High RPM Backfire when fully warmed

[TT5.9mag]

I’ll just drop this here for reference

 

[mygasser]

and don't forget to use an 'e-core' ignition coil with that gm hei module too.
neil.

 

[MOPAROFFICIAL]

I think these are all great suggestions but I don't think the ignition design is the root of his problem.

 

[TT5.9mag]

and don't forget to use an 'e-core' ignition coil with that gm hei module too.
neil.

I use an MSD blaster 2 designed for 12volts. Works great. Looks stock.

 

[TT5.9mag]

I think these are all great suggestions but I don't think the ignition design is the root of his problem.

Yea. Testing will answer all the questions I think. I will say this, Ive seen Chrysler boxes do exactly what he’s describing except for the hot/cold anomaly.

 

[Newbomb Turk]

Yea. Testing will answer all the questions I think. I will say this, Ive seen Chrysler boxes do exactly what he’s describing except for the hot/cold anomaly.

Yup. Me too. I just had a Mallory Unilite burn me. I’ve had them fail and quit and just not work, but never have I had one warm up for 12-15 minutes and quit. And then start 45 minutes later.

That one drove me nuts.

 

[TT5.9mag]

Yup. Me too. I just had a Mallory Unilite burn me. I’ve had them fail and quit and just not work, but never have I had one warm up for 12-15 minutes and quit. And then start 45 minutes later.

That one drove me nuts.

Yea that’s maddening. I’ve had a coil do that. And it tested perfectly fine hot or cold. But would quit working when hot.

 

[TheGrimSpeed]

Problem has been fixed! Installed the MSD unit and boom! She rips pulls to 6000-6500 no misfire at all!

Thanks everyone for everything!

I got the unit for $110 bucks on eBay thru Holley refurbished units, they have them on there for $134 obo!

 

[Swinger 340]

Okay, so I guess there’s my issue. Not sure on installed height. I just had bought Hughes locks and retainers and those 901 springs and gave them to the machine shop to slap them together. So I’m probably going to have to pull the heads it’s crazy that I been running the car like this for a while now.

Another question Hughes 1110 springs would be the cure for this? How much more lift would these handle just in case later down the road I install a hotter camshaft?

You don't need to pull the heads to install springs. You just need an air compressor to keep the valves from dropping. Just a thought. Is it possible your oil vis is not high enough or dropping while heating up? Causing the miss only when the motor is heating up, thinning the oil.

 

[TheGrimSpeed]

You don't need to pull the heads to install springs. You just need an air compressor to keep the valves from dropping. Just a thought. Is it possible your oil vis is not high enough or dropping while heating up? Causing the miss only when the motor is heating up, thinning the oil.

Hey! That a good thought! But the problem was solved it was my ignition system