Erratic Timing all cylinders

[Fl_Richard]

One of my two 1995 150s has a sneeze at idle it's power output at WOT is not what it should be.

While diagnosing things I hooked my modern inductive timing light up to it. And noticed the light flashes were not evenly paced as youd expect. I first blamed the timing light. Then I hooked it to my car and it flashes regularly. So I reconnected it to the engine and again erratic flashes on all wires. So I hooked the light to the twin engine and it flashes regularly.

So for sure I've got erratic timing on the engine. How do I diagnose and fix this.

PS this engine has the Optical Ignition System (OIS)

Thanks in advance

Richard

 

[ezeke]

Re: Erratic Timing all cylinders

Best bet is the CDI Electronics Troubleshooting Guide.

Go to: http://cdielectronics.com/

Then navigate to "Downloads" for the Troubleshooting Guide. It is a large pdf file, so be patient; works quicker if you right click and save it to your computer.

 

[Fl_Richard]

Re: Erratic Timing all cylinders

The culpret WAS the timing light. When clamped on the plug wires results looked erratic. If I clamp the pickup right on the sparkplug boot the results are what you would expect.

The troubleshooting guide is a nice tool too . Thanks!!