VANHALEN

iTrader: (3)

I don't see how it's possible but I'm getting spark only on L2. L1 has no spark.
Anyone come across something like this? I know it's not the wires since I swapped it with L2 and it's the same. There's only 1 igniter for both L1and L2 so how can one be good and other be bad???

HAILERS

Can't happen unless the spark is leaking at the wire going into the coil and then you'd hear/see that if that were happening.

Using a timing light to come to this conclusion? reverse the timing light clamp on the lead wire that *isn't firing*.

VANHALEN

iTrader: (3)

Hey Hailers..up early!
Today the motor sounded like it's running on one rotor so I thought one side was not firing. I grounded the plug boot and all but L1 was sparking. Seems strange. How can that be? When the motor does start, although very difficult and floods from a rebuild, it sounds like it catches for a split second then out again. I tried changing wires but it's the same

HAILERS

Yeah. I thought of that and that's why I returned to this thread. I was going to suggest swapping the two lead sparkplugs and see if that helps. Even better try a new plug in in the rotor that isn't working OR maybe take the TRAIL PLUG from the good rotor housing and put it in the LEAD hole of the non working housing.

I figure the *spark* of the bad plug is shorting to gnd, so to speak and therefore letting the other one work normal.

I'd NEVER buy four new sparkplugs. If you go buy new plugs, just get the Lead plugs. Trails have little effect on starting and running the engine.

Not up too early. Watching MotoGP on the weib. My man done falled off his bikle (Ducati), darn it.

RETed

Don't understand what you're asking...

L1 doesn't fire, right?
Are you visually checking that it doesn't fire?

What do you mean by grounding the plug boot?
If you do that, it can cause damage to the coil!
Do you mean you're verifying that a spark is firing from the plug boot to ground?

When you switch the wires, L1 still doesn't fire?


-Ted

VANHALEN

iTrader: (3)

Yea..I grounded the L1 plug boot to see if there is spark.
I tried swapping wires but L1 does not spark.

HAILERS

I used to fool around with Lead coil assy. I got two coil assy. Spliced the little white connectors to each. Had one sparkplug wire from each coil assy going to one lead spark plug. To make the things work, I grounded the other sparkplug wire from each coil, the one not going to a sparkplug wire. So now one lead coil assy was feeding one sparkplug and the other lead coil assy was feeding the other sparkplug. Worked for a couple of months til I tired of the sillyness.

Then bought a Crane FIREBALL! and installed it. Made me feel good all over for a while til I came to the conclusion it really was zippity better than the stock coil assy. Only reason I have not removed it is........lazyness and I spent a few bucks on it, so it stays.

All that bs above is to let you know if one sparkplug wire is gnd'd then the other will work. Kinda what your problem is now in some way.

You might try a fuel cut switch to help start that car.

NoDOHC

Shouldn't the engine still run on both rotors even without leading spark?

There may be another problem.

VANHALEN

iTrader: (3)

Hell...I haven't checked the inside where the boot goes in to see if it is corroded. It had not been started for a long time.

HAILERS

You have a point, but have you ever heard a RX running on only the trail plugs???? Sounds similar to a blown engine imho. Or crummy if you will.

It won't hurt anything. Get your engine hot. Then at idle, pull the Lead plugs off and listen to the engine..........if it will stay running. Only takes a few minutes.

VANHALEN

iTrader: (3)

Hmmm...makes sense. I'll try another coil pack when I find one.

Yea...the cut off switch is going in. Silly to be pulling the EGI fuse when it floods.

VANHALEN

iTrader: (3)

Yea it will run. Sounds like a loud lawn mower but almost impossible on a fresh rebuild and it needs all the spark and fuel it can get.

HAILERS

Sorry, that was meant for NODOHC and what he wrote. NOT for VanHaylen to do. Non productive thing to do.

It's difficult for me to think the Lead coil assy is bad. One plug fires the other has to. Try another if you have one. Or swap with another RX

NoDOHC

Wow! You weren't kidding. Stock ECU runs pretty badly on just the trailing plugs. I had tried it with the haltech '86 and it ran just fine with only trailing plugs, made good power and everything (this was a 12 degree split at idle, Leading at 0 BTDC. Apparently the stock 15 degree split and 5 ATDC is considerably worse.

I appreciate the lesson and apologize for the rabbit trail.

To break the engine in, you could advance the timing and use the trailing coils only on the leading plugs. (It seems that a 20 degree advance should make the trailing plugs match the expected leading plug timing pretty well.)

This should at least help to isolate the problem to the coil pack and not engine compression or something else (I distrust timing lights and spark plugs hanging in the wires against something).