weak spark on two cylinders

[slide86]

im working on a car at the momnet with a hypo atmo engine in it. its not toyota but it may help others some day

its got haltech ECU running a waste spark system with single coil and a seperate CAS. quad throttles with injection before the butterfly and some other goodies.

the problem that we are getting is that its got a real reak spark on 3 and 4.

1 and 2 are strong, but its pretty crap on the other two cylinders. Its a pretty fresh engine, when it was first started, it seem to run fine, but now its got this problem.

Ive replaced the coil and the leads, narrowed the gap on the plugs. Im going to comp test it on the week.....

Just want some ideas or advice as to what you guys think may be the problem?

[stahlz_ae86]

I would have said leads but you've done that... hmmm?

Free bump.

[MWP]

Which cylinders are paired in the coils?

[Squid]

Is there a solid earth on the block?

[takai]

Also, what is the dwell time set to for the ignitor. Could be breaking down on consecutive firings.
Another thing to consider is whether the CAS is wired up properly.

It would be much easier if you were to give us a whole lot more specs, such as coil and ignitor type, ecu type etc.

[ra23celica]

its running a waste spark system with single coil and a seperate CAS

Tell me more about this single coil and waste spark set-up. I thought you needed a coil for every pair of cylinders 'joined' together in a waste spark system....

[takai]

Tell me more about this single coil and waste spark set-up. I thought you needed a coil for every pair of cylinders 'joined' together in a waste spark system....

The man makes a very good point.

[MWP]

Tell me more about this single coil and waste spark set-up. I thought you needed a coil for every pair of cylinders 'joined' together in a waste spark system....

He probably means its one single box containing the two coils for 4cyl wasted spark.

Wasted spark coils also do not need a good earth as the spark is not earthed through the coil mounts.

[takai]

But the engine needs a good ground, as the spark plug is earthed through the plug casing.

[slide86]

yeah sorry. its a single type system with dual coils on the same igniter. similar to the commodore V6 setup (minus 2 cylinders, ofcousre!)

initially the setup ran well, but no its got this problem. i am going to get a hold of a laptop and plug the ecu in to see whats going on. the guy who owns the car doesnt have access to a laptop. (doesnt help the situation!)

[takai]

Std firing order?