Spark Plugs...

[Steady Eddie]

The spark plugs that I changed out yesterday were or could have been the OE plugs @ 192K miles. They were the same type and brand as the originals and had gaps so wide that you could have thrown a cow thru them. Remember that this was our son's first vehicle (which he beat on severely) and I doubt he ever changed the plugs or oil or anything. This S10 was just recently put back into service as a gas economy rig, by me, to help out my wallet during these times of high gas prices.

There exists a situation, above peak torque RPMs, where the Iron Duke just seems to lay down. I have found mention of it on the Fiero Boards (same engine family). It is most often blamed on valve spring float, but in reality it is a spark issue. It seems that the GM/Pontiac engineers did very well with the HEI system, but one of the things that they DID NOT do well was sizing the output of the 32,000 volt stand-alone ignition coil. The Fiero Guys addressed the issue by installing a 48,000 volt Accel yellow coil AND by narrowing the plug gap. These two mods really wake up the Iron Duke.
I followed their ideas yesterday and gapped my new Platinum plugs at 45-thou.

What a difference!!

It starts right now and idles as smooth as your first girl's butt.

I still have the OE coil, no Accel coil...yet.

[purpleblaze91]

thats pretty cool. i'm looking to get a performance coil after my truck is back on the road. the e3 plugs and accel race wires on my truck made a big difference. did you do wires too?

[ironduke2.5]

Hey guys
Im looking at some spark plugs as well but i dont know which to buy? Should i buy the E3s, bosch +4, or some NGK Iridium tip? Or something else? I will be buyin a MSD Blaster coil 2, some 8mm wires (dont know what brand yet either) and some spark plugs. Any help will greatly be appericated. Thanks

[Steady Eddie]

I want to be the first to say that often something bad happens when you break up the team with regard to a GM ignition system...that said, for example, the Iron Duke has a very good way of routing the spark plug wires--thru little plastic click-lock wire holders, which keep the wires apart, but they are made for an OE sized wire and the newer, bigger-around aftermarket wires flat don't want to fit them. The parts guys don't tell you that. The only downside to the OE silicon wires is that they are quite fragile and you can physically "break" them by the slightest amount of yarding on them. I like the fact that the OE wires are a basic gray-color and mine have the cylinder numbers printed in black along each wire. The coil wire even says "C" right along it.

Doing one change at a time, (to the engine) saves money.

My OE wires are great..I thought: Plugs first, then see if it runs better and if not, then do new wires. But, at 192K miles, I cannot imagine that the distributor cap and rotor are anything but worn out. I will change them out based on common sense....and make it run even better.

[Steady Eddie]

My S-10 project is solely for the point of gas economy, and towards that end, it has to run perfectly, and do it without spending a sh!tload of money.

So---I bought the cheapest Platinum plugs I could find: Autolite AP666's at a couple of bucks each. They turned out OK.
For those seeking the best, the AC Delco 41-816's are best. But, nobody here had any, they were a week out, and I would have to pay shipping on a plug that now costs $11-something..each. No thanks...

[-DouG-]

Hey Eddie,

What gap on the plugs is the factory spec?

I bought my S10 for the same reason -cheap! Economy is what I'm shootin for -on a budget.

The plastic wire clips on the valve cover can be carved out carefully wuth an X-acto knife to fit your 8mm wires -if you have the patience!

I ripped one of my wires pulling it off the plug the other day so I replaced them with a set of accel super stock 8mm wires that my friend gave me -they are the ones with the stainless braided line on them - but hey, they were free - he tore one, then bought new wires -I only needed 4 of 'em! lol!

btw -i laughed when I saw the 666 on my spark plugs when i put them in...

I noticed a big difference in how smoothly the truck ran after doing plugs and wires... then it was a little better yet after i did the cap and rotor! That along with it now being quiet after welding up the cracked exhaust manifold made a big difference.

[Steady Eddie]

DouG--

The OE gap is 60-thou...and that gap on a fresh set of plugs works just fine, as wide gaps tend to fire a lean, "smog" fuel-air mix easily. That is the *why* of the large gaps. However, even double platinum plugs wear over time, and the gaps increase. As I posted, my gaps on the old plugs were big, very big. A 105 feeler slipped right through them!! I am amazed it ran at all.

The narrowed gap trick was discovered by Brazel's RV Shop, while studying a high speed power loss in the HEI systems of BB 454 Chevys. They discovered an inherent high-speed misfire in all HEI systems, one that happened
(timewise) so often that the the stock PCM did not have the resolution to "see"..but it was there. The OBD2 rigs after 1996 have the ability to see a mis-fire of one plug, one time, and begin to flash the SES light. Our S10s do not have an OBD2 brain-box but they DO have an HEI set-up. So, being how I wanted maximum fuel economy with
NO mis-fire at ANY RPMs--I went with the 45 thou gaps.

