7720 with 7730 controller. using the launch retard in the 7730 grid to pull timing to run index class.
Grid pulling timing as map programed one week, go back the next week and it's not actually pulling the timing but data from the 7730 says it is, car picks up .200.
I go back a couple of weeks later and it pulls the timing as programed
I decided to replace the 7730 since it is 5 years old, check the timing map operation in the shop with a timing light and it works perfect as programed.
Head to the track last night and first pass the car is .200 fast again, again 7730 data acquisition says it pulled timing as programed but it actually did not pull the timing. In the pits checked it with a timing light and it was pulling the timing as programed. Made 4 more passes it pulled the timing as programed and car was on the index!!

WTF is going on?

For clarification of what I am doing I am pulling 10* at .400 on launch retard back in at 2.5 secs and another 5* from timer on delay box at .500 using step 1 pink wire all back in at 1.5 secs

It there any possibility that the step 1 at .500 intermittently cancels out the 10* at .400 since they are activated so close? My gut feeling says it is still pulling the 5* when it does not pull the 10* but no way to verify it

jr.couldnt identify this issue ?

do you use a k&r box

quote:

Originally posted by rusty:
jr.couldnt identify this issue ?

Nope, it makes no sense. Thats why I decided to buy a new 7730 controller but it did it again last night. the 7720 is dumb, it only does what the 7730 tells it to do

Yes K&R delay box

I dont think the 5* pulled on the delay box timer does much on its own, but it does when used in combo with the 10* pull. But the reason I have it is so I can make a last minute timer change to slow or speed up the car up as needed

I'd be rewiring everything. The fact it's doing it sometimes and not others sounds like bad connections.

Do you have more than one version of MSD software installed on your laptop? I worked on a car where the racepak recorded timing and it would report a different timing curve than the grid. I got MSD and racepak over and they agree that the racepak was correct. MSD swore it didn’t have anything to do with the grid software but somebody on here said they had seen the exact problem and it was fixed by removing all MSD software and old files from the laptop, updating the grid to the latest firmware

And it continues to get weirder, I separated the launch retard and step 1 retard activation by .300 and everything worked perfect until I got down to 3 cars last night and the grid did the polar opposite of what it has been doing, its pulled the timing but instead of bringing the timing back in at 2.5 seconds, it did not put it back in until 4.2 secs and of course the car slowed .150 for the loss.
Again the grid data acquisition showed everything worked as programed but it clearly did not

quote:

Originally posted by BJs Wild Ride:
Do you have more than one version of MSD software installed on your laptop? I worked on a car where the racepak recorded timing and it would report a different timing curve than the grid. I got MSD and racepak over and they agree that the racepak was correct. MSD swore it didn’t have anything to do with the grid software but somebody on here said they had seen the exact problem and it was fixed by removing all MSD software and old files from the laptop, updating the grid to the latest firmware

No Racepak here, we run RPM Logger. No other versions of MSD View, V4.4.0.0.5 . I'm running the software update to 4.5.8 right now. Not much faith it'll change anything.

Here's what the 7730 is telling us.



The first one, entry 0004 you can see it didn't pull the engine down at all when it claims to have pulled 15 degrees stepping to 10 degrees. Doesn't make sense. Went 5.67

Entries 0008 and 0009 you can see it pulled the engine down as the timing came out. Went 5.78 and 5.77.

Entry 0018 you can see the engine took a long time to recover from the timing coming in, as if the timing was still getting pulled. Doesn't make sense.

Entry 0019 it behaved how it is supposed to. 0018 and 0019 we even pulled more timing, 17 total at the front, to get closer to the 5.80 index.



Entry 0021 really does not make sense. It took almost 2 seconds from when the GRID "thinks" it went to full timing, before the engine recovered. Looks like the timing was still getting pulled.

https://photos.app.goo.gl/9djRYEzh2r4vPUEs7



https://photos.app.goo.gl/7FssGyehSKeXP7gw7



https://photos.app.goo.gl/gtEBnK9Kk2W5HY8SA



https://photos.app.goo.gl/g8t5yanjUYdXphtM7

I would still delete all the old files off the laptop and start fresh. There’s another timing box (can’t think of the name) where that’s common practice about once a year. Not saying I’ve ever seen it with the grid for that exact reason, but have definitely seen this issue and it’s been fixed by wiping everything and starting over with fresh software install and new files

For what its worth When I replaced the 7730 controller last week, all the parameters were programmed fresh, not copied from a saved file or the previous SD card

If you haven’t already, I suggest to try wiring the 7720 power (+12v and Ground) directly to the battery on separate isolated wires.

What does the battery voltage channel look like in the DA of a good and failed run for comparison?

quote:

Originally posted by markemark:
If you haven’t already, I suggest to try wiring the 7720 power (+12v and Ground) directly to the battery on separate isolated wires.

What does the battery voltage channel look like in the DA of a good and failed run for comparison?

Here is the info for all of the runs we made this weekend.

