Rough Idle and Electrical Problems.. HELP!

[TS87FC3S]

Other update with brake booster unhooked and both sides blocked off car stills trys to die when u hit the brakes.. Also I can run it on either rotor and it runs smooth no hiccups or anything but hook up both rotors and it has a bad miss I'm completly lost

[RETed]

Compression check?


-Ted

[TitaniumTT]

Originally Posted by TS87FC3S

Im using the car for AutoX, Drift, as well as dd. im used to race cars and the positive engagement of the clutch and highly prefer that feel, and i want the holding power so that as i upgrade stuff and get more power the clutch will hold.

The only upgrade that would warrant a 6 puck on an N/A would be low comp rotors and a big ass turbo. If you want a 6-puck for the feel, fine, but an N/A doesn't make the kind of torque that warrants it.

check the voltage at the coils

[TS87FC3S]

Originally Posted by RETed

Compression check?


-Ted

I did a poor mans compression check turning it over with the plugs out and it sounded great, im doing a real compression check tomorrow, along with another vaccum check, and ignition system check..

[TS87FC3S]

Originally Posted by TitaniumTT

The only upgrade that would warrant a 6 puck on an N/A would be low comp rotors and a big ass turbo. If you want a 6-puck for the feel, fine, but an N/A doesn't make the kind of torque that warrants it.

check the voltage at the coils

The clutch came with the car as I said and I love the feel I know that it is way overkill.

What should the voltage to the coil be?

[TitaniumTT]

Withen a few percent of what it's at coming off the alternator. If the current is too low the coil can't fully charge and as the RPM's increase etc etc etc

[My5ABaby]

You can also check the resistance of the coils. I believe all 3 should be 1.0 ohms or less (FSM has it so check in it).

[TS87FC3S]

ok so i tested coils all showed fine , so i hooked it up to ignition scope i found that my trailing wires are bad so i unhooked trailing and ran just leading to see if same issue, of course same miss, ignition scope looked good... so i hooked up timing light, timing seemed fine... but while i had it hookep up i noticed that one one of my leading wires the signal would drop out with the miss so i put timing light lead next to coil, and found that one side was randomly losing fire, how this is happening i have no fin clue at all.. im hoping this was the issue but not sure if this would cause my dieing at stoplight issue. my buddy has an s5 thats gonna let me use his coil and wires so if that fixes it i know what im gonna need if not ill update... any idea on the dieing at stoplight???

[RETed]

Originally Posted by TS87FC3S

but while i had it hookep up i noticed that one one of my leading wires the signal would drop out with the miss so i put timing light lead next to coil, and found that one side was randomly losing fire, how this is happening i have no fin clue at all.. im hoping this was the issue but not sure if this would cause my dieing at stoplight issue. my buddy has an s5 thats gonna let me use his coil and wires so if that fixes it i know what im gonna need if not ill update... any idea on the dieing at stoplight???

That's normal.
The stock ignition system cannot handle constantly firing everything properly.
(This is why we run CDI boxes to "fix" this problem.)
It's not the cause of your problems, unless it's triggering a larger problem down the line...


-Ted

[TS87FC3S]

Originally Posted by RETed

That's normal.
The stock ignition system cannot handle constantly firing everything properly.
(This is why we run CDI boxes to "fix" this problem.)
It's not the cause of your problems, unless it's triggering a larger problem down the line...


-Ted

only one side of the coil is dropping out and this is happening at idle.

[RETed]

Originally Posted by TS87FC3S

only one side of the coil is dropping out and this is happening at idle.

That is correct.


-Ted

[TS87FC3S]

"When the pulse switches from high to low, the igniter turns off the current in the primary leading coil winding. Since there is only one leading coil and there is no spark distribution, both leading spark plugs are arced. Obviously, one spark is wasted but with no ill effects."

This being a wasted spark i still do not see how one side of the coil "drops off" and then just starts working again, both sides of coil recieve the same signal and spark.. so im just not seeing how this is normal?

[RETed]

To understand what's going on, you need to understand the dynamics of wastespark ignition...
Most people understand the part about a dual tower coil firing into two "chambers" at the same time, but it's what's happening on the spark plug end that makes it interesting.
A spark plug firing into a compressed chamber requires more power to overcome the (spark plugs) gap - as compared to firing at "0 atmosphere" or outside of the engine.
Add fuel into the whole mixture (no pun intended), and it gets even harder to fire.
A spark plug firing into a chamber that has already ignited is surrounded by ionized gases and particulates (combustion by-products) that helps the arc jump the gap.
Add to the fact that the later scenario is usually at the tail end of the combustion cycle (and starting into the exhaust cycle) which means that pressure in the (compressed) chamber is starting to drop at this point.
Less pressure = easier for the spark plug to fire

Now, let's look at the wastespark, dual tower coil...
It's just a step-up transformer with the two tower (outputs) coupled.
Fire voltage through the low side, and it gets stepped up by the coil depending on the ratio of the windings.
Now, the coil can fire either:
1) tower 1
2) tower 2
3) both towers
Most of the time, it does fire through both.
When it doesn't have enough power, it tends to fire only one side.
Now, remember earlier about the imbalance of the chambers?
Guess which side it's going to fire if it had to pick?
Due to this phenomenon, this is why the coil drops one side occassionally.

rising chamber pressure + fuel = increase resistance to spark plug arcing the gap
dropping chamber pressure + burnt gases = decrease resistance to spark plug arcing the gap

This is why a totally stock ignition FC will sound like this when idling...

brrrrrrrrrrrrrrrrrrrrrrrr, brr, brrrrrrrrrrrrrrrrrrrrrrr, brr, brrrrrrrrrrrrrrrrrrrrrr

Even with the car in top shape and running perfectly, the wastespark is still dropping a spark every so often.
That small hiccup is an ignition misfire.

Partially to blame is the inadequate electrical charging system in the FC.
The stock FC alternator SUCKS.
At idle, the alternator is barely producing enough voltage to charge the battery.
Once the RPM's climb, this isn't much of an issue, so you don't get misfires above idle speeds.

We fix it by installing CDI boxes which totally cures this "problem".
I run a Crane Cams HI-6 myself.
I usually install CDI boxes in all my customer's cars.


-Ted

[TitaniumTT]

I'm really curious to see what the dyno tells us when I test all the different ignition systems. To me, a CDI is just a band-aid for a near stock car but what I believe to be the better answer isn't possible with the stock ECU. While I completely agree with what you're saying Ted, I think a 4 coil system would be a better way to go than putting a CDI box on. The slow rotor speed, I would think, would want to see the slow burn of an inductive coil.
Personally I was running 4 D580 (LS1) coils and never had a hiccup at idle...... except when I wet fouled the plugs once after rebuilding an engine. Those coils I believe are inferior in the higher RPM/higher boost just becuase of a lack of ignition energy. Voltage not being an issue as my alt pumps out 14V @ idle.
Now get to combustion pressures higher than what I'm making and a CDI might give more of a benefit.

[TS87FC3S]

Ok now that helps alot thanks, would runnin a different wasted spark coil help?and mine actually charges at 14.4 at idle not that it really matters... If it not the coil then y would I lose power over 6k and last nite it happened at lik 5k. It happens worse the longer it's been running.