Working with an 88 TII. I noticed while I was setting timing, I was getting a spotty reading off L1. I swapped to L2 and got a perfect reading. Is this any indication of a failing coil?

I have been tirelessly chasing an issue that's essentially causing the car to fall on it's face. I'll do my best to list everything I've already checked:
- TPS set and checked (no dead spots/jumps)
- idle is solid
- CAS stabbed and timing set
- brand new Walbro 255 and also complete fuel pump rewire with resistor eliminated

Mods would include:
- BNR stage 3
- FMIC
- 720/1000 injectors
- FPR with parallel fuel setup
- RTEK 2.1
- emissions delete
- DP/exhaust

Any advice would be greatly appreciated.

 

The igniter receives a ground via the coil being mounted to the fender in a suitable manner so recheck this. Also, the plug wires might be at play here. You might want to exchange the plug wires from the known working trailing coil and using them on the lead coil to see if it makes a difference.

And the Green/Yellow wire is the trigger wire for this coil and it comes from the ECU. W/key to on the voltage should be 0 volts. As the main pulley is rotated by way of rotating the alternator pulley the voltage will ever so briefly bump up to 5 volts and then quickly revert back to 0 volts and it will do this over and over.

 

For what it's worth, the wires are fairly new, but I will certainly try swapping them for peace of mind. Also, the coil grounding was checked via multimeter, but it wouldn't be any skin off my back to try and check again.

 

Couple thing to try.
wire the coil to ground,for the hell of it.
Another thing is switch the Wires on L1 and L2 ..seeing they fire at the Same time it will NOT hurt the engine to run it that way,and then check your "spotty L1" to see if it is now L2..
if it is you have narrowed it to L1 coil.
if not,Check the wires?
How about Spark plugs?..fouled?..check em.change em,try that yet?

 

Update:

It's funny, sometimes you assume the simplest things couldn't be at fault when they are. Upon swapping L1 and L2 wires at the coil itself, sure enough the spotty signal followed the wire. So obviously I'm going to be replacing this lead.

For the hell of it, we put the gun on the trailing coil next. T1 was spot on. However, T2 would fire the light, but would not fire at the appropriate time to even see the mark on the main pulley at all. Is my T2 behaving normally, or is this indicative of a problem? Sorry, I'm just not familiar.

Thank you so much for the help thus far.

 

There is no T2 mark on the pulley. So there's nothing to match it up to.

 

Thank you sir. For my own knowledge, may I ask how the trailing coil fires/why T1 and T2 fire differently?

 

Check out the illustration attached. If rotor #1 is at TDC, it looks like the top right illustration. Rotor #2 will look like the bottom right. It's fine if the leading plugs fire together. But if the trailings fired together, it would try to ignite the next chamber long before it's compressed. No bueno.

 

So I have replaced the plug wires and the issue still follows the wire!!! I metered the plug wires as well and they were both identical. Is it possible that a spark plug could be effecting what's going on? To clarify, when I "swapped wires" to troubleshoot, I merely swapped them at the coil, I did not swap them at the coil and at the plug. The plugs are basically new and the last time I inspected them they looked fine, but if I need to change them I need to change them.

 

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Exactly...I don't understand how the issue could be following the wires and not a specific coil, it's just not making sense. For good measure, I grounded the coil with a 4g wire straight to the battery for testing. Still nothing.