R33 Gtr - No Injector Pulse

[Candy]

Hi,

Have an R33 GTR - mods of note running a PowerFC and bigger injectors. Previously tuned and hasn't missed a beat.

Haven't driven car for about a month and the battery died. It was replaced with a new one, and is now cranking and not firing.

The following things have been checked out as okay:

- crank angle sensor

- plugs (not fouled & clean)

- fuel supply (pump, lines etc)

- spark is good (coilpacks, etc)

- AFM (no dry circuits, etc)

However threw on a noid and there's no injector pulse. Any reasons why this would happen or what I can do to get it going? Thanks!

[Waldo]

i have the exact same problem and everything seems to be fine on my car except it doesnt fire one bit i have also checked the following. let me know how you go. cheers

[Ryan1200]

How did you test the crank angle sensor? The crank angle sensor has two outputs one for spark and one for injector. I had the same problem i had spark but didnt have injector pulse, i then assumed i had spark then the crank angle would be fine so i went about testing the injection/wiring side of things. After pulling my hair out for a couple days i was led back to the crank angle after we used a friends scan tool. I changed it for a known good one and it instantly fired up and ran fine. Ryan

[Waldo]

that could possibly be my problem i thought the crank angle sensor only timed spark, how can i test for injector pulse, i know my injectors are ok cos i put 12v across them and they click open, but when cranking i dont get any fuel into the cylinders but i have spark.

[Adriano]

Check for power at the injectors, check the sen/switch screen on the PFC, see if anything lghts up.

[Waldo]

i have checked the sensor part on the power fc and nothing is highlighted

[Ryan1200]

With the scan tool we noticed we didnt have a signal coming back from the crank angle for injectors but spark was fine. Without the scan tool im not sure how you could test the sensor. I ended up using a an rb20 one from memory and it worked fine.

Edited August 6, 2007 by Ryan1200

[Adriano]

All the early CAS's are compatable, try to borrow one to check

[T04GTR]

How did you test the crank angle sensor? The crank angle sensor has two outputs one for spark and one for injector. I had the same problem i had spark but didnt have injector pulse, i then assumed i had spark then the crank angle would be fine so i went about testing the injection/wiring side of things. After pulling my hair out for a couple days i was led back to the crank angle after we used a friends scan tool. I changed it for a known good one and it instantly fired up and ran fine. Ryan

no it doesnt lol. it sends rpm and no.1 cylinder referance to the ecu.

have you got power at the injectors? one of the 2 wires should have around 9 volts. (after going thru the resistor near the fuse box)

if there is no power at either then you need to check the resistor or a fuse.

if you do then the ecu isnt getting a signal that the engoine is spinning. ie crank angle.

does the fuel pump turn on when you crank it?

[T04GTR]

With the scan tool we noticed we didnt have a signal coming back from the crank angle for injectors but spark was fine. Without the scan tool im not sure how you could test the sensor. I ended up using a an rb20 one from memory and it worked fine.

the crank angle sends a signal to the ecu that its turning,and where abouts number 1 piston is. the ecu does all the spark/fueling control. just so you understand whats going on.

[Candy]

have you got power at the injectors? one of the 2 wires should have around 9 volts. (after going thru the resistor near the fuse box)

if there is no power at either then you need to check the resistor or a fuse.

if you do then the ecu isnt getting a signal that the engoine is spinning. ie crank angle.

does the fuel pump turn on when you crank it?

Hi Dave,

Yep there's power to the injectors, but the pulse is very very weak.

Fuel pump turns on, primes, no problems there.

[T04GTR]

very weak? what voltage is at the injectors??

[Waldo]

where is the fuse for the injectors?

[Ryan1200]

Dave any idea why i had spark fine but no injector. I assumed (1st rule never assume) the CAS had two outputs and were not getting injector signal. Once i changed the CAS problem was solved. Strange

[Waldo]

well i sorte my problem i changed the cas and all my plugs were fouled, so i replaced them and broom!!

[Candy]

Solved.

Traced back to a short in the ECU loom harness. Replaced plugs too and she's apples.

Thanks for your help!

[T04GTR]

Dave any idea why i had spark fine but no injector. I assumed (1st rule never assume) the CAS had two outputs and were not getting injector signal. Once i changed the CAS problem was solved. Strange

very odd. as the cas has nothing to do with the physical conection to the injectors or spark. (its not like a dissy) it tells the ecu how fast the engine is spinning and where in the 720 degree engine cycle where number 1 is so yhe ecu knows where to spark and fire the injectors.

did you replace it or a workshop?

[Ryan1200]

Nope replaced it myself but yeah it might have been one of those things..

[Themauler]

On 09/08/2007 at 7:14 PM, Candy said:

Solved.

Traced back to a short in the ECU loom harness. Replaced plugs too and she's apples.

Thanks for your help!

I know this is really old but is there a place you pinpointed the fault to??

[iruvyouskyrine]

11 year thread bump, nice.

Visually inspect the loom and look for the worst looking place. If I had to guess I would say where it passes from the cabin through the guard and into the engine bay. Or around the exhaust.