Something to note, we are shifting at 0.7 seconds using an electric hammer shifter and that is consistently showing up as a voltage drop in the graphs. But the voltage is staying between 15 and 17.5 volts overall.

The 7720 and 7730 are wired to the MSD Filtering Capacitor.

Run 0004: (Testing 1)
Engine never pulled down
Timing was out 0.3 to 2.8
Voltage was 17.3 at the launch, dropped at 0.7 seconds to 16.1 volts, went back to 17.3 volts at 1.3 seconds.

Run 0008: (Testing 2)
Engine pulled down from 0.7 to 3.25 seconds
Timing was out 0.3 to 3.0
Voltage was 17.3 at the launch, dropped at 0.7 seconds to 16.1 volts, went back to 17.3 at 1.25 seconds

Run 0009: (Testing 3)
Engine pulled down from 0.5 to 2.5 seconds
Timing was out 0.3 to 2.5
Voltage was 17.3 at the launch, dropped at 0.7 seconds to 16.1 volts, went back to 17.3 at 1.2 seconds

Run 0010: (Testing 4)
Engine pulled down from 0.5 to 2.2 seconds
Timing was out 0.3 to 2.3
Voltage was 17.3 at the launch, dropped at 0.7 seconds to 16.1 volts, went back to 17.3 at 1.25 seconds

Run 0011: (Testing 5)
Engine pulled down from 0.5 to 2.0 seconds
Timing was out 0.3 to 2.0
Voltage was 17.2 at the launch, dropped at 0.7 seconds to 16.0 volts, went back to 17.3 at 1.25 seconds

Run 0014: (TT 1)
Engine pulled down from 0.75 to 2.1 seconds
Timing was out 0.3 to 2.0
Voltage was 17.2 at the launch, dropped at 0.7 seconds to 16.0 volts, went back to 17.3 at 1.25 seconds

Run 0015: (TT 2)
Engine pulled down from 0.7 to 2.0 seconds
Timing was out 0.3 to 2.0
Voltage was 17.2 at the launch, dropped at 0.7 seconds to 16.0 volts, went back to 17.3 at 1.25 seconds

Run 0016: (First Round)
Engine pulled down from 0.7 to 2.05 seconds
Timing was out 0.3 to 2.0
Voltage was 17.2 at the launch, dropped at 0.7 seconds to 16.0 volts, went back to 17.3 at 1.25 seconds

Run 0017: (Second Round)
Engine pulled down from 0.7 to 2.75 seconds
Timing was out 0.3 to 2.5
Voltage was 17.2 at the launch, dropped at 0.7 seconds to 15.9 volts, went back to 17.1 at 1.25 seconds

Run 0018: (Third Round)
Engine pulled down from 0.7 to 3.0 seconds
Timing was out 0.3 to 2.5
Voltage was 17.3 at the launch, dropped at 0.7 seconds to 16.1 volts, went back to 17.1 at 1.25 seconds

Run 0019: (Fourth Round)
Engine pulled down from 0.75 to 2.5 seconds
Timing was out 0.3 to 2.5
Voltage was 17.2 at the launch, dropped at 0.7 seconds to 15.9 volts, went back to 17.2 at 1.25 seconds

Run 0021: (Fifth Round)
Engine pulled down from 0.7 to 4.5 seconds
Timing was out 0.3 to 2.5
Voltage was 17.0 at the launch tapering to 16.6, dropped at 0.7 seconds to 15.4 volts, went back to 16.7 at 1.25 seconds

For anyone who didnt follow along in the build for this truck I had posted, the entire truck was 100% rewired. I should note I am using a single XS 16V battery with a 100 amp HOP mini alternator. This is the main electrical panel

quote:

What is the large solenoid in the upper right side of this picture used for???

7720 appears to be wired to the two +/- bus bars , or positive for 7720 is to a fused junction point below bars??

Where is the 3 pin crank trigger cable located? Are you using the supplied crank trigger cable?

How long a time period is the shifter programmed for?

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

Solenoid upper right is for starter
The 7720 is wired directly to the MSD noise filter which is fed from the Pos/Neg buss bars
Crank trigger cable is MSD supplied cable and is connected directly to 7730 mag pick up connector
Shift on time is .500
The fused junction feeds the shift solenoid thru a separate relay triggered by the K&R panel

This message has been edited. Last edited by: Big Steve,

If it were me troubleshooting, I would remove the wires from top of capacitor to 7720, and take #10 wire with one hole connectors and nut (small screw with nut) the 7720 leads to the one hole, and then directly to the battery. Wrap the nut connector in electrical tape… it’s just temporary.

You’re isolating Grid from everything on that power buss that you have it attached to.

I would program the shift for output switch to 0.250 duration. Most PG will shift faster than this. My th400 will shift 0.250 output and it’s dead slow.

Mark, that power buss is fed from the #8 red wire connected to the battery side of the starter solenoid which is a 1/0 cable directly from the battery.
The power buss feeds the K&R relay panel, the MSD capacitor and that fuse block, the fuse block feeds 2 things the shift solenoid and all the steering wheel buttons, I wanted both of them fused separately from the K&R panel