eriksseven

iTrader: (6)

Anyways, I've been troubleshooting a buddies bone-stock 1987 Turbo II, because he's getting a terrible misfire throughout most of the powerband--especially 4k RPM's and beyond. The car has been unable to build boost in 1st and 2nd gear--I believe this is directly or indirectly related to the misfiring.

While I was initially checking and resetting the timing, I noticed that the *flashes* from the timing-light were very sporadic, when the gun was hooked up to L1 and L2. However, it was good enough for me to be able to dial in the timing via the main pulley dash-mark and front-cover pin (of course reading the signal from L1). Out of curiousity, we hooked up the gun to T1 and T2--and the flashes were perfect and there were NO misses at all...

The next day we realized that the actual leading-coil PLUG was GONE, on the harness side--and the previous owner had simply STUFFED the two wires into the leading coil plug... Again I hooked up the timing light and held down the trigger. I noticed that if I *wiggled* the poor plug connection, the spark flashes intensified in their frequency--although there was still an occasional misfire, it was much better. We redid the connection by cutting off the coil-packs remaining plug and wiring in 'spade' connectors on both sides.

We took it out for a test-drive and miraculously we were able to build boost in 1st and 2nd gear! But the hesitation was still there, albeit higher in the powerband (5k+). Once we were even able to take it to redline in 1st gear at 7psi. However, we knew the hesitation was still there and we had not fully fixed the issue.

At this point we believed that replacing the leading coil-pack would fix our issues, because it was obvious that the spark-pattern was inconsistent and could be traced to the coil-pack... So to make sure, we hooked up the timing gun to MY Turbo II, which runs and boosts perfectly--and to our confusement, my leading coil-pack did the exact same inconsistent firing!?

My question is; is it normal for the leading-pack to spark like this? While the trailing-pack creates perfect spark?

Where am I wrong in my thinking?

BTW, the next step is to swap the fuel-pump and secondary injectors.

HAILERS

Normal as can be.

Usually one of the lead wires will show to fire consistently but the other wire will seem to fire irregularly. IF using a timing gun with a clamp on the wire, you will find that reversing the clamp will make the irregular wire fire just fine and vice versa with the other wire.

I'm talking about one of those wire clamps that have an arrow on it pointing towards the sparkplug. reverse the clamp til the arrow points toward the coil assy.

eriksseven

iTrader: (6)

Right on. Thanks HAILERS.

The timing gun that we're using does have a clamp. It's got a "pincher" that opens up and rests loosely over the plug-wire when clamped. I'm not sure if the clamp on the gun that we're using has an arrow on it, because I never thought to look. I'm sure I've just thrown it on there both ways without knowing the difference.

Either way, thank you for clearing that up. I however need to clear up that my original post in which I stated "we're not seeing boost because of the misfire", was a LIE! We weren't seeing boost because our ghetto boost-gauge (that we ran from under the hood and through the pass. window) was being CLAMPED off everytime we shut the hood. So yeah, we're actually seeing a consistent 7psi in all the gears, regardless of the hesitation.

Thanks, and I believe everything should come together successfully once we're done with our "engine bay clean-up" etc.

I do have to say, the previous owner(s) were a bunch of n00bs. There is some haggard nonsense going on with shoddy wiring etc. All of it should be corrected here in the next couple of days. BTW, the turbo is PERFECT. No end-play and just the most minimal of shaft-play. This is after 160k miles. This thing has not seen a hair over 7psi in it's lifetime.