(02-06-2021, 10:21 AM)1995 toad Wrote: tps was calibrated...the jump is purely caused by ECU. ECU runs all timing advances.
have checked all wires from tps to their other ends
no bad wires.
found white wire from cps has shielding that wasn't connected to a ground on cps end...just laying in looming...grounded
tested wires from cps to coil, ignitor. noise suppressor. and cpu.... all wires checked good
not sure how to check suppressor.
every thing runs good till warm up then the problems start
havent driven it since all this
mounted cpu on kick panel to ease in testing wires to cpu... it is grounded btw.
started and ran fine no codes but didnt have time to drive it or warm it up.
the timing retarding was happening before the tps code showing up
with the code it still drives the same except the same timing jumping to 3* atcd
wish i had a spare cpu to test
would the noise suppressor cause intermittent timing drop
the timing jump is very intermittent and is happening on at lest the front two cylinders witch was all i tested with the timing light.
as I said Failsafe (limhome) mode can last 1 second and clear, so fast you can never see it happen. CPS sensor is one that can do that. (hit clear, ok, ok , hit) hit/clear is DTC.
CPU failure cuts dead all spark totally at the coil (spark coil)
why not try a new spark coil if you thinks spark is bad.
the ECU been RECAP'ed yet? ( I forgot this)
the retarded spark jump is ECU created or one input to the ECU is wrong. or a bad ECU.
to find that kind of error on any car for sure this old, takes a scope,to find what input is bad to the ECU. at the odd event. (hot engine)
lacking such tools and long hard work one can only guess.
I do not believe the noise suppressor is bad and they are very rare to find, super rare and is only a cap and resistor inside and very super reliable.
but suppressor output on the brown wire is the TACHOmeter output, and if it fails for any reason (drops out) the ECU instantly cuts all injection.!!! even for 1 second happened.
a shorted out tachometer or cruise box will do the same thing , cut all fuel injection dead, for the duration of the signal lost at the brown wire.
why it does not fail on cold engine?, is a key fact too. a part (any) warms up and fails, is the cause. of that, a thermal failure.
A bad spark coil, bad Distributor, bad ECU, or any other sensor is intermittent hot. (iat,ect,cps,02,tps) cps=distrib fail, cam pos. sensor )
not sure me.
http://www.fixkick.com