Hello folks, So i have a small problem well maby its a big one. I've recently converted my 1972 c10 402 BBC over to TBI, I'm burning my own chips, ect, ect, truck runs but ive discovered 3 dead cylinders < the not so small part of my problem! Prior to the swap everything ran well except the ever to often flooding Q/j. So my question is > does anyone have a idea on what may kill three cylinders in elctronic controlled ignition system? Rotor and cap are not new but look good, module tested ok at the parts store, I replaced the pickup coil, new wires and plugs. There is spark to the plugs but it is very speratic, the way I know the cylinders are dead 1,7,8 is the header tubes are cold over those cylinders. Im trying not to through parts at this problem. BtW compression is good on all cylinders and valve train appears to be ok no strange sounds or movments.. I'm leaning towards module or maby distributer "ebay" is worn out? Sorry for the long read

 

Got a spark tester? If not, you should invest in one. The HEI version is what you're looking for, although some spark testers have an adjustable gap.

This is the sort that I have.

http://www.amazon.com/KD-Tools-2756-...=2VLYZKC3HBBDO

Find out if the plug wires to the dead cylinders have spark--strong enough to fire across the spark tester. If they do, the problem is fouled plugs, non-burnable air/fuel ratio, or low compression.

If they don't have strong spark, the problem is bad plug wires or issues within the distributor including a defective cap.

 

a new cap and rotor are cheap. i would replace them first. then check the firing problem. or you can pull the plugs and check the porcelain. if they look good swap them to another cylinder. then retest.

 

Thank you for the response guys but found my problem, brand new spark plugs where bad 3 of em, replaced the three dead cylinders with some old plugs i had and bamm the engine woke up...Never had bad plugs out of the box before but changed them with the swap... Go figure

 

glad you got it.