Scott, did all the above, usually 2 at time. Except the coil which is 2 yrs. old - did not replace

We felt the only thing that could cause the whole engine to shut off and come back had to be electrical in nature. So, If we would have still had the problem our next steps were to use a different switch on the switch panel for the ignition. This would also verfiy the relay board (K&R wiring kit) because using a different switch on the switch panel would also use a different relay on the board. Next would have been replacing the pickup wiring and connectors, disconnecting the alternator, maybe disconnecting all peripherals from the ignition, maybe a different battery, re terminate (put new ends on) all wires for the ignition box. If after all that it still had the problem... I dunno...

Scott

i have seen this before and it was a voltage drop across the k&r board under high load the volts would drop below 10 and cause the ign to misfire.wired around k&r to ign and it was fixed.the key is the board components and load from wot on the ign

quote:

Originally posted by rusty:
i have seen this before and it was a voltage drop across the k&r board under high load the volts would drop below 10 and cause the ign to misfire.wired around k&r to ign and it was fixed.the key is the board components and load from wot on the ign

Rusty, this is an excellent post if this brand relay board (if any) is being used by the OP.

I have one last comment to make. Because the OP does not have any Data Acquisition besides a delay box rpm recording, he is limited in looking at what could be causing the problem he is experiencing.

If he was using a $400 MSD Grid 7730 attached to his present ignition system, not only would he have ignition control, he would also have a free data acquisition that could possibly help solve his problem.

I agree that this limited DA that is included in Grid is not comparable to RP or RPM features. But show me a programmable ignition control that will attach to your present ignition for $400 and offer all these control features along with DA of what it is controlling for this price.
If you want some powerful ignition control that is less expensive, GO GRID!!

Yes, the wiring is 23 yrs old. I have relays right near the components, i.e., Water pump, fan, Shifter Solenoid and tiny fuel pump (not on while on track).
Updates include, welded studs to cage for grounds, dedicated #10 power wires for MSD directly to battery, new Shielded MSD trigger cable.

This message has been edited. Last edited by: Richie,

Ignition data acquisition accepts multiple runs

Mark, What is it recording? RPM's? … How would I view the data?
I WILL buy this tomorrow if it will help fix my issue..
Rusty, That is why I suspect the Solenoid causing this, 1. electrical problem. 2. Solenoid is activated while experiencing my MISS. 3. Had friends tell me the voltage drop because of Solenoids VIA RacPac.

Maybe it was the CONVERTER
After thinking of the timeline & miss here's what I came up with: April, real bad MISS > FTI conv. 6800 fallback/7800 cross, 7400 shift rpm (400 rpm overlap)
May, Trans Spec. conv. 6800 fallback/7400 cross, 7400 shift rpm (no rpm overlap) THIS is when the severity of the MISS lessened, about 6-8 passes = no miss at all.

July, FTI conv., 6500 fallback/7500 cross, 7200 shift rpm (300) still missing about the same as May...


Could the Solenoid still cause Havoc after rebuild & wire change? got to wire to Delay box for sure!

This message has been edited. Last edited by: Richie,

Hi Richie,
I've had issues like this before (breaking up top end) and every time it was something different.
It was hard to diagnose because it wouldn't do it every pass.

First time I replaced and created more grounds (added directly to heads). Fixed it.

Second time I changed the fuel curve. I ran alky with NO high speed. I added a high speed to remove fuel up top and that cured it.

Third time I noticed that the electric shifter was getting quite warm. I took a couple passes with it unplugged and shifted by hand, no more miss.

Last but not least, fourth time missing top end after chasing all these other things I finally took the advise of ATI (I was not using their converter at that time, talked to them at a divisional). Swapped my converter, problem fixed. It was broken and I didn't know it.

This has been over many years in different cars, since I started racing. And yes every time I had an issue I went thru the whole electrical system with all new MSD ignition parts and none of the times did that fix it.

So my point is it could be anything.
Hope you find it and GREAT JOB coming in number 2 with your car not 100%.

quote:

Originally posted by Richie:
Maybe it was the CONVERTER

I don't think it's the converter. Or alcohol for that matter. When watching the playback on the delay box the RPM drops 1000 in .01 then right back up again; that screams electrical to me.

The different converters might load the engine differently so that could be why it changes with converters.

It sounds to me like your next steps are crank trigger wheel, shift from your delay box, reterminate or replace wiring. Wait a second, didn't you disconnect the alternator earlier this year and it helped it? Did you ever disconnect it again or just replaced it?

Which -9 plug are you using? The R5672A9 is an extended reach - if you have the room for it, I've heard of it clearing up some miss issues on alky.

quote:

Originally posted by Richie:
Ignition data acquisition accepts multiple runs

Mark, What is it recording? RPM's? … How would I view the data?
I WILL buy this tomorrow if it will help fix my issue..
Rusty, That is why I suspect the Solenoid causing this, 1. electrical problem. 2. Solenoid is activated while experiencing my MISS. 3. Had friends tell me the voltage drop because of Solenoids VIA RacPac.

Your car sounds like it could use a complete rewiring and component upgrade in the future, but now you need to try and resolve the problem least expensive way.

Although I do agree with what to check and try from others as it could very well be non-electrical, even limited data acquisition could possibly offer some help. It might possibly tell you it’s not electrical.

