Mid-high RPM ignition cutout

[HALIFAXHOPS]

Ignition Coil or Orange Proform ECU Ignition Module

With all the Chinese aftermarket Mopar ECU Ignition Modules made today , honestly I can’t even recommend a decent replacement

But one or both of those are just about 100% your issue you are describing

NOS or older NORS tested ECU is your best bet. I can test them and also have some Mopar and NORS

How to tell a "fake" ECU from a real one

There are a ton of fake ecu's out there two easy wats to tell at a glance are the height of the transistor, usally the fake ones are around 3/8" high and a real one 5/16 or so. Another way to tell at a glance is if there is printing on the...

www.forabodiesonly.com

 

[vance.dykes]

i dont understand you go thru all the work of install your efi but the efi dose not control timing ?

 

[Bee1971]

I'll start with the ECU since ive had the coil for a while now and I don't believe it had this problem before I switched over to the electronic distributor + components...now to figure out which replacements worth a damn

Post 21

If you want to stay with that same distributor setup from Proform

Obviously there are alot better options
in regards to ignition systems to work with that Sniper System

Anyways
Talk with Halifaxhops

He will set you up with a good tested ECU and possibly a better coil matched with that same ECU Ignition Module

Great guy to work with

 

[HALIFAXHOPS]

I like the tester I use breaks whats wrong with a ECU like low dwell, bad low/med/high speed etc.

 

[Rchab]

The trace looks like it's on a rev limiter. There is no way a fuel issue could be that quick. I'd say you have a distributor or ignition box issue. Though I never discount the idea of a bad ground. In this case I don't think so. Doubt its a coil either. Why? Because it's rpm triggered. One other posibilty. The tach. Does it have a rpm limiter? As for the battery. 12.66 is 100% state of charge at 80 degrees F. If the temp varies so does the state of charge level. My bet is it's fine. See here
Doug


View attachment 1580608

Just ordered a new ignition box, hopefully that's all I gotta do. Kinda wanted to replace it anyway so I won't be too heartbroken when it doesn't fix it

 

[threewood]

i dont understand you go thru all the work of install your efi but the efi dose not control timing ?

I don't see the need unless the motor is boosted.

 

[Bird 426]

I haven't exactly heard great reviews of that Proform chinisium dist pkg.

 

[vance.dykes]

I don't see the need unless the motor is boosted.

when the big 3 started with fuel injection they tried many different ways to control timing and most failed and they did not perform with hall and crank /cam timing control it times the fuel injector with the spark. so ok no need to time events together.

 

[vance.dykes]

I like the tester I use breaks whats wrong with a ECU like low dwell, bad low/med/high speed etc.

View attachment 1580702View attachment 1580703

most dont think of dwell and is is still used in the systems today.

 

[O'l geezer]

I chased a 5k rpm miss on my 440 and after replacing everything I could I found 2 rocker arms that were too tight. Adjusted and all is good.

 

[Rchab]

Finally coming back to this thread. So I got the new Ignition box and no surprise it didn't help. I went through and temporarily wired the switched wire for the sniper unit to the battery to rule out any sort of issue there with voltage drop and whatnot. I took some more datalogs which I've attached and noticed that right at the time I hear the popping it looks like my AFR goes lean. My hunch is that I've got a vacuum leak that shows up at higher RPM? If so what is a good way to test that? I can also provide screenshots of the log to show what I'm talking about if that helps.

 

[72redbird]

I just had to change out the ignition box on my buddies 71 Charger R/T. He has a 4 speed and that thing would not rev past 3300 rpm under load, and it would start bucking and cutting out. Installed one of my old orange boxes at that took care of the problem. It started and idled smoother also.

 

[RJRENTON]

I just had to change out the ignition box on my buddies 71 Charger R/T. He has a 4 speed and that thing would not rev past 3300 rpm under load, and it would start bucking and cutting out. Installed one of my old orange boxes at that took care of the problem. It started and idled smoother also.

There is a "program-able" uni-junction transistor (programmable thru an internal resistor network) that controls the turn on time of the main switching transistor (turn on time equals the coil's dwell time or charging time or distributor/crankshaft degrees of rotation). IF this dwell time determining network changes due to component failure, via uni-junction timing transistor or resistor timing network, the dwell time will vary (gets shorter) resulting in the coil's insufficiency in charging and poor or irratic Or no ignition, or spark. Remember that the main switching transistor turns OFF to create the spark and the dwell time, or ON time, allows the coil to charge to get ready for the next turn OFF cycle to create the next spark. Substituting different coils with different primary resistance and inductive reactance will upset the dwell time, resulting in poor ignition.
To MarPar......did I get theory of operation correct or mis-spell anything?.....just curious.....please advise.....
BOB RENTON

 

[INTMD8]

Finally coming back to this thread. So I got the new Ignition box and no surprise it didn't help. I went through and temporarily wired the switched wire for the sniper unit to the battery to rule out any sort of issue there with voltage drop and whatnot. I took some more datalogs which I've attached and noticed that right at the time I hear the popping it looks like my AFR goes lean. My hunch is that I've got a vacuum leak that shows up at higher RPM? If so what is a good way to test that? I can also provide screenshots of the log to show what I'm talking about if that helps.

There isn't any vacuum at WOT unless the throttle body/carb is undersized and a restriction.

Wideband will show lean any time it misfires.