Time for a new 3.0L/MegaSquirt/EDIS thread. First, I’m running the coil pack now instead of coil-on-plug. Redoing the wiring for the CoP didn’t fix anything, so I’m guessing a coil is bad or something. Since the coil pack works, I’m tuning with that for now. I’m going to go to a junkyard later and try to source a more easily mountable pack and some longer wires. I might switch back to CoP after I’ve run the coil pack for a while.

Anyway, the car now starts, but it shoots up to 2000 RPM and stays there. This is after I turned the throttle adjustment screw all the way to closed, too. However, when I used IAC Test Mode in TunerStudio to completely close the IAC, the car starts and idles at around 800 RPM when cold. It starts the lose RPM as it warms up, so I adjusted the throttle screw a bit until it stayed running, and adjusted the fuel table to keep it in the 14.7 AFR range for good measure. It seems to idle fairly well once warmed up.

My question is about this high idle on cold start with the IAC. It’s about 45 degrees ambient today, in case that’s relevant.

I’m thinking I just have the IAC set up wrong. But I want to make sure there isn’t a vacuum leak before I delve into that. Since closing the IAC seems to let the car idle properly, that implies there’s no leak, right? Otherwise the car would still be idling way too high, wouldn’t it? But it seems odd that I have had to open the throttle a little to keep it running as it got warmer, too — I thought I’d need to close it more, if anything.

I also have an analog vacuum gauge hooked up. With the engine up to temp it shows >30 inches Hg at idle (it maxes at 30), well outside the marked green zone of 17-22, but I really have no idea what that means. Some Google searches suggest that it should be idling in that green zone, so that implies a leak.

But TunerStudio shows a MAP of 40 kPa, which I think is OK?

I previously set the ignition timing as best I could, with a 1 mm gap between the VR sensor and missing tooth wheel, centered as accurately as possible six teeth before TDC. So I think the timing is right, anyway. At least the exhausts aren’t glowing.

I’ll attach a log and tube when I get home. It’ll be of a warm engine; I didn’t take one of the engine cold.

It’s looking like I’ll be able to drive this thing soon.

Thanks!

— Joe