Hey,

I just replaced my D16a8 with a rebuilt DOHC ZC, i originally used the harness that came with the engine, but it threw a code 6,9 and 10. While diagnosing that i found a broken wire at the coolant temp sender, so i pulled off that harness and used my old harness. Using the old harness cleared the codes, but it still runs rough. Sounds like a subaru.

What i've checked:

-Continuity to sensors
-Engine is definitely at TDC
-All sensors and harness plugs are connected, except for a single wire connector which (on my old d16a8) plugs in under the distributor, behind the CTS, which the ZC does not have (so it's just hanging there because i'm using my old harness).
-While diagnosing the previous codes, the sensors were within correct resistance ranges.
-Thermostat ground is connected

I'm running:

DOHC ZC with a PM7 ECU.

So the problem i'm stuck with is, no codes, but rich smell and smoke from the exhaust, lumpy idle. Car revs ok, but the rich smoke increases.

Any ideas appreciated, i have a tonne of DOHC D parts i can interchange with to help locate the problem.

 

sounds to me like it could be a MAP sensor. or IACV.

IACV is VERY likely to cause all those problems. very easy fix two bolts hold it to your intake mani take it off, and clean with carb cleaner. fixed my b18 a while back when I had similair codes.

 

I've had similar symptoms before when my map sensor went bad, although it's definitely connected correctly, I'll try swapping it with another this afternoon. I can't recall a bad iacv having these symptoms, but I guess it's worth a shot. I'll report back later tonight.

 

map sensor is the first of the sensors to correct fuel. I would start there. Next in line is coolant temp I believe or o2 sensor. then IAT. Then atmospheric pressure. And it also uses the tps to calculate fuel tables. So check the map and tps. make sure the tps is getting good vacuum. Check plugs wires cap and rotor. You can check the wires for proper resistance since you know how to use a meter.

 

does the map sensor connect to the top of the throttle body? That's where I had it connected on my old engine, though I was using an obd1 manifold (now using an obdo manifold) so it's possible the connection points are in different locations.

 

On my obd0 ls it connects on the drivers side of the intake manifold. There are no provisions to hooking it up to the tb. With that said I have never even seen a dohc zc.... Good luck Steve!

 

you can hook up the map sensor vacuum to the skinny port on the tb. if ur map doesn't have vacuum thats ur problem

 

Yeah that's where it's connected, i'll be sure to check that port is open on the inside of the manifold as well though.

I'm actually thinking about swapping my old manifold back on to see if that clears the problem.

Cheers guys! I'll try a few things out when i get home from uni.

 

possible wrong injectors? maybe they are obd1?

 

Ok..... So gay.

I had the map sensor connected to the charcoal canister port on the intake manifold. Swapped those over and it fired up and runs clean.

So i was running coolant through it , with the front jacked up to get the top of the rad hose to the highest point, and while i'm running it through i check my temp gauge and it's past H. At this point i'd run it for maybe, a minute or two? I turn the car off. The engine is hot to touch, so i guess it was running for a bit, but i didn't think it was long enough to be able to get it that hot.

So i let it cool off, and turn the key to ign 2 and the temp continues to spike past H... So now (or there always was and i never noticed it before) an issue with the gauge or sender (which is connected). So i go to start it back up and it just cranks now, throwing a code 15 (ignition output signal).

I checked and the dizzy is getting voltage, what are the chances of frying a dizzy though, right now, seriously. I'll be swapping it over tomorrow, hopefully that clears up the code and gets the car started again... So close!!!

Any thoughts on my temp gauge or code 15 LMK.

Cheers.

 

Well the code 15 was due to a wire falling out of the plug that connects to the dizzy, so it starts again now, but the temperature gauge still fluctuates heaps and eventually sits above Hot, i took a vid.. This is a few seconds after startup:

http://www.youtube.com/watch?v=bb3pkWM6v80

 

I'd be inclined to change the temp sensor - inexpensive way to eliminate one possibility. Check wiring connections.

 

****ing wiring i swear, so the one wire connector from the sender was grounding on the transmission housing, causing it to fluctuate to hot. Plugged it in and she's running sweet now, thanks for your help guys!