Plug wire integrity

[jrd1990zr1]

I have a set of 1990 OEM spark plug wires which I want to install on my car for ahow purposes. Is there any way to test them before I pull the plenum, install them and then re-install the plenum. Would be a real PITA if one was bad after I install the plenum.

Thanks in advance.

John

[WVZR-1]

Originally Posted by jrd1990zr1

I have a set of 1990 OEM spark plug wires which I want to install on my car for ahow purposes. Is there any way to test them before I pull the plenum, install them and then re-install the plenum. Would be a real PITA if one was bad after I install the plenum.

Thanks in advance.

John

I'd think for general purposes an 'Ω per inch' evaluation of what you've got. There's maybe many thoughts regarding this but most I'd think should compare to the Prestolite 'generalization'.

http://www.prestolitewire.com/pages/...ic_tips/56.php

SPO mentions lengths @ 1 = 36, 2 & 4 = 32, 3 = 28, 5 & 6 = 24, 7 = 20 & 8 = 26

I didn't find a GM/Delphi spec for the wire but I didn't look very hard either. I might later.

[Roadster]

Originally Posted by jrd1990zr1

I have a set of 1990 OEM spark plug wires which I want to install on my car for ahow purposes. Is there any way to test them before I pull the plenum, install them and then re-install the plenum. Would be a real PITA if one was bad after I install the plenum.

Thanks in advance.

John

John, just conduct an ohm test before install......here are the results for me when I checked mine......

Continuing to check as much as I can anywhere there are things to be checked.
Did an ohm test on the spark plug wires, I also have a spare set, so I compared the two sets.
According to my findings, I think #8 plug is bad, reason being is that I could not get a reading on the wire. It stayed @ 1 on the meter even though it intermittently flashed numbers for a spilt second or so, no matter how many times I tested the wire.
The range in specs allows up to 30,000 ohms, any reading above that the wire is to be replaced. Thank you Jep for that info as per the FSM...
So I set the meter @ 20k and figured any reading above that would surely seem suspect. Also to my understanding is the different length in the wire(s) will give you different readings. So all wires will not give you the exact same result.
I believe my wires are original as far as I know.

Results are in "thousands"

Original wires.................Used original wires.........
#1 9.25------------------8.94
#3 7.00------------------7.74
#5 4.87------------------6.12
#7 4.63------------------4.92

#2 6.88------------------7.91
#4 7.27------------------8.25
#6 4.82------------------7.62
#8 no reading-----------8.73-------extra #8 7.29

hope this helps......it helped me find a bad wire on mine......#8 as you can see......it was replaced.....between this and the other issues I corrected with the pull.....resulted in a LT5 which runs extremely well for being stock....with the only mod being a Haibeck chip for the ECM.....
Good luck with yours......

[jrd1990zr1]

Originally Posted by Roadster

John, just conduct an ohm test before install......here are the results for me when I checked mine......

Continuing to check as much as I can anywhere there are things to be checked.
Did an ohm test on the spark plug wires, I also have a spare set, so I compared the two sets.
According to my findings, I think #8 plug is bad, reason being is that I could not get a reading on the wire. It stayed @ 1 on the meter even though it intermittently flashed numbers for a spilt second or so, no matter how many times I tested the wire.
The range in specs allows up to 30,000 ohms, any reading above that the wire is to be replaced. Thank you Jep for that info as per the FSM...
So I set the meter @ 20k and figured any reading above that would surely seem suspect. Also to my understanding is the different length in the wire(s) will give you different readings. So all wires will not give you the exact same result.
I believe my wires are original as far as I know.

Results are in "thousands"

Original wires.................Used original wires.........
#1 9.25------------------8.94
#3 7.00------------------7.74
#5 4.87------------------6.12
#7 4.63------------------4.92

#2 6.88------------------7.91
#4 7.27------------------8.25
#6 4.82------------------7.62
#8 no reading-----------8.73-------extra #8 7.29

hope this helps......it helped me find a bad wire on mine......#8 as you can see......it was replaced.....between this and the other issues I corrected with the pull.....resulted in a LT5 which runs extremely well for being stock....with the only mod being a Haibeck chip for the ECM.....
Good luck with yours......

Thanks Roadster,

I may be crazy but I am going to have the car judged at an NCRS event for a second time and want to put an original set back on the car. I had the car judged in 2010 but National NCRS refuses to acknowledge my Top Flight award since the National Judging Chairman "forgot" to record 3 cars from our meet into the NCRS database. They received all the records (I have a copy of the full set but refuse to look through their files for them since it "was too long ago".

I actually have 2 OEM sets and did the resistance test on the first set:
#1 8.82
#2 8.34
#3 7.22
#4 7.88
#5 5.71
#6 5.92
#7 4.62
#8 7.86

Meter set at 20K ohms. My results are similar to your readings, so it appears this is a good set.
I also calculated the ohm/inch length. High was 0.3023 for the # 8 wire with a low of 0.2310 for the #7 wire. Average ohm/inch was 0.2535 for the set.

I am going to also do the same for the second set and use the best set.

Thank you for the advice.

John

[Roadster]

Originally Posted by jrd1990zr1

Thanks Roadster,

I may be crazy but I am going to have the car judged at an NCRS event for a second time and want to put an original set back on the car. I had the car judged in 2010 but National NCRS refuses to acknowledge my Top Flight award since the National Judging Chairman "forgot" to record 3 cars from our meet into the NCRS database. They received all the records (I have a copy of the full set but refuse to look through their files for them since it "was too long ago".

I actually have 2 OEM sets and did the resistance test on the first set:
#1 8.82
#2 8.34
#3 7.22
#4 7.88
#5 5.71
#6 5.92
#7 4.62
#8 7.86

Meter set at 20K ohms. My results are similar to your readings, so it appears this is a good set.
I also calculated the ohm/inch length. High was 0.3023 for the # 8 wire with a low of 0.2310 for the #7 wire. Average ohm/inch was 0.2535 for the set.

I am going to also do the same for the second set and use the best set.

Thank you for the advice.

John

Hello John,
Yes, your results are very similar to mine, which is very good. I think our findings were in the lower end of the scale, so I would imagine that we will still get lots of miles out of them, for sure!!!

I would still check the wires for any cuts, or burn marks (which you already may have done), just to be sure. Repeating myself, after replacing #8 and correcting #7 wire (which would not stay completely on the coil terminal(kept popping off), I run up through the rpm range with absolutely no problem whatsoever.....

Wish you the best in your NCRS event.....hope everything goes well!!!
And glad this helped you out.....