12-19-2020, 09:34 PM
(12-19-2020, 04:32 PM)1995 toad Wrote: i understand that the freeze doesn't work when you start to rev the engine.all 91 and newer sidekick and newer cars.(all) DIZZY Timing PLATES ARE GONE forever (in fact EPA banned)
when i start to rev it the advance goes up like it should.
as you hold it at a higher.. cant see the tach... rpm you can watch the timing mark intermittently go from approx 20 * to 3* atdc...
i have never seen this happen before. (when things fail many things new things are seen)
don't know what controls the advance or retard of timing without a advance plate in the distributor. (that plate ended year 1990, gone for ever and ever)
the ECU does all spark advancement, electronic computer controlled spark advancement, in fact all cars do that. from then to now.
Did you see my full color 3D color spark advance map above?, that what all EFI does then and now, it just TABLE in the ECU ROM memory.(3d viewed !)
the distributor in this car has no vacuum and advance nor centrifugal advance inside, zero.
that spark triming JUMP you see (spark strobe test light) is dead wrong;
"intermittently go from approx 20 * to 3* atdc..." (you mean 20 to the left of zero and then the strobe flies 3degrees to the right of zero. (0)
20 BTDC to 3 ADTC retarded, use these words so it is clear.
if you saw that , it mean just 2 thing wrong. (spark is bad) now we know,, that and only why matters)
1: and input to the ECU is bad. (distributor bad) or wires to it bad. (same goes for cam jumping or jittering wrong a pure mechanical failure of cam drive)
2: the ECU is bad.
- the input is CMP (cam angle sender) inside the distributor is bad or bad connection or grounds to the distributor.
- or ECU is bad.
Spark advance then and now. (rules) WHO ECU MAKES SPARK:
the CPM must not be dead, if dead there can be NO SPARK.
the CPM sends a pulse to the ECU. (PCM new name 1997) eLECTRONIC ENGINE CONTROL UNIT.
a scope connected to CMP looks just like this(click me!) at idle and does not EVER MISFIRE< if does?, the CMP is BAD.(or ground or all wires to Distrib are bad)
- this signal CMP the ECU uses to generate spark.
- next the ECU looks at RPM , engine load to find the correct timing using the MAP matrix in color I posted before this post)
- {{ if freeze jumper not present , hold timing at static 0 means -5DegBTDC}} IF ecu in limphome mode advance now dead.means not DTC code 12.
- It finds that MAP(chart) table data matching that load (etc) and then fires the IGNITOR to SPARK COIL, and spark HAPPENS now.
- jump to 1, this jump means a loop in software and just repeats spark endlessly in a loop, jump to #1 (or is and ISR method, "CMP interrupt code")
CMP is the master timing device. if dead spark end. if drops out spark fails and misfires.
IF CMP shows bad signals that means it is bad or the cam is jumping bad and wrong. (CMP lies or is telling the truth and CAM is bad(jumping badly)
as I told you the CMP can fail and not be anything to do with ECU , spark ,coil ,ingnitor, distributor at all.
The cam belt loose makes the CMP misfire. (even confuse the ECU)
The cam has 1 belt and 2 COG wheels, if either are bad, the cam can JOG like mad and the CMP is driven from this cam end. and if the cam acts wildly so will CMP.
If the crank cog is bad then it is. ALL Spark generation starts here, at the Timing belt change out 60k miles we just look first the set the bolt to new spec 94ft.lbs )
like this, if this happens the cog jogs, if loose it goes wild and cam and CMP + distributor goes wild. THIS what causes TIMING GONE WILD (#1 common fail)
http://www.fixkick.com