A simple "speed secret" that works.

[Steady Eddie]

DouG wrote:
"..btw -i laughed when I saw the 666 on my spark plugs when i put them in..."

Yeah, me too. What in the world were the marketing guys thinking when they tagged the plugs with THAT number??

Autolite's upper management must have their collective heads up their asses.

Everyone in America (almost) that had to sit and suffer through Sunday School Class knows that 666 is the mark of the beast...but whatever...I just swallowed hard (gulp) and stuck the plugs in there...

I do not consider myself devout in any sense of the word, but I'd sure think twice before going on Flight 666....

[Steady Eddie]

Just this morning I have noted that the tail pipe on the S-10 is getting cleaner!! It is not "mis-fire black" anymore!!

Yep, the inside of the tailpipe cleaning up is a sure sign that the tune-up and 180* t-stat install is working...we are getting a clean burn...

[beaniebmx]

or someone waxed their tailpipe inside and out

on a sidenote, i had an electric fan and could turn it on with the switch, i always turned it on before starting on hot days, and it worked great too, got good mpg with it, 27-30 highway, 25 if speeding and racing it on the highway.


another sidenote, i traded it in 2 weeks ago on friday, went out of town saturday morning at 11am, seen it outside dealership right near the entrance to the inside of the building... came back around 4pm and the truck was gone... been wanting to see who bought it.. well i was sitting in the window today watching neighbors roof their house.. and i heard a familiar sound.... sure enough here comes my chrome grille and bumper with primered hood... parks in the driveway across the street.... drops off the girl at her grandmas.. and leaves..... 40 year old or so driving it... it was so awkward, because shes seen it sit in my driveway and the street for 10 months, and me underneath it for 5 months

[85_s10]

your not supposed to gap platinum plugs

[Steady Eddie]

Quote: Originally Posted by 85_s10

your not supposed to gap platinum plugs

A common misconception...plug mfgs suggest not gapping platinum tipped plugs because they only put a speck of platinum on the electrodes--double platinums have TWO specks, one on the electrode and one on the ground side..these specks can and will "pop off" the metal that they are applied to IF you are ham-handed and not careful doing the re-gap. Just use a bit of caution during the re-gap job and all will be good...

[kamesama980]

Quote: Originally Posted by 85_s10

your not supposed to gap platinum plugs

if you read close, you're not supposed to re-gap platinum plugs. at least that's what they've all said for me on both Cressidas and the duke.

autolite platinum whatever the computer spat out for me with bosche wires ($14 on rockauto.com) and crap cap/rotor (cap terminals are bent so it's 3 angles of metal instead of 1 button or curved bit) runs like a top except the idle control thingamjig needs a good cleaning.

[s10-den]

very interesting info......just got me one of those "dukes" to save on gas....just put clutch,pressureplate,flywheel,plugs,oil sending unit...yea, you know the routine..lol

[Steady Eddie]

Quote: Originally Posted by s10-den

very interesting info......just got me one of those "dukes" to save on gas....just put clutch,pressureplate,flywheel,plugs,oil sending unit...yea, you know the routine..lol

Just don't spend a wad of cash on it...do it like I did...investigate on the 'Net, find out what works and what does not. Find out why people say that AC Delco/Delphi sensors are best, then investigate other options, like NAPA parts. I found out that they are good, too. For a fraction of the price. Sure, it's nice to be able to afford the 41-816 AC Delco platinum plugs, but the Wal-mart Autolite Platinums
seem to work just fine at $2 each. Things like that...It is nice to know that, in the example of the S-10 Iron Duke, you have a vehicle that will pay you back any money you put into it to make it "right"...

[s10-den]

YES, thats the whole point of me keeping a 4 banger,...lol

[s10-den]

so should i pull the plugs out and re-gap them at 45-50?How much is the coil you guys are buying,getting wires and coil today when i get off work...

[Steady Eddie]

Quote: Originally Posted by s10-den

so should i pull the plugs out and re-gap them at 45-50?How much is the coil you guys are buying,getting wires and coil today when i get off work...

Yep, gap 'em at 45 thou. Get NAPA's "best" set of wires and keep the sales slip in a zip-lock baggie in the glove box, they are warrantied for life. Any problems with the wires in the future and you get a new set--FREE. The new
OE AC-Delco coil is $55 to $59 dollars. This is about the same price as a new 48K volt aftermarket Accel or MSD coil. My OE coil and OE wires are fine. For now....

