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No Spark with a 7730
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DRR Sportsman
posted
When I parked the car at the end of the last year it ran fine. All I did was fog it and back the rockers off.

I tried to fire it yesterday and I have no spark. from the coil wire. I am running a 7730. When I connect my MSD tester directly to where my crank trigger plugs in I have good spark. Plug the crank trigger back in no spark. I am also getting a message in MSD view saying low crank input voltage. I am going to borrow a new 7730 and try it later but Here is what I have tried so far I am curious if anyone has any other suggestions.

I played with air gap everywhere from .020 out to .100

I substituted a known good pickup and it did the same thing.

I put a scope on my pickup and I am getting approximately a 1V peak to peak signal at cranking speed.

I double checked in the grid that I have network ignition selected.

I double checked the pins on the both the MP harness and the pickup itself to make sure I do not have a bad connection.


B.J. Masiello
 
Posts: 250 | Location: Connecticut | Registered: November 27, 2007Reply With QuoteReport This Post
DRR Pro
Picture of rusty
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weak magnets ???bad file??output enabled in settings??? the fact that it works on tester makes me think everything is on and the wheel magnets are weak


honesty is the best policy,insanity is a better deffense
1.036, 6.16@ 224

 
Posts: 1396 | Location: texas | Registered: February 17, 2006Reply With QuoteReport This Post
DRR Sportsman
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I did check that output is enabled

It is possible that the file somehow got corrupted I could try clearing and reloading it.

I didn't think of the magnets getting weak because it seems strange that all 4 would at the same time but not saying its impossible could be worth trying another wheel.

Thank you for the suggestions.


B.J. Masiello
 
Posts: 250 | Location: Connecticut | Registered: November 27, 2007Reply With QuoteReport This Post
DRR Pro
Picture of RacerVX54
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Check under the dist cap.. I mine did the same thing. There was so much rust and corrosion under the cap.. Known issue for MSD dist.


"Just Shut Up and Race"

Brian Martin
Martin Racing
5.66 @121.55
 
Posts: 1385 | Location: Va.Beach .Va | Registered: August 03, 2005Reply With QuoteReport This Post
DRR Sportsman
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Thank you

I am checking for spark at the coil wire before the distributor though. Although I have seen that as an issue in the past.


B.J. Masiello
 
Posts: 250 | Location: Connecticut | Registered: November 27, 2007Reply With QuoteReport This Post
DRR Sportsman
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I also forgot to mention in my original post that both pickups measured around 90ohms. What did did not think to do was go to the other end of the MP wire and check it at the box. I am giong to try that as well if the new 7730 does not fix it.


B.J. Masiello
 
Posts: 250 | Location: Connecticut | Registered: November 27, 2007Reply With QuoteReport This Post
DRR Trophy
Picture of Rodney Pryor
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Just went through this about a month ago. s10 ran fine when we first started it for the year. Went to load it in the trailer and it would not start. Checked many of the items that you already listed here. Ended up swapping in a new 7720 / 7730 combination and it fired right up. Then swapped them individually and it ended up being a bad 7730 box.
 
Posts: 116 | Location: Richmond, VA | Registered: December 07, 2002Reply With QuoteReport This Post



DRR S/Pro
Picture of SCDIV1
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Bill I used a MSD magnetic pickup dist. for a long time and had some issues at one race a couple years ago

After that I went to a crank trigger but still have the same distributer. I also changed from an MSD 3 to the complete grid system

I set it up so I could quickly switch from the crank trigger to the distributer pickup.

I did it as a test and the timing was within 1 degree from one to the other...
 
Posts: 2733 | Location: Where ever I am, I'm here and it's me | Registered: March 15, 2007Reply With QuoteReport This Post
DRR Pro
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If Pick-up measures 70 – 90 ohms it is considered good. You should be able to measure the same ohm value at the end of the three pin connector cable that plugs into 7730. Set the Pick-up to 065” gap.

