Piranha

Alright, well the prelude to this story is here..

https://www.rx7club.com/forum/showth...hreadid=121813

I decided for the helluvit to unplug my trailing coil. After all, its the trailing one. Who needs it right?

Well, all of a sudden, rev the engine, no chirpy chirpy sounds... no detonation. I take the car out, 1 psi, 2, 3, no sounds. So I take it to 5, sounds excellent. 7, SWEET.

So, why is my trailing coil doing this? How can I stop it?

Should I just leave it unplugged? (although I can't read the tach now)

Thanks..

DaleClark

iTrader: (55)

Most likely you have the trailing plug wires on backwards - the car will detonate and run funny if they're hooked up wrong.

Dale

scathcart

Even more of a reason to believe the wires are crossed, like TED said.
Crossed meaning not trailing on leading, but the wires that are supposed to go to the front rotor are on the rear rotor, and vice versa, on the trailing coil only.
Check it.

Piranha

if by wires, you mean those big long things that connect to spark plugs, no, they ARE on correctly. I've checked about 10 times from the coil to the spark plug and rotor housing to make SURE I'm not a retard, and it turns out, I'm not, unfortunately. I dunno man. Its strange.

Piranha

I have T1 going to the front top plug and T2 going to the rear top plug. :| I even ran outside to check before I wrote this

DaleClark

iTrader: (55)

The other possibility is your timing could be somewhat off - double-check that. You *have* to set your timing with the engine idling around 750 RPM or so.

Dale

Piranha

did that too, with the jumper, below 1000, with a timing light.

scathcart

and you checked the timing on the trailing plugs as well?

zyounker

What is the heat range on your leading plugs?

Piranha

I did not run the timing light on the trailing plugs unfortunately. My timing gun is on the other side of Michigan, in Novi, and I'm going there Friday. I'm going to check them then. And put new plugs in.

The heat range is whatever the stock NGKs are. 7 and 9s?

Piranha

So is there anything bad about just running with the Leading coil? other than not seeing your RPMs? I'm going to try to fix it this weekend, but I have to make the 120 mile trip home first.

SaabGuy

It may misfire and smell a little worse but if you gotta do it then hell... I would.

Or get a tow.

Piranha

it hasn't misfired yet (actually runs better) . Tow? no thanks

Turbonut

iTrader: (1)

Question-When you took the car out for a test drive with the trailing wires off, did you take the engine up slowly, or did you jump on it? Just wanted to see if you really got into it if the problem wasn't there.

Piranha

I did both. Problem wasn't there? Hearing knocking, pinging, whatever it is went away after I disconnected the trailing coil. Now I only disconnected the 2 wire plug on it. But apparently it disabled it.

RETed

A recent thread popped up claiming that misadjusted/bad TPS reading can mess with the trailing ignition...

Check the TPS?



-Ted

Piranha

Update..

Well, I changed the plugs, got out the timing light, initial set jumper, RPMs below 1000. They are about 750 now. L1 and L2 are on the yellow mark. T1... I don't see any marks on the pulley. T2 is RIGHT on the red mark. Yes, T2. I trace the wire, yep, T2. I swapped T1 and T2 on the motor, engine starts better, revs without the detonation sound, and sounds excellent.

So what happened, or what is wrong?

Thanks

Piranha

I swapped a coil and an ECU, and nothing changed. I wondered if something happened to my crispy harness when I moved it around, but the harness that goes to the coils I didn't really touch.

Anyone know of a way to troubleshoot this?

DaleClark

iTrader: (55)

Is the timing light flashing when you have the gun on T1?

Also, just to double-check - T1 and T2 are stamped into the plastic on the coil, and you're referring to them as such, not just by what's near the front of the car or whatever. Right?

If both plugs are firing, but #2 fires like #1 should be, just swap the plug wires and call it a day. Your timing and select signals must be getting crossed somewhere or something is weird. Anyhow, if it seems to run right and doesn't detonate, then you should be cool.

Dale

Piranha

Yeah, I am looking at what is stamped on the coil. T1 does flash. I was going to try something RETed suggested and put some white-out on the other side of the pulley, 180 degrees from the red mark. Yeah, hopefully it doesn't re-cross. I just don't understand how this could happen :|

RETed

On the off-chance this could've happened...

The T1/T2 are actually plastic covers and are easily switchable.&nbsp I dunno why anyone would do this, but it could be possible someone switched them???


-Ted

Piranha

The covers were fine.

Magically, the problem has dissapeared. I took a CAS off another car, put it in mine, set the timing, and I had the same problem as before. I swap the CAS back and we go out to get some coffee (late night swapping front clips) and I hear some pinging. I'm like wtf.... Well, I don't want to mess with it because it is 30 degrees, so I drive the 2 miles home very slow. This morning I get out the timing light, hit the leading coil, perfect. hit T1, (which is going to the T2 plug) and the mark is there. WTF?!? hit the T2 coil going to T1 plug, and the mark is gone. WTF?~!?!?!??!? It switched back?!?! Yep.... so I shut it down, swap the wires, and its been running ever since.

Now I just carry my timing gun everywhere I go in my inner jacket pocket (ask FreedS4).

If anyone has any insight on why this happened, I'm wondering. My guess is dirt in the connectors, but who knows.

My car is great!