LegendsRacer - Legends & Bandolero Racing Forum
LEGENDS => Engine Care & Tuning => Topic started by: Chunk on August 26, 2011, 12:26:11 am
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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!
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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
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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
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Bad ground, bad ground, or bad ground, probably one of those 3.
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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!
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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 ~
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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
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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.
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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.
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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
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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
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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 (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 ~
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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!
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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
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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
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Just an update on what i've found, the grounds seemed to be all tight, but where the plug wire connects to the spark plug boot the boot can turn. 2 of the wires are like this and the other 2 aren't. I was able to pull the boot off on cylinder 2 and the wires are all exposed and not doesn't look right. On cylinder 3 the plug boot also spins, but when i pulled that boot off they had more of a "screw" look inside. That might have just been enough to cause a problem.
Dan
www.winterracing.net
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Thanks for the update... Yes, where the plug caps connect to the spark plug wires if you look inside the opening, there should be a wood screw looking metal center stud. New caps screw onto the spark plug wires. Sounds definately like you had a resistance issue... LOL
~ Gimp ~
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Thanks for the update... Yes, where the plug caps connect to the spark plug wires if you look inside the opening, there should be a wood screw looking metal center stud. New caps screw onto the spark plug wires. Sounds definately like you had a resistance issue... LOL
~ Gimp ~
Yup i figured when the book came right off the wire and looking at the wire, theres no way it looks to have anything screw in to it the only way i got the plug boot back connected with the wire is by pushing it on, and even then its still loose feeling while all the others are tight and can't turn
Dan
www.winterracing.net
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... and even then its still loose feeling while all the others are tight and can't turn
Dan
www.winterracing.net
Sound like you need a new one; http://www.rpmracingca.com/proddetail.asp?prod=Ignition%3ASPB
Randy - RPM
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Thanks for the update... Yes, where the plug caps connect to the spark plug wires if you look inside the opening, there should be a wood screw looking metal center stud. New caps screw onto the spark plug wires. Sounds definately like you had a resistance issue... LOL
~ Gimp ~
Yup i figured when the book came right off the wire and looking at the wire, theres no way it looks to have anything screw in to it the only way i got the plug boot back connected with the wire is by pushing it on, and even then its still loose feeling while all the others are tight and can't turn
Dan
www.winterracing.net
If you have any slack, cut 1/4 to 3/8 inch off the end of the spark plug wire with a wire cutter
~ G ~
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I'll have to try that then the spark plug boot seemed fine just the wires were loose and could be pulled, not screwed out easily.
Dan
www.winterracing.net
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I'll have to try that then the spark plug boot seemed fine just the wires were loose and could be pulled, not screwed out easily.
Dan
www.winterracing.net
Oh sorry, I mis-read what you had posted; Like Greg said cut off the wires tip and re-install by screwing it back on.
Randy - RPM
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Just an update to my problem. I finally got to start tearing things apart today, looking mostly for bad grounds or melted wires. The one thing that I found was there is a butt connector connecting the oil sensor wire to another wire that goes to the main harness. The wire on the harness side of the butt connector seemed to have been loose or completely disconnected altogether. There is a posibility that that wire was contacting the oil pan. However, I couldnt find any power on the harness side of the connector, just the sensor side. I dont believe there is any way that the sensor side of the connector could have been grounding out. Especially because the only time that wire is hot is if the sensor triggers for low oil, correct me if im wrong. I am going to try it without the oil sensor hooked up. If it still has a miss, I am going to un hook the neutral light as well as a few other things. The main grounds seemed to look good and intact to me. One thought I had is that I possibly have a bad master power switch. As of now, I use it to break the ground. I may try to bypass the switch alltogether. I am really hoping that it isnt the stator/triggers on the back of the crank case!
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No, don't worry about that oil sender wire in relevance to this issue. Possible that the pulser (pickup coil) on the rear of the engine is bad, if you need the ohm spec on that item, let me know. Honestly I still question the fuel pump or it's ground. Bypassing that toggle switch for test is a good idea. Might want to disconnect the main harness connector at the firewall, clean it, wipe some dielectric grease across the contact face of the connector and reconnect it. I'm anticipating issue resolution on this one...
~ Gimpster ~
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Thanks for the info Gimpster. I will go over the fuel pump connections tomorrow. The thing that is odd to me is that after changing the ign boxes, I had the same miss but it happened at a higher rpm. Im not sure if that just has something to do with the settings in the box itself? The one on the car is all but brand new and the spare is pretty old.
