Home page
SPONSOR AD SPONSOR AD

Topic: intermitent fire

in Forum: C3 Electrical


intermitent fire

Posted: 1/13/04 12:02pm Message 1 of 23
Former Member
Send PM
jacksonville, FL - USA
Joined: 10/28/2003
Posts: 44
Vette(s): 81 Silver/Drk Blue, #684 made in Bowling Green 67xxx miles 87 Maroon metal, lots of miles but very fast and solid
My 81 has a strange problem.

It has a 79 ditributor and carb, no computer. This setup worked fine for about 6 months until one day on the way to work the car just shut off. Turned over fine, no fire. The problem (so I thought) turned to be a poor connection on the ignition power wire. I cut the wire off about 5 inches from the distibutor and put on a new spade connector, BINGO fire runs fine for two weeks. Then my battery goes bad, I had known for a while that the battery was failing but was always able to jump it off. I finally replaced the battery and all worked great again until a few days ago, I jumped the car and again had no spark, I checked for 12v at the coil and found no problem. I then opend the distibutor and checked everything out visually, no problems. Took out the coil, cleaned all connections and put it back together checked for spark again and it started right up? I assumed that I had fixed the problem by cleaning the connections etc. and went on my merry way. BUT the next morning the same thisng happened, no spark, 12v at the coil, plugged everything back in and it runs fine.
It has done this three times now, it seems to work great after I take it apart put it back together for one day, if I park it overnight (in a warm dry garage) I will have no spark the next morning.

What I have tried:
1- before attempting to start it I check for coil power (always good)
2- connect a spark gap tester before I start it without touching anything else (never has spark in the morning)
3- SLOWY turned ignition while watching voltmeter (it cleanly sends 12v to coil at the same place everytime)
4- left a drop light with a 75w bulb hanging under colum overnight to keep it warm and dry (no effect)

I am tempted to run a wire directly from battery with toggle for the ignition- bad idea? why besides the obviuos cosmetic reasons.

perplexed |headscratch|


|B|Two vettes, one is broke at all times!!|/B| |IMG|http://home.comcast.net/~edwarhdgs1/81and87-veryverysmall.jpg|/IMG|
SPONSOR AD:: (Our Sponsors help support C3VR)

intermitent fire

Posted: 1/13/04 5:08pm Message 2 of 23
Profile Pic
Lifetime MemberLifetime Member
Moderator
Send PM
CUYAHOGA FALLS, OH - USA
Joined: 12/2/2003
Posts: 6424
Vette(s): 1975 C3 Red, T-Tops, Black Interior. All I need is time and money! Getting there!
Check the distributor pick up and wires to the pickup. Unplug the wires from the module to the pickup. Use an ohm meter and measure the resistance on the two wires to the pickup. The resistance should be between about 700 to 1200 Ohms. This reading may vary slightly between years. If it's out of range, replace the pickup. While checking the ohm reading, wiggle the wires around. Sometimes the wires break inside the insulation. They look okay but lose contact. This is a result of the vacuum advance moving the wires back and forth. You might feel the wire broken inside the insulation even before you use the ohm meter. I have replaced several of these for both of these reasons. Let me know what you find.

Ken Styer.

|UPDATED|1/13/2004 5:08:33 PM (AZT)|/UPDATED|



intermitent fire

Posted: 1/14/04 7:59am Message 3 of 23
Former Member
Send PM
jacksonville, FL - USA
Joined: 10/28/2003
Posts: 44
Vette(s): 81 Silver/Drk Blue, #684 made in Bowling Green 67xxx miles 87 Maroon metal, lots of miles but very fast and solid

Thanks for the quick reply Ken.

The resistance was about 1K.

After putting the dist back together it fired right up again, this time I yanked on all of the wires and connectors just short of unplugging them... not a stutter.

I pulled of the coil cover and started it up again, pulled-poked-prodded no problems.

My wife doesnt trust my car anymore and she wont ride in it until I "fix it".



|frown|


|B|Two vettes, one is broke at all times!!|/B| |IMG|http://home.comcast.net/~edwarhdgs1/81and87-veryverysmall.jpg|/IMG|

intermitent fire

Posted: 1/14/04 8:26am Message 4 of 23
Profile Pic
Lifetime MemberLifetime Member
Moderator
Send PM
CUYAHOGA FALLS, OH - USA
Joined: 12/2/2003
Posts: 6424
Vette(s): 1975 C3 Red, T-Tops, Black Interior. All I need is time and money! Getting there!
This is somewhat rare, but check it out. Sometimes the dist housing loses it's ground to the engine. No spark. Metal to metal contact can lose electrical contact with good physical contact. Temp, moisture, etc, can cause this to randomly change. When it won't start, use you ohm meter betweent the distributor housing and the manifold. If it's bad pull the distributor and clean the base and the hole in the manifold, as well as the distributor hold down on it's contact points. As I said, this is a long shot, but I have seen it happen a few time.

