Author Topic: Prob with waste spark setup on V8  (Read 6497 times)

Offline NOTORIOUS VR

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Prob with waste spark setup on V8
« on: August 26, 2010, 09:29:10 am »
A little background,

it's a Porsche V8 with a 60-2.  Running 1.1.74 FW.

It was running a single coil w/ a dizzy.

We upgraded to 4 dual pole GM coil packs for a waste spark setup, but I cannot for the life of me get all cylinders to fire.

Under the setup with the dizzy, I had to enable all 8 ign outputs configured as the same physical output and set the trigger ref table as: 0 15 30 45 0 15 30 45

Now normally my 6 cyl waste spark setups are 3 ign outs and the trigger ref table is: 0 20 40, so I followed that scheme with the V8 and enabled 4 ign outputs, configured the pins/outputs and changed the trigger ref table to: 0 15 30 45. 

It sounds like one or two cylinders are not firing at all or very much @ the wrong time.  I'm getting popping in the exhaust.  I have also tried reversing the ign outputs and obviously get nothing but backfires.

What am I doing wrong or missing here.  It was running with with the dizzy.  This should be straight forward to me, but I'm guessing something isn't right with the trigger ref table.

Offline mattias

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Re: Prob with waste spark setup on V8
« Reply #1 on: August 27, 2010, 12:29:39 am »
Just repeat the wasted spark outputs twice in the ignition output table, all 8 ignition output events are used.

You must still define the entire 4-stroke cycle, so the ref tooth table is as you originally had it : 0 15 30 45 0 15 30 45


Offline NOTORIOUS VR

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Re: Prob with waste spark setup on V8
« Reply #2 on: August 27, 2010, 01:48:08 am »
Yepp tried that...

Ended up being 1 dead coil + 2 bad spark plugs (diagnosed today).... Buddy is gonna pick up a new coil and 8 new plugs

Offline MGV8

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Re: Prob with waste spark setup on V8
« Reply #3 on: September 04, 2010, 12:12:10 am »
Try upgrade to newer firmware, some of the old versions have problems with dwell control with noisy trigger signal.
I blow two coils on my Rover V8 with wasted spark setup – was using far too big fuse 20A pr. Coil! Changed to 7A fuse pr. coil and this was some times blown during start up.  Upgraded to FW 1.1.80 and problems was gone.
Running with 60-2 trigger
 
MGB Roadster 4.0 Rover V8 - Vems 3.2 firmware 1.2.11 60-2 trigger, wasted spark, modified SD1 inlet to clear bonnet
- with Rotrex waiting to be drop in when Vems is running

Offline NOTORIOUS VR

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Re: Prob with waste spark setup on V8
« Reply #4 on: September 09, 2010, 05:34:25 pm »
Can't say I ever had that issue... But it did end up being a blown coil (how the connections to the coil were made when my buddy connected them it grounded out and let the coil over heat) + bad spark plugs (2 or more were actually firing through the ceramic).

In the end, the car runs great now.  Also had to change the plug wires from crappy Taylors to MSD's because of crazy interference from the Taylor wires.