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It may not be the cause of your problem BUT, I had simular problems a while back with simular symptoms....
Sometimes the car would seem to get intermittently fuel starved latter in the races. Then it would start running OK again. I tried replacing the fuel filter and fuel pump but the problem kept coming back.
I went to the fuel pump and noticed it was only kicking in intermittently.
A friend of mine (with allot more Legends experience than me) noticed that my car had an emergency fuel shutoff switch. He said that they often caused problems and most people bypassed them along time ago. If you car has an emergency fuel cutoff switch, it will be under the dash.
We bypassed the safety switch and life was good again!
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I have seen that problem as well. I wired my car myself and made sure not to include that switch. I've heard it has caused a lot of red boxes to go bad.
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check your blue plate. The actual pickups on it... Here is what happens: when you install the blue plate, most people just throw it on, adjust the timing, and tighten the screws. This will work for a while, but most likely you will have problems down the road. The reason is that there is that you need to set the clearences between the rotor on the crankshaft, and the actual pickups (the black pieces on the blue plate) When you install the blue plate, take 2 matchbooks, and fit the thickness of the matchbook cover in between each pickup and the rotor. (a 13-14 thousandths feeler guage works too, but I have found that a matchbook is easier.
To check if this is the problem, remove the pickup plate and look at the inside surface of the pickups. if there is any worn, or flat spots, they are likely the problem. What happens is with to little clearance, over time, all the dirt, rubber, etc, that gets thrown up, rubs away at the pickups. This could take a month, or it could take 3 years, but it will happen if there is not enough clearance, and it will drive you CRAZY trying to find the problem. I have found the problem also gets worse as the engine warms up, not sure why, but it seems to me it does.
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Update: I have tried yet another red box, jumping the ign switch and main switch, plug wires, carbs, plugs, and checked compression and back lash to make sure I didn't drop a valve seat. Still no fix. The only thing I haven't changed is the coils and blue plate. I took the stator cover off and checked the gaps. They looked fine and no visible damage. I think my next move is to just try a different blue plate! Thanks for the help!
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On the blue plate where the wires pass through the gromet, I have seen several short out there. Does the car spit and sputter in the shop or just on the track after a while?
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It does it just sitting on jack stands at 6-7 thousand as well as on the track
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Are you SURE you do not have carb issuse?
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I am positive. I have swapped them.
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if you have red coils make sure sparkplug wires are all the way in you should not see the connector. if notthat spray wd40 around carb boots and behind where those vaccum boots are
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Have you changed the pick up plate yet??
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Have you changed the pick up plate yet??
no, that is my next move
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I've been waiting the plate swap result before my next suggestion too
~ G ~
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Do you run the cover? If so, make sure that the plate does not contact the cover at all, look for evidence of contact/shorting.
Have seen different model year cover gaskets that are thinner that will allow contact/arcing.
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Jim,
I heard there was some arcing going on inside your helmet too....Now I know why you have no hair on your melon. ;D
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Man... that last comment sure explains the realavence of a recupitulation valve to an infragnator stage point !
(whew) motor should rock in rpms now.... main topic answered ?? hmmm
~ Gimp ~
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Sorry Gimp....I just couldn't resist. ;)
Now back to the original post of assisting with the ignition problem.
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Lol... all in good fun ! Made me chuckle. I was waiting responce from Jim in defense or agreement
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I'm just waiting to see how long it's going to take to put in the pick-up plate...
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I hear ya... was wondering if it was a valve issue or a cam follower hanging up in the head if the plate doesn't fix it
~ G ~
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I am pulling the engine out this weekend. My wife has a long list of Hone-do's before I can get back to work on it. I do run the cover and will inspect for wear and maybe even space it out a ways?. I am putting the engine in a different car to get ready for the nationals so I am planning on pulling it out and inspecting the plate and pick ups well, and changing it regardless of how it looks. Thanks for the help guys!
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I never ran the cover on the rear of the engine. Didn't have any issue with rocks or debris etc.. hindering operation, over the years. Before I washed the car I would stick 3 strips of duct tape together side by side and cover it though...
Honey-do list before the race car. That sounds serious !! (LOL)
~ Gimp ~
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Update: I took the engine out and began to take the blue plate off. I noticed that the gaps between the rotor and two pick ups were a little different and it looked like one had been rubbing. I changed the plate and spent a decen amount of time re-timing it. I fired it and it seemed to run great on jack stands. I am taking it to the track this week to test it. Thanks for the help guys!