Intermittent spark problem

[max]

Hi everyone ! I just do not have time to do some complete search . Please do not get angry . I hope for that if someone can give me quick pointers what to check .
problem is like that . Was driving onna 55mph road , and when overtaking some car ,felt like car momentarily shut down . Then after some seconds again when accelerating not really hard car just died . Pulled out of gear , stopped, and she did not start . Cranking good but no fire up . After 40 minutes of waiting for the trailer tryed it again , started from a half turn and drove 2 miles to the gas station , shut it down , started , all good , pressed the gas some pop and it died .
No start again , Took it inna garage, next evening tried to start , half turn start !!. Next evening again no start , checked spark , no spark .
Now , what do I check and how ? commutator ? Coil ? GM's anti theft Vats system ??
I always hated them electrical problems . Just have to deal with it and repair it .
Please help !

 

[vette-dude]

Hi everyone ! I just do not have time to do some complete search . Please do not get angry . I hope for that if someone can give me quick pointers what to check .
problem is like that . Was driving onna 55mph road , and when overtaking some car ,felt like car momentarily shut down . Then after some seconds again when accelerating not really hard car just died . Pulled out of gear , stopped, and she did not start . Cranking good but no fire up . After 40 minutes of waiting for the trailer tryed it again , started from a half turn and drove 2 miles to the gas station , shut it down , started , all good , pressed the gas some pop and it died .
No start again , Took it inna garage, next evening tried to start , half turn start !!. Next evening again no start , checked spark , no spark .
Now , what do I check and how ? commutator ? Coil ? GM's anti theft Vats system ??
I always hated them electrical problems . Just have to deal with it and repair it .
Please help !

I would guess bad ignition coil (the one in dist cap) or bad ignition module inside dist. (Might also be the pick up coil inside dist.) Anyone else??

Randy

 

[max]

So there is pick up coil and ignition coil inside distr ? How to check them if they are bad . Iknow manual says to measure the resistance of a coil and okey , That I will do , but is ther any other ck ups I should know ?
I am really desperate . My other car's compressored engine died too the other day ... And now this with my vette !

 

[vette-dude]

So there is pick up coil and ignition coil inside distr ? How to check them if they are bad . Iknow manual says to measure the resistance of a coil and okey , That I will do , but is ther any other ck ups I should know ?
I am really desperate . My other car's compressored engine died too the other day ... And now this with my vette !

No there is an ignition module and a pickup coil inside the dist. The ignition module is the black plastic looking piece with the small colored wires plug into the end of it. That is the most likely part to fail.

Check the coil in the dist. cap first. This has to be checked as per the manual. Then if this checks okay, replace the ignition module. I doubt the pick up coil in the dist is bad. Very rare for them to go bad.

Randy

 

[max]

thanks Randy , gonna go now, check

 

[Hrtbeat1]

I had a problem similar turned out to be the wiring harness that the ignition module plugs into. I think I got the new one from Eckler's. It seems they called it a Distributor terminal board w/ cap (capacitor.) It was the one on the backside of the distributor near the firewall. The section that comes to the inside of the distributor has a little moulded piece that had broken on mine. One of the wires of the term board is a ground and attaches inside the distributor with a small screw. If this is not attached the car will crank all day long but not start. While I was replacing I changed out the module also. It seems like you need the 7 pin module. Once I replaced the above items mine started right up and haven't had a problem in over 2 yrs.

 

[max]

Well, got inna garage yesterday . Took distributor apart . Came out that pick up coil shows 1 (resistance. ) Which as I get it means I have to ditch it .
Ordered the new one , have to wait 2 weeks . cost is little over 50 bucks .
As Randy said , very rare for'em go bad . My friend said the same . I still have a feeling that something else needs a check up .
Now the only thing which is left is to take dist off and take the pole out to get the coil.
Hope I succeed.

Oh . How to check if the module is okey ?

