Car shaking after changing spark plugs

Mike Romain Wrote:
> * wrote:
> >
> > jeffcoslacker > wrote in
> article
> > >...
> > >
> > >
> > > I'll cocurr with the others...cracked insulator or damaged plug
> wire
> > > most likely, gap not so much so, but possible...if they were
> platinum
> > > plugs with the preset gap, they are rarely ever wrong...the
> electrode
> > > is tough as hell and doesn't bend easily..
> > >
> > > I agree also, Bosch Plats are crap, I'd throw them away if that's
> what
> > > you got, get Motorcraft or Autolite for it...
> > >
> > >
> >
> > I, for one, would be interested in hearing what, exactly, is "crap"
> about
> > the Bosch plugs.
> >
> > Resistors? Metallurgy? Ceramic composition?
> >
> > Where do they fail in your testing?
> >
> > What type of testing did you subject them to?
> >
> > What is it, exactly, that makes them inferior to other spark plugs?
>
> Don't know what is wrong with the suckers, but if you put them in a
> Jeep
> 4.2 carb engine and in most Jeep 4.0 FI engines, they will work for a
> few miles, then they carbon up and the engine starts running like crap,
> especially at idle. Pull them out, put some real plugs in like Champion
> and bingo, the engine runs well again.
>
> I have seen this well over a half dozen times in the last few years and
> the fix is always to toss the plugs out.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
> Canadian Off Road Trips Photos: Non members can still view!
> Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
> (More Off Road album links at bottom of the view page)

It's called empirical data, or experience....

I'm seeing replies here similar to my experiences with Bosch
plats....fouling, unstable idle, short life, etc. Same thing I've
noticed in my own cars when I tried them, as well as customer's car
(who insisted that I install them, against my advice, and nearly always
came back within a month or two wanting them replaced for the reasons
listed above...)


--
jeffcoslacker
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jeffcoslacker wrote:
> I agree also, Bosch Plats are crap, I'd throw them away if that's what
> you got, get Motorcraft or Autolite for it...

I got Autolite, the basic ones, less than two dollars for each.

On Sun, 27 Aug 2006 08:33:38 -0500, "*" > wrote:

>
>
>jeffcoslacker > wrote in article
>...
>>
>>
>> I'll cocurr with the others...cracked insulator or damaged plug wire
>> most likely, gap not so much so, but possible...if they were platinum
>> plugs with the preset gap, they are rarely ever wrong...the electrode
>> is tough as hell and doesn't bend easily..
>>
>> I agree also, Bosch Plats are crap, I'd throw them away if that's what
>> you got, get Motorcraft or Autolite for it...
>>
>>
>
>
>I, for one, would be interested in hearing what, exactly, is "crap" about
>the Bosch plugs.
>
>Resistors? Metallurgy? Ceramic composition?
>