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ok.
now we are really grasping at straws.
the ign system on that engine is composed of two primary parts.
ignition PRODUCING.
ignition CON*****ING.
that is why we start by testing ign PRODUCING components.
easiest way is can it jump a 7/16th gap.
if it can we are mostly done with that part.
now we can move on to ign CONTROL
does the CPS work correctly?
does the TPS work correctly?
does the ECT work correctly?
if so we can move on to fuel control.
does the MAP sensor work correctly?
does the intake air work correctly?
at idle warmed up with the lower unit SUBMERGED does the O2 sensor voltage scale between about .35 and .6V?
at idle you can cover the #1 cyl intake air bypass hole and watch the O2 sensor voltage,should climb close to .9v when covered and rapidly drop when uncovered.
at a steady cruise of about 3500 RPM the O2 sensor voltage should stay at about .35V.
excessive rail pressure at low speeds will cause issues,
monitor rail pressure at all RPM's.
once all the above things are looked at pulser coil outputs and CDI outputs can be monitored.
there are such things as in range sensor failures.
if a sensor,other than O2, fails you will see base ign timing lock at 7*BTDC.
depending on the sensor it may or may not advance past 7*BTDC and top speed may or may not be reached.
if a pulser coil were to fail.
that cyl wont spark.
fuel would be injected to all 6cyl via the intake air pressure sensor.
ign timing will be FIXED at 7*BTDC.
idle speed at about 1100 RPM and top speed cannot be reached.
what I typically see after a backyadigan got his skinners on an OX66 is something failed, idle speed increased so the backyardigan starts skinning on the throttle stopper screw.
remember EFI does NOT have an idle speed screw.
unplug any sensor other than O2 and intake air and you will see ign timing jump from about 7*ATDC to about 7*BTDC and idle speed jump to about 1100 RPM.
a faulty intake air wont affect timing at idle but it may run rich.
the O2 sensor is not monitored other than does it have any signal.
if unplugged,no signal at all,
then fuel is fixed rich at idle and lean above 4000 RPM, DO NOT run above 4000 RPM.
if the ECU gets a signal from the O2 sensor it will act on that signal reguardless of if the signal is correct or not.
this is where a Kv tester ,fuel rail tester, diagnostic test lamp and my DVA come into play.
my Kv tester can quickly confirm or eliminate spark.
it can isolate what cylinder has excessively low or high Kv.
low compression,rich fuel,fouled plug or weak primary coil inputs can cause low Kv.
open gap,bad cap resistor or lean A/F mix can cause a high Kv.
now we are really grasping at straws.
the ign system on that engine is composed of two primary parts.
ignition PRODUCING.
ignition CON*****ING.
that is why we start by testing ign PRODUCING components.
easiest way is can it jump a 7/16th gap.
if it can we are mostly done with that part.
now we can move on to ign CONTROL
does the CPS work correctly?
does the TPS work correctly?
does the ECT work correctly?
if so we can move on to fuel control.
does the MAP sensor work correctly?
does the intake air work correctly?
at idle warmed up with the lower unit SUBMERGED does the O2 sensor voltage scale between about .35 and .6V?
at idle you can cover the #1 cyl intake air bypass hole and watch the O2 sensor voltage,should climb close to .9v when covered and rapidly drop when uncovered.
at a steady cruise of about 3500 RPM the O2 sensor voltage should stay at about .35V.
excessive rail pressure at low speeds will cause issues,
monitor rail pressure at all RPM's.
once all the above things are looked at pulser coil outputs and CDI outputs can be monitored.
there are such things as in range sensor failures.
if a sensor,other than O2, fails you will see base ign timing lock at 7*BTDC.
depending on the sensor it may or may not advance past 7*BTDC and top speed may or may not be reached.
if a pulser coil were to fail.
that cyl wont spark.
fuel would be injected to all 6cyl via the intake air pressure sensor.
ign timing will be FIXED at 7*BTDC.
idle speed at about 1100 RPM and top speed cannot be reached.
what I typically see after a backyadigan got his skinners on an OX66 is something failed, idle speed increased so the backyardigan starts skinning on the throttle stopper screw.
remember EFI does NOT have an idle speed screw.
unplug any sensor other than O2 and intake air and you will see ign timing jump from about 7*ATDC to about 7*BTDC and idle speed jump to about 1100 RPM.
a faulty intake air wont affect timing at idle but it may run rich.
the O2 sensor is not monitored other than does it have any signal.
if unplugged,no signal at all,
then fuel is fixed rich at idle and lean above 4000 RPM, DO NOT run above 4000 RPM.
if the ECU gets a signal from the O2 sensor it will act on that signal reguardless of if the signal is correct or not.
this is where a Kv tester ,fuel rail tester, diagnostic test lamp and my DVA come into play.
my Kv tester can quickly confirm or eliminate spark.
it can isolate what cylinder has excessively low or high Kv.
low compression,rich fuel,fouled plug or weak primary coil inputs can cause low Kv.
open gap,bad cap resistor or lean A/F mix can cause a high Kv.
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