A friend bought it not-running after previous owners were unable to get it running. It sat for "a few years". Someone worked on the wiring: the ICU was unplugged; FI relay case open, loose wires under the dash, ...

It runs now via some new/used parts: fuel pump, fuel filter, white-label 951, FI relay, plugs, cap, wires, coil, intake manifold gasket, bellows, vacuum lines, FPR, O2 sensor, timing belt, IAV cleaned, throttle body cleaned, grounds removed, cleaned, reinstalled, good used MAF, TPS clicks, cat's not clogged, power stage stays cool, ...

Problems: starts and stalls 2-3 times (when motor cold) before it'll stay running; rough idle when motor is warm; poor MPG, black tailpipe, black smoke idling. Drives smoothly, has decent power.

Codes:
o 1-2-3 ECT
o 1-1-3 Fuel Injector Signal
o 1-2-1 Failed signal to/from AMM (MAF)

1. I pulled the IAV (2-wire) and tested again. It clicks on the bench but not when it's hooked up in the car. Wires from the IAV are OR (orange) and GN-R (green w/ a red stripe). In Bentley (p 241-6) it looks like the OR joins the injector wires in the junction under the intake manifold; GN-R goes to the ICU.

Hooking a test light between a battery post and the IAV plug I got:
- Key off: both wires lit the test light when hooked to bat + (indicating they are grounded)
- Key on (engine not running): OR lit the test light when hooked to ground. Otherwise nothing.

I expected the GN-R wire to show 12V. The wiring harness looks intact. The OR wire broke inside the harness and made contact with 12V? I believe 1 black or brown ground wire goes back from the wire cluster to the ICU.

It'll be easy to run a new ground from the IAV to the intake manifold but if there's no power on the GN-R wire ...?

2. The intake-manifold gasket I replaced was intact but showed signs of leaking - dark areas in the center. Perhaps the intake manifold is warped.

3. It's possible that the MAF is failing and/or O2 sensor is fouled/failed.
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240 drivers / parts cars - JH, Ohio