PLEASE HELP! KA24DE Problem

[Widebody S14]

Hey guys, I have been having troubles with my car for the past few months but now it has just become unreliable. So to start things off the car is a 1996 S14 5 speed motor wise the car is all stock (KA24DE). The problem is you have to crank the car for at least 5 seconds while being on the throttle to get it started. It has a very rough idle and does not want to stay on. If you try to rev the car it will bog out. Recently the problem has gotten much worse half the time the car wont even start. When im driving around town the car has alot of short cuts in power usually around the 40-60 km/h range, While coming to a stop you have to put the clutch in and be revving the car to keep it on. Also on deceleration the car pops and backfires a ton im not sure if this is normal for a stock KA. It is definitely running rich as the plugs are completely black. Also if the car stalls out you have to just give it about 10-15 minutes of it sitting there for it to start back up. Only thing I have changed so far is the Coolant Temp Sensor and about 3 sets of plugs.

Please help me get this thing back on the road I just wanna go sliding! Let me know if you guys have any questions, thanks in advance!

[2_Liter_Turbo]

I would it sounds like a fuel problem or a sensor problem. I would check the factory service manual (see signature for a copy) and test the 02 sensor, MAF, throttle position sensor, and the air idle control valve. I would also check you fuel pressure regulator using the FSM. Also check fuel pressure and your injector o-rings for any leakage. A good way to do this is to take the fuel rail off the manifold with the injectors still in and just turn the ignition on (don't start it!) to get the fuel pump to turn on. You'll know real fast if you have a injector seal that's bad. Also, check the injectors themselves to see if they are sticking open (using a multi-meter referencing the FSM). Make sure to have some towels to pick up any leaking fuel when testing fuel system stuff. Hope that helps, good luck! Best to test things rather than throw parts at it. Much cheaper

[Widebody S14]

I would it sounds like a fuel problem or a sensor problem. I would check the factory service manual (see signature for a copy) and test the 02 sensor, MAF, throttle position sensor, and the air idle control valve. I would also check you fuel pressure regulator using the FSM. Also check fuel pressure and your injector o-rings for any leakage. A good way to do this is to take the fuel rail off the manifold with the injectors still in and just turn the ignition on (don't start it!) to get the fuel pump to turn on. You'll know real fast if you have a injector seal that's bad. Also, check the injectors themselves to see if they are sticking open (using a multi-meter referencing the FSM). Make sure to have some towels to pick up any leaking fuel when testing fuel system stuff. Hope that helps, good luck! Best to test things rather than throw parts at it. Much cheaper

So far I have tested the MAF, TPS, checked the fuel pump and resistance on all injectors. All of those checked out good. I will check out the O2 Sensor, FPR and leaky injectors as soon as I can. When I did a fuel pressure test it was all good except on the first prime of the pump that was 10 psi lower than usual. Thanks for the response!

[2_Liter_Turbo]

For sure man, definitely post up your findings when you get a chance to check the rest!

[Widebody S14]

For sure man, definitely post up your findings when you get a chance to check the rest!

I also have a question. I plugged a scanner into the OBD2 port and got no codes or CEL. So I went to check codes from my ECU and there is no LED on it. I have done diagnostics on a different ECU so I know what im looking for too. Is this because the car is OBD2? If so how would I complete the O2 sensor test that requires holding on the throttle and then checking the ECU for flashing lights?

[PapaSmurf2k3]

OBD2 (plugging directly into the port) should tell you if there are any problems. You shouldn't have to count blinking lights like the S13 guys do.

I'm wondering if you have a fuel problem that is messing with your idle and normal operation, or if you have an idle problem that is so damn bad, its fouling your plugs and causing a run problem.
When you put new plugs in, does it run well for a little while? Or is it immediately garbage?

[Widebody S14]

OBD2 (plugging directly into the port) should tell you if there are any problems. You shouldn't have to count blinking lights like the S13 guys do.

I'm wondering if you have a fuel problem that is messing with your idle and normal operation, or if you have an idle problem that is so damn bad, its fouling your plugs and causing a run problem.
When you put new plugs in, does it run well for a little while? Or is it immediately garbage?

Ive been through 3 sets of plugs and none of them have changed anything car still runs like crap. Although when I got the car I did full service on it myself including the plugs. Soon after I changed the plugs it originally had, these problems started occurring. I thought it was just a concidence.

[2_Liter_Turbo]

What plugs are you running and what gap?

[Widebody S14]

What plugs are you running and what gap?

I never checked what plugs the car came with these are the ones that I installed later.

1st Set: NGK BKR5E-11 V-power
2nd Set: NGK BKR5EIX-11 Iridium
3rd Set: Denso K16PR-U

All plugs were gapped to .044"

[2_Liter_Turbo]

Hmm, those plugs should be fine.

[Widebody S14]

Hmm, those plugs should be fine.

Do you think it is a air, fuel or spark problem based on the information given?

Thanks for the responses guys! I havent had a chance to work on the car yet ill give you guys an update soon.

[2_Liter_Turbo]

Not sure man, I would definitely keep testing things out. Won't take too long to stumble on something that is out of whack.

[PapaSmurf2k3]

Try pulling the vacuum hose to your fuel pressure regulator and seeing if that helps things. Don't cap it or anything, just pull it so you induce a vacuum leak.

[Widebody S14]

Finally got some chance to work on the car. Took the fuel rail off and ignition on. 3 of the 4 injectors had fuel coming out. Going to install some new o rings thanks alot ill keep you guys up to date!

[Widebody S14]

Hey guys I had a questionm When I did injectors on my SR it had black spacers between the rail and manifold. The KA doesnt have these but I have some extras. Should I install them?

[PapaSmurf2k3]

No.