Anyone with ignition problems (misfires, stuttering)

[gig]

Hey all,

Just thought I'd post this message that might help someone. I've been chasing a missing problem for the last 2 years on my 97 Firebird 3.8 V-6. It started at 36,000 miles, and my car now has 84,000 miles. So far I've replaced the wires 4 times and plugs 5 times along with the fuel injector on cylinder 6, camshaft sensor, PCV valve 2x, fuel filter 3x, all coils, and ignition module. Yup, I've done it all, and that misfire just kept coming back.

Well, just last week I needed to replace my Autolite Racing AR103 plugs with new ones. When I removed the wire for cylinder 6, the spark plug boot was split and burnt quite a bit. You could break the boot apart easily, and these were MSD Superconductor 8.5mm wires mind you. I checked all wires with an ohm meter, and the wires tested like new. The heat from the exhaust, and the proximity of the manifold to the plug boots were ruining the boots though. If this happened to high quality MSD wires (only 30,000k on them), I can see why the stock ones don't last at all. GM replacing the wires was a quick fix, but not the cure for the problem. Read on...

Here's what I did to cure this problem. I replaced all plugs first with new Autolite AR103 racing plugs (very low resistance, but only last 20-25K miles). Then, very carefully I cut off the boots of the wires, since the wires tested fine. MSD sells the boots separately, so I purchased some to replace the ones I cut off. Napa sells some spark plug wire heat sheathing to go over the wires, good for 500 *F constant and 1200 *F radiant heat. With the boots off, I installed this on the wires for cylinders 6, 4, 1, and 3, up to where the wires go into the looms. Wires 2 and 5 were far enough away to not need the wire protectors up to the looms. I then put the new boots on, and installed spark plug boot protectors from Design Engineering Inc. on all 6 spark plug wire boots. These are also good for 500 *F constant and 1200 *F radiant heat. For the looms, I used Made For You's 6-6 nylon wire looms, good for up to only 8mm. However, I drilled them out slightly to fit the 8.5mm wires perfectly.

So far, my car runs better than ever. To me the way the engine is mounted causes the heat to ruin the wires prematurely, causing misfires too easily and possibly ruining the ignition module and coils. In my case, the MSD wire boot in cylinder 6 was fried, causing it to arch and misfire constantly. And these were high quality wires, not the cheap stuff. Up to now, the dealer, my friend who is a mechanic, and another independent shop could never pinpoint the problem. I landed up spending a lot of money replacing things that probably didn't need to be since this problem was never diagnosed properly. GM's replacing the wires was bogus, since they'll eventually go early (and most other sets) due to the extreme heat. I guess that's typical--they took the cheapest way out.

Well, sorry for the long message, but I hope this information will help someone avoid spending a lot of money unnecessary, only to have this problem constantly come back. The boot and wire protectors will keep the heat from ruining the wires/boots and causing that darn misfire.

[sac2165]

Thanks, I'll have to check that out [img]graemlins/thumbsup.gif[/img]

[apiccola]

What did you do with the metal heat shields that cover each boot?

[gig]

Yo Appicola,

My 97 Firebird 3.8 didn't come with the metal heat shields that cover each boot. The first time my car started missing, I took it to the dealer and they replaced the set of wires. I didn't check prior to them doing this if my car had the shields. But after they changed the wires, no shields. So your guess is good as mine. Knowing those bastards at the dealer, they probably never put them back like idiots.

Anyway, since I have MSD wires, the stock metal shields probably wouldn't fit anyway on the bigger boots. If you want to do what I did and use the boot protectors from Design Engineering, you'll probably won't be able to use the metal heat shiels. You won't need them anyway. And I did see pictures of the metal shields in a Haynes repair manual; the Design Engineering ones will protect much better in my opinion since they are bigger and cover the entire boot.

If you don't have performance wires already, I would consider buying some. I recommend MSD Superconductor 8.5mm, since these wires have low resistance and with over 30,000 miles on them, they still tested like new. Only the unprotected boot got messed up from the heat. MSD sells a universal set I used for my car (it's for a V-8 or V-6) in which you have to cut the wire to length and make the end that connects to the coil. However, they give you the tool, and it is very easy to do. In addition, MSD actually sells both ends of the wire (spark plug boot, coil-end boot) so you can replace later them if necessary. Prior to slipping the boot on, I would buy the spark plug wire sheathing and install that on the wires up to the looms. Cylinders #2 and #5 don't need this as they are far enough away. I've checked some different spark plug wire sheathings; the one Napa sells is very well made and feels more substantial compared to some of the other ones on the market. That's what sold me.

