Ignition problems

[Chunk]

Ok, half way through my last main event my car started to spit and sputter as if it were a carb problem, ignition, running out of gas type of thing. It wasnt as if it was down a cylinder. So, I changed carbs and went to the track today hoping that was it. As my luck would go, that didnt fix it. So, I tried changing plugs, changing ign boxes, and double checked the plug wires but no luck. The only thing that made any difference was the ignition box. The one on the car sounded pretty bad and would start sputtering halfway down the straights. The second box seemed to get off the corner much better but still sputtered at the end of the straight. I dont think there is a problem with the ign box but could it be something with the pick ups or??? Im not much of an engine guy!

[Winterracing]

I've been fighting that same problem with my car lately, about 5 races ago we had that happen, changed the plugs and it was fine for 5 races.  Then the last race in practice it occured again.  We changed the plugs which temporarily fixed the problem till about 2 to go in the feature.  We just rebuilt the carbs thinking that was the problem, but if not me might change out the coils.  Have you tried that yet?

Dan
www.winterracing.net

[Hoopy_boy]

Other items to check...
Bad ground or battery
Bad alterntor ( taking  juice away from the ignition)
Bad spark plug cap (improper resistance) One bad plug cap will break the field down in that coil, dropping both cylinders fired off that coil
Bad ignition switch
Bad fuel pump (stops when hot)
Bad harness connection at the firewall
Bad pickup coil behind the rear engine cover (not likely with stock ignition but may fail with redbox ignition)

... just to name a few issues to look into that will cause those symptoms

[VMS Motorsports]

Bad ground, bad ground, or bad ground, probably one of those 3.

[bandostuff.com]

I've seen those little tiny wires on the blue plate chafe where they turn the corner on the plate.  That will send you straight to the Rolaaids bottle!

[Hoopy_boy]

I was just going to ask if we are dealing with red box ignition or not when the site warned that someone had posted and to review my post

~ Gimp ~

[Winterracing]

Bad ground, bad ground, or bad ground, probably one of those 3.

so could it be a bad ground?  Which Ground on the car should i check?  How do i check if the fuel pump is bad or not?  I still think my problem might be in the coils since when we changed plugs it was always a temporary fix for the problem.

Dan
www.winterracing.net 

[VMS Motorsports]

Check them all. if you only have two, add another one from the enging to the chassis.
This is a very weak ignition system we are dealing with, especially if you have any electronic gauges, tach, fans. etc. running off of it.
New plugs fire easier than old plugs, so a bad ground could cause that temporary fix also.
Fuel pump will pump or not pump, so it either runs or doesnt run. Do check anything that is in the same circuit as your fuel pump. Wasted half a season last year with an intermittant issue like you are having and it turned out the hardwired transponder was intermittently shorting out the fuel pump.

[knoxracing]

Have you had ANY charging problems? If you have a week battery or a charging issue the car will get worse as the race goes on, especially if you run a fan. The car will act like you have a crb or electrical issue.

[Winterracing]

Check them all. if you only have two, add another one from the enging to the chassis.
This is a very weak ignition system we are dealing with, especially if you have any electronic gauges, tach, fans. etc. running off of it.
New plugs fire easier than old plugs, so a bad ground could cause that temporary fix also.
Fuel pump will pump or not pump, so it either runs or doesnt run. Do check anything that is in the same circuit as your fuel pump. Wasted half a season last year with an intermittant issue like you are having and it turned out the hardwired transponder was intermittently shorting out the fuel pump.

Now you've got me thinking, i do run the direct wired transponder and it is in the same connection as the fuel pump, but i've just started to have this problem and i would assume that i would have had it all year, but you never know, i think to be safe i might directly wire the transponder to the battery and just add a switch for it?  How did you fix the problem?  Or how did you find the problem?

Dan
www.winterracing.net

[Winterracing]

Have you had ANY charging problems? If you have a week battery or a charging issue the car will get worse as the race goes on, especially if you run a fan. The car will act like you have a crb or electrical issue.

The battery was brand new at the beginning of the season and i only run the fans during cautions, but i guess it probably would be a good idea to fire the car up and make sure the battery is still charging

Dan
www.winterracing.net

[Hoopy_boy]

 Most electrical issues can be found by performing a peak voltage test. Checking the fuel pump I clamp down the fuel hose after disconnecting it from the carbs with one of my Snap On fuel line clamps http://buy1.snapon.com/catalog/item.asp?P65=&tool=all&item_ID=66783&group_ID=1461&store=snapon-store&dir=catalog and restricting down the fuel flow to very little into another fuel container. Let the pump run a tank or 2 of fuel run through the system this way. In case the pump gets hot and shuts down. If it passes this test, I will pump another tank from it letting it run, clamping off the hose to pressure up the pump to shut down, letting off the pinch and repeating the process while another tank of fuel runs through it. Fuel pumps will stop from getting hot or the pressure shut down goes to heck so you have to test both systems of the pump.
 If Jim didn't nail it with his suggestion, I would unscrew the spark plug caps from each wire and ohm them out, probing from the wire to plug connection side. The resistance should be 5000 plus or minus 1000 ohms. Plug cap internal resistors can and will go bad from heat or vibration. Like I said before, one bad wire cuts that coil out of the system. Poor resistance will also fool the silicate capacitor (rev limiter) in the ignition box. Also, like Dennis suggested, low battery voltage, shorted internal voltage regulator etc.. of the alternator will cause issues with the silicate capacitor in the ignition box. Bad chassis ground or shorted plate in a battery will effect it also

~ Gimp ~

[Chunk]

For me, I know the alternator is working good. I havent had any problems there. I dont have a hard wired transponder but I think what I am going to do is pull the nose off the car and pull the engine forward. I have some oil leaks to fix anyways. I do have a cover over the stator and have heard from some people that this could be a bad thing due to heat? I have a sneaking suspicion that it is either a wire with a bad connection, grounding out, or just a bad ground. For me, it only happens under load which makes me think that vibration is worsening whatever it is.

Thanks guys!

[VMS Motorsports]

Check them all. if you only have two, add another one from the enging to the chassis.
This is a very weak ignition system we are dealing with, especially if you have any electronic gauges, tach, fans. etc. running off of it.
New plugs fire easier than old plugs, so a bad ground could cause that temporary fix also.
Fuel pump will pump or not pump, so it either runs or doesnt run. Do check anything that is in the same circuit as your fuel pump. Wasted half a season last year with an intermittant issue like you are having and it turned out the hardwired transponder was intermittently shorting out the fuel pump.

Now you've got me thinking, i do run the direct wired transponder and it is in the same connection as the fuel pump, but i've just started to have this problem and i would assume that i would have had it all year, but you never know, i think to be safe i might directly wire the transponder to the battery and just add a switch for it?  How did you fix the problem?  Or how did you find the problem?

Dan
www.winterracing.net

I didn't find it,  finally the transponder  stopped working, so I bought a wireless one. Replaced it and all the problems went away

[Winterracing]

Alright well i plan on basically going through the car and checking all the connections and grounds to make sure those are working, whats wierd is its only under acceleration after i've been racing for a while and then if i get a caution is seems to help it.  But if i don't find anything wrong i'll see if i can borrow someones spare set of coils and try that and if not i'm going to just unplug the transponder and go from there

Dan
www.winterracing.net