 

[max]

Hrtbeat1 .. Do you think I should order the module also ?
I checked that harness with a capacitor for resistance
and wires all turned out to be okay . Whats interesting
my harness enters the dist from engine side not from
firewall side ...

 

[vette-dude]

I would replace the module also. Just one more thing that can give you fits.

Randy

 

[Hrtbeat1]

Hrtbeat1 .. Do you think I should order the module also ?
I checked that harness with a capacitor for resistance
and wires all turned out to be okay . Whats interesting
my harness enters the dist from engine side not from
firewall side ...

You found one of the harnesses ... the front one. That harness plugs into the ignition module (semi-cicular w/ 7 pins, two screws holding it down) the other end of the ignition module plugs into the harness I was refering to. There is a capacitor on one of the wires. You may get resistance from all the wires but if the capacitor is leaking you wouldn't know. You would have to test it for leakdown. (A capacitor builds a charge to a certain point, holds it, and then when called for releases it.) You can charge a capacitor and set it aside for hours or even days, if you short the two terminals it will let off its charge. A mean little joke done with small capacitors around our shop. Always short a capacitor before handling.

The coil should be in the top of the distributor cap. It can be removed with out pulling the cap off the distributor. There are two screws one between #8 & #4 and one between #5 & #7 for the coil cap. Then there are four screws that hold the coil down. The coil will have three wires with one going to ground, the other two go to the terminals in the "hump" of the distributor cap.

 

[max]

Oh , Hrtbeat1 . I guess I described it wrong. The coil is yeah under the plastic cover on top of dist. I checked that , it seemed ok. But there is another one . The pick up coil or pole piece with a magnet as they call it inna Ecklers. basically a crank sensor but situated inna dist under rotor . has 2 wires runnin from it , plugs inna harness which is at the firewall side of a dist and which is plugged in 2 contacts end of a module . The other side of module has 5 contacts (ends) and harness with a capacitor is plugged into it .
So that pick up coil showed infinite resistance , which means it is shorted ...
or am I messin' something ?
Sorry man , if I bored you , but just I am not at all electronics man I am mostly a powerslide man if you know what I mean.

PS I actually still don' understand how to make sure capacitor isn't leakin' ?

 

[max]

To Randy . They offer some high perf ACCEL module . Is it worth something ?

 

[vette-dude]

To Randy . They offer some high perf ACCEL module . Is it worth something ?

Sorry -- can't answer as I have never used one. Have replaced stock ones with aftermarket standard modules and they do all I ever needed. I think the Accel module would work as well or better than the stock item if you wanted to spend the money. I have had good luck with other Accel ignition parts in the past. Hope you get it fixed soon.

Randy

 

[max]

Well, why to spend the money for smth , that does nothing ...
Thanks Randy.

 

[max]

Well It's been some time , but I've been busy driving her as much as I can get . Inna end of october it will be a sleep time for us , as conditions here start to be not really good .
Turned out to be pick up coil , installed the new one put it all together , still missed one tooth , cause had to turn dist about 20 degrees off it's previous position . One problem though , where inna world is that timing mark . I never found it , had to "tune it " by sound of the engine and 3 or 4 drives around the block.
In the begining I guess it was really advanced and spark cables were touching each other at the dist area . Idle was kinda erratic , like one or two misfires in 10 sec duration , turned it back a bit and carefully spread the cables , now idles good , smooth , no misfires . All good . went for a test ride , sideways
Another problem solved solely by me ( I mean by that , not the shop )and you , guys Thanks for support .
Guess though , will need new cables , or maybe even plugs .
Those platinum Bosch plugs interested me . Is it a good buy ? I mean is it sensible ? and maybe someone have those already ? whats the specification of those , the number I ask at Bosch dealer ? She is L98 91.
Thanks to all max

 

[my_85_vette]

one thing you might want to check is the throttle positioning sensor .. happened to me ... just a thought