Attach to Grid and open the GAUGE 1 tab in the upper right corner. Drag the display to the left (parting line) to open the page more for viewing. Select the ENGINE RPM channel. Crank engine watching the display. Does it show cranking RPMs??

If you find the 7720 box to be faulty, it is repairable at MSD.The 7730 is a throw away.

This message has been edited. Last edited by: markemark,
 
Posts: 2447 | Location: 53056 | Registered: December 30, 2009Reply With QuoteReport This Post
DRR Sportsman
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quote:
If Pick-up measures 70 – 90 ohms it is considered good. Set the Pick-up to 065” gap.

Attach to Grid and open the GAUGE 1 tab in the upper right corner. Drag the display to the left (parting line) to open the page more for viewing. Select the ENGINE RPM channel. Crank engine watching the display. Does it show cranking RPMs??

If you find the 7720 box to be faulty, it is reparable at MSD.The 7730 is a throw away.


Thank you

I do usually run them at .065. I just moved it both ways because I was grasping at straws

I will try the gauge tab.

That 7730 is less than a year old and has less than 15 runs on it but I have seen crazier things happen.


B.J. Masiello
 
Posts: 250 | Location: Connecticut | Registered: November 27, 2007Reply With QuoteReport This Post
DRR Pro
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Here’s the next thing to check if you see cranking rpm displayed on Grid.

There is a “small” 4 pin connector (black, red, white, orange) connecting 7730 and 7720. Unplug this and look at the male pins in the female connector, but pay close attention to the Male connector with the Female pins. The female pins need to be tight up against the back side of the plastic orange plate cover. If there is die-electric grease in the female pins clear with compressed air. If any of the female pins appear not to be tight against the back side of that plastic plate, pry the plate off with a small screwdriver and check to see if the pins are locked in position. Re-install plate.

 
Posts: 2447 | Location: 53056 | Registered: December 30, 2009Reply With QuoteReport This Post
DRR Sportsman
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quote:
Originally posted by markemark:
Here’s the next thing to check if you see cranking rpm displayed on Grid.

There is a “small” 4 pin connector (black, red, white, orange) connecting 7730 and 7720. Unplug this and look at the male pins in the female connector, but pay close attention to the Male connector with the Female pins. The female pins need to be tight up against the back side of the plastic orange plate cover. If there is die-electric grease in the female pins clear with compressed air. If any of the female pins appear not to be tight against the back side of that plastic plate, pry the plate off with a small screwdriver and check to see if the pins are locked in position. Re-install plate.



I really appreciate the help. If I do see cranking RPM I will try checking this next. I have used those Deutsch connectors a lot and have come across that issue with the pins getting pushed at other times so it is definitely worth a check.


B.J. Masiello
 
Posts: 250 | Location: Connecticut | Registered: November 27, 2007Reply With QuoteReport This Post
DRR Sportsman
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Was your battery charged up?

Seems like mine would do that a couple times a year and maybe only when the battery was low enough that it cranked slow. Most of the time I could cycle power and/or clear the code and it would fire right up, but I think once or twice I had to charge the battery. May have just been a coincidence when mine worked after charging but slow cranking speed will drop the crank sensor output voltage.
 
Posts: 928 | Location: my own little world | Registered: July 20, 2005Reply With QuoteReport This Post
DRR Sportsman
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Thanks everyone for the advice

It turned out to be a simple fix. I when to check my MP resistance at the 3 wire connector near the ignition box and found that that plug was not snapped in tight. I must have been making just enough contact to pick up the signal from the tester but with low voltage from the crank trigger the drop was too much and it was not firing.

I feel like kind of an idiot on this once but at least its fixed. I am really not sure how the connector ended up unplugged.


B.J. Masiello
 
Posts: 250 | Location: Connecticut | Registered: November 27, 2007Reply With QuoteReport This Post



DRR Pro
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quote:
Originally posted by MasRacing:It turned out to be a simple fix.