Ken Styer


intermitent fire

Posted: 1/14/04 8:21pm Message 5 of 23
Former Member
Send PM
Canada
Joined: 11/27/2003
Posts: 147
Vette(s): 1974 T-top 454/400 auto w/delux interior, power windows, white w/black int.,American Racing mags w/Goodyear tires. previously owned... 1969 convertible - 427/390 auto w/hardtop 1965 coupe - 327/300 4 spd
Not saying this is it, but this happened to my '74. (with electronic dist & coil).Kept cutting out, leave it sit for a bit (or cool down) starts right up again. Drove me crazy. First started by replacing parts in dist, then whole dist. Then one day quit and wouldn't go no matter what I did.Had it towed home and tore apart the wire loom going to the dist. Some knucklehead had used one of those squeeze crimp connectors to lengthen the b+ wire to the coil and it would sometimes come loose. Haven't had any trouble since.
Good luck
Phil



intermitent fire

Posted: 1/15/04 2:25am Message 6 of 23
Former Member
Send PM
TWENTYNINE PALMS, CA - USA
Joined: 8/6/2003
Posts: 245
Vette(s): 77 Vette L82, black.
Not sure on your model, but if you have an ignition module i'd check it as well. Both the module and the connection.


|IMG|http://www.C3VR.com/member_uploads/3701_3800/3714/duskbgoddesssmall.jpg|/IMG| |B|Semper Fidelis! |/B|

intermitent fire

Posted: 1/15/04 7:55am Message 7 of 23
Former Member
Send PM
jacksonville, FL - USA
Joined: 10/28/2003
Posts: 44
Vette(s): 81 Silver/Drk Blue, #684 made in Bowling Green 67xxx miles 87 Maroon metal, lots of miles but very fast and solid
Well 2 days, 6 starts, 50 miles and no failures. I hate to start replacing stuff that works.
It has been dry and warmer the last few days, I guess I'll what happens when it gets cools off again.

BTW, pardon my ignorance but.. what is "b+ wire"


|B|Two vettes, one is broke at all times!!|/B| |IMG|http://home.comcast.net/~edwarhdgs1/81and87-veryverysmall.jpg|/IMG|

intermitent fire

Posted: 1/15/04 2:20pm Message 8 of 23
Former Member
Send PM
Canada
Joined: 11/27/2003
Posts: 147
Vette(s): 1974 T-top 454/400 auto w/delux interior, power windows, white w/black int.,American Racing mags w/Goodyear tires. previously owned... 1969 convertible - 427/390 auto w/hardtop 1965 coupe - 327/300 4 spd
If you have a dist. with the coil on top, as I think you do, there will be 2 wires going to it. One will be for the tach ( and should say " tach")the other will be the power wire supplying 12v to the coil and should be labeled "B+"



intermitent fire

Posted: 1/16/04 10:40am Message 9 of 23
Former Member
Send PM
jacksonville, FL - USA
Joined: 10/28/2003
Posts: 44
Vette(s): 81 Silver/Drk Blue, #684 made in Bowling Green 67xxx miles 87 Maroon metal, lots of miles but very fast and solid
Thanks Snoopy

My "B+" wire connector has been replaced with a crimp on blade connector. It seems to be real snudge (I have crimped down the blade edges and wire crimp)I actually have to remove the coil cover and hold down on the male end from the top while I push on the connector from the bottom.


|B|Two vettes, one is broke at all times!!|/B| |IMG|http://home.comcast.net/~edwarhdgs1/81and87-veryverysmall.jpg|/IMG|

intermitent fire

Posted: 1/30/04 12:43pm Message 10 of 23
Former Member
Send PM
jacksonville, FL - USA
Joined: 10/28/2003
Posts: 44
Vette(s): 81 Silver/Drk Blue, #684 made in Bowling Green 67xxx miles 87 Maroon metal, lots of miles but very fast and solid
Problem solved!!!!

After all the messing around I replaced the ignition module (the old one tested good at the parts store)

BINGO- runs better then ever, big long spark on my tester

Thanks for all the help guys, next time yer in Jacksonville I'l buy ya beer or two. |cheers|


|B|Two vettes, one is broke at all times!!|/B| |IMG|http://home.comcast.net/~edwarhdgs1/81and87-veryverysmall.jpg|/IMG|

in Forum: C3 Electrical


SPONSOR AD: (Our Sponsors help support C3VR)