Can timing adjust itself?
 

I guess what was really confusing me is that my timing will change on its own. I adjusted the timing slightly retarded today (@about 800 rpms), took it for a drive and it began detonating. I came back and now my car was idling at 1500 rpm's, checked the timing and i was running about 20* ADVANCED. (and yes, i tightened down the CAS before driving )

Then while i still had my timing light on it, my engine rpm's suddenly dropped to normal idle and my timing went back to being a few degrees retarded... out of the blue.

I was thinking that my detonation problem was caused by a faulty leading coil, but now i think its something bigger...

How can the timing adjust itself?

i think S5s do that.....i am not too familiar on the subject.

S5 ECU timing curve starts at 1000 rpm, hence to adjust timng you have to adjust below 1000 rpm idle.

Yeh, you gotta remember the marks are gonna move on ya at other speeds- this is a good thing- the ECU does the advancing/ retarding for us :)...That, and rotary ignition systems seem to trip out our timing lights every now & then...

I ask because im having detonation even when i retard the ignition like over 8*. I retarded the ignition, took it for a drive and started detonating. I drove home, and checked the timing and i was 20* advanced with a very rough (vm-bla-vmmm-bl-bla-bla-vmmm-bla-vm) idle at like 1300 rpm or so.... then magically a few minutes later it changed right in front of my eyes, timing went back to being 8* retarded and idle dropped down to normal.....

Gotta keep in mind that when you're retarding the ignition thinking of what position the front rotor's in, the rear rotor is 60* different. And, since the leading plugs both fire at the same time, you might have the rear plug firing right as the apex seal is coming by, causing the detonation...Makes sense in my head- anyone else follow?

I feel you on that, but at 8* retarded (eccentric shaft rotation) the apex seal in the rear rotor should be nowhere near the spark plug. It takes 180* eccentric shaft rotation to rotate a rotor 60*.

Anyone? any sugestions at all... could my ECU be malfunctioning? Coils?

Checked the CAS, its working properly

You HAVE to set your timing with the engine idling BELOW 900, or the ECU will start feeding in timing.

The BASE timing of the FC never changes, but timing floats after that depending on RPMs, load, throttle, etc...

The timing was set below 900 the first time when originally retarded.

Another question is: (this only applies when starting the car whens its cold, or when it gets flooded) what would cause the trailing plugs to fire only for the first second upon startup then stop? I can tell because the car runs like ass, i have no tach reading (displays 0), adn when i put a timing light on either of the trailing wires i get no signal. If i turn the car off and restart it (considering it doesnt flood again) it will begin working. This only happens when its flooded, and very occasionally when its cold. I think that could very well be part of my problem, or a symtom of it?

Have you tried replacing the leading coil?

No, i havent replaced it yet. I just dont see how the leading coil could effect my trailing coil not firing sometimes.

On the subject i was planning on it because regardless, i think my leading coil is messed up on me.... The L-1 terminal doesnt fire consistantly all the time (sometimes it will fire on the initial spark and the waste spark, other times it will just fire on one or the other, or intermitanly fire both)

bump

I dont understand that only when my car floods my trailing plugs wont continue working. It will work for the first second after the engine catches, but then they will turn off.

Anyone please?

Have you read out the ignition "signal" voltages at the ECU? And the CAS inputs too, while you're there...

And the actual coil assy itself, I'm sure you've read that out by now, right?

And the 12v inputs to the coils from the main relay...

How are you testing these "alleged" misfires? Using an inductive timing light? IF so, thats your first mistake.

The trailing coils have a feedback system to the ECU. If the ECU does not "see" the coil fire, it will shut them down. Fouling the plugs (from flooding) could cause this.

-Henrik

He should be getting a CEL, then...

I think you nailed it, Henrik, I think he's drowning his plugs too...

I read a thread that since the 86-88 rx's dont have a CEL light, i have to build this thingy to be able to read if i have any codes being thrown at me.

Because of this, i havent checked to see if im throwing codes.
How would i got about "reading" these inputs? As well as the 12v inputs to the coils... just with any DMM?

Yes, it is a good quality snap-on with a built in tachometer. I know its still made for a piston engine, but regardless, the timing light when on the leading coil was stuttering and jumping around EXACTLY in sync with my motors stuttering, so i know the signal coming from my leading coil (most of the time the L-1 terminal) is mis-firing on me (i do believe, unless there is someting im missing)

i'm have the similar problem mainly in the rear rotor. i can start the engine and it shutters out of control then i can take the leading or trailing coil wire off of the coil and hold the wire close enough to the coil so that the spark will jump to the wire steady and the engines starts to clear up right away . but if i plug the wire back into the ciol it will start misfiring again.

Just having bad plugs can cause this? The coil doesnt send out a singnal regardless?

I have had the same problems with poor timing lights, thats why I switched to an in-line spark checking system.

My guess now is either your plugs are bad, or youve got a grounding issue.

Alrighty, will get new plugs asap. That should help with the bogging and flooding problem, but i dont think that will help out with my mis-firing problem.

Should i suspect a the leading coil or grounding? Is there any more info i can give to help you better?

Okay, so the basis of this is your getting detonation. Correct? Tiny Keebler Elves banging on your motor with hammers under boost?

So, lets get some more information:

Boost level?
Mods?
Any codes? (IE pressure sensor)