racingiron

So, I'm on my way to Mid-Ohio, enjoying the cooler weather and the urq... The problem started as a very occasional and brief cut of power while under partial boost (5-10 psi). It was just like a quick hiccup, then everything was fine again. Then it progressively got more frequent and pronounced. It would idle OK and seemed to smooth out under full boost, but part throttle on or off boost was bucking wildly. For a time I could downshift to 4th and run about 4200 rpm with fewer troubles, but even that eventually got bad. It got to the point that full boost wouldn't even work right, and idle would sometimes be bad, even stalled a few times.

Here's all the stuff that didn't fix it:
- Parked for about an hour while I had dinner--problem returned almost immediately after restart.
- Pulled cap, it and rotor look fine, as do wires. Haven't checked the plugs yet.
- Unplugged O2, still bucked but there seemed to be more unburnt fuel, lots of backfire pops accompanied by smoke.
It got so bad that it was undrivable on the interstate. I parked it and have continued on (luckily, the fair Elizabeth was following in her Mini).

So, it doesn't seem isolated to a cylinder, so I'm thinking the coil's dying, or maybe the ignition module? Am I overlooking anything? Any BTDT or advice for me?

What are my chances of scoring a coil on a holiday weekend? Is this coil shared with other I5s or is it special to the urq?

I'm headed for the hotel right now and will return tomorrow morning to see what can be done.

Thanks in advance,
Eric R.

urq20vt

Eric,
I would look at the ignition module, coil to distributor wire and perhaps flywheel sensors. I had an ignition module fail with the same kind of symptoms. After that, I kept a couple spares in the glove box just in case.

Also do the usual checks for intake leaks, especially the igloo to turbo hose.

Gotta love 25 year old cars....

Steve

racingiron

Turns out it was indeed a failing coil. A new MSD unit from FLAPS has it running like a champ. We'll see how it handles the baking from a few sessions on the track...