With my method, the wires and boots are very well protected from the heat. I hope this helps. Let me know if you have any further questions.

[Pike]

Your my hero! This problem has kicked my in the arse 3 times in 14 months! Where did you get the design engineering boot protectors? at your local parts store?

anyway, thanks for the info, hopefully this will cure that damn misfire once and for all!

[gig]

Pike,

I bought the spark plug boot protectors from Checker Auto Parts here in Hawaii. If you check www.cskauto.com and www.summitracing.com (I think summit sells them too) you can order them online. You can also check www.designengineering.com and click on the Retailers link to see who sells them in your area. The part is officially called "Protect-a-boot", part number 010501 (pack of 2). I got the silver, but they come in black, red, and blue as well. I put these on all 6 plug boots.

Also, I would add the spark plug wire sheathing. Check out Napa for it, or you can even use Design Engineering's Protect-a-wire. However, Napa's wire sheathing was a lot cheaper and offered the same level of protection, so that's what I used. Napa's comes in a 12ft length that you cut to fit.

As I stated before, if you're going to go through the trouble of adding this protection, I would be sure to use a high-quality set of spark plug wires. A lot of people use Taylors, but I prefer MSD Superconductor 8.5mm's for their low resistance and high quality.

I hope this helps.

[morbid]

there's some good info here gig. thanks.

my 98 comes stock with 3 metal boot protectors on cylinders 3,4,6. maybe they started putting these one for the '98+ models. those boot protectors work well enough to preserve the boots a while. i recently replaced the stock plugs/wires with NGKs and Taylors (reusing the looms and boot protectors). the stock wires, boots, plugs were fine after 42000 miles of use. which is why i regret ever touching them. I would say Taylor wires are either 1)really fragile, 2)poorly controled for quality of crimping or 3)both. after I installed the plugs/wires, i've had nothing but problems. lots of hesitation and stuttering. today i found out 2 of the 6 wires had really high resistance, but it was caused by a really bad crimping job at the factory or wherever they got crimped. after trying to work this out for a week i'm ready to give up. tomorrow i'm putting all the old plugs/wires back and hope they work.

leave well enough alone is my lesson learned.

just curious, those with a 99 and older model with the rediculously hidious exhaust menifolds instead of the 2000 and up header-like exhaust, when you replace plugs and/or wires, do you have to get undernethe the car to get the 'inner' 4 plugs too? my arms must not bend the way GM engineers must envision human arms are supposed to bend. whoever designed the exhaust manifolds should be boiled alive in a gigantic pot.

ok, that's the end of my rant. sorry. really pissed.

[ December 24, 2002: Message edited by: morbid ]</p>

[Pike]

Yeah morbid, I feel your pain man. The only ways I know of to convieniently change my plugs is to systematically break my arm in 2 places or get under the car and take all day making 1000 2mm turns on the plugs (and then you get to put the new ones back in again!)

[Go4broke]

I have changed my plugs like 4 times now and I hope the persons that made those stock headers burn in hell for all the hand cramps and cuts I have receved. But now I have headers on and it takes like 3 min to change the spark plugs and wires.

[gig]

Morbid, Pike, etc.:

I felt your pain when I was changing the plugs and putting on the boot protectors/heat sheathing on. This job takes a whole day, some cussing, and about a dozen cuts on your hand and arms. Damn GM!

I had the factory wires changed once by the dealer and used Autolite Pro-Fit wires (same quality as stock) before changing them to MSD 8.5mm Superconductor. Since this job was a pain, I did some research prior to purchasing the MSDs. I checked out the Taylors since everyone was using them, but found on other message boards of people having problems with them. They're inexpensive, but you get what you pay for.

When I was having my car serviced by an independent repair shop, the owner recommended the MSD 8.5 wires to me. He had a sample to show me, and I was very impressed. He builds race cars too and has been in business for 25+ years, and said he never had a problem with MSD wires. I also checked out MSD's website and was quite impressed. So that's what sold me, even though the set I bought cost about $90 (universal set).

From my experience, I would highly recommend the MSDs. Although the boot on #6 burned, probably because of no heat shield, all the wires tested like new with an OHM meter after 30,000 miles. I wouldn't put back the stock wires, since after 42,000 miles the heat probably has taken a toll on them. At the very least, I would purchase a new set. Be sure to check the resistance with an OHM meter.