2017 no issue /been running this car for 23 yrs., 2018 bought & rebuilt a 632 w/ HH383, has a top end only miss after 7300, feels like the motor is shutting off and back on really quick, D.B. playback shows rpms drop from 7400 to approx. 6500 then repeats 3-4 times before finish. Things I replaced or ?: MSD Hi rpm chip, MSD 7al (gold), shift rpm chip, plugs, wires, cap/rotor, MSD eye, MSD shielded cable & re-routed, checked all grounds, MSD noise filter, alternator, Optima red top battery, MSD directly wired to battery, IGN. rocker switch inside & master disconnect @ rear, no broken springs (don't feel like valve float), lash stays, 32* timing, NGK -9's, TORQUE CONVERTER, larger alky pump & pilled both ways, rebuilt electric shifter solenoid & #10 power wire >> I'm going to put a switch on shifter so Solenoid will only fire in 1st. The only parts on new motor not changed are: empty MSD dist., Moroso crank trigger wheel. The miss was really bad at first (April) and seemed to lessen all on it's own as there was no noticeable change after all of these 'fixes'.
I also run a dry sump system.

I managed to finish #2 in points @ L.V. & want to be ready for Bracket Finals @ Atco soon! Thanks

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

Stop hitting the 3-step button on the top end....... Sorry, just had to.....

If I can actually think of something useful to say I'll do it later.

I've had racers tell me tell me they heard me peddelin' LOL.....

It's the converter!

Try it with no high side chip

What gap is the crank trigger set at?

at first...about .200 by mistake, adjusted now to approx. .045. Didn't noticed a diff. here either.
I even wrapped the 6" wires coming out of the eye w/ Rubber tape to try & shield it?? it IS VERY close to the alternator

Biggest noticeable DROP in the severity of the MISS was after a converter change.....I don't think it's related...

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

Have you watched the trigger wheel while cranking to make sure it doesn't have runout?

Just thinking out loud.....

Did not study it, but didn't notice any runout. Only a few thou. there at most anyhow..I had it @ .200 and it fired.

It runs 8.00 @ 2710 lbs. 169 mph. Best of 7.928 @ 170.15 w/ 1.132

I suggest shifting the car with the Delay Box using a Time Output and disable the RPM shifter by removing the shift chip or power to it. If your delay box will output from RPM and program for only 1 shift then this would be a better method to try.

You could possibly be shifting in the BO box also if not wired correctly. If you are using a RPM activated switch with a chip to shift with, the “ON Time Window” should be controlled with your delay box and not on all the time or activated with a toggle or position switch.

I only have a Biondo200 box. Already use SLE, don't know how many options I have, not many.

It appears I can do that w/ the Mega 200, Thanks Mark! switch on the shifter seemed like a band-aid...

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

quote:

Originally posted by Richie:
I only have a Biondo200 box. Already use SLE, don't know how many options I have, not many.

Look at Page 8 of your Mega 200 Delay Box instructions HERE . This is what should be controlling your shift function.

Change crank trigger. It's losing signal.

In your initial posting did you write that the Ignition ON rocker switch was replaced ??

Wheel? already changed transducer / eye.

YES, Mark. & high amp 4 pole switch out back.

Have you tried it on gas? Had a buddy with a similar combo and problem. Switched it to gas per the engine builder and the issue went away.

Sounds like fuel to me? Is this gas or alky and is there a fuel filter, if filter is present just toss in the file 13 section no matter what the issue is.

Shane Carr

Disconnect the tach and try it

I had a 555 that had a miss I never could get out of it. Same ignition and fuel system as my previous 565, chased it over a year and never fixed it. Dropped 598 in there and poof, no more miss. My guess was cam or engine combo wasn’t agreeing with my alky set up.

We just had a similar problem. Engine would just shut off for a split second and then come right back. Like you said almost sounding like a quick whomp, whomp like some do when driving the finish line. It would only do it noticeably when making the pass and rpms above 6500. First we replaced the coil which was no help. Not wanting to chase it for weeks we took somewhat of a shotgun approach at it. We replaced all at once the distributor, pickup, cap, rotor, spark plug wires, coil wire, and the master disconnect switch. We also not only checked the grounds (they were tight and no noticeable corrosion) BUT we took all of the grounds off the posts on the chassis and wire brushed the eyelets along with the posts and any washers before reassembling. Problem is gone now...

Scott