Truck does not start reads code 12 spark seems to be of and backfires when I try to start
what engine? size? 22R 22RE or 3F-E? 3VZ-E?
never work an car with out knowing what engine and if old EFI or carb.
look at it , in USA the under hood sticker clearly states engine in car.
does your motor have a timing belt for the cam>?
ever change it every 60K,,, oops////
on old cars ,and this one is.
I always check compression,, at WOT, (wide open throttle)
if 80psi the cam slipped. if 150PSI x4 its a winner
next is spark, if the cam slips, BTW< the spark timing is GONE
OUT TO LUNCH timing, no , dont change it ,fix the belt first.
and back firing is caused by bad timing....
22R and 22R-E engines have a cam chain.
but seen many cars with a screaming chain, owners ignore it....
seen them slip too.. as hard as it is to believe. (im never shocked)
#2, do that 60k tuneup for spark and filters now, amazing what a simple tune up does, with new spark wire, in winter they short.
and air filter and fuel filter,
spark timing> spec:
At idle the 22R-E should read 10-14deg BTDC, 3VZ-FE should read 8deg BTDC, and the 3F-E should read 12deg BTDC.
if way off, the cam is out of time. (no one messed with engine)
means the ECU found a dead sensor (spark) NE, G1 or G2
these are all sensors for spark, cam or crank or both.
the FSM covers this.
code 12 are loss of sensor for 2 second cranking
and is a bad sensor, not calibrated , or bad wire to it,, etc.
think about this. (no engine stated, so generic answers happen)
IF the cam is off time.
the CAM sensor is fibbing, as compared to the crank sensor.
so it would not be a suprise to me, that code 12 throw.
that is why i check spark timing first. then if way off
check compression 2nd, and if way off.
the cam end is exposed and timing verified.
if engine is interference type, is use a total different strategy.
do no harm, is first. (visual inspections of cam are first)
next time post the engine you have.
merry Chrismas and hope we find it fast.
Dec 24, 2013 |
1991 Toyota Pickup