injectors are not spraying

[BoostFab]

my rb20det only starts when starting fluid is spray into the IM...sound like the injectors are not spraying, so i decided to pull the injectors and all 6 are dry, no fuel. they might be stuck closed for sitting too long.

any one have an extra set i could borrow for testing?

[jayz706]

Check to see if they have power. Is your MAF plugged up? How bout your cam sensor ,is it plugged up? Im pretty sure one of these being bad or not plugged up will cause your injectors not to pulse.

[JonPowell]

There are 3 wires going to the injectors....one for power(probably grey) one for ground and one for trigger. check and see if they are getting power, might not have wired a power supply to them.

[jayz706]

I thought there was only 2 wires.

[BoostFab]

I thought there was only 2 wires.

yes, the injectors has 2-wires

Check to see if they have power. Is your MAF plugged up? How bout your cam sensor ,is it plugged up?

these plugs are connected.

[BoostFab]

might not have wired a power supply to them.

which is the power supply for the ijectors? i thought the ecu is supplying power for the injectors.

[jayz706]

I think it has its own power supply, the ecu just triggers the injectors with a ground signal or something like that.

[jayz706]

If i remember its a 14 gauge red wire, in one of the plugs inside the car near the ecu plug

[jayz706]

Do the injectors have 12 volts with the ignition switched on?

[jayz706]

Are you sure your getting fuel to the rail?

[BoostFab]

Are you sure your getting fuel to the rail?

i double check the fuel going to the rail. lines are hook up connectly. i will double check my wires again & test volatage to the injectors.

i hook up four wires, when i use the ka lowerrb black/red -> ka black red (gray oval plug)rb white/black -> ka red (gray oval plug)rb white/purple -> ka white ignitionrb black/pink -> ka black/pink (brown plug)

[BoostFab]

I think it has its own power supply, the ecu just triggers the injectors with a ground signal or something like that.

isn't the green relays near the ecu supplying power for the injectors?

[JonPowell]

The green relay supplies power to the injectors, the ECU pulses ground, I wasnt thinking last night when I said 3 wires, I apolgize. One of the wires will be the same color on ALL the injectors, that is your power wire. Check that for +12V. If that is good, check for continuity between the differing color wires and the ECU.

[Wulfgang]

IIRC, on the RB20 the injectors were wired directly to battery (no relay). I wired them to ignition instead (on S14), just to keep with the KA wiring scheme.

But yes, the ECU has low-side drivers which basically short the other side of the injectors to ground, causing them to turn on.

I once bought a KA that had frozen injectors. To unfreeze them I connected a 9-V battery across the terminals of each injector and tapped them until they slowly began to unfreeze. After maybe 1 minute on each injector they were all ticking happily and the engine was able to start.

Not the best solution, but one that worked. The best would be to pull them and send them to rceng.com for a good cleaning. They have quick turn around, so you could be back up and running in a few days.

[BoostFab]

IIRC, on the RB20 the injectors were wired directly to battery (no relay). I wired them to ignition instead (on S14), just to keep with the KA wiring scheme.

But yes, the ECU has low-side drivers which basically short the other side of the injectors to ground, causing them to turn on.

I once bought a KA that had frozen injectors. To unfreeze them I connected a 9-V battery across the terminals of each injector and tapped them until they slowly began to unfreeze. After maybe 1 minute on each injector they were all ticking happily and the engine was able to start.

Not the best solution, but one that worked. The best would be to pull them and send them to rceng.com for a good cleaning. They have quick turn around, so you could be back up and running in a few days.

thanks for the insight. do you think this is the case for me, the injectors are frozen? i might pull them again and send to RC for cleaning. I hope someone in DFW area have an extra set of working RB20 injectors i could borrow for test, just making sure my wiring isn't the issue?

btw! i haven't had a chance to test the voltage at the injector, i will do that today after work.

thanks everyone

[jayz706]

Im sure you will find you dont have 12v to the injectors. The red wire i was talking about also supplies your ecu with backup power.

[JonPowell]

I stand corrected once again, the power from the battery feeds the injectors and the relay, I just looked at the diagram quickly and saw a line from the relay to the injectors but never really paid any attention.

The injectors get power constantly and the ECU controls ground.

[FAST-DATSUN]

the best way to test the injectors is to pull the CAS and turn it by hand and use a NOD light(s) to see if the computer and the CAS is doing there job.the light should flash and you should be able to hear the injectors cycle this way... You can also test the spark this way

[BoostFab]

If i remember its a 14 gauge red wire, in one of the plugs inside the car near the ecu plug

is this red wire possibly be on the same plug as the black/pink fuel pump wire? i'm not at the car right now.

[BoostFab]

I stand corrected once again, the power from the battery feeds the injectors and the relay, I just looked at the diagram quickly and saw a line from the relay to the injectors but never really paid any attention.

The injectors get power constantly and the ECU controls ground.

ok, i believe this wire is referred by jayz706. everything else looks right for the engine-start-up-formula, just missing fuel.

[BoostFab]

ok, i just scan over WolfGang's rb20det pin out diagram (here), on the O plug, pin h - Black/white wire powers the ECCS realy, injectors, and backup power to the ECU (pin58).

I believe this is the one I need to connect to the 12V switched source, but shouldn't the rb white/black (on the 6-wire plug in the cabin) -> ka red (gray oval plug) is the same?

[crxcess]

Re: (FAST-DATSUN) "the best way to test the injectors is to pull the CAS and turn it by hand and use a NOD light(s) to see if the computer and the CAS is doing there job.the light should flash and you should be able to hear the injectors cycle this way... You can also test the spark this way"

This sounds like the right path to take.

sam

[BoostFab]

use a NOD light(s)

what's that?

[crxcess]

its the light bulb test i told you about "noid light test".

[BoostFab]

its the light bulb test i told you about "noid light test".

ok, i pulled the CAS and was able to test the first two injectors w/ a light bulb, no power. it's raining hard outside, i'll try this again tomrrow, if it's dry.

jon: i haven't had a chance to test the in 58...man do i hate the rain!

anyhow, i'm i missing a wire for powering the injectors? is this the redwire off the gray oval plug by the battery?