Timing light

[big moe]

Anybody else experience a abnormal rpm reading at idle with a MSD ignition and a digital timing light ? My light has rpm capability , and it is reading high at idle 3500-4000 rpm tach in the car is at 1200 . This is a unknown 6al box msd says its my light well it's not,my light checks fine on 3 other cars with the same ignition 6al .only difference is this car has a digital tach that is wired to the coil not the box . And the strobe light seams to be fast as well .

[cgarb]

Multiple spark ignition is messing with the light. Use a standard style light with the dial on the back or no dail and use the marks on the balancer. We had the same trouble with our snap on digital light. A Craftsman dial back light works fine.

[big moe]

My light I don't think Is the problem works fine on other cars with the same MSD ignition only this car does it do this '!!!!! All other car rpm matches the tach in the car !!! I believe there is a problem with the box was asking to see if anyone had a box do this before .

[tenxal]

My light I don't think Is the problem works fine on other cars with the same MSD ignition only this car does it do this '!!!!!

Had one do this with a MSD 6 after changing coils.

[cgarb]

Well you could always swap out the ignition box and see if the timing light is bad....

[Tuner]

Try it on a different cylinder and see if it still does the same thing. A bad plug wire will cause things to get confused. Number 6 should show the same timing as number 1. If there is a few degrees difference the error is probably because the distributor reluctor is offset and has runout.

[Tuner]

Different brands of plug wires have different resistance and that will affect the EM pulse the timing light induction pickup receives from the wire. Also, narrower or wider plug gap affects firing voltage, and so can influence triggering.

Have you tried it with the induction clamp turned over, reversed on the wire?

[MadBill]

To get my 50 year old Craftsman light to work on some cars, I have to add and clip onto a short length of non-resistance wire..

[big moe]

These are new moroso wires which I know don't mean much have used this light on these same wires on a different car I will try a different plug wire my timing mark is steady and where it should be . Is there a chance that the multi spark function of this box or something else in the box is going awry ?

[hoodeng]

I know i am talking about a brand you are not using but this may be useful to those that are ,I had similar experience when i bought my Snap-on digital timing light many years ago with timing scatter and sketchy operation when used on a highly modified ignition on a fuel bike ,and reported it back to Snap-on ,the reply was to dial it up a degree or two then try it ,worked fine after that ,we just factored the +2°into the final figure.

Cheers.