Recommended Spark Plugs run rough?

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Originally Posted By: cmhj
Because they aren't matched to the system you're trying to use them in.
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Whats to match? Thread size, depth of electrode. It creates spark thats all. No?
 
You would think they'd look poorly if that was the problem. The plugs looked fine.

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All I can tell you is they won't work.

Where were you 25k miles ago.
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EVERY person, without fail who has installed Bosch plugs in a GM vehicle (most despite being warned NOT to do so) has had problems with them.
Maybe their internals are just NOT compatable with GM ignition systems as has been stated.
I would just stick with AC Delco and NGK product in GM vehicles (as I tell/suggest to anyone who asks).
 
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Bosch seems to bury their center tip, in a chunk of ceramic. I never understood why.

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NGKs & just about everyone else, are fully exposed.

Better access to the F/A mixture?
 
Originally Posted By: Headnsouth
Originally Posted By: cmhj
Because they aren't matched to the system you're trying to use them in.
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Whats to match? Thread size, depth of electrode. It creates spark thats all. No?


That is one of the mysteries. I replaced, on average, ~10plugs/day and for whatever reason the Bosch plugs were problem children. I never really got a straight answer from FoMoCo engineering on the subject other than "ck for non Motorcraft plugs" when diagnosing misses/missfire codes.

I did learn ignitions can be finicky beasts on later model cars. Plug variables that effect secondary voltage, or spark duration can effect the feedback the PCM gets. I don't know how far FoMoCo went with it, but engineers were able to get cylinder pressure curves, and other data goodies just from realtime monitoring of the spark feedback data. Spark/fuel/timing variables could be changed on the fly, in each individual cylinder, in order to maximize cylinder pressures/efficiency.
 
"Over the years I've run into this a lot. Certain plugs just don't work well with certain systems. In many cases the plugs suggested by the manufacture seem to in most cases be the way to go.

It's a whole lot easier to just use what is suggested or what you know worked in the past."

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So true to my experience.10 years ago, I had Pepboy did a tune-up for my car (94 Dodge Intrepid 3.5), and I asked for Platinum plugs, I thought it would be better,paid more for it .
The car did not run as smooth and peppy as it should after tune-up, I thought well the car is 5 years old and over 6ok, may be that's what would eventually happened.
One year later, the engine started having problem, I took it to an individual mechanic who was formerly a tech in one Chrysler dealer, he said one spark wire was bad and one plug was dead, and recommended all wires and plugs be replaced.I went for it.
When working on the car he told me that "I notice you used platinum plug, but this engine was designed to use Champion spark plug which is cheaper and works better, and that might had caused those problem you had".
After the "new" tine up, the car ran so well and I got a speeding ticket on a hilly interstate trip.
using the wrong plug (Platinum in this case) caused me $270. LOL
 
Originally Posted By: Kindergardener

After the "new" tine up, the car ran so well and I got a speeding ticket on a hilly interstate trip.
using the wrong plug (Platinum in this case) caused me $270. LOL


Oh gez, but what you have experienced is not uncommon per how a late model engine can be effected by using parts aren't matched to your system.

Very good.
 
I'd have to agree on the NGK's they are recommended over bosch for the wifeys 325I.

Thank you Punisher & JonnyZ for some insite to the Bosch plugs instead of "don't use them".

Since the replacement of the Bosch plugs the misfire codes are gone, the van runs great and smooth as new @172K miles.
Just one DTC to go and I'm sure the DTC P0420 catalytic yada, yada, yada code will disappear as ARX does its needed cleaning.
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I doubt it. In general, that code is usually thrown when the O2 sensor downstream of the cat fails. However, in your case with the misfires, it is possible that the actual cat has plugged up, although that usually comes with severe driveability issues.

As much as ARX is awesome, I don't think it goes and cleans the cats out for you.
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The reason I mention the ARX is 2 other vehicles I'm using ARX in both had DTC pointing towards the cat. I replaced O2's in both and still had the same DTC. After continuing to drive the vehicle both DTC cleared themselves. No cats were touched and both have 170K miles.
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My money is on ARX.
 
Frank answered this for me from over at his site. Here's a copy:
Originally Posted By: Frank
Auto-Rx cleans all internal sensors not just oil lubricated rotating engine parts.Internal Engine Sensors attract dirt-contaminants etc.

Once rinse mode was done none of what you described would have been an issue.


It is not unusual for oil light -temp guage to fluctuate during clening phase all returns to normal after rinse phase is done. This includes all pressures also.


Originally Posted By: Frank
Having trouble? Can't pass your state's emissions test? We can help.

Auto-Rx® is designed to clean your engine from the inside, breaking up carbon deposits and removing varnish from all lubricated surfaces, thus improving compression and combustion and reducing exhaust emissions.

Need Proof? Click here for the PDF file of North Carolina's testing results on a 1990 Chevrolet S-10 using Auto-Rx® .


If you go to http://www.auto-rx.com and scroll down menu to emissions you can click on PDF file. When ever you clean an engine and take load off of it you reduce amount of load converter has to work with.
 
I thought about ARX cleaning the engine enough to remove a bunch of emissions, but the O2 sensor(s) that babysit the cats aren't "internal". Can burnt up ARX exhaust do that much that far? If not, it seems like you've just reduced the symptoms by feeding less emissions through the cat, but haven't fixed the problem.
 
ARX will improve emissions as stated by Frank. And I believe my DTC is caused by ARX as with my other vehicles. We'll see as I'm using the van as my dd to get some miles on it.
I certainly hope it does I really don't want to spend $$ on a cat for 98 with 172k miles.
 
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