Quote:
Originally Posted by -=Jeff=-
Just looked..
Get a 1991 power switch ( unless you are bypassing it) I am sure I can figure out a way to use the 1990 switch for the 1991 design
run a new wire to the knock sensor and get a 1991 knock sensor.
Add the ESC board to the PROM.. Run 1991 code..
I think that is it..
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Jeff,
Are u suggesting to use the 91 Mask for a 90 ZR? Is there a difference in the 90-91 sensor? I would think the frequency would be the same for any of the LT5s?
On a different vein, the ECM runs a forced knock test. Some info from RBob over at ThirdGen.
This is from ThirdGen.Org. RBob is a moderator there and a tuning guru among other talents.
“Code 43 is set by one of two different ECM tests. The first test is run-away knock. If within a period of 3.9 seconds more then ~245 knock counts are detected code 43 will be set. This can be caused by an open wire or a non-existent knock filter.
The other test is that the ECM will advance the spark timing in order to force knock (detonation). The ECM will attempt this twice, the second time with more advance then the first. If both forced knock tests fail code 43 will be set.
The forced knock test takes place under PE conditions. Once knock is detected PE and HighWay SA is now in effect and the forced knock test is done.
“Hook up a scan tool and check the knock counts. If the counts are constantly incrementing then you have run-away knock. You then have either an open wire or the filter is bad.
If after some spirited driving there is no knock and code 43 pops up, then either knock did not occur or the knock sensor/filter is not reporting it. If no knock is reported then test the system by holding the rpms > 1200-1400 RPM and rap on the engine block. This should be picked up as knock.
If so then you'll need to figure out why the ECM can't force the knock. Check the timing and the EGR system. Have you checked to see if the chip is stock? Maybe running 93 octane can do it?”
May need to check filter (ESC).