[s10-den]

i thought you said to get a high power coil????My sister works at Napa...

[Steady Eddie]

Quote: Originally Posted by s10-den

i thought you said to get a high power coil????My sister works at Napa...

s10-den---
What I meant was: the OE 32K volt coil AND the 48K volts aftermarket coils co$t the same. And..if you are going to get a new coil anyway, why not get a stronger one for the same money??

I wish I had "family" working at NAPA...

[s10-den]

oh ok gotcha,thanks for the info.Yea, It comes in handy "alot" for my lil sis to work there,haha___Eddie,you got a part number for the coil?Im getting mixed up here..lol

[Steady Eddie]

Quote: Originally Posted by s10-den

oh ok gotcha,thanks for the info.Yea, It comes in handy "alot" for my lil sis to work there,haha___Eddie,you got a part number for the coil?Im getting mixed up here..lol

Don't buy anything, like a new, aftermarket coil, just yet.
Put the 45-thou gapped Plat plugs in it and see how it does.
The Duke IS NOT a F**d!! With those, you throw money and parts at them, and hope for the best. GM products are different. Do one thing at a time and check the results....

[bear76]

I just re-gaped my plugs to 45 and it ran like shit. The plugs are newish ac delco's, I put them in last year with a 60 gap. I started it up the first time and it revved high then the check engine light came on. I shut her down for a minute and tried restarting again and the the engine lopped around like I was missing a cylinder. I shut her down again and disconnected the battery for a few minutes to reset the computer. On restart she sputtered and smoothed out but the RPMS have to be sitting at 11-1200. I took her around the block which was OK accept the hesitation and the RPMs at stop signs. I was able to put her in second take my foot off the gas and it took me up a light grade with no lugging. Any suggestions?

[lesterl]

bear, what kinda setup u got man? might have damaged something on the plugs, does the spark look hot? What kind of wires u runnin? replaced cap and rotor lately how do they look? what kind of plug were the delcos? Did you remove any vaccume lines/ not seal the intake back down?

[bear76]

Everything is stock except for a 180* thermostat. I don't think I disturbed any lines and was real careful when putting the plugs back. I haven't changed anything else yet, it all looks in good shape. It was running pretty good before, I just can't figure it out.

[lesterl]

perhaps it is running sooo good you just think it runs like poo :-)

[Steady Eddie]

Quote: Originally Posted by bear76

Everything is stock except for a 180* thermostat. I don't think I disturbed any lines and was real careful when putting the plugs back. I haven't changed anything else yet, it all looks in good shape. It was running pretty good before, I just can't figure it out.

Bear--

The new, high idle speed points right at a newly created vacuum leak. Take a deep breath, go back to it, and re-check all the vacuum lines. When something like this happens, you have to go over it all again. Unless, like Les has said, it was SO FAR out of whack, that with the new plugs and narrow gaps, it would naturally run better and pick-up RPMs. So, far, with the 180* t-stat mod and the narrow plug gaps, you have done nothing wrong. These two mods are positives NOT negatives. Be sure to check the Main Vacuum line, the one that heads off to the Power Brakes and the Heater Controls from the rear of the intake manifold. The rubber tubing gets a tiny crack in it at the fitting and it blows-up into a BIG leak. On these Dukes, the tiny vacuum, hard lines get holes rubbed through them from rubbing on some metal edge, I had one, rubbed through near the EGR Sol. Valve from it resting on the mounting pad. I fixed that one with black electrical tape...the 180* t-stat mod eliminates the degradation of these lines from heat in the engine bay, and once the lines are fixed, they'll stay fixed...

[tectron1]

Is there any reason the old universal Accel super coil(the big yellow one) wouldn't work if I extended the wires and mounted it to the fender well, I am unsure if there would be impedance issues due to the HEI setup.

I have a hard time spending $50 for a new coil when the one I have is working.Those super coils are cheap at car swap meets salvage yards etc.

[bear76]

I'm throwing a 12, 15, and 44 codes now. I'll look them up.

[Steady Eddie]

Quote: Originally Posted by bear76

I'm throwing a 12, 15, and 44 codes now. I'll look them up.

Bear--

12 = Normal "I am OK" code.

15 = Coolant sensor problems.

44 = A lean burn.


Not much help, but you can ignore the 12 code, the 15 code is either the sensor or it's wiring, and it can cause a 44 code, but the 44 code is a biggie, could be most anything from a weak fuel pump to a plugged injector.

You are in the S-10den Zone...with the 44 code.