Coil Pack Gone?

[Slomove]

I am having trouble with my engine for a week (Zetec ZX1, Ford Contour US version on carbs with Dunnell ECU). It happened suddenly while driving:

- Start, idle and low revs are somewhat O.K. but does not go beyond 3500 rpm when floored driving, creating a burbling and choked engine sound and a hell of a racket from violent exhaust explosions.

- Camshaft timing is o.k. as well as compression

- Carbs are synchronized, jets are cleaned and fuel pressure is o.k.

- Plugs are fine at low revs but begin to blacken in the problem rev range.

- Sparks are present when cranking in the open

 

However: I checked the coil pack and secondary resistance is 11.4 kOhms (cylinder 2+3) or 14.8 kOhm (cylinder 1+4). That shuld be 12.8-13.1kOhms according to the book. Can that be the root cause? Would not mind to get a new pack but only if it makes sense.

 

Thanks for any feedback and if you have other suggestions what to check for PLEASE let me know!

 

Gert

 

Edited by - Slomove on 18 Oct 2003 05:44:08

[Slomove]

Never mind the previous post, that wasn't it. Swapped ignition cables

and coil pack and still the same trouble. Somebody needs a coil pack?

 

Noticed someting else: The digital rpm reading of my timing light display (inducive clamp-on type)

reads sometimes double the actual value and is quite unsteady. Maybe

there is something wrong with the Dunnell ECU, after all. I will hook up a scope to the coil drive next week.

 

Still looking for opinions or other help, though.....

 

Gert

[ChrisC]

I suspected a coil pack during a recent spell of bad running. I turned out to be my ECU (a know problem with MBE 906 units) I am not saying this is the case for your setup, but my testing method might help.

 

Assumption first.

You have three wires to your coil pack, +12v ignition, and a wire for each pair to the ECU.

You have check for poor connections on the ignition circuit, and in particular the two wires from the coil pack to the ECU.

 

The Test I used.

Use an analogue volt meter, or dwell meter on the coil pack lead that goes to the ECU. Engine not running +12v, engine running less as the revs rise. If you see +12v while the poor running is occurring on one coil pack wire to the ECU and not the lower voltage, I would suspect the ECU.

 

This is what happened to me, and how I tested it. I replaced my ECU and the car is now running better than ever.

 

I must stress this is only a test procedure, because my engine, ECU etc etc is completely different to yours

 

Hope this helps.

 

 

Chris....

H15 SVN Get it !