Ignition Problem (Please Help)

3rd Mini Stock I have built, never had this problem before. Have TFI distibutor, have rewired car several times. Problem is tachometer bounces around at high rpms (6000 - 7000) but I do not feel or hear a misfire. If I connect the alternator or timing light to the system the car automatically begins misfiring at all rpms. Have changed distributor, ignition module and rewired car according to appropriate wiring diagrams. Have also checked and added all possible grounds. Tachometer is new autometer tach purchased this season. Have been chasing problem for weeks and can not find issue, please help!!!

Had this exact same issue a month or so ago. Had to switch from an MSD box to a TFI and every time I would pull the trigger on the timing light it would go to missing. I could run the timing light from another battery source and it would be fine. I finally narrowed it down to the starter solenoid. I had run a battery cable to the solenoid and then had run all of my switches came from the solenoid. After I unhooked all the switches and hooked them straight to the battery the miss went away. But about a week later the solenoid started to hang up. I replaced it with a 100% duty cycle one and have had no more problems.

Thanks for the input, i will try throwing another solenoid in the car however my switches are already wired directly from a 200 amp on/off switch. I only have a power cable going from on/off switch directly to the solenoid.

Have you tried a different coil.Most problems I have encountered with the tfi have been either the coil or the tach.

I have tried another coil and the result was the same. I have not however tried another tach. I am beating my head against the wall with this thing.

I've seen this happen a few times. Snap on lights *the digital ones* are bad about fouling the ignition. Unhook your tac from the coil and see if the timing light still fouls the ignition to miss. Have you cleaned your plug wires with anything like WD40?

I am using a snap on timing light but not a digital one. I have unhooked the tach from the coil and the miss is still there. I have also tried another set of plug wires with same result. Right now I have my alternator unhooked because as soon as I connect it the engine misses. It seems like any extra draw I put on system (alternator or timing light) it misses. If I power the timing light with a battery sitting on floor instead of power from car it works perfectly fine.

Have you tried a different battery of had yours tested with a load tester?

Is the primary ground on your battery a good one to the frame. sometimes all the grounds on the engine arent enough if the main ground is bad or loose. Had this happento mine. As soon as you try to add any load other than idle, it will act up. When you hook your timeing light to a stationary battery off the car, you and drawing only fromthat batt. Not the one on the race car. Check it out. run your primary ground directly to the frame. If it alreay is, then check it anyway.

Dan

Hey Dan,remember that miss we fought all last year? we changed EVERYTHING...including the fuel cell,EVERYTHING got replaced with brand new items...and it was baffling because the stuff we took off would work fine on the other cars with no issues....well,2 weeks ago we found that son of a b**ch...it was that pretty black and blue Esslinger cam gear...it wasnt machined correctly so the center,even though the 5 bolts were tightened down..was advancing and retarding itself.

Erick, a lot of racers are finding that the little pin on the cam that fits in the cam gear slot wears a lot and pretty soon the slot is worn loose. some in the pro 4s are machinging the gear for a keyway, and also the front snout of the cam . It fixes that problem. that little cam pin works fine on the steel gear but wear on the aluminum gear especially at the rpms they are turning. Doesent happen all the time, but some guys have reported it. I have personally seen one do it. .

Dan.

I have changed the battery, rechecked all the grounds and still same issue. My engine builder claims he checks the cam gears for just that reason but i am going to double check it myself. Thanks to all for your great suggestions, i have looked into most of them. Still chasing the problem, I know its gonna b something stupid.