7730 Grid 2 step limiter issue

[ChrisO]

As indicated in the title... I have a new 7730 #11057. It initially limited on the 2 step first 2-3 times I tried it, but then it quit. Looking at it live it recognizes the launch input and indicates launch for rev limit selected, but it doesn't do it. I have it wired to a 10Plus using the Legacy yellow 2 pin wire. Continuity is good on the wire. All other functions are working - timing retard, output switch, shift light... This was a replacement for my last Grid that suffered a Com Port failure when the mini USB connector broke. When I first got that Grid the 2 step worked a few times then quit. I sent it in to you guys, got it back, and it worked fine until the Com Port failure. Does this one have to get mailed in too?

Thanks!

[msdtech1955]

put a low rpm chip ( 3000) in the 10 ..start the car ...test the limit ........is the rev- limiter working ?

[ChrisO]

put a low rpm chip ( 3000) in the 10 ..start the car ...test the limit ........is the rev- limiter working ?

Mod 1 or Mod 2? I never ran the 10 without the Grid... want to be sure I run the test right. Thanks.

[ChrisO]

put a low rpm chip ( 3000) in the 10 ..start the car ...test the limit ........is the rev- limiter working ?

Ok, looked up the 10plus directions and plugged a 3200RPM chip in MOD1. Rev limit works.

Now what to do? Do I need to test in MOD2 as well? I do not/have not had the yellow wire location (2 step) installed on the 10plus. Is it supposed to be installed to ground to make MOD2 active for the Grid? Odd that it worked a couple times if so...???

Thanks!

[ChrisO]

Ok, looked up the 10plus directions and plugged a 3200RPM chip in MOD1. Rev limit works.

Now what to do? Do I need to test in MOD2 as well? I do not/have not had the yellow wire location (2 step) installed on the 10plus. Is it supposed to be installed to ground to make MOD2 active for the Grid? Odd that it worked a couple times if so...???

Thanks!

Ok... figured it out. I used the MSD 8 wiring diagrams when wiring my 10Plus to the Grid - this is a rather commonly given direction on the internet. It's a good direction with the exception of the yellow ground wire on the MSD 10plus that the MSD 8 wiring diagrams don't have. When wiring the MSD 10plus to a Grid you have to ground the yellow wire for the 2 step limit to function correctly.

All that said... once I got it working I don't like it. The rev limit is very harsh through the Grid compared to putting a chip in the 10Plus box. My intention is going to be to run the 2 step off the 10Plus box and wire the Grid in for the advance timing and other controls it offers.

Thanks!

[msdtech1955]

yes the msd 10 ( discontinued about 10 years ago) and the 7al-3 both have a bang bang style rev-limter when used with a power grid .
we recommend that you use the 10/7al-3 for the revlimits ..

as you can see in this drawing
http://documents.msdperformance.com/...ng_diagram.pdf