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Discussion Starter · #1 ·
I have a fouled plug which is causing a check engine light. It's at 63k so I am going to do all 6, what should I get? The only NGK my local store had were $17.00 a piece so I did not get them. What do use guys use? Part number? Champion is a not compatiable, right?

Thanks,

Tim

3.2 still running through oil like a drunken sailor
 

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Tim- Definately use whatever brand came with your truck. It will be either NGK, Denso, or dometimes even Champions were used (isuzu stopped w/ the champs because of problems w/ them). I know NGK's & Denso's are hard to find, but usually parts stores that specialize in import & performance stuff have them. They are pricey, like $6-$8 each, but $17 is insane!! Call Merlin at St.Charles isuzu as well @ 800-727-8066. I've yet to find anyone who can beat their prices. ANY other brands of plugs WILL CAUSE misfires & CEL's on 1998+ isuzus. I've seen/heard of it happen time & time again. The ignition systems on these trucks are super sensitive to plug brand. NGK's and Denso's will last a good 60Kmi, but you should pull, clean & re-lube them every 30Kmi. G/luck!!
Joel
 

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Wrenchead.com has them for 12.69 a peice.

That is just for reference. I would still order them from St. Charles. Those guys are the best.
 

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Discussion Starter · #4 ·
It had original Champion plugs. I replaced the plugs with Autolite as recommended by NAPA, but the problem still exists. It's still running very, very rough. My mechanic said it could also be the coils. From a visual standpoint they look fine but how can I check them? They look clean and have no residue. However I don't really know what a bad one would look like. Help!

Tim
 

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Tim- the problem is that the ignition systems on 1998+ 3.2/3.5's are super sensitive to the resistance value of the plug & the radio interference given off by the plug. The autolights may be firing OK & look OK, but they drive the ignition system nuts. 2000 & up models are even MORE sensitive!! Stick with NGK or denso & you'll be fine. Use a good di-electric grease on both the plug & the boot/tube as well. G/luck!
Joel
 

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the problem stems from the resistance/ conduction of the plug. with the newer computers the spark plugs are not just for igniting the fuel but also act as a sensor to measure the ion charge in the combustion chamber to determine fuel burn, knock, ignition charge, etc. since the bosch plugs don't have an exposed core they can't read the chamber. other lesser plugs just can't acheive the sensativity.
 

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I'm a professional tech and I can tell you with confidence that Autolite is perhaps the worst spark plug known to man. As far as I'm concerned, the NGK is the best plug. Denso and Bosch are about the same. I've personally never heard of a spark plug acting as a sensor in and of itself. There are feedback systems that tell the ECM how to modify long term and short term fuel trim and duration of spark and timing, for example knock sensors, intake air sensors, O2 sensors, direct coil feedback and so forth. My clearest advice is get the plugs that came with your engine. If you are still having problems in the ignition system, have a tech look at live data provided by a scan tool connected to your ECM and have it hooked up to a good scope with a tech who can actually read a scope pattern. Good luck.

-Kevin
 

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Hey guys. Joel thanks for the article. I was unaware of any such system, and I will definately add it to the memory bank. Is Isuzu the only manufacturer using this system? Just curious. Also, is it possible to clean these ion plugs with the traditional sand blaster?

Personally, I can't wait for the camless engine to come around (solenoid operated valve train). I've also heard of GM bringing back the 4/6/8 or as they call it "variable displacement". Anyone have any info on these systems.

-Kevin
just trying to keep up with the changes
 

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I guess it's nothing really special with the spark plugs themselves, my 2002 rodeo 3.2 has regular Denso K16PR-P11 plugs. Unless your engine has a major malfunction, I dont see where just cleaning/ blasting the plugs would hurt. It's a good idea to pull & anti-seize them every so often anyway. I dont know of any GM vehicle that uses the GM/delphi ion sensing system yet. Kinda funny how GM uses isuzu as their personal electronics test dummy :roll: !! Yes- camless valvetrain will be great!! no more timing belts/chains, no more trashed engines do to interference/ clearance issues!! I'm curious to see how that high pressure, direct injected isuzu 3.5 will work out- atleast it doenst need EGR :D !!
Joel
 

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Discussion Starter · #12 ·
It ended up being water in an injector. The intial OBD-II readout was a bad plug. I will remove the Autolite plugs and replace. It had Champion when I bought it and I at least knew enough to boot those. One question is if Autolite is crap why did NAPA sell me those, good margin?

