Engine won't fire at all with new electronic dizzy and coil

[ricky8664]

Thought it best to create a new thread on this. Cannot get the engine to run at all with the new electronic dizzy coil and leads.



My mechanic and I have spent 6 hours fitting the new dizzy (and re-fitting it) and trying to get the car to start.. Doesn’t even sound as if it wants to fire apart from one almighty backfire that literally exploded the front silencer.





Checked that the dizzy is timed in the correct place by No 1 cylinder & there is petrol getting to the engine.





We are getting one thing that does not seem right. With the ignition switched on we are getting 12 volts at the + terminal on the coil (from the ignition switch) which I did expect. However we are not getting 12v across the coil (i.e. between the + and – terminals. Only getting 0.8v there.





However, we are getting 12 v between the + terminal on the coil and the output (HT) lead from the coil. And this is just with the ignition on, not cranking. Seems like a short within the coil.



Fuel is being delivered BTW. It would not even start with go juice squirted into the carbs, which is how we got it to fire up when first starting the engine last spring. Absolutely dead.









Having taken everything apart twice and re-connected , we took all the spark plugs out and then tested them in their respective plug leads against a good earth.





All of them were producing a very good strong regular spark. However, in between the strong regular sparks, each plug was also producing repeated small sparks at the electrode several times between each big spark. I have never experienced that before. Usually only get the big regular firing spark.




Next time we will be substituting a good coil. But I also think it may be the new electronic dizzy that is faulty.





BTW we have also checked the compressions. Whilst a couple were down at 130psi, most were between 160 and 180 psi, below the stated 180 to 190 psi on a good engine, but still not so low as to prevent a start.





And as I said, it has turned over without even trying to fire or sound like it wanted to run apart from the exploding silencer incident.



I have written to the supplier with the problem but have not yet heard back.



Any suggestions?


If the known good electronic coil does not work, we will take off the rocker covers to make sure all the valves are moving, in case the massive backfire did some internal damage, though we have already used one of those borescope cameras to check the cylinders and could not see anything obviously wrong. And the engine sounds normal turning over.

If that doesn't work, might get my old dizzy rebuilt as an act of desperation.

[Mike’S-a-loon]

Sounds like the dizzy is 180degrees out of position.

[ricky8664]

I was hoping it was something simple like that, but it isn't.

When we crank the engine with the timing light connected to No. 1 lead, it lights up the crank pulley right on the timing marks.

[enigmas]

In the initial outline of your problem you haven't listed the mechanical specification of the V8 Rover engine in the car. Is the engine a standard configuration early SU carbed 3.5 V8 or a Rover V8 engine from 2006 onwards.

From reading your post and the current dilemma you state you have a mechanic working alongside to help sort the issue. It shouldn't be this difficult for an experienced, professional mechanic to sort this simple ignition problem on an engine and fueling system as basic as a Rover V8.

I'm presuming you checked the following but it's worth looking at again if the ignition problem still remains.

A few pointers/checks to ensure that ignition takes place on the appropriate cylinder at correct time.
Early 3.5 Rover V8 engines have a firing order 1-8-4-3-6-5-7-2 and the later post 2006 Rover V8s have a firing order 1-2-7-3-4-5-6-8. (This depends on the engineered camshaft timing.)

Have you checked the direction that the distributor rotor rotates when the engine is cranked over so that the firing order is in the correct sequence?

Have you removed the rocker cover above cylinder 1 (RHD car, the cylinder bank on the passenger side) rotated the engine to confirm that both the inlet and exhaust valves are closed (fully up) and that the the piston is at TDC. Remove the spark plug and check the piston location with a screwdiver through the spark plug hole.

Reference the above against the existing timing marks and pointer. It should be close to TDC or near enough for it to position the distributor rotor button at terminal No. 1 for the engine to start.

Note: Once having done the above.
That whatever clock position the distributor rotor button is pointing to is the terminal on the distributor cap that becomes number 1 cylinder firing.

If nothing else is askew the engine should fire and run. Once running you can adjust the timing to optimize it. Use a vacuum gauge connected to manifold vacuum to optimize the timing (your mechanic should know how to do this) and then check the existing timing marks with a strobe light to see what is confirmed. You may be surprised.

Good luck.

Link
nerdycar.com/firing-order-rover-v8/

[ricky8664]

After more than two months (on and off) of trying to start the car with its new electronic dizzy and coil and HT leads, I finally bit the bullet and bought a recon standard points dizzy from JRW last week. My mechanic came round this morning, removed the electronic dizzy (again) and coil, and fitted the recon points dizzy and my old coil. With just basic points gap setting and static timing the car fired up 2nd time. After it had warmed up we set the timing and dwell angle electronically and balanced the carbs. Now starts 1st time and runs fine.

Its a bit noisy as the front silencer exploded when we tried to start a few weeks ago with the electronic dizzy. And I do mean actually exploded, splitting it open!

I have contacted the seller for a full refund. He may well winge about wanting to test the unit before giving a refund but the simple fact the car started second turn with the reconned standard dizzy proves either his dizzy and or coil and or instructions for installation were defective.

I'll update here if the seller proves reluctant to provide a refund so others can avoid them.

At least I can continue with the resto now!

And I would like to express my thanks to JRW for the speedy way he got the new dizzy to me.