whorider

Ok its an S5 NA streetport. Just got a little over 1000 on rebuild. I never really tried too set timing to a T until I got about 950 miles on it. I finally got the idle down under 900. Set timing and replaced plugs(NGK's). Now I've got a detonation issue only under heavy load over 3k rpms. I have checked timing about ten times. Switched back to old denso plugs. Restabbed CAS with top plate off to watch gears, because I was suspecting maybe my timing light was screwed. And reset timing, again. Still have detonation. Any help is greatly appreciated.
One more thing. How do you adjust the gap on our plugs? Or can you?
P.S. Yes I searched , alot.

quasar

Try to advance your timing a bit more, if you have a stand alone watch your tables and make the adjustments where needed, if it's N/A cut back on your split, if it's turbo add more split.

whorider

Isn't advanced timing what causes detonation? What do you mean cut back on your split?

rx7vadim

how do you know its not lean?

slo

iTrader: (1)

are the trailing plugs firing out of phase?

NA's won't usually detonate just because they are lean, heavy detonation under load is most likely an ignition issue

whorider

Wideband. AFR is around 12.5 give or take a little, when this occurs.

whorider

Yeah I checked trailing firing, its on the mark.

Oh yeah, I thought I should mention it is really hard to start cold, and fine when hot. It use to start great hot or cold.

Today I'm going to try another timing light.

arghx

iTrader: (3)

what makes you think it's detonation? Are you actually hearing a thunk or tink sound? I NEVER detonated my n/a. I advanced the crap out of the CAS at one point, ran 87 octane, and made 172rwhp. In fact I only detonated my T2 (which in hindsight needed bigger injectors and ran 13 AFR(!) under boost sometimes) when I spiked 20psi in cold weather...

slo

iTrader: (1)

disconnect the trailing coil and drive without the trailing, see if it still happens.

K-Tune

iTrader: (26)

what are you doing for oil injection? stock omp? premix?

slo

iTrader: (1)

What I am saying is not the the trailing is zero'd but that it could be out of phase. Trail cannot fire waste spark, and with a minor wiring mistake it will fire front rotor trail when its supposed to fire rear and vice versa, this will destroy and engine.

Also if your solution for your ecu involves waste spark firing of trail (firing both trail coils all the time like the leading) this will also kill an engine same as the above.

its also easy to make the mistake of reversing one or both lead and trail plug wires.

My suggestion still stands, disconnect the trail coil, check the plug wires to make sure they are hooked up properly and try the car again.

rx7vadim

what type of wiring mistake can be made? That scares me, i ran no trailing before, seemed like it hurts low end power only.

slo

iTrader: (1)

Reversing the trailing plug wires, actually what I was thinking of is not a wiring mistake, but a mistake in either stabbing the cas or setting the timing within the ecu's configuration options (standalone only obviously). Basiclly if I go into my standalone options and change the trigger angle by (either 180 or 360 degrees not sure which off hand) running waste spark then the lead will still be perfect but the trail will go out of phase. I did this when I first setup the haltech, this is why you always check timing of the front trail coil.


If running discrete trailing igniter's (like the stock FD) rather than the stock mazda (toggling) trail igniter then switching the trailing coils signal wires has the same effect as reversing the trail coil plug wires.

whorider

Ok I rechecked timing with another light, its right on with both lights. I disconnected the trailing wires and drove it. No detonation with them unplugged. Though it backfires a bit and chugs on bottom end, but, no detonation noise or power lose. I know the trailing wires were hooked up right. It's idiot proof with T1 and T2 on the igniter and the rotor housings.
So what does this mean my ECU is send random waste spark signal? Trailing coil pack is screwed?
Arghx.......I think its detonation because of the sound and lose of power during occurrence.

whorider

Bump.........Anyone.......Why would (trailing)waste spark be causing detonation? I'm running the stock ECU.

slo

iTrader: (1)

For some reason myself and others reading your thread thought you where running some kind of after market ECU.

download the factory wiring diagram out of the FAQ section of the forum, use the section that explains pin by pin what each pin on the ecu is for, in combination with the section that explains the coils

What you need is most likeley a new trail coil pack, (really just the ignitor) its most likley fine to get a used one, but first take the one you have apart and check for resistance between the toggle wire (might be called coil select in the FSM) and the pin it goes to on the ecu. You will need to unplug the pin from the ecu. If there is too much resistance try cleaning the connector to the trail coil (the larger 4 wire connector), also make sure that the toggle select wire isn't just grounded maybe to the firewall (real unlikely).

What can happen, is 3 things:

the igniter can just go bad (most likely)

or the wire or connector could be bad (less likley, unless there was an engine /wiring fire)

the ecu could be bad

The way the stock trail coil works, is that it has a single signal input wire, a toggle wire and 2 outputs. If the toggle is pulling to ground and the signal wire fires off then the igniter fires the #2 trail coil,

if the toggle is not pulling to ground when the signal wire fires then it fires the leading coil.

So what could potentially happen is the ecu goes bad and just fires on #2 constantly never firing #1, which means it firing #2 when it should be firing #1 (cause of detonation on rotor #2). Same thing except, it never provides the toggle signal or the wire or connection is bad, then it only fires number 1, again detonation but on rotor 1, same thing happens if the toggle circuit goes bad in the igniter itself (usualy goes bad firing only #1).

It could also be intermittent with any of these problems like any electrical issue.

Until you get that fixed just drive around on the leading only, you can advance it a little to make up for not having the trailing, you will only be down maybe 8 HP

whorider

Thanks alot slo. I will start troubleshooting as soon as the rain lets up. For the time being I'll run on leading coil only advanced 10 degrees.

rx7vadim

im dieing to see dyno difference with trailing and without. I bet it will be like 1-2 whp loss . Toss trailing to the garbage, im running leading on msd 6a only.

rx7vadim

Tralling makes difference at low end.

specialop

I think slo is correct. I was having detonation and power loss issues also. When I disconnected the tachometer signal clip(a two prong white clip) off the trailing coil pack the engine would run pretty well. The tach would not work at this point. So today I just swapped the wires on the trailing coil pack and now the tach works with no detonation or power loss. That's a simple wiring mistake.

whorider

Its seems to make a big difference on mine. Though I have no aux. port sleeves. Stupid previous owner. Also I get backfires of sorts on heavy acceleration with no trailing spark.

Anyhow, I need some help on diagnosing the toggle of the ground for the signal wire. I can't seem to find anything in the FSM.
While messing with trailing coil wires, I noticed that spark is coming from both. Is there a condition where both will fire, just out of time?

whorider

I'm confused about this. Could the detonation be the leading firing when the trailing is supposed to?
Or is that a default where it just runs off leading and won't fire trailing?

slo

iTrader: (1)

No, insert #1 trailing coil, where I put leading coil. That was a typo.

What I was saying in summery is that if the toggle isn't working than the trail will fire out of phase every other firing event.

whorider

Update
Got a used coil pack to swap, same issue. I have hooked up timing lights to both trailing wires. The #2 fires normal, while the #1 will skip a fire pretty regularly. I switched timing lights around just to make sure it wasn't a timing light issue. Still #1 skips firing. So this means it isn't toggling to ground.
Where is this ground at?
It could be the computer?

I should have sometime this weekend to mess with it. Thanks for all the help.
On a side note, running on just leading plugs SUCKS!!!!!!!!!!!!!!

arghx

iTrader: (3)

could a bad CAS/bad CAS wiring cause this problem?