PDA

View Full Version : KA not running, but it should? Help please!


Totalsuperhero
08-23-2019, 10:24 PM
:bite:New here, first post. So please go easy on me.

I bought an s13 240sx hatch off a coworker. It had everything there, but the motor was out of the car due to him rebuilding the head gasket after he bought it from a friend. So I slaved away, put the motor in the car in a week, got everything I was missing, and here we are now.

The motor is a ka24de from an s14, which I discovered after looking at the valve cover. The car is in alright shape, but the wiring harness is missing a few things. There are a few connectors near the firewall that seem to go nowhere. The previous previous owner also used scissors to remove the knock sensor/ idle air control valve sensor and I can’t figure out where it goes.
The wiring harness under the front driver fender was also in rough shape, but I was able to solder in new wire to fix everything. I’m still trying to work out where those cut sensors and wires go... I also had a bad 75a alternator fuse and a bad 25a fuse, so new ones are on order. For the time being, I’ve bypassed them with copper and it seems to be working just fine.

I had two former Nissan techs and my old tuner check the timing (do it for me) so that’s spot on.

We also checked the compression. Cylinder 1 has 120, 2 has 90, 3 has 120, and 4 has 120.

I also have new spark plugs in the thing, they ALL spark perfectly.

As for fuel, all of the injectors work, I have pressure, and it pumps through a solid amount. During that test, I discovered its fairly dirty fuel, but nothing too bad.

When I turn the key, it cranks but the motor refuses to catch and start. All over the forums, I have found different ignition sequences, and we’ve tried them all. At best, I get a very rhythmic popping from the exhaust manifold as if it is TRYING to start, but nothing more than a flame from the open headers.

The next step will be to diagnose the intake manifold, in case there is a vacuum leak, but I don’t think that’s the case. Since I’m completely unfamiliar with the platform (I’ve owned 3 skylines so rb’s are my JAM) I really don’t know what the issue is.

I have spark. I have compression. I have timing. I have fuel. Why won’t it start?!?!?!

Any help would be hugely beneficial. I’ve found a few similar posts while lurking, but it doesn’t seem to be any of the other issues.

If anyone needs pictures, please tell me what you need and I’ll take the pictures tonight or tomorrow afternoon sometime.

Please help me get this boat anchor running under its own power...

S14rebuild
08-24-2019, 07:40 AM
With low compression numbers like that..id say ur wasten your time right now. That motor is hurt and will be an issuse from the get go

EFITTZY
08-27-2019, 03:59 PM
You do NOT in fact have compression, normal comp numbers range from 125-155psi. Ditch the boat anchor, and find a known good motor. :2c:

As for wiring, I'd look into replacing the entire harness... Otherwise you will be fixing all of the PO hacked ass work which will be a complete nightmare.

kennedy8383
08-27-2019, 07:28 PM
How do you know the car getting fuel? Health Ka24de compression should be around 150 to 170 psi on warm engine.