84mustang

well, he tried various spark plugs and the arc we really faint on all of them when he held it to the metal and all 3 agreed that there wasn't enough fire and they were rebuilding another 302 and showed me what it should look like and there was obviously a longer brighter spark. He said, "it's either the ignition module or distributor. I'm just wondering if it's the timing because again, he didn't use a timing light. Can you set the timing accurately without a timing light? Hope this helps, thanks for the help. I'm being as descriptive as I can and i know it's hard for you to diagnose here but thanks for trying.

mjr46

no timing can't be accurately set without a light... ned a light for that and the test they showed you isn't the most accurate IMO, BECAUSE STRENGTH of spark can depend on a few things like coil used and type of ignition box and also plug gap...if a gap is set at. 030 and viewed, spark jumping gap will look a lot smaller vs a view of one at .060 lets say, the conclusion they have arrived at based on the evidence they are using to support their claim has me worried because that conclusion can leave a lot of room for error and inaccuracy unless of course there was a strong noticable difference, without seeing it myself it'd be hard to validate their claim and accuracy, however a good technician would search for the misfire using an occiliscope and one who does will not go wrong, problem is alot of technicians who work on todays cars use the ecms diagnostic capabilities through OBD 2 TO PEFORM A DIAGNOSIS, on older cars where no computer diagnostics are availible to an extent vs newer ones the occiliscope is a surfire way to locate misfires expecially random ones, but you need to find a shop who has one and uses it and believes in them and knows how to read ignition pattern, I do such day in and day out....and if spark truely is weak try replacing the coil but using a dvom make sure you have 12v supplied to coil to saturate it sufficently, all the dizzy does is send a signal to the ignition box to trigger the coil on the proper cylinder in the firing order, and once the coil saturation is triggered the voltage is transfered through the cap to the rotor to the proper pin on the cap and through the wire and to the plug where spark jumps the gap

mjr46

P.S if weak spark were and issue and or is ,.....a firing voltage test viewed on the occiliscop would indicate low firing voltages all accross the board represented in KV, THAT'S HOW YOU CAN VALIDATE THEIR CLAIM

HACKGT350

wow he is good. when i worked at the lincoln mercury dealer i only saw one tech ever use a scope and knew how to use it too, none of the other techs new how to use them so never touched them which is pretty stupid. they are pretty easy to learn how to use...atleast i think so

Gary H

Double check all the ground wires too. Same with the connections from the module to the harness.