Diagnosing worn cam angle position sensor 1989 NA 120k
Discussion
when i try to set my base timing at ~800-900rpm the mark on the pulley waves around all over the place. i think, at least i've tried to set it around 12 degrees but it wanders around between 10-14.
i tried to see if the lightened flywheel was causing it by raising the idle to 1000rpm but i think the ecu starts to advance the timing itself at that point
do the cam angle position sensors wear out at around 100k miles or are there other things i should consider before i part with £240?
all i can think of is:
magnecor leads suppress the guns pickup
or
the timing gun is faulty
ideas?!
i tried to see if the lightened flywheel was causing it by raising the idle to 1000rpm but i think the ecu starts to advance the timing itself at that point
do the cam angle position sensors wear out at around 100k miles or are there other things i should consider before i part with £240?
all i can think of is:
magnecor leads suppress the guns pickup
or
the timing gun is faulty
ideas?!
well, the inductive sensor thingie clips round the ht lead - seems pretty foolproof
was using a spare battery as 12v power supply - i assume the gun will either work or not work
left the dial on the back of the gun to zero
moved the CAS around until it covered 12 degrees more than the rest of the scale!
unless there's some complicated reasoning into using the same 12v the coil's using, some heffer sat on the gun, or the leads are crap for timing from, i'm thinking the worst
was using a spare battery as 12v power supply - i assume the gun will either work or not work
left the dial on the back of the gun to zero
moved the CAS around until it covered 12 degrees more than the rest of the scale!
unless there's some complicated reasoning into using the same 12v the coil's using, some heffer sat on the gun, or the leads are crap for timing from, i'm thinking the worst
My timing gun works differently - it attaches 'in line' with the lead, ie you pull the lead off the coil pack, fit the timing gun attachement, and fit the lead to the top of that.
The ones that clamp over the lead and pick up the signal through the insulation are notoriously rubbish from what I recall. After all, the whole point of the lead is to insulate against that signal escpaing.
The ones that clamp over the lead and pick up the signal through the insulation are notoriously rubbish from what I recall. After all, the whole point of the lead is to insulate against that signal escpaing.
i did ground GND and TEN with a paper clip, though maybe some scrubbing at the contacts to insure connection wouldn't go a miss
i thought the inductive'ness and the ht voltage are... pardon the pun, 'poles apart' i.e. even magnecor's should be able to use for timing - maybe i'll try a standard lead
just got off the phone to a well regarded auto electrics, bosch certified garage - before i got round to asking about whether CAS's were rebuildable he cut me off asking if it was an early one, when i said it was he said 100% the timing issue was...
short nose crank failure
i did mention i checked the main crank bolt was up to torque, but he mentioned that the keyway could well have been damaged previously and re tightened in the wrong place
i thought the inductive'ness and the ht voltage are... pardon the pun, 'poles apart' i.e. even magnecor's should be able to use for timing - maybe i'll try a standard lead
just got off the phone to a well regarded auto electrics, bosch certified garage - before i got round to asking about whether CAS's were rebuildable he cut me off asking if it was an early one, when i said it was he said 100% the timing issue was...
short nose crank failure
i did mention i checked the main crank bolt was up to torque, but he mentioned that the keyway could well have been damaged previously and re tightened in the wrong place
dylan0451 said:
i did ground GND and TEN with a paper clip, though maybe some scrubbing at the contacts to insure connection wouldn't go a miss
i thought the inductive'ness and the ht voltage are... pardon the pun, 'poles apart' i.e. even magnecor's should be able to use for timing - maybe i'll try a standard lead
just got off the phone to a well regarded auto electrics, bosch certified garage - before i got round to asking about whether CAS's were rebuildable he cut me off asking if it was an early one, when i said it was he said 100% the timing issue was...
short nose crank failure
i did mention i checked the main crank bolt was up to torque, but he mentioned that the keyway could well have been damaged previously and re tightened in the wrong place
theres a 1.6 on nutz for sale for £100 i thought the inductive'ness and the ht voltage are... pardon the pun, 'poles apart' i.e. even magnecor's should be able to use for timing - maybe i'll try a standard lead
just got off the phone to a well regarded auto electrics, bosch certified garage - before i got round to asking about whether CAS's were rebuildable he cut me off asking if it was an early one, when i said it was he said 100% the timing issue was...
short nose crank failure
i did mention i checked the main crank bolt was up to torque, but he mentioned that the keyway could well have been damaged previously and re tightened in the wrong place
i checked the crank bolt over the weekend - workshop manual states 88 ft/lbs - torque wrench clicked with no movement at 88, then 95, then 100... so i decided it's hardly moving/falling off
which means the flickery timing, may well be diag box connections as you mention griff500, thats something to check
incidentally, re. a short nose crank fix if a worn keyway is the issue:
make sure the pulley is up to torque, obviously
use a micrometer/vernier etc. to find true TDC through spark plug hole
remark/notch the pulley for TDC, then some elementary maths to mark 10, 12, 14 degrees
fit some vernier pulleys to the cams and let a RR time everything up accurately
is there anything i haven't thought of ?!
which means the flickery timing, may well be diag box connections as you mention griff500, thats something to check
incidentally, re. a short nose crank fix if a worn keyway is the issue:
make sure the pulley is up to torque, obviously
use a micrometer/vernier etc. to find true TDC through spark plug hole
remark/notch the pulley for TDC, then some elementary maths to mark 10, 12, 14 degrees
fit some vernier pulleys to the cams and let a RR time everything up accurately
is there anything i haven't thought of ?!
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