BlackLS1Z

I recently purchased some NGK TR55's and received TR5's instead. I called the supplier and they said they were the same as the TR55's (which i found hard to believe), the only difference was the gap. So I gapped them to .50 (they came gapped at .35 i think). So I get these things put in....and now it doesn't pull has hard as my stock plugs that have 80k on them. Now....what could be the problem? I checked and didn't see any hoses disconnected or lose wires. Would the car run rough firing only on 7? It runs smooth...it just doesn't seem to want to climb through the RPM's like it use to. Should I take them out and gap them at .35? Any help would be much appreciated. Thanks!

Colin
98 Z28

cobray

Did you disconnect your negative battery cable? If you didn't, disconnect it for 20 minutes or longer so the computer can reset. Maybe your computer needs to adjust with the new plugs. If that doesnt work, try putting stock plugs (or clean up your old ones) and put them in and see if that changes anything.

cobray

I think the TR5 might be a "hotter" plug than TR55. Do you run 93 (or better) octane?

If I were you, I would tell whoever you got your plugs to send you what YOU ordered not what they think is best for you! Your the customer. Personally I think it is pretty rude of them to tell you that. Who did you buy them from, so we all know who to stay away from?

RTCamaroSS

I know i changed out my stock plugs for TR55's and 10.4mm wires and i noticed a huge difference in power.. that is.. i gained a lot of higher rpm power.. Gotta love those plugs...

gwj

I believe TR5s are the same heat range as TR55s, only they are gapped lower. FWIW, my understanding is NGK recommends not changing the plug gap more than .010".

zZAndrusZz

.070?!? <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" /> How many miles were on those plugs. I'm baffled, you should have gained by installing correctly gapped plugs, unless you have done enough mods to have them gapped to .070. You check all your plug wires making sure they were all tight, and all going to the correct plugs?? Good luck.

BlackLS1Z

So I take it thats a little excessive on the gap huh? :-) This car is stock...except for lid. I just went out and checked it again....each wire goes straight down from the coil to the plug...nothing crossed. Is there anything on Autotap I can look at to see if anything is wrong? Thanks.

Colin
98 Z28

BlackLS1Z

Forgot to mention...the stock plugs had about 80k on them.

zZAndrusZz

Yeah, .070 is a little excessive, how are you determining that it doesn't have as much power as it did before. I've done mods and expected it to be a noticable gain, and then being disappointed thinking I had lost power, when in fact I hadn't. I gapped my plugs to .055 cuz I got headers and a few other mods. If all you did was change plugs, I would think you have a bad/corroded (maybe) connection somewhere. The two on the back, driver and passenger sides, are both hard to get to, Did you do new wires too??

BlackLS1Z

I only did plugs. Wires looked fine so I didn't touch them. Maybe I should get some? I'll have to run my gtech to see if it runs the same. Maybe I'm losing my mind? Thats always possible I guess. :-)

Colin
98 Z28

zZAndrusZz

With 80k on the car, it wouldn't be a bad idea to do wires too, I'd get a good set of taylor or magnacore wires. I've seen the connectors in the stock wires bent all to hell before, kinda hard to transfer energy when they aren't hugging the plug like they should. Good luck with it.

<img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />
Andy

BlackLS1Z

Oh yeah. She's down on power. Ran the gtech and it ran a 15.XX at 97mph!!! <img border="0" title="" alt="[Mad]" src="gr_images/icons/mad.gif" /> I had run it a couple times before and if I remember correctly, it ran in the 13's at 111mph or so. I'm going to try and switch the plugs back but I don't see why it would make that much of a difference. I have a feeling I must have disconnected something by mistake....but I can't see anything. <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />

Colin
98 Z28

zZAndrusZz

Yeah, something is up with that much of a discrepancy (spelling) If anything you should have gained by going to the ngk's. I'm stumped, we need some more autotap/tuning type people in here.

gwj

I don't have any first hand experience with the TR5 plugs, but the stock gap on those seems pretty low for few/no power adders. Maybe switch to TR55 plugs and run .055 - .059 gap? I've tried the TR55s @ .050 but could tell no difference, I'm back to .055 now. Another alternative for hot weather running would be the TR6 plugs, they are colder and the smaller gap on those shouldn't hurt you.

BlackLS1Z

*clicks microphone* "Houston we have a problem." Well let me first start off by saying once you change the plugs a couple times it becomes a fairly simple procedure. <img border="0" title="" alt="[Roll Eyes]" src="images/icons/rolleyes.gif" /> I changed them back...not much difference. Its weird because if I give it half throttle it pulls ok then the more I press the accelerator at that point it doesn't seem to make much of a difference besides creating more noice from the intake....is this normal? Probably doesn't help it was 85 and humid today. What does the dealer usually change during a standard tune up? Plugs and wires? I'm going to order some new plugs (tr55's or 6's) and new wires. I'll have to post a message in the computer section to see if anyone can help me atap this thing to try and diagnose the doggyness. Thanks guys. Anyone need a plug change, i'll be glad to lend a hand <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

Colin
98 Z28

jmX

Are you sure you are getting the wires snapped on the connectors tightly? Should be one click on each plug and 2 clicks on each coil.

BlackLS1Z

Well I went out there today and took all the plugs out and gapped them to how I received them (.035). I disconnected the battery while I did the adjustment. Took it out again...no difference. Does disconnecting the battery reset the computer? If so how long does it take to relearn everything? I was checking out the old plugs and noticed the gap on those things are .070 and only one had the little puck on it. I guess my next step is to put the stock plugs back in to see if the power comes back?
I'm getting pretty good at this plug change thing :-). Thanks for the help guys.

Colin
98 Z28

gwj

Two things you might try: run the engine in the dark and look for any stray flashes (leaks) around the plug wires, and/or pull each plug wire and check the resistance and see if one is way high.

BlackLS1Z

I have bad O2 sensors I think. Would this give me lousy performance?

Colin
98 Z28

cobray

Yes, Bad 02 = Bad Performance.
Your PCM needs the right voltages from the 02 sensor to figure your A/F ratio correctly!