances from the tone wheels to the Sensors... All were between .030 and .017 (inches)

Anything I've missed???

[THE NEW GUY]

Originally Posted by Ironhydroxide

UPDATES

Well, I've run EVERY option I can think of on this.

I got a hold of an oscilloscope and checked BEFORE the ignitor for ground signall.. EVERY wire had a Pulsed ground signal when cranking EXCEPT the ground (middle of the 7 pin connector) and the #6 Coil (Far to right, Blue green wire)

I checked the Crank angle, and BOTH cam angle sensors AT the ECU for signal.. CLEAN signal pulsed on all...

STILL misfire ONLY Cylinder 6. NO SPARK at all... I traced wires in the engine, checked for continuity (and maybe shorted) All wires were within 1 ohm and had NO connection to other wires.

I am totally at a loss here...

it almost HAS to be mechanical... BUT WHAT???

the only interface between mechanical and electrical is the Crank and Cam angle sensors... I would think if one is going bad, the miss would alternate cylinders, but my problem is ALWAYS the #6 ALWAYS...

I've even used feeler gauges to check distances from the tone wheels to the Sensors... All were between .030 and .017 (inches)

Anything I've missed???

Dear Ironhydroxide:
please let me the wiring diagrams for the ecu and sensors involved. also please let me some pictures of the sensor locations. Where is the 7 pin connector you talk about? Is your osciloscope 1 or 2 channels? can you check the cam sensor input and the #6 coil signal output at the same time to check timing?
I have more ideas but lets do it step by step.

[Ironhydroxide]

http://www.seccs.org/tech/1992%20SVX...G_DIAGRAMS.pdf

Pages 4 and 5 are the Engine Wiring Diagrams.

on page 5 you will find the Ignitor and Coils the 7 pin connector of which I speak is the Connector coming FROM the ecu and INTO the ignitor

my Scope does have an option for 2 signals... BUT i don't have a second lead.....so....yeah.

[THE NEW GUY]

Originally Posted by Ironhydroxide

http://www.seccs.org/tech/1992%20SVX...G_DIAGRAMS.pdf

Pages 4 and 5 are the Engine Wiring Diagrams.

on page 5 you will find the Ignitor and Coils the 7 pin connector of which I speak is the Connector coming FROM the ecu and INTO the ignitor

my Scope does have an option for 2 signals... BUT i don't have a second lead.....so....yeah.

ok. I´m going to read the wiring. In the meantime, please check if the problem continues if you remove the screw that holds the ignitor #6 in place...

[THE NEW GUY]

tell me one thing: do you know the firing order and which cylinder is who? is the cyl 1 the most advanced on the passenger side?
connect the oscilloscope on two oposite ignitors, check the signals: if both fire at the same time, then just put the ignitor 6 in parallel with it's opposite.
You will need to get the missing lead for the channel B on the oscilloscope.
let me know.

[icingdeath88]

Originally Posted by THE NEW GUY

tell me one thing: do you know the firing order and which cylinder is who? is the cyl 1 the most advanced on the passenger side?
connect the oscilloscope on two oposite ignitors, check the signals: if both fire at the same time, then just put the ignitor 6 in parallel with it's opposite.
You will need to get the missing lead for the channel B on the oscilloscope.
let me know.

They don't fire at the same time. The SVX isn't wasted spark.

[THE NEW GUY]

OK ironhydroxide. the wire that arrives to the ignitor (7pin connector) and corresponds to the cyl #6 is the 25 (blu-wht) and comes from the ECU, pin 8, of the 26pin connector.
that is where you have to confirm the ECU output signal. If you have a signal at that point but it does not get to the ignitor (7pin connector) then you found the problem: the blu-wht wire is opened or grounded.

[THE NEW GUY]

Originally Posted by icingdeath88

They don't fire at the same time. The SVX isn't wasted spark.

Hi icingdeath88, do you know the firing order and the ID of the cylinders?
thanks

[huck369]

Originally Posted by THE NEW GUY

Hi icingdeath88, do you know the firing order and the ID of the cylinders?
thanks

1,3,5 on the right side (passenger side US)
2,4,6 On the left side (Driver's Side US)

Numbers start at the front of the motor.

[THE NEW GUY]

Originally Posted by huck369

1,3,5 on the right side (passenger side US)
2,4,6 On the left side (Driver's Side US)

Numbers start at the front of the motor.

thank you huck369.

[THE NEW GUY]

OK Ironhydroxide. I think the problem is in the combination of signals from the cam sensor and the crank sensor. Even if the gap is good. You have to connect your oscilloscope channel A to the cam sensor and the channel B to the crank sensor. let the engine run and try to record the data in the osc. You will see a missing pulsed signal there. Just check wich channel is the one for the missing pulse and voilá.
please let me know the results. I want to do the same test here with mine to know the pattern. I´ll let you know.

[b3lha]

I think you can forget about cam/crank angle signals. They don't affect individual cylinders. They just tell the ECU the shaft positions and the ECU decides when to fire the plugs. The ECU will never decide to fire 5 out of 6. If the position signals are messed up then the ECU would throw an error code and not fire any plugs.

Originally Posted by Ironhydroxide

UPDATES
I got a hold of an oscilloscope and checked BEFORE the ignitor for ground signal. EVERY wire had a Pulsed ground signal when cranking EXCEPT the ground (middle of the 7 pin connector) and the #6 Coil (Far to right, Blue green wire)

Check those same wires carefully at the ECU end. It sounds like the ECU is happy and sending out a signal to fire #6, but that signal is not getting to the ignitor.

If you can't see anything visually wrong, unplug the ECU and test the continuity of that wire from one end to the other. Check also that it is not shorting to ground.


As far as I can see, the only two possibilities are bad ECU (you already checked that) or bad wiring from ECU to ignitor.