Nobody can seem to solve this (including me!) - can you?

[Robb_]

OBDII KA24DE, n/a
Auto trans

I checked voltages on the white wire of the MAF, 1.7 at idle, 2.6-2.8 at 4000RPM. Obviously doesn't seem right. Cap, Rotor, Plus, Plug wires were all replaced when trying to troubleshoot this. I also cleaned the MAF with no luck.

I had a friend pull another MAF for me. Welp, said MAF did not work. Read 2.6-2.8v, again. So I went out and bought a brand new MAF, 2.6-2.8v at 4000 RPM. Engine grounds show continuity, TPS is checking out.

I checked the injectors, replaced the fuel filter, replaced the distributor cap, checked for vacuum/intake leaks, cleaned the IACV, regapped the plugs with note of signs of fouling due to unburnt fuel on all four plugs, also noted that timing was a few degrees off. Retimed the motor and set idle but still having issues.

Idle = misfire every 30 seconds - 1 minute
Press on the gas slightly = fine
Press on the gas 1/4-WOT = stumbles until 2500 RPM then takes off
Above 2500 RPM = Pulls nice and hard

Put in the new CTS and set timing again. No luck

Rev:
http://www.youtube.com/watch?v=E1wkDhEayQ8

Drive:
http://www.youtube.com/watch?v=y3CZraEsXmQ

The thing sounds like a Subaru when on the throttle until it gets going. I like the sound of a flat four, but not in this car, hah. Beginning to suspect a bad coil, but that's in the distributor since it's an s14, right? Ideas/Comments/Opinions? Really need some help here..

[WithHonor037]

Mine did something similar whenI replaced the head gasket. Turned out to be the intake gasket so in your case im leaning towards a possibly vaccuum leak. Did you try spraying ether or carb cleaner on your vaccum connections yet? If the spark at the plugs is ok I wouldnt suspect a bad coil.

[Robb_]

Yeah, used that method to check for leaks - nada.

[AZhitman]

Dumb question - Did you check firing order?

[Robb_]

1-2-4-3, checked.

[Riedell]

Im not familiar with the dohc engine, but if i was to disconnect/wiggle this specific plug (something to do with the temperature [ka24e]), it would have the same bog issues like you. Sometimes the engine's RPM's would go up and down like very little to where you can notice. Im pretty sure its the plug that i circled on the image (credits to http://www.modified.com/features/modp-0 ... to_04.html for image)



Check the wire for corrosion, maybe clean it up. If you have to go further check voltage.

Edit: If its not that plug check up by your injectors on top of the intake manifold for the plug connection.

[Robb_]

That looks to be the CTS, which I just replaced today.

[biggie]

That looks to be the CTS, which I just replaced today.

To be clear there are 2 CTS, one for ECU and one for Gauge. ECU one (bigger) is the one you'd want to replace.

[Robb_]

Yes, the colored harness connector (two wire). I replaced the one to the ECU. The cluster doesn't make sense to replace, that wouldn't affect anything motor wise.

Also, found out that Autozone stocks the incorrect part number for the s14 CTS.

[Robb_]

A friend dropped me a fuel rail with FPR I will swap out.

Backtracking to fuel, wouldn't it cause everything to lean out if the fuel pump was going bad? I've eliminated injectors/o-rings because ALL plugs are fouled, highly doubt all four would fail at once. So I would imagine FPR if anything involved with fuel.

I was also suggested O2 sensor. Recommendation on testing/thoughts?

[Robb_]

Replaced the FPR today - that wasn't it

[Armstec_S13]

You try an extra ground? I had something similar and like you said my 240 sounded like a Subaru come to find out my alternator was bad and making my cars fuel injectors got nuts, changed that and it was fine then it started up again and on my single cam there were two grounds that were not connected after I cleaned and tightened them it was running solid.... May help noticed tha these cars are really picky with grounds


•••EDIT•••
the grounds I tightened and cleaned look like they were coming from the fuel injector harness right under the valve cover on the intake mani side, I know I'm talking about a single cam but it may be the same on a dual cam

[Robb_]

I'll try it for sure, just replaced the alternator not too long ago, so hopefully that's not the case.

Also replaced the O2 sensor for good measure, noted it was white like lean deposits. But the plugs are fouled with carbon as if it's not burning all the fuel.

[hudy]

Firing order is 1, 3, 4, 2 isn't it?

[compactfean]

Yes, with the dizzy going counter clockwise.

[Robb_]

Just fixed this, replaced the distributor and it seems to be running great.