After an oil delivery issue, I'm back to getting my 3.0L conversion idling. I'm having trouble, though, and I may have tracked down the cause, but I want to ask if anyone has any ideas before I tear the engine apart again.

First:
- Ignition timing at idle is currently at ~14 degrees. I confirmed that what TunerStudio shows is the same as what a timing gun shows, so I believe this to be correct.
- Coil-on-plug via EDIS, spark plugs are all firing
- Fuel delivery appears to be good
- Engine cranks and starts, but seeks at idle (500-800 RPM)
- DPI headers, Magnaflow CARB-compliant cats, Borla Pro XS muffler
- Fairly sure there aren't any vacuum leaks...

The first problem I had was that the passenger side exhaust pipe and part of the catalytic converter (on the outlet side of the cat) was glowing once the engine got up to temp. Theorizing that this the silencers were too restrictive, I put in new pipes without silencers. I also replaced the cats with shorter ones that gave me a little more room for mounting, which also rules out the cats. Neither of these had any effect, other than the glowing was limited to the cat now. It's worth noting that ONLY the passenger side cat was glowing in both cases, and that the passenger side headers were reading about twice as hot as the driver's side with an IR thermometer.

I found out that the throttle wasn't closing all the way (mis-adjusted throttle cable). I fixed that this morning, but I didn't have much time to play with the car, so I only had time to start it once and let it idle. It never quite got up to temperature during that time, and eventually stalled out as I played with the VE table to try to smooth it out.

Using the IR thermometer, I got a reading in the high 300s (350-375 F) for the driver's side at the point where the header pipes merge to the exhaust pipe before the cat. On the passenger side, however, I was only reading in the low 100s (115 F or so). I individually tested the header pipes from each exhaust port as well. I got in the low 100s for cylinders 1, 2 and 3, in the high 300s for 4 and 5, and a more like the mid 300s for 6. I'm guessing some variance is normal given the inaccuracies of the IR thermometer and ambient heat in the area, but not the amount of variance I'm seeing between the driver's and passenger sides.

In all of these situations, the AFR reported by TunerStudio via my LC2 O2 sensor was way too high. With the slightly open throttle it was around 22:1, and now it's down to around 19:1, but as I understand it I want 14.7:1. Note that the single O2 sensor is installed in the driver's side header (there's a narrow band sensor plugging the bung in the passenger side header, but it isn't hooked up to anything).

The question is: Why is the passenger side's temperature so much lower than the driver's?

My current theory is that I may have incorrectly installed the timing chain to the passenger side camshaft. If it were off by a tooth, that might explain why it's running so lean (I think?). Of course, I need to pull at least the valve covers and I think the timing cover (and thus the muffler to get enough room) to re-time. I'd really prefer not to take all that apart to find out that it's not a timing problem, so I'm wondering if anyone else has any other ideas first. It does seem like it would explain all the issues, though. Really wish I'd though to recheck this when I replaced the main crank bearings...

I've attached a TunerStudio log from today's test in case anyone can glean anything useful from that. It took three tries to start the engine, and I started playing with the VE table near the end to try to smooth out the idle a bit before it eventually stalled out.

Thanks!

-- Joe

Glowing Cat:
IMG_1224.jpg

TunerStudio Log: 2018-07-14_09.08.05.msl