RB20 Turns over but won't crank?

[driftjunke]

We got the RB20 wired up, and tried getting it to crank, we hooked up the jump box since battery was low, Well it turns over, a little hesitant at first, but turns over and keeps turning, but won't crank, we have no vacuum leaks, and all of the sensors are plugged in. Its on a 90 HB, and we used the lower ka harness, and connected the 4 wires needed to be connected, everything is grounded, and seems to be in order. We pulled plug #1, and had no spark. We have fuel and air, so this seems to be the problem. What would be some of the easiest first things to check to see what is posssibly wrong. The motor is a stock motor, and has never been touched so timing should be fine. How can you test the ignitor, the gray oval plug in front of the ignitor the thick white wire shows power, and on the plugs that go into the ignitor, on the passenger side, it has pink wires coming out, and all of the wires are showing 12volts, on the other side, dirver, there are blue wires coming from the plug, and they show no power. With the multi-meter on any of them, it still shows the same thing, no flucuations in power. Does the ignitior sound fine, or is there something else that might be the cause, a wire or something?

Thanks for your help

J.D.

[Yellow4g63]

Do you have the Green Relays in near the ECU? should be 2 of them that plug onto the harness near the ecu. Check to make sure your fuel lines aren't reversed either. Good luck

[BoostFab]

driftjunke, did you get it started?

[driftjunke]

Car still doesn't crank yet. The fuels lines are in the correct spots, the return goes to the upper metal line then the feed goes to the lower metal line. Yes the green relays are hooked up, they make a funny buzzing noise while trying to crank the car.

J.D.

[Wulfgang]

Funny buzzing noise? That would probably be a short in your wiring or a pretty bad ground somewhere. Those relays should click once when the ignition is turned on. Check the power wire to those relays and the ground on the ECU first.

[skillzilla]

Someone check my Green Relay thread, if you could.

Thanks

[driftjunke]

Well I don't think the injectors are firing also, and we replaced all of the plugs, they looked like ****, still no spark with coils out of car. The red light on the ecu comes on, but doesn't stay on, light will fluctuate as the motor turns over, then when we stop trying to turn it over, the light will shut off, and stay off until we try cranking it again.

Hopefully the ECU isnt fried.

J.D.

[Wulfgang]

Your symptoms are screaming out at you! Check your wiring for shorts and bad grounds.

[lyon23]

you said you wired the 4 wires which ones are those??? did you connect the white/purple and the white /black?

[driftjunke]

I connected 4 wires, 3 of which came from the rb 6 wire plug, on the rb there was black/red, white/black, white/purple, and the fuel pump wire black/pink, which was spliced into the ecu from the brown plug. The black/red wire from the rb went to to the black/ red on the KA gray oval plug, the white/black from the rb to the red on the gray oval KA plug, and the white/purple from the rb spliced into the thick white wire coming from the ignition fuse under the fuse box. We used the KA lower harness also.

Thank you

J.D.

[driftjunke]

I also checked the ecu for codes, I am assuming I have a code 55, it flashed 5 times slow,the 5 times fast.

[Yellow4g63]

55 says everything is gude.

[driftjunke]

I guess thats not good since it's not cranking.

[Yellow4g63]

I guess thats not good since it's not cranking.

Since you said the motor ran in the clip but not when you swaped everything over I would just start over with the wiring. pull it off and redo everything. Did you just use the Engine harness or did you try to put the skyline interior harness into the 240 too?

[driftjunke]

Only used the skyline engine harness, theres not too much wiring that really has to be done, only 4 wires when using the KA lower harness.

Is there any way you can test the Ignitor, or CAS without swapping them out?

[Wulfgang]

You don't need to test your CAS if your relays are buzzing! Get your wiring fixed FIRST!

Let me spell it out: if those two green relays are buzzing, then the voltage on their coil sides is too low during cranking. And since they only draw a miniscule amount of current, there must be a bad connection somewhere. You will measure good voltage while not cranking because no current is being drawn. Then when the starter turns over, the current spikes, and the voltage across whatever bad connection you have drops too low to power even a measly little relay. And one of those relays gives power to your ignitor/coils, which is probably why you get fuel but no spark..... Need I say more?

[driftjunke]

Well it fired up, changed out the battery with a optima, the startbox must not have been providing enough juice to get the engine going. But it fired right up, I think it might have also been a connector issue too on the battery, new terminals fixed it.

It sound like we have a skip, so we might have a bad coil. I knew it wasn't in the wiring, because the last 2 RB20 swaps I did we did the same as this one, it's just this car wasn't in as good of shape as the others.

Appreciate the help everyone.

ThanksJ.D.

[skillzilla]

My car still wont turn over, but a new problem arose. Check my fuel pump thread when you get a chance.