First time out since last October and 2 of 3 runs the shifter made the 1-2 and immediately made the 2-3 shift. It was as if it was shifting from 1st to 3rd but the logger shows that it made 2 shifts. What would cause this? T 400 trans with Biondo/Digital Delay shift box and Biondo solenoid on a Cheetah shifter and air compressor.

Which box…… 2 Shift, 1067 5 shift, 1068 Time + Rpm shift ??

what was the rpm fallback after the 1/2 shift....?

The box is a 1067.

The first time it shifted weird, it shifted at 6700 fell back to about 5850 and shifted again about .106 later.

The 2nd run it shifted at 6600, fell back to about 5800, stayed there for about .13 seconds and shifted again.

There was a run between the two times it malfunctioned and it shifted correctly on that run.

The only thing I've changed on the car since last season is the change to a 6AL2 box.

Try setting the Shift Pulse Time to .99 seconds.

I can try that Mark. It's currently set at whatever it was set at when I bought it cause I remember Biondo telling me not to mess with that, LOL.

Leaving the air shift solenoid activated for .99 on a Cheetah will not hurt anything. What this is doing is increasing the amount of time to 1.49 seconds before the 2-3 shift will be enabled to activate at the programmed RPM setting.

Because the 6al2 is new this year and this problem has started, if the shift pulse increase to .99 does not correct the problem try this. Disconnect the gray tach wire from 6al2 to the tach and only have the rpm shifter attached to this wire. Return the Shift Pulse Time to the original setting.

MSD ignition Pos / Neg should be terminated at the battery as MSD recommends.

Second last resort is to install a MSD 8830 noise capacitor.

I set the shift pulse to 99. I think it was on 60 before I moved it but 60 was also the setting for my 1-2 shift so I'm not sure what I was seeing.

I tested the shift a few times in the pits yesterday and all seemed good but if you think it's noise from the msd, maybe I could test with the engine running. Would there be more noise as rpm's increase??

MSD is grounded to an intake manifold bolt and the main ground cable from the battery is attached to a starter bolt. Maybe I should move the msd ground. The msd hot is directly to the main hot from the battery.

MSD ignition power and ground should be at the battery. The battery is a big noise filter. Both cylinder heads should to be grounded also. The intake manifold is a poor choice for grounding the ignition.

I would look at your grounding first before continuing on.

The shift pulse set to 60 initially should be adequate for the rpm drop when added to the .50 shift delay time.

I'll move the ground and I think I'll leave the pulse at 99.

Heads and alternator are grounded to a bolt in the frame rail that has a 10 gauge wire directly from the battery. The fan and water pump are grounded at the same bolt. I also have a 0 gauge cable from the battery to the frame rail in the back of the car.

Thanks for your help Mark, I know I can be exhausting.

You need to make a ground cable from battery to the front or the motor. The frame is a poor ground at best.

quote:

Originally posted by Wooley:
You need to make a ground cable from battery to the front or the motor. The frame is a poor ground at best.

Thanks, I posted above that the main ground cable goes to a starter bolt, but I also have one to the frame rail. I think one is 0 gauge and the other is 1 gauge.

UPDATE: After making changes and sending the rpm box to Digital Delay with no improvement on shifting, I decided to unhook the 6AL2 and run the digital 6 box that I ran last year. I made 2 runs with the shifter acting correctly. So my 6AL2 doesn't get along with my Digital Delay rpm switch.

The 6AL-2 (6421) is a digital box.

I have posted this before. You could try adding a MSD-8830 noise filter to this wiring electrical feed of the 6aL-2 if you want to try this again. You can leave the 8830 in permanently when running any ignition.

quote:

Originally posted by markemark:
The 6AL-2 (6421) is a digital box.

I have posted this before. You could try adding a MSD-8830 noise filter to this wiring electrical feed of the 6aL-2 if you want to try this again. You can leave the 8830 in permanently when running any ignition.

Yep, both are digital and it shifts correctly with the 6A and not the 6AL2. I was hoping that fact might have given you more insight to a fix. I had planned to buy the 8830 if I didn't hear differently from you. I sent the 1067 to Digital Delay for testing and they told me it was fine.

Update from 4/29: Installed the MSD 8830 filter and made 2 passes with the same result, first to third. I have one connection point with the tach wire from the ignition box sending engine rpm to the logger, the rpm switch and the tach. I unhooked the tach like Mark said and the car shifted properly. I hooked the tach wire back up and unhooked the logger wire and it shifted properly. Then I hooked the logger wire back up so it was like it was at the beginning of the day and it shifted properly. I'm thinking I have a bad terminal connection in one of those wires and my movement has made the connection good somehow. So I guess I put new terminals on all 4 wires and see what happens, unless Mark or someone has a better idea. I'm thankful for suggestions.

Damn them loose terminals. Went thru it last year with my shifter.

Was your 60ft really good yesterday. I've never been 1.36 before with my junk.

If you believe you now have it isolated to the wires and or possible terminal ends or junction point this is what I suggest. Don’t put new ends on the wire, replace all the related wires and ends with new.

You could possibly have a break in the copper strands of one of the wires.

quote:

Originally posted by Tom Reyer:
Damn them loose terminals. Went thru it last year with my shifter.

Was your 60ft really good yesterday. I've never been 1.36 before with my junk.

My 60's were about normal when it hooks really well. Yesterday it spun a little on every run but still had good numbers and it was very consistent. 1.310, 1.307, 1.296, 1.301, 1.305. Not exactly printing tickets but good for a little spin.

quote:

Originally posted by markemark:
If you believe you now have it isolated to the wires and or possible terminal ends or junction point this is what I suggest. Don’t put new ends on the wire, replace all the related wires and ends with new.

You could possibly have a break in the copper strands of one of the wires.

Thanks Mark, I have 2 questions.
1. How do you suggest replacing factory wires to the MSD box, tach and Racepak? The only wire I installed is the one to the rpm switch.
2. How would you suggest attaching those 4 wires together? I have a ring terminal on each wire with a one screw attaching them all to an old fuse panel. It's worked well for many years until this event.