Distributor '87-91, Open Bowl
Integral ICM, Push-Start (Gray)
The distributor-mounted TFI-IV Ignition Control Module (ICM) is known to suffer from overheating, and commonly fails. A special (but cheap) tool is required to change it, and the distributor may have to be rotated or lifted, which requires resetting the base timing as described on the VECI label under the hood. For the complete testing procedure, see Ch.5 (usually Sec.5 or 7) in the Haynes manual:
TFI-IV (DI) E-core Coil Specs:
Ignition coil primary resistance ( to - input terminals): 0.3-1.0 Ohms
Ignition coil secondary resistance (output post to either input): 8-11.5 KOhms
Ignition coil core to any terminal: >10 KOhm (open circuit)
In addition to the areas described in the top Right pane, the entire plastic interior of the cap should be coated with a thin film of silicone dielectric grease to prevent condensation from causing spark leak.
I recommend keeping a trickle charger on the battery all the time until you get it running. The Battery Tender (~$40 @ Sam's Club or Costco) or Battery Tender Jr. (~$35 on Amazon) are among the better ones.
The V8 timing marks are stamped into the edge of the harmonic balancer; I6 are bolted to the timing cover on the passenger side, between the smog pump & HB. Use steel wool, a wire brush, or sandpaper if necessary to clean the the marks so they're clearly visible. Use a socket & breaker bar to rotate the crankshaft if necessary. The V8 timing pointer is bolted to the timing cover; I6 is a tiny notch stamped into the lip of the HB.
Remove the #1 spark plug (V8 RHF) and rotate the crankshaft until the pointer aligns with 0. Use a hose to blow into the spark plug hole - if it's easy, and you hear the air coming out the throttle body, rotate the crank 1 full rev back to 0, and recheck. If it's difficult to blow air in (#1 compression stroke), and ALL the air comes out around the threads, drop a plastic drinking straw into the hole so it rests on the piston and rock the crankshaft gently to make sure you have the piston EXACTLY at top dead-center (straw as high as possible). Then re-check the pointer. If it's slightly off, adjust it so it's dead-on 0. If it's WAY off, replace the balancer.
Set the cap into place on the distributor body and make a mark on the bowl directly under the #1 tower (should be molded into the cap). Remove the cap, install the rotor on the dist shaft, & rotate the rotor so it points at the mark. With the dist bore clean & a light coat of clean motor oil on it & the dist O-ring, drop the dist into the bore so its connector points toward the wiring harness connector (or the vacuum advance is in a clear area). You'll have to wiggle the rotor to get the gear teeth to align AND the oil pump shaft to fit into the bottom of the dist. shaft. When it drops all the way down, check if the dist body can be rotated so your #1 tower mark moves to both sides of the rotor tip. If not, raise it, & reset the rotor so it's centered in the mark's range of adjustment. Then loosely install the dist clamp & bolt so the dist can't rise, but it can be rotated with some effort.
Next, read this caption & check for timing chain/gear slop:
Replacing the gears is a BIG job that's best done by removing the engine, so don't dive into it on a whim. But if it's worn out, the engine will never run right until it IS replaced. Only you can decide since you're the one looking at it & paying for it. When you're finished, set the HB to 0 and the dist with your mark directly under the rotor tip.
Finally, install the cap & wires EXACTLY as shown in this diagram:
After checking everything (connectors, fluid levels, battery charge, rags hanging in the fan blades, etc.), put the key in RUN and use a starter relay trigger
to crank the engine while you GENTLY work the distributor back & forth until it fires up. When it does, use either a timing light (SPOUT pulled) or vacuum gauge to set the timing close while it warms up. Then follow the instructions on the VECI label to set timing properly.
Distributor Clampdown Bolt 24-33 Nm; 17-25 lb-ft