1991 L98 Spark Plug Wires Arcing
Thread Starter
Drifting
Joined: Apr 2011
Posts: 1,925
Likes: 441
From: Albuquerque NM
1991 L98 Spark Plug Wires Arcing
Working on the new to me 1991 L98
I hasn't been running right since I got it. Noticed tonight that 2 spark plug wires have pretty consistent arcing.
Previous owner installed some very cheap Hedman uncoated headers that run freaking hot. Could these have killed the wires?
I assume I should replace all the spark plug wires as a first step?
If I end up keeping the car I'll probably replace the headers with ceramic coated ones, but in the meantime, should I use those spark plug protector boots?
Arcing on two cylinders, how might that be affecting performance? I fixed a vacuum leak and it is running slightly better, but I still wouldn't say it pulls well by any means.
I hasn't been running right since I got it. Noticed tonight that 2 spark plug wires have pretty consistent arcing.
Previous owner installed some very cheap Hedman uncoated headers that run freaking hot. Could these have killed the wires?
I assume I should replace all the spark plug wires as a first step?
If I end up keeping the car I'll probably replace the headers with ceramic coated ones, but in the meantime, should I use those spark plug protector boots?
Arcing on two cylinders, how might that be affecting performance? I fixed a vacuum leak and it is running slightly better, but I still wouldn't say it pulls well by any means.
Le Mans Master
Joined: Jul 2004
Posts: 6,228
Likes: 698
From: Clifton Park, NY ............Clearwater, FL ... 85 Original Owner
Working on the new to me 1991 L98
I hasn't been running right since I got it. Noticed tonight that 2 spark plug wires have pretty consistent arcing.
Previous owner installed some very cheap Hedman uncoated headers that run freaking hot. Could these have killed the wires?
I assume I should replace all the spark plug wires as a first step?
If I end up keeping the car I'll probably replace the headers with ceramic coated ones, but in the meantime, should I use those spark plug protector boots?
Arcing on two cylinders, how might that be affecting performance? I fixed a vacuum leak and it is running slightly better, but I still wouldn't say it pulls well by any means.
I hasn't been running right since I got it. Noticed tonight that 2 spark plug wires have pretty consistent arcing.
Previous owner installed some very cheap Hedman uncoated headers that run freaking hot. Could these have killed the wires?
I assume I should replace all the spark plug wires as a first step?
If I end up keeping the car I'll probably replace the headers with ceramic coated ones, but in the meantime, should I use those spark plug protector boots?
Arcing on two cylinders, how might that be affecting performance? I fixed a vacuum leak and it is running slightly better, but I still wouldn't say it pulls well by any means.
Thread Starter
Drifting
Joined: Apr 2011
Posts: 1,925
Likes: 441
From: Albuquerque NM
Previous owner self reported service record documents shows new wires 4k miles ago
I would have expected them to last longer, which is why I am suspecting issue with the headers.
Previous owner also claims heat soak starter issue, and the hood has a suspicious clear coat fade spot right above the passenger side valve cover, yet the targa top clear is in great shape.
All that to say, I think this car might have an underhood temp issue perhaps?
I would have expected them to last longer, which is why I am suspecting issue with the headers.
Previous owner also claims heat soak starter issue, and the hood has a suspicious clear coat fade spot right above the passenger side valve cover, yet the targa top clear is in great shape.
All that to say, I think this car might have an underhood temp issue perhaps?
Race Director
Joined: Nov 2003
Posts: 12,221
Likes: 446
From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
C4 of Year Winner (appearance mods) 2019
Yeah...Ceramic coating helps A LOT! You COULD have them coated too. If they're not in bad shape. Might not be that much cheaper tho.
Melting Slicks
Joined: Aug 2011
Posts: 2,844
Likes: 176
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Burning Brakes
Joined: Apr 2014
Posts: 829
Likes: 192
With proper boot ends (some may need 90 degree, others straight) it depends on the header tube positions, along with proper routing and securing with looms it should be able to last. You surely dont want any parts of wires touching header tubes. Excessive resistance in the spark plugs can also make arching more likely. So check or change the plugs too
Thread Starter
Drifting
Joined: Apr 2011
Posts: 1,925
Likes: 441
From: Albuquerque NM
Hmm
New plugs and plug wires. Set valve lash. Getting a crank no start condition, with backfires.
Firing order was off at first, checked it, fixed it. Checked it again, seems good. Will check again.
Things to investigate? Was running and driving fine prior to working on it today.
New plugs and plug wires. Set valve lash. Getting a crank no start condition, with backfires.
Firing order was off at first, checked it, fixed it. Checked it again, seems good. Will check again.
Things to investigate? Was running and driving fine prior to working on it today.
Thread Starter
Drifting
Joined: Apr 2011
Posts: 1,925
Likes: 441
From: Albuquerque NM
New wires did the trick! Car is running and driving significantly better now!
Had to reset the timing entirely as previous owner had reinstalled the distributor with everything rotated one over from the normal FSM distributor firing order diagram. Putting the plug wires back on per the FSM distributor firing order diagram resulted in the crank no start due to firing being completely off.
Got it sorted!
Had to reset the timing entirely as previous owner had reinstalled the distributor with everything rotated one over from the normal FSM distributor firing order diagram. Putting the plug wires back on per the FSM distributor firing order diagram resulted in the crank no start due to firing being completely off.
Got it sorted!
