02-07-2021, 10:02 PM
(02-07-2021, 05:40 AM)1995 compression Wrote: was done stone cold... (is useless test but I bet normal warm hot) It is bench mark test and leak down test even betterfails only hot. (when, Cruising fast, accelerating or at WOT or when? driving is complex when does it fail and when does it not both, while driving hot)
engine runs great until timing changes intermittently
i thought it was a fuel injection problem at first
so checked all the fuel sensors and all checked good
then did the caps still intermittent miss
then i decided to check timing and found the timing jump...aka miss
so then i started checking ignition components
and the timing belt was taken apart to check keyway
before i did any thing i did cap rotor...making sure they were brass...wires, plugs and fuel filter
then the tps code showed...
so i thought i finally thought i found the issue...nope..
so now i have traced wires made sure they were all good
all the while it has been drive-able very annoying but back and forth to work until November. under acceleration it was fine and idle it was fine...havent driven since i did the tracing and bonding of the coil wire shielding.. (not sure this,, only CMP runs shielded wires and CKP in 1996 up)
the fact is the spark timing changes wildly all the time on all EFI engines, but not with timing freeze jumper planted, and not as bad as yours, best I can tell.
we know the ECU does that ,only IT CAN, there are no magic parts inside the distrib, ignitor or coil to do that. (delay, retard-ment is delayed spark, not dead)
the ignition parts (all )can in fact cause spark to DROP out, for sure hot, but that is DROP out not a timing change.
has the ECU been RECAPPED or still running, 26 year old caps there and worse those dang RUBICON black monster known to fail hard.
best I can tell is the ECU is bad or the ECU has an Intermittent sensor of any kind the fails at random and goes to limphome mode which does cause RETARDED spark grossly.
all inputs to the CPU must not be intermittent, even for 1 second or the ECU will go to limp home mode for that duration.(retarded and super rich misfiring.)
WHAT ABOUT CAPS. (Be a shame to replace all sensors, distrib, ignitor,spark coil, IAC,IAT,TPS, and O2) just to find the 3 caps that love to fail are bad. a $5 fix.
Caps = electrolytic caps in the ECU , love to fail often even every 10 years in hot geography. (weather) spec is 20 years at best, 10 is more common. Rubicon less i bet.
the CaB of the car can hit 200f parked in the hot sun, this is not good for CAPS.
The bad caps cause the ECU to crash and reboot, it is firmware in the ROM (EProm) deep inside that crashes. and is never ever good to have that happen
it can get so bad the ECU even rattles all relays and VSV like made , key or running. (crashing)
there are only 2 ways to fix bad ECU with bad caps (besides the rebuilts from Cardone 1)
replace them blind. (slam in new caps.)
test them, with ESR meter, and if lucky see them slit open or leaking acid, but looks do not matter if they look ok, as they do in fact simply DRY OUT inside and are DEAD)
I always had a spare ECU for mine,
after all they do not get get easier to find, nor in the future. some of these cars even have wrong ECU installed, for for sure worst is calif ECU in FED car, or the reverse .
ECU are no the same for 8v./16v,calif, fed,2wd/4wd , transmissions. and body 2dr/4dr . (and smog options and year) The calif ECU has extra ground pin that tells it that the body of car is wired for CALIF and with CALIF sensors. and if missing that ground the ECU set code 53. (wrong ecu)
spare parts to have on this car are , ECU and TB.
those parts hard to find and or takes for ever get hands on,. (down time issues matter?)
and front 4wd axle hubs, not sold now, omg hard to Find.
CAPS good bad or ugly, below is classified ugly to the max , huge damage. some look perfect and are DEAD and dry inside, the big cans are CAPS. that fail
the huge CORNER caps fail most. this ECU is now dead forever.(land fill) the with SIP are saved, and not sold on earth, so those are saved, BORIC ACID leaked out fast.
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