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Wedge Need help with TR8 no spark

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sammyb

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Oh LBC gurus -- help please, as this one has me baffled! '80 TR8 dual Stromberg car that when I got it had spark, bad fuel pump and dying starter. Would run on starting fluid. I put in a new fuel pump and starter and now has no spark. Figuring I toasted the Lucas Opus distributor, I just installed a Pertronix Ignitor II and new Flamethrower .3 ohm coil. Still no spark.

Same condition with the Pertronix as with the Opus: tried getting an arc off the coil lead to the dizzy to the engine, but nothing. Won't run on starter fluid.

I ran a jumper from the fuse box to the coil to get full 12V, so I've bypassed the ballast resistor. Went Ignitor red and black to + and -, and then jumper to + and even tried a jumper ground from the - to the unibody. I know there's power, because my test light goes on. (Unfortunately, I caught my multi-tester lead in the engine bay and broke the wire, so I have to grab my other one from home.) Tach wire isn't hooked up yet, but that shouldn't matter. I've been looking at the wiring diagram and still can't figure out the issue.

I also had to replace the starter switch, as it was destroyed when I got the car in the summer. Still, if I have the starter cranking and power to the coil, shouldn't it be firing???

Any ideas?
 
FWIW Pertronix catalog says Ignitor II should have a 0.6 ohm coil, even in V8 applications. I wouldn't think that would damage the module; but it might refuse to work with the 0.3 ohm coil (ie trips the overcurrent protection feature).

Get your multimeter going and double-check the actual voltage between the red lead and the plate that the module is mounted to, while cranking the engine. I have no experience with the Ignitor II, but I know the Ignitor I will refuse to work with less than about 8 volts, which is still enough to crank the engine. That black wire is not a ground; it's the switch output to the coil, so grounding it will disable the ignition.

If all else fails, set your multimeter to 50v DC (or higher) and check between the black wire and ground while cranking. You should see the voltage jump around (or the needle kick if you have an analog meter). If it stays stuck at around 1-3 volts, you've probably got a bad module. Stuck at ground or 12v is probably a wiring problem.

I think you said this, but JIC, be sure to check for spark coming right off the coil tower. Rotors can sometimes fail and short the spark to ground even if they look brand new.
 
Thanks Randall -- it's been so long since I've been active on BCF I had almost forgotten what a rock star you are. I think it is actually a .6 ohm coil. (I ordered a Pertronix 45011 and the packing slip here at the house from Pertronix indicates that's what shipped.)

I'll make sure to take the ground off the negative terminal. (Hope I didn't fry it.) I'll then start muti-testing per your instructions as soon as I get a willing helper to crank. It's probably something simple -- bad ground or not enough connection to get full volts from the jumper wire. Already had a bad earth cable from the battery in the boot that prevented the new starter from spinning. (Wire brush and two large clean washers fixed it quickly.)

At least this should be easier to troubleshoot than my install on my 308 GT4: two coils, two dizzys (one for each bank of four cylinders), but the pertronix is mounted in one dizzy with two modules (master/slave) and the dizzy has to come out for installation...and each dizzy had two sets of points...AND the dizzys are not keyed, but rather have teeth at 5-degree intervals (so not just "correct" or "180 off"). So much to go wrong!
 
Have you checked fuel flow? Just because pump is new does not mean line is clear. You also do not mention plugs. Have you check the plugs. Plugs could be fouled due to the bad fuel pump you replaced.
 
Larry - Yes, I checked the fuel flow...but even if I hadn't the TR8 has an in-tank electric fuel pump, which in this case was a) seized and b) had a rotted-away rubber hose from the pump to the outlet, so that meant no fuel was leaving the tank to the the twin Strombergs. Since Strombergs (like SUs) don't have accelerator pumps, that means no fuel getting into the cylinders to foul the plugs. I did check plugs.

The key, though, is that I have confirmed that I have no spark. If I had spark a) I would guess that I'd see an arc from the coil lead and b)it would start on the starting fluid like it did before I replaced the starter.
 
Recheck the wires to the starter, and the coil resistor wire. Possibly plugs are coated with varnish and still look fine, might scratch a little to clean. Call petronix, they have a help line when desperate. Friend had to on his, needed non- wire core wires and matching coil. Ran good afterward. Don't leave key on too long will destroy electronic points.
 
This is an Ignitor II, so it has the protector circuit to prevent burn-out with the key on. Already installed the new matching coil.
 
Getting spark now. Ground strap to the engine block wasn't sufficient. As soon as I ran a jumper cable from the - terminal of the battery to the engine block, I saw sparks from the coil tower to the closely placed lead. Unfortunately, the engine still isn't quite catching and running. Had a couple of pops through the carbs, so I think the timing might be a little too advanced. (Didn't remove the dizzy, but it's possible the pickup created a small change, I suppose.) Also, the spark plug wires are pretty nasty, so I'll replace those and the plugs.
 
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