98 S-10 Arcing Problem

[potts200]

This problem has been perplexing me for a few weeks
I've got a 98 S-10 4.3L X code engine with 107,000 miles on it. I recently gave it a tune-up including new AC Delco Platnum plugs gapped to .060 in, Bosch plug Wires, Bosch cap and rotor, and new ignition coil. I also replaced the fuel filter, air filter, and the pcv valve. After all of this was done I noticed the truck was missing a little at idle speed. Upon further inspection I noticed at night that I could see arcing from the sparkplug boot. I have rechecked all of the gaps and they seem to be okay. Even the coil arcs a small bit when the throttle is opened. I used a small amount of dielectric grease on the boot at the spark plug end and anti-seize on the plug threads. I have read a lot of cautionary comments about using anything other than AC Delco components so to be thorough I bought the Delco cap and rotor, plug wires, and ignition coil to try and eliminate the arcing but no luck, it still arcs. Acrs at the coil when the throttle is initially opened and at the sparkplug boot at idle speed . Through all of this the only code being thown has been P0300 Multiple/Random Cyclinder misfire. I will take any advice I can get at this point . I have a multimeter so I can make basic voltage checks and resistance checks. Is it possilbe that the Ignition Control Module (IC on the bracket next to the coil) is bad? What is the function of that modeul anyway? Or have I missed somehting really simple?

[MT-2500]

Originally Posted by potts200

This problem has been perplexing me for a few weeks
I've got a 98 S-10 4.3L X code engine with 107,000 miles on it. I recently gave it a tune-up including new AC Delco Platnum plugs gapped to .060 in, Bosch plug Wires, Bosch cap and rotor, and new ignition coil. I also replaced the fuel filter, air filter, and the pcv valve. After all of this was done I noticed the truck was missing a little at idle speed. Upon further inspection I noticed at night that I could see arcing from the sparkplug boot. I have rechecked all of the gaps and they seem to be okay. Even the coil arcs a small bit when the throttle is opened. I used a small amount of dielectric grease on the boot at the spark plug end and anti-seize on the plug threads. I have read a lot of cautionary comments about using anything other than AC Delco components so to be thorough I bought the Delco cap and rotor, plug wires, and ignition coil to try and eliminate the arcing but no luck, it still arcs. Acrs at the coil when the throttle is initially opened and at the sparkplug boot at idle speed . Through all of this the only code being thown has been P0300 Multiple/Random Cyclinder misfire. I will take any advice I can get at this point . I have a multimeter so I can make basic voltage checks and resistance checks. Is it possilbe that the Ignition Control Module (IC on the bracket next to the coil) is bad? What is the function of that modeul anyway? Or have I missed somehting really simple?

I am not sure it is the problem but you need to find someone with a good engine capable scanner and check the cam retard offset. If it is off more that 3 degrees - or + have it reset back to specs.
What it is is the centering of the dist rotor to the dist cap spark plug terminal.
If the dist rotor is not center right the spark gap will be to wide in there and cause the spark voltage to go way up and spark will go all different directions.
Also recheck the ends of the spark plugs.
MT

[potts200]

MT, thanks for the reply. I just have a few questions: Is the cam retard offset periodically adjusted by the PCM and is there some condition or fault that would cause the PCM to make this adjustment such as timing chain stretching or a bad crank position sensor? When I replaced the cap I noticed that the worst of the wear was to the left of each point if looking at it from the bottom and coil terminal pointing to the left. I thought that might indicate that the timing was advanced to much. Lastly, do you know if there is a simple resistance check to diagnose a faulty or failing crank position sensor? Thanks!

[MT-2500]

Originally Posted by potts200

MT, thanks for the reply. I just have a few questions: Is the cam retard offset periodically adjusted by the PCM and is there some condition or fault that would cause the PCM to make this adjustment such as timing chain stretching or a bad crank position sensor? When I replaced the cap I noticed that the worst of the wear was to the left of each point if looking at it from the bottom and coil terminal pointing to the left. I thought that might indicate that the timing was advanced to much. Lastly, do you know if there is a simple resistance check to diagnose a faulty or failing crank position sensor? Thanks!

Bad crank sensor will usually trip a code or engine will quit running.
It takes a lab scope to run a good test. A sensor will ccome and go or act up when the tempture changes so a resistance check will not always so a bad one.

