Thread: EFI Dramas Continue

Originally Posted by PhilipA

The TPS input is 5Volts and the output to the ECU varies between about 0.5 volts and 4.8 or so when you hold the throttle open.
The third wire is an earth.
Either your multimeter is reading incorrectly or you are reading it incorrectly.

Regard sPhilip A.
BTW the MAF also controls injector duration once the engine is going, and it is the primary engine demand sensor unless you have o2 sensors.

Hi PhillipA,

Thanks for your replies,

I will double check the yellow wire 2mrow and get back to it here to let uno.

I defiantly have good spark at all cyld, i went all over this and have replace most of it.

Tnx
Jason

Oh and don't be afraid to mash the accelerator pedal to the carpet to clear a flooded engine. I would also consider spraying some oil into the cylinders and cranking it in with the plugs out to replace the oil washed out of the rings by all the petrol.

Originally Posted by bee utey

Leave the spark plugs out overnight to let the excess fuel evaporate, make sure your battery is fully charged, fit the plugs and crank. Check the injector firing with an LED test light to each bank of injectors, the yellow + stripe wires will pulse to near zero volts each time the injectors open.
Depending on your weather leave a fan heater under the engine for an hour or so.

I will whip the plugs out first thing tomorrow morning, i have done this a few times to dry it out over time and does the trick to start again, either that or full throttle

I started to play with the injector wiring after our last post, but i didnt have a led light so i used a heavy duty test light, i will run into town tomorrow and grab a led light to make it easier, but this what i have found so far.

Using the battery as earth i had power on both the yellow striped and the brown wire to make it shine. I cant find my notes so i will double check 2mrow on what colours did what, but 1 constantly shined and the other pulsed while cranking, this happened on both banks.

I stuck the multimeter on and found both gave .006v with the ignition off and while cranking 0.32 to 0.68 with a rise and fall pattern, i will dig into it tomorrow to double check & return with more specific notes.

Thank you very much,
Jason

you seem to have checked nearly everything.
check the fuel pressure infront of injectors while running. turn off and watch aswell.
when runing change engine speed to make sure pressure valve is working.
i think bosch injectors work on about 27psi above manifold pressure.
also check vacum line and efi water temp sensor. maybe a air temp sensor and map or maf sensor.
my money is on fuel of map/maf sensor.
on commodores when they play up the cars realy turn into dogs

Originally Posted by PhilipA

The TPS input is 5Volts and the output to the ECU varies between about 0.5 volts and 4.8 or so when you hold the throttle open.
The third wire is an earth.
Either your multimeter is reading incorrectly or you are reading it incorrectly.

Regard sPhilip A.
BTW the MAF also controls injector duration once the engine is going, and it is the primary engine demand sensor unless you have o2 sensors.

Looks like i have read this wrong, not sure how i made such a larger error lol...

Here is the real results for the TPS ( i double checked lol)

Before Plug (unplugged)
red/black = 0.02v
Red = 0.06v
Yellow = 5.60v

Tps Plugged In (other side of plug)
Red = 0.86 to 5.36
Green = 0.02 (no volt swings when throttle is moved)
Yellow = 5.42 (no volt swings when throttle is moved)

Matching notes
red/black = Green
Red = Red
Yellow = Yellow

I see what u mean, the red plug has 0.06v then after i plug it in it jumps
to the 0.86 to 5.36 on both sides.

Originally Posted by centy

you seem to have checked nearly everything.
check the fuel pressure infront of injectors while running. turn off and watch aswell.
when runing change engine speed to make sure pressure valve is working.
i think bosch injectors work on about 27psi above manifold pressure.
also check vacum line and efi water temp sensor. maybe a air temp sensor and map or maf sensor.
my money is on fuel of map/maf sensor.
on commodores when they play up the cars realy turn into dogs

Hi centy,

I stuck a old pressure gauge on the fuel rail, it shows 40 psi and jumps up and down between 38-42psi, around 2.5bar while cranking, i will chase up a new gauge just to be sure, this one has been in the shed for over a decade.

Im not sure what u mean by checking the pressure in front of the injectors while running, can tell me how this is done?

Tnx,
Jason

I await for a m8 to drop of a led light to check the pulse on each injector.