date not saved · #1
what controls the injector pulse? i have fuel and spark but the injectors arn't opening.??? can any one help?
no injector pulse
This thread was saved without dates. "Around Aug 2004" is estimated from neighbouring threads.
date not saved · #2
ECU opens and closes them. Check the wiring and stuff before you go replacing anything though.
date not saved · #3
See if you can trace the injector firing pulses, starting from the injector and working back along the harness to the ECU. Ideally you would use an oscilloscope, but if you don't have one (and you probably don't, a decent portable digital scope is not cheap!) then you can make a probe out of an LED and a 1K resistor like below.
LED 1K
Injector wire o---|<|-----\/\/\/\----o +12V
LED and resistor should cost you less than 50 cents :)
Check each wire first at the injector; if the LED pulses on when you turn the car over, the injector is receiving the pulse. If the LED doesn't flash, check for pulses again at the back of the ECU in case its your harness thats got a problem.
Its worth checking for pulses in a fairly dim area as start up injector pulses will be quite short duration (i.e. brief and hard to see) and you don't want to miss the LED lighting up because of too much ambient light. You can widen the pulses that the LED sees with some more circuitry if you're keen (pm me), but its probably unnecessary.
date not saved · #4
a little light bulb would probably be a lot brighter than an LED. I have a set noid lights I bought to try and track down a problem I had
date not saved · #5
Light bulbs are (can be) brighter, but LED's have a shorter turn-on time. The light bulb may not blink in the time the injector fires at idle.
date not saved · #6
Check the fuse links that run from the battery, i think one of the goes to the ecu and has soming to do with the injectors.
date not saved · #7
would the crank position sencor have anything to do with it? just wondering because it just cranks and cranks
date not saved · #8
ummmm I dunno, I have to admit its possible that with the stock ECU, if it doesn't see the Crank Angle Sensor (CAS) then it might not provide fuel. Someone else on here who's up with stock ECU for CA18ET might be able to tell you.
date not saved · #9
my 84 had this problem replace the box below the ecu they can be found at junkyards for $5