D16Z6 Intermittent Idle/Power Problems

marek94

New Member
I've searched around to find if anyone has had the same problem as I do with my car, and have not found any.

My Car: 1994 Civic Hatchback DX, swapped with a d16z6 and manual trans, along with all wiring harnesses.

I finished the swap back in late August, and it has ran perfect, loads of power compared to the stock d15 and auto trans. But when it came to early October, I was having problems with the idle and power, this started while I was driving on the highway.

So let me describe the idle/power problem. When I drive the car its runs perfect, but then suddenly the car almost cuts out, sputters a bit, then holds the idle at 1000k, even when the car is all warmed up. Whenever it idles like this, it runs pretty powerless, and it super sluggish when I start driving in first gear. Also, sometimes when it runs like this, I can hear some little pops coming from the back of the exhaust, something that doesn't happen when it runs good.

I felt like the car was clogged up somewhere in the intake, so I sea foamed the intake and cleaned the IACV, and the problem still remains. Also looked to check the o2 sensor, but it seems to do nothing whether it's plugged in or not. I'm kinda lost on this issue, just wondering if anyone has experienced this or why I should check to fix this issue. Thanks!
 

CAFROG

Honda Minion
VIP
It's seems like a sensor is not working consistently...going off/on. Do you get a CEL? When you unplug O2....no change and no CEL? I was 1st thinking TPS or MAP sensor. Maybe check TPS voltage in both normal and when it's acting up. (Closed and WOT voltage readings).
 

marek94

New Member
It's seems like a sensor is not working consistently...going off/on. Do you get a CEL? When you unplug O2....no change and no CEL? I was 1st thinking TPS or MAP sensor. Maybe check TPS voltage in both normal and when it's acting up. (Closed and WOT voltage readings).
No check engine light when it runs bad, and when the o2 sensor is unplugged no change and no CEL. I will definitely check the voltage readings when I get to my garage this weekend. Either that or I'll just grab a multimeter from a shop near my college. Thank you.
 

awptickes

unimpressed by you
VIP
Make sure your CEL bulb actually works... it sounds like it doesn't. I'd bet someone removed it from the cluster... lol. Maybe you really don't have a CEL, or maybe you do. Is the ECU chipped? Do you have datalogging? Post a picture of the ECU and if it's not 100% stock post a picture of the inside.

If there's no CEL this is a good opportunity, so let's do this methodically:
Air - I'm going to assume you don't have a compression tester, so here's the easy way.
Fuel - Again, I'm going to assume you don't have a fuel injector test light, so we'll do it the sound way.
Spark - There are a few ways, I'll cover two.

Fuel:
Unplug all of the fuel injectors, turn the engine over a few times. Plug them all in, and then with the engine idling, unplug one at a time for a second or two. You should immediately notice a difference in the idle quality, and if you do, that injector is bad/plugged. If nothing seems bad, move on. Unplug them, and leave them all unplugged.

Air:
Easy to check if it is getting air. Pull all the spark plugs, spin the engine by hand. Does it spin super freely? Yes? Good, that means you don't have any horrible mechanical issues.
Now, put a spark plug in cylinder 1. Try to rotate the engine twice, did it get hard at one point? Good. Now do this a for each cylinder.
If it took approximately the same effort for each cylinder, you're probably alright. Don't sweat it. Compression is very rarely the issue, and based upon your symptoms this isn't likely, but you should still check.
Leave the spark plugs out for the next step.

Spark:
Now, put the spark plugs into the spark plug wires and set them on top of the cylinder head so they make contact. Go into the car, and start it. It should crank super fast, and you should see hot blue/white sparks.
If you don't get a spark out of one, it's probably a wire. If you don't get spark out of all of them, it's probably your distributor's ignition coil, rotor, or the cam sensor.
 
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