Tercel techs? (1 Viewer)

[Kief]

OK, so I'm not an awesome tech!! I had this thing running great so I thought but it doesn't want to start if cold.. Good spark, 180-200 psi compression, tested TPS, air and water temp sensor, fuel pressure, fuel regulator, and the injectors work great BUT the manual shows a split bank system meaning #1 and 3 injectors fire at the same time and 2 and 4 fire at the same time and this car is firing all 4 simultaneously which may explain the wet plugs and no fire.. I tested the wiring and it deviates from the OEM manual drawing that shows two separate circuits/terminals and then I found a factory splice on the loom... Hmmm.. If it ran before then maybe it should be left alone but the only thing I have left to check is the flow rate on the injectors or just figure the ECU is firing the injectors too long...
It seems like if I pull the plugs and air out the cylinders then it will start.. Grrr..

 

[gnob]

is the car MAP or MAF

if you are hard starting a MAP car i would look for a vacuum leak.


the wiring issue is probably a non issue. most of the older EFI fires them all at the same time, "batch" fire.
you need to 'noid light and make sure they are flashing and not sticking open as well.

 

[Kief]

You know, I was wondering that myself. All it has it an air temp sensor and then it goes straight to the plenum. According to the manual it monitors Intake manifold absolute pressure (vacuum sensor), coolant temp, rpm, throttle valve opening angle, exhaust oxygen content, etc.. So it must utilize those factors to calculate the dwell or duration of the fuel firing.
Batch system, yes, but I find it weird that the manual shows two separate outputs from the ECU, separate wiring and then I find the wiring as indicated in the manual but then spliced together more than once in the harness. For fun I opened up the splice I found and the wires still had continuity with the injectors removed and I wasn't about to tear into the whole deal.
I went ahead and pulled the dizzy and checked the Ohms and tolerances and adjusted the pick-up cold even though the manual says to chuck it if it doesn't gap at .008 to .016.. It was really close on one lobe and the other one was fine.. Every thing checked out, I blasted it with some electrical cleaner and the connectors too, cleaned up the rotor- it hasn't been replaced, sprayed it down and put it all together. It started on the first crank... Weird.
Came home today and tried it again. Fuel pressure had dropped to 0 psi since last night. It fired up after a second or so and ran fine. Weird!
I had pulled the fuel rail, tested the injectors for volume and dribble and they were fine. Fuel regulator seemed to be behaving and not leaking past the diaphragm. Occasionally it seemed as though the check valve wouldn't do its job but that was very rare. I'm hoping it is happy now..
My hat is off to you real wrenchers who have to deal with this stuff all the time.. You deserve a raise!

 

[Kief]

Nope.. Keep trying.

 

[CreeperSleeper]

Don't these have some sort of "5th injector" or cold start valve?

 

[Kief]

nope- checked for vacuum leaks and blocked cat/exhaust, next is to make sure the intake valve aren't way loose..