ihiryu

iTrader: (7)

Hey guys, I'm working on a swap right now, it's a 1uz into a S14.

The car was running great last week, and now this week, it's running on half the cylinders.

I've checked for spark (which it has), and I used some noid lights to make sure we had injector signal.

But it's only running on Bank 1 (driver side), but again, we have spark, and fuel. I pulled the plugs and they were BLACK! I just replaced plugs and started her up, and same deal.

At first I thought it was ignitors (I had this problem when I did my 1uz to MKIII supra), made sure they were grounded, and checked for power. Car runs pig rich, I swapped the ignitors around, just to be on the safe side, and it only runs on that single bank.

I doubt it is coils, because I've got spark coming out of it. I just find it strange because if you recall the wires go to both banks (so you've got 1, 4, come out of their respective banks, but 2, and 5 cross over to each other), the only other possibility I can think of, is that it's a mechanical issue, but I did the timing belt over a month ago, and didn't have any issues with it running.

Ali SC3

iTrader: (10)

check compression would be the next step, odd to loose it on all 4 though.
its rare but sometimes the cam alignment dowel shears off and throws one bank out of alignment as the cam usually rotates some more before the bolt tightens down again (usually stretches the bolt and it can even snap off). I would pull the covers and check the timing belt job and the cam on that side.

a leaky waterneck outlet where the thermostat is can also cause the belt to slip and put one bank out of timing, since ther is no gasket and just sues rtv you need to keep an eye that it sealed correctly. I agree it sounds mechanical and since its all 4 one one side that rules out ignition since each distributor runs 2 cylinders on each bank like you said.

line it up at TDC and check the cam on that bank. also check any cam sensor wires didn't get chewed up by the belt, that causes funny stuff to occur as well.

bigwhite

I had a bad ecu do the same thing.

ihiryu

iTrader: (7)

You guys aren't gonna believe this.....

I had the intake/AFM off, and the car was running smooth without it. So I ended up capping off some of the vacuum lines off with my thumb, then it started running on all eight. WEIRD. I pulled off the injector clips one at a time, and sure enough it was running.

I let go of the vacuum lines I was capping off, and then it would only run on four cylinders. I tried this a few times to test it, but I've NEVER encountered an issue like this. Blows my mind completely.