Originally Posted by 1LUCKY
I have a 1990 geo tracker with the 1.6 5spd 4wd. It turns over fine, has good compression, it is firing the spark plugs, the engine will run as you spray fuel in throttle body.
Have checked fuel pressure ant it is with in specs. Tachometer will move up to about 300 rpm when turning engine over with starter, seems like the computer is not sending signal to injector, vehicle was running when it was parked just will not start now cranks over fine.. Have ohmed wires from pcm to injector and both are good. Have checked all fuses under hood and dash and see no problems. I am sure there is something that is causing ecm to shut injector down maybe throttle position sensor or something, looking for some advice from someone that has been down this road.
good review btw.
my no start pages covers this for 10 years of motors
ive posted this here 1000 times at least (SSDD)
but 1 more
and will do 1990 special as it is VERY SPECIAL.
1: The ECU dont make spark in 1990 , only the DISTY and coil work as one
stand alone. but....
here are all things that stop injection (besides obvious blown ECU injector driver transistors ) DeAD NOID
2: ECU thinks ( even if good) that spark is bad.?
ECU dont mAKE spark but does MONITOR IT, FOR SURE.
Tacho moving ,should make ECU happy in this regard. Tacho sig = ecu monitor sig !
but not cranking motor with DIAG jumper in PLACE is really missing the boat, why not let ECU talk to you while failing and cranking. save a $100 maybe. huh?
3: last is the TPS Throttle angle POT, wiper getting stuck at near 5v. AKA. WOT. wide open throttle.
this halts all injections.
this is super secret unflood mode.
so if the wiper is 2v, its good, of 0v or 1v ok, but of 4v or above bad. ( the industry std for WOT is 75% ball park) most tps go from 1 to 4v so....
if ECU dont throw code 12, but rather does 41, then dont blame ECU.
41 is ignition fail (yes, even if you have spark for this, it's reality) 41 fail is crash an burn prevention software. required by law.
that is all the ways to kill a NOID. (besides obvious wires , open , corrosion etc)
if all check out then ECU is bad.
cut fuel if:
WOT cranking (TPS fail or ground wire cut)
spark read bad dead. DTC 41s cranking.