I would suggest removing all devices that are attached to the Ignition Tach terminal with the exception of the delay box and trying. I’d also suggest removing the alternator belt and making a run with battery only as another suggested.

MSD Grid 7730 will record 19 channels of Data Acquisition. And it has the ability to record other channels if you add different modules through CAN-Bus. With your problem I would be looking at RPM, Ignition IN pulses, Ignition OUT pulses and Battery Voltage.

Grid will record and store hundreds of runs. Easily accessible with a usb cable plugged into your Windows 98, 7 , 8 or 10 laptop.

Although you may be able to more clearly see what is happing in Grid Data Acquisition of your problem, it does not mean you will be able to resolve it. By this I mean that it could very possibly take a complete rewiring of your car to resolve if it is electrical. I just went through this in my 25 yr old door car that had original wiring from late 2016 to early 2017. Rewiring the car and replacing the toggle switch panel and adding a relay board I never had resolved my electrical problem. And Yes, I knew it was electrical.

If you decide to add a 7730 Grid to your present ignition now, I can explain how to attach to your 7al temporary that will make for a quick and easy install and removal keeping all the wiring harness at full lengths. It will be easy to remove in the event you want to go back and run your present system as is also.

Had a Gold 7AL2 in my EFI LT-1 Firebird stocker...

Out of nowhere it started missing up around 6500-7000rpm....pretty bad miss

The Tach would literally drop like the ignition was shut off...


I Borrowed an identical box from my buddy and it ran flawless...no missing whatsoever


Sent MY box to MSD.....They said nothing wrong with it...


Put mine back in car.......Same thing, missed bad and tach shuts off when it misses....


Put buddies box right back in for next run.....ran flawless....no other changes..


This sounds like a hard miss and electrical.......like a box issue......and I know you said you tried a different box....

I just recently had issues with my ignition rocker switch....would not turn on everytime...Turn off and back on and it would work...


K&R switch panel and relay board.....both from 2003.....

I checked all wire connections and made sure they were all tight.

Pulled plug from switch panel to relay board and made sure it was clean and tight....


Switch works everytime now....I had no issues once it was running or going down the track....

Also checked main battery cutoff switch and wire connections and batteries....

The little stuff can get ya.....

Thanks Frank! I was thinking of trying High Speed, I have $200 win credit w/ Ron's...

Just to be clear, my last post I believe the CONVERTER indirectly caused the skip by putting the engine in a certain RPM range that the kept the Shifter Solenoid engaged for a longer time period on top end.

183N, Yes - I did disconnect the alt. for 1 pass, seemed like miss free? my miss is so sporadic that I'm not sure about that test. I need an alternator, don't want to charge every pass & worry (NO - I am not going 16V.) so I purchased a new one in hopes the old had issues.
BILLY, Killer James also suggested another plug, I currently run NGK R5671-9's

Thanks Markemark, I might do the grid, I'll let you know if....I agree 100% wiring needs to be all replaced....

This message has been edited. Last edited by: Richie,

I do not think a hotter plug will fix it but since it is so cheap and easy to try might as well.
I hate to say it but it sounds like to me it is time to retire whole car. A broken wire can cause intermittent problem that will drive you crazy.

Its not a hotter plug, same heat range but an extended tip. I've heard of a few instances where it cleaned up a misfire on a non-conventional headed motor on alky. Most motors seem to like them if you have the clearance... chicken soup at this point, might not help but can't hurt.

Not a good idea to put an extended tip plug or a long reach plug into any engine if it was not checked for plug to piston interference.....

Big dome pistons hitting spark plugs makes a mess.....

They might clear just turning the engine over......but hit once it is running at higher rpm.....

Lots of good suggestions up there.

If it were me, I would run a 10gauge wire from the battery thru a 30 amp fuse to the MSD box. Another wire from there, 14 guage, via a 10 amp fuse, to the yet to be installed ignition switch. You can leave your other one in there for your other stuff, but add a new switch JUST for the MSD box. Make a small bracket that you can zip tie safely somewhere. Yeah, gonna be a PITA to remember to operate BOTH switches, but this is just for a quick test!

Borrow or get a new coil also, they do go bad.

quote:

Originally posted by BD104X:
Its not a hotter plug, same heat range but an extended tip. I've heard of a few instances where it cleaned up a misfire on a non-conventional headed motor on alky. Most motors seem to like them if you have the clearance... chicken soup at this point, might not help but can't hurt.

My conventional-headed 632 misses badly on injected alcohol if I don't use a projected tip plug. I use the NGK FR5.

The way this has been described, more like shutting off briefly, I don't think this is the issue.

Lots of good suggestions here. I'd be shifting it by hand for a day/weekend. Was going to suggest disconnecting the tach as someone else said. Of course, you can only do one of those things at a time unless you have a really good ear!

Mine was doing something similar but it was a loose wire on ignition switch. Since you have already replaced that I think it may be a bad wire some place.

Lenny5160, My MISS varies, in the beginning (April) it was so severe I had to lift @ 1200', as time goes on (converter changes) the miss is just a few pops w/ no effect of E.T., then like the last 2 weeks of points, 3 - 4 real hard pops or misses > puts you in the seat belts....

Something else for everyone to think about...could outside temp. be affecting/causing this? the Miss has also followed the heat change of Season's?

I'm alittle shy about extended tip plugs not knowing how much space I have, and not sure if I will get a chance to test before Bracket Finals.

This message has been edited. Last edited by: Richie,