The timing chain chain or timing does not affect the cam retart setting.
Base timing is set by crank sensor. Turning the dist has no affect on timing.
The cam retard is set by turning the dist and watching the reading on scanner. When it is set it should stay set. The computer reads it all of the time over 1000 rpm but does not change the reading untill the dist is moved .
If the old cap terminals were ate off on one side is a indication that the cam retard is off.
Good luck MT

[RahX]

Turning the distributor on those engines won't change the ignition timing at all, just the cam sensor timing. I think the PCM will set a check engine light if the cam sensor timing is off by like 5deg or more. All the wires arc? Sounds like crappy wires IMO, take em back and spend a bit more cash and get the delco wires and see if that helps.

[BLAZERBOY69]

Not Sure If I'm Right Or Not, But Aren't The Plugs Supposed To Be Gapped At.45? .60 Is Not Much Bigger, But Might That Not Affect The Plugs Rate Of Fire? That Might Cause The Misfire Code Posibly.

[MT-2500]

Originally Posted by BLAZERBOY69

Not Sure If I'm Right Or Not, But Aren't The Plugs Supposed To Be Gapped At.45? .60 Is Not Much Bigger, But Might That Not Affect The Plugs Rate Of Fire? That Might Cause The Misfire Code Posibly.

You are right on plug gap on it factory specs is 45" on that one with ac 41-932
But the 2004 AC delco spark plug book gives 54" gap. on a 98 S-10 4.3 w
And spark plug No as 41-975
Sometimes specs are changed after they come out.
On a 96 up with the newer ign system and vcm they should run at 54-60" with no problem. The wider gap gives a little hotter spark.
MT

[busa4]

spark plug gap for a 98 s10 with a 4.3 is 0.060". if your arcing just one plug then there is a high resistance in that plug. remove the plug and install it in another cylinder. if the arcing changes then you have a bad plug.

[Southern Comfort]

You may have got a hold of some defective diaelectic grease. Go to a local auto
parts store and buy some brake clean and spray it on every place you put the diaelectric grease on and clean it well. Then try it without any diaelectric grease, if it stops misfiring, then that was your problem.
Thanks
SC

[busa4]

what did you find? keep us updated.

[potts200]

Thanks for all of the replies. I haven't had much time experiment with it. Nobody I know has a scan tool so I may purchase one or see if I can't find a shop that will work with me and check what I want them to check. And of course alert me to any other problems they might see. I am going to pull the plugs tomorrow, clean them up and check the gap again. I am running AC Delco 41-932s with a gap of 0.060 in. That is what's listed on the emission sticker under the hood. I found some sort of GM Tech training manuel that says the 4.3L EDI distributor cannot be adjusted but on the larger V-8s it can. I under stand that timing can't be changed by moving the body but I agree with MT that by moving the dist. body that should bring the rotor and cap terminal in closer alignment at the precise firing moment. Has anybody acutally moved the dist. body with sucess and no codes thrown? Here is the link to the manuel; it's really a nice read for novices like me!
http://fsunw3.ferris.edu/~millerm/SWB_a8_m09_Final.pdf

[MT-2500]

Originally Posted by potts200

Thanks for all of the replies. I haven't had much time experiment with it. Nobody I know has a scan tool so I may purchase one or see if I can't find a shop that will work with me and check what I want them to check. And of course alert me to any other problems they might see. I am going to pull the plugs tomorrow, clean them up and check the gap again. I am running AC Delco 41-932s with a gap of 0.060 in. That is what's listed on the emission sticker under the hood. I found some sort of GM Tech training manuel that says the 4.3L EDI distributor cannot be adjusted but on the larger V-8s it can. I under stand that timing can't be changed by moving the body but I agree with MT that by moving the dist. body that should bring the rotor and cap terminal in closer alignment at the precise firing moment. Has anybody acutally moved the dist. body with sucess and no codes thrown? Here is the link to the manuel; it's really a nice read for novices like me!
http://fsunw3.ferris.edu/~millerm/SWB_a8_m09_Final.pdf

On adjusting some of the dist is where gm bits you in the rear.
Some are not adjustable. But where there is a will there is a way.
I have sloted the hold down clamp on some to be able to adjust them.
But you will need a good engine capable scanner to check and adjust them.
Good Luck MT.