I like “EASY”. Thanks for the update.
 
Posts: 2447 | Location: 53056 | Registered: December 30, 2009Reply With QuoteReport This Post
DRR Trophy
Picture of PostHaste
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quote:
Originally posted by markemark:
Here’s the next thing to check if you see cranking rpm displayed on Grid.

There is a “small” 4 pin connector (black, red, white, orange) connecting 7730 and 7720. Unplug this and look at the male pins in the female connector, but pay close attention to the Male connector with the Female pins. The female pins need to be tight up against the back side of the plastic orange plate cover. If there is die-electric grease in the female pins clear with compressed air. If any of the female pins appear not to be tight against the back side of that plastic plate, pry the plate off with a small screwdriver and check to see if the pins are locked in position. Re-install plate.



Thanks as well for this! I had the exact same issue, took orange cover off and blew out all the grease (there was a lot), made sure pins were locked in. Connected back together and we have spark!

I sure hope this was it for the issue. Kinda seemed too easy but makes sense why it worked one start up and then not the next. Appreciate the advise!!
 
Posts: 15 | Location: Albuquerque, NM | Registered: January 22, 2009Reply With QuoteReport This Post
DRR Sportsman
Picture of 369dragster
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quote:
Originally posted by MasRacing:
Thanks everyone for the advice

It turned out to be a simple fix. I when to check my MP resistance at the 3 wire connector near the ignition box and found that that plug was not snapped in tight. I must have been making just enough contact to pick up the signal from the tester but with low voltage from the crank trigger the drop was too much and it was not firing.

I feel like kind of an idiot on this once but at least its fixed. I am really not sure how the connector ended up unplugged.


Who wired that thing. Haha
Glad you found the issue BJ


Ken
 
Posts: 319 | Location: Massachusetts | Registered: March 15, 2007Reply With QuoteReport This Post
DRR Sportsman
Picture of 329L
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MAS, if i remember right, low cranking voltage is because you spun the engine over with ignition off. The grid was seeing the voltage, and that is why it through the code. This is what was explained to me years ago by the msd techs. I kept seeing this code, in my grid, and it was the only code. I have an injected car, so i always roll the engine and then throw the switch. Even tho now i dont need too with the timing ramp i have programmed in, plus 16 volt battery, but old habbits die hard...


Jeremiah Hall
 
Posts: 704 | Location: Evansville, IN | Registered: February 24, 2010Reply With QuoteReport This Post
DRR Trophy
Picture of PostHaste
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So same issue happened this weekend. Started, ran fine Friday night (4 runs total until rainout). One time trial Saturday afternoon, 30 minutes later, no start. Sat until rain out (about 11pm) then gave it one more try before we tried to push it on the trailer and fired up. Only thing was after backing up and pulling forward, it went to an 1100 rpm limit even though the safety run time limiter is set to 2500. Turned it off, started it again and no issue/limiter.

Going to order and throw a new 7720 at it since new 7730 and coil did nothing when it wouldn't start. You all think maybe the heat could be an issue? Door car and it was 90+ degrees Saturday and this being the 3rd time doing this only during the day. At night, it's fine.
 
Posts: 15 | Location: Albuquerque, NM | Registered: January 22, 2009Reply With QuoteReport This Post
DRR Pro
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quote:
Originally posted by PostHaste:Going to order and throw a new 7720 at it since new 7730 and coil did nothing when it wouldn't start. You all think maybe the heat could be an issue? Door car and it was 90+ degrees Saturday and this being the 3rd time doing this only during the day. At night, it's fine.


Nope.

Did you attach to Grid when the no start problem happened to see if there was any error codes? Does it show rpm in Grid Gauge 1 display when cranking?
 
Posts: 2447 | Location: 53056 | Registered: December 30, 2009Reply With QuoteReport This Post
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