Spark Plugs

[FatNasty231]

just wanted to get a few members' advice on what would be the best spark plug to run in my '87 GN. i will also be running MSD wires with them.

 

[750H.P.V6]

If the car is stock to lightly modified run AC R43TS gapped at a tight .035". For a higher performance level use an AC R42TS gapped at .032". Autolite plugs work well too. It's personal prefference at that point.

Neal

 

[87GNSteve]

I have used the NGK v-power with good results.
UR4 stock UR5 Modified

Currently using the Bosch Super (conventional NOT PLATINUM) and very satisfied.
#7975 stock #7969 modified

Do NOT get the Bosch Platinums, Platinums 2 or Platinums 4

 

[TurboDave]

If the car is stock to lightly modified run AC R43TS gapped at a tight .035". For a higher performance level use an AC R42TS gapped at .032". Autolite plugs work well too. It's personal prefference at that point.

Neal

Neal, what kind of symptoms might one see if gapped too tight, like a tight .028? Especially at idle.

 

[750H.P.V6]

Dave,

To be honest I'm not sure as I don't gap my plugs that tight. I wouldn't think it would make a great difference in idle quality.

Neal

 

[SPOOLFOOL2]

I've had good luck with NGK-R BPR6FS plugs gaped at .028" on my low eleven second, street driven, GN. Heck, it just passed CA. smog with them in.

 

[87NAT]

I normally run autolite 23@.032. A while back when I was troubleshooting a high RPM miss DUsty Bradford told me to run them at .028. I did so with no ill effect at idle or WOT. Dusty told me at high boost(25+psi) he picked up between 30-40 HP on the dyno from spark blowout going from .032 to .028

I always listen to a guy running 8's....

 

[750H.P.V6]

I run an MSD DIS4 instead and gap the plugs at .035".

Neal

 

[TurboDave]

I'm just clutching at straws. I was troubleshooting a WOT surge/lean misfire, and cured it with a ign.module/coil pack swap, but also added new plugs gapped at around .028-.029.

But all of a sudden a new problem has arose. Now, after startup and during warm up, the idle quality is horrible and the A/F ratio is all over the board from 10. up to 17.
Also notice while driving if I really really slowly tip into the throttle it goes quite lean, about 17:1
This doesn't happen if I tip in even just a little quicker than normal.

 

[87NAT]

Turbodave, I dont think the .028 gap will give you any idle issues. Must be something else. The problem I thought would be not enough spark at WOT but it worked okay at the upper RPM band. I dont run crazy boost now to justify a small gap but it was part of a troubleshooting plan that I tried at one time.

 

[DCVING 6]

I've always had the best luck with the Delco CR43TS.

 

[buttonfly]

I'm just clutching at straws. I was troubleshooting a WOT surge/lean misfire, and cured it with a ign.module/coil pack swap, but also added new plugs gapped at around .028-.029.

But all of a sudden a new problem has arose. Now, after startup and during warm up, the idle quality is horrible and the A/F ratio is all over the board from 10. up to 17.
Also notice while driving if I really really slowly tip into the throttle it goes quite lean, about 17:1
This doesn't happen if I tip in even just a little quicker than normal.

Have you had a guage to check fuel pressure, is the fuel system up to par?? (i.e.pump, tank, filter) I had a similar problem, and I had to replace the fuel tank, because after a few minutes of driving the fuel sock would get contaminated with rust particles. I put in a new tank and everything it cool now. What other info can you give us??

 

[TurboDave]

Have you had a guage to check fuel pressure, is the fuel system up to par?? (i.e.pump, tank, filter) I had a similar problem, and I had to replace the fuel tank, because after a few minutes of driving the fuel sock would get contaminated with rust particles. I put in a new tank and everything it cool now. What other info can you give us??

Yup, got a fuel pressure gauge under the hood that I can/do monitor. Doesn't seem to be fuel delivery related.
Brand new R43TS's
As soon as it stops raining (if it ever does) sometime this weekend, I'll get a powerlogger recording at and after startup.

 

[XXQUICK6XX]

Hey Dave,
I tried AC plugs but in the past having weird problems arise I was suggested to try Autolite plugs and my problem disappeared? And been running them since.

Steve