Thanks for all the responses, I do appreciate the help!
 

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Just a comment about Autolites. My grandpa (old farmer) hated these plugs and used to take them out of trucks, tractors, stationary engines, etc. My own experience working on motors had proved to be the same. Nearly everytime I find fouled out plugs they are Autolites.

NAPA sells everything. I don't know why your parts guy would ever recommend the Autolites over the NGKs, particularly for an Isuzu. I think Ford has an interest in Autolite, and they are the recommended plugs for Fords. Regardless, for any Japanese engine I always buy the NGKs.

-Kevin
 

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if you have not had the chance to drive an isuzu with the direct injected engine I suggest going down to the dealer and taking one out for a ride they are noticebly more powerful but could have used a larger throttlebody I am really anticipating tearing one down to see whats under the common chamber
 

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zukeeper said:
I used bosch platniums and they run pretty good, just the same as the ngk's
same here...been using regular Bosch Platniums in both my 98 Rodeo and 98 Trooper since day one!

I have NEVER hada CEL.

A shop did try to put in Bosch Resistor type (standards) in my truck, but they came out as soon as I learned of it.

It's just irresponsible to say the ANY other brand WILL cause CELs.

We all have our preferences, and you too will soon have yours.
 

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I'm going to go with Bosch Platinum plugs as well in both my 94 Trooper and 97 Rodeo. The Bosch plugs are $2.09 a piece compared to $10+ for Denso's and NGK's. I just can't afford anything over the Bosch plugs!!!

I did have a really bad experience with spark plugs once. It was a 97 Saturn SL1 (I will never own another Saturn piece of s*&t). I replaced the spark plugs at 45k and put in some Champion plugs I picked up at Wal-Mart. Unfortunately these plugs FRIED the ignition system - a $900 replacement. It seems that the ignition system only works well with AC Delco plugs - other plugs don't have the correct resistance value and screw the system fatally.

Even so -- I'm going to use Bosch because I'm 100% certain that Isuzu's are as cheaply engineered as plastic trash Saturns!
 

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ShoresTrooper said:
It's just irresponsible to say the ANY other brand WILL cause CELs.

We all have our preferences, and you too will soon have yours.
ShoresTrooper- 3.2's and even 3.5's up to year 2000 will probably do fine on bosch or any other spark plug. Try a bosch on a 2000-2004 3.2/3.5 & you will have problems. The GM/delphi ion sensing ignition sytems in these trucks was designed around denso plugs.

Irresponsible? That's pretty harsh :roll: . I don't know about you, but I'm here to learn & help people the best I can. Not to spout crap like that.

Joel
 

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Got Bosch plat +4 in my 93 Trooper, runs great, fact. plugs in my 2000, works great. I have 235,000 miles on my 93 PLASTIC TRASH Zu, drives like a new one, GREAT. I guess once you buy a SATURN It really screws up ones way of thinking, hey sell the 94 I hear the VUE is a great truck!
 

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JTK said:
Irresponsible? That's pretty harsh :roll: . I don't know about you, but I'm here to learn & help people the best I can. Not to spout crap like that.

Joel
Didn;t mean to ruffle you....but as yours and other posts mentioned... the concerns apply to the 2000+ ION systems, and the owner that started the thread had a '99.
hence...that is where I was coming from...didn't make "cents" for him to spend more than he had to.

it's hard to know a persons tone on the boards sometimes...especially if they forget to use the smilies!

ditto on the help and learning too! we hopefully are all here for that.
:wink:
 
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