Ok. Recently put a msd grid in buddies car. Fired up and ran great for about two hours then grid died. Diagnosed and msd agreed it was a bad grid. Ordered new one and installed. Now the car will only occasionally spark during cranking and is very hard to start. If you pull a plug while it's running it Sparks fine.

We have changed everything. His grid works perfect in my car during cranking.

We even thought new one might have bad harness. Put in old one from dead grid and it does the same. Changed pickup etc.

Rewired entire main electric system with new wires. New battery... Attached two batteries.

Connected starting system of car to separate battery vs grid and vice versa. Bypassed start switch, ignition switch... Same thing.

After it won't spark during cranking if you jumper the crank signal it fires perfect. If you touch nothing but just pull the distributor and turn it by hand it fires perfect. Put it back in car and crank it in a ten second starting scenerio it might spark once.

Changed the starter... Still same problem.

This is the most buzzar thing I've encountered.

My next recommendation to him is to change the msd pro billet distributor, even though pickup was charged but have no idea how that could be it since it works fine when turned by hand.

I've installed several grids and this is rediculous. Msd is really no help. They answer and suggest things but many we already did.

Has anyone seen this type thing.

We have literally rewired the whole car and nothing. Even when the grid is the only thing being powered and voltage at grid is 12.6 while cranking it will not fire.

Grid updated with latest firmware. Put it in my car and it works perfect. We have doubled every wires for redundancy... reconnected every wire.

Car is mint 66nova with very basic wiring. All accessories etc have been removed from grid. Have power plus and minus, ignition 12v, two coil wires, plugged I into 7720 ignition. Won't fire consistently.

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

I would start by checking you voltage at the grid during cranking. To me it sounds like a voltage drop issue and its under the required voltage to work properly.

Sounds like about all it can be is a goofy ground or a resistor in a wire somewhere...sounds like any resistors would have been removed when the original wiring was replaced though. Definitely a head scratcher!

You didn’t mention if you had any start retard programmed.

Have you had more than one laptop plugged in? If so, do any have more than one version of the grid software installed?

I ran into an issue where the grid was “lying” to the software about the programmed timing curves. Once I got rid of the different software versions on the laptop and reprogrammed, problem went away.

MSD claimed that was impossible but saw it with my own eyes.

Grounds could be your best friend here.. Make sure the engine block is grounded to the negative side of the battery, and I've heard people say do the heads to the block also.

what i read was "fires just fine in atmospheric pressure but when exposed to cylinder pressure it miss fires" so can i ask Have you changed the coil?

Joe

Dragster or door car? If dragster what brand? IM asking for my own count of issues. Anyway, same questions for your car that it worked on. Now after you answer that, replace the battery disconnect and try again.

Thanks for suggestions.

Disconnect switch changed.

Brand new batteries installed.

Brand New 00 run from battery to ground in back of car, and front of car. Plus positive run to front.

Removed, reinstalled software. As mentioned works perfect if put in my car.

No cylinder pressure involved... Just watching coil wire.

Block is grounded to new ground lines. Heads to Daisy chained to together, and to ground and to negative on coil.

Car is 66 Nova

New starter.. Other was brand new.

Last night we put simple msd 6 ignition in without grid car started right up and has good spark.

Going to connect grid to msd6al today. In think it's the 7720 box or connections. If this works he is running the 6al.

You didn’t answer about start retard. If your car has a larger distributor cap (or crank trigger), a start retard wouldn’t knock it out of phase as easily. But if your always watching the coil wire I guess that eliminates any kind of phasing issue.

quote:

Originally posted by BJs Wild Ride:
You didn’t answer about start retard. If your car has a larger distributor cap (or crank trigger), a start retard wouldn’t knock it out of phase as easily. But if your always watching the coil wire I guess that eliminates any kind of phasing issue.

Correct watching coil wire. And no retards.

Installed just 6al box car works great. Hook up grid to that exact box nothing. Even tried a 7al box.. Nothing.

I'm convinced the grid is bad despite it working perfect in my car. Well at least sparking at coil.

Changed coils as well in above testing... Nothing.

Going to smash them both to pieces and send them back to msd so they can't resend them out. How can a company like that send that many defective pieces out knowing it drives people insane and costs them tons of money and time troubleshooting. My busy has spent at least 1500 dollars not to mention is both countless hours researching and redoing wires. Rediculous!

I'll never suggest one of these to another person. Conceptually and if you get one that works they are great. I loved mine and it's functions but it's a crap shoot if you get one that works. Read the forums... Lots of bad units.
Lesson to be learned. If you get one and your sure the wires are right and it acts up.. Send it immediately back and insist on a new one... Continue till you get one that works. Don't start second guessing everything in the car. It's the grid.

On that note, what is the best comparable (digital) alternative to a grid on the market?

My 6AL Programmable doesn't do all the stuff that a Grid does but so far it has been flawless. Didn't cost a zillion bucks either.

quote:

Originally posted by Rawe Power:
On that note, what is the best comparable (digital) alternative to a grid on the market?

MSD 6530 imo

Had similar problem where if car started, it ran fine but would not always start. Finally it left me stranded while teching in at a race. Got back to trailer and started trouble shooting. I found that I had no spark using timing light on coil wire. Eventually I found the crank trigger pick-up was bad. It only had 12 dyno pulls as this was an off season freshen up so couldn't believe that was it. I put a 15 year old spare pick-up on it and it works great.
Now for the interesting part. I took the "bad" pick-up to the MSD guys at a National event and they said thet could test it. The strange thing was they wouldn't test it in front of me because they were busy. I was the only one there! So I came back 10 minutes later and was told it was good and they even ops checked it on the test bench with me watching. I put it back on the car and the problem came back. So that part is in the trash and I bought a new one that works fine.
MSD's quality control is lacking at best. I would try another known good pick-up and see if it works.
David

Check the pin outs I’ve had several msd pins not crimped correctly mainly on the main power/coil plug

Thanks for more suggestions.

The entire wire harness as well as every wired connected and run to coils, pickup, pickup itself have been interchanged and swapped to no avail.

The ONLY things that have not been swapped out are the motor itself, the distributor base, and car chassis.

Every switch, relay, battery, coil, etc have been changed. Most perplexing problem I have every faced.

Leave any of the above in the car and change to just the 6al and it runs and sparks during cranking just as it should.

Brought the grid controller to my car and it worked flawless. I was not tearing my wire harness out of my car to try to. so unless he has two wire harnesses that are wrong I dont know what it could be.

I ohmed, checked pins etc. Weird thing is sometimes you will get a spark in a 3-5sec cranking of the motor. Other times you will get 3-4 sparks and others you wont get a thing.

RPM spinal to the grid display is irratic which is I am sure why its not firing - I just cant see why its not seeing the signal. Again other boxes fire fine with all other components.

He sent everything back to Jegs and Summit/MSD. Going to start with all fresh stuff again and see if 3rd time is the charm. Suggest he gets the 77303 box which is just a color different but maybe is a different lot of circuits and components if there were a bad batch is circulation.

If there is a comparable / Legal box out there that can handle launch control, and shift signal - please let me know. Maybe we will go that route. That is the only reason I suggested he get the grid so we can tame down the launches and get the car consistent. Dont really care how fast it is. Car has a 615, best of everything, and weighs about 2900lbs so going fast should not be a problem.

At this point we would be happy to have it run and get a single run out of it. The hours spent on this problem is astronomical. Several very good people have looked it over and just cant seem to isolate the problem. I've never been able to not narrow it down to a cause before. - Well I think we know what the problem is just cant figure out why its occurring.

Keep you all posted. Just thought someone might have a solution like on these cars the bumper needs to be grounded to the brake caliper and back to the coil or something crazy. LMFAO.

^^^^^^^^ It may be of some help if you shared how and when this problem first occurred.

As was told to me, engine was running and in tech area, the master disconnect was shut off and engine would not fire after disconnect was turned on.

If both boxes (7730 /7720) work in another car boxes are not problem.

If getting new boxes replace with included harnesses.

Replace anything only 1 time and move on. The only thing not replaced with different that I can see is distributor.

Disconnect any leads to the MSD Grid tach output and disconnect any wires to the alternator to try when cranking.

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

quote:

Originally posted by markemark:
^^^^^^^^ It may be of some help if you shared how and when this problem first occurred.

As was told to me, engine was running and in tech area, the master disconnect was shut off and engine would not fire after disconnect was turned on.

If both boxes (7730 /7720) work in another car boxes are not problem.

If getting new boxes replace with included harnesses.

Replace anything only 1 time and move on. The only thing not replaced with different that I can see is distributor.

Disconnect any leads to the MSD Grid tach output and disconnect any wires to the alternator to try when cranking.

First grid was killed or died after tech guy turned off power. Was confirmed by msd there was a problem with 7730. Msd said there was nothing related to the car being shut off that should cause that. I checked, v replaced switch everything...

Second grid arrived, new harness... This is when it would only spark occasionally. Everything replaced except distributor base.

I took the second grid to my car and plugged it into my harness and it worked. Here is the perplexing problem. I tried the original harness from first box that died, and new grid does same thing. So maybe we had bad first grid, with faulty harness. Got new grid which is good, but again faulty harness.

Tried the no alternator connection and wire

Just throwing this out there what is your air gap on your pickup set at? It seems that the grid is more sensitive or maybe I should say less sensitive to a crank signal than the analog boxes. I have not personally come across the problem but know of other who have. I think you mentioned you had spark when you jumped the magnetic pickup leads. Remember voltage from the magnetic pickup is lower at low rpm and with a bigger air gap. If you have spark once the engine is running but not during cranking and you have eliminated a voltage drop issue to the box this might be worth looking at.

Checked original pickup gap.. And again when we changed the pickup