Valkyrie

Does anyone know if it's normal that one of my leading coil packs can give a strong reading on a timing gun but the other one doesn't?

I'm thinking that maybe a weak leading spark on one rotor might be the cause of my crappy idle (it either wants to idle too high or too low when I try to set the idle and timing).

Would it even be worth trying out another coil pack on it?

phoenix7

have you tested it yet? why remove it, buy another one and install it if you're not sure that's the problem?

Valkyrie

The only test you can do without a coil checker (which I"m sure is farking expensive) is the resistance, which may or may not have anything to do with it's actual performance (it'll only check whether or not it's broken).

And I've been through everything so many times that I can find any other reasons that it would idle weak (not terrible, but enough for me to nitpick about), except for compression, which should still be fine.

I mean, I've set the TPS hundreds of times, I've eliminated any vacuum leaks, exhaust leaks (unless I've developed new ones...), replaced plugs and wires, I've set timing over and over again (although I need a new gun since I don't trust the one I have... it has a crappy "advance" gauge on the back that I trust as far as I can throw it). I've also checked throttle clearances, and cleaned the TB...

OTOH, there's a long list of other parts I want to replace before I replace something that's probably not going to help much at all...

Also, it might be an ECU issue, because for some reason the timing likes to spring forward several degrees whenever I give it throttle, and sometimes never goes back to normal until I mess with the CAS, idle, or turn the car off.... my ECU might be retarded when it comes to advance.

Valkyrie

The issue might have to do more with the ECU since it does have a strong enough signal, but it's not timed right, since the yellow mark doesn't show up most of the time... but only on L2. L1 shows up fine.

Boosted11

iTrader: (11)

Coil packs arent something you just wanna go out and buy, they're fairly pricey.

Valkyrie

New, yes...

Used, not so much. (as long as you're buying it from a junk yard and not an RX-7 owner...lol)

RETed

First, most inductive timing guns have a problem with the stock ignition system.
You can "trick" the system into pushing out a stronger signal by loosening the spark plug wire.
By pulling off one of the boots about an inch or so, you force the coil to fire more, which triggers the timing gun more consistently.

Second, you can kinda get an idea of how well your coil is firing just by removing the spark plug (with spark plug wire still attached), and grounding the threads.
I usually use the strut tower studs, since this is a convenient place.
TURN OFF THE FUEL - either disconnect the fuel pump connector from the rear or pull the ENGINE fuse from the driver's side kickpanel - either will keep the fuel pump off.
Be careful, as there is still residual fuel in the rails, so it's going to spit at you the first few revolutions.
Having a friend really helps here - have them crank the motor over, while you keep an eye on the tip of the spark plug.
It would help to have new or newish spark plugs here, as a slightly fouled spark plug will throw a weak spark.


-Ted

AbortRetryFail

Correct me if i'm wrong, but don't both leading plugs run off the same coil?
You might want to make sure the wires are good.

Valkyrie

It seems that the issue isn't the lack of a strong spark, but that the timing is slightly off compared to T1 (when they should be the same).

RotaMan99

You ment L1 correct? Since Leading and trailing fire at different timings.

If you find one leading coil coil seem to be firing at a different time, im sure its the inductive timing light not picking up a good signal from the wire.

do what ReTed said and you just may get different results.

Valkyrie

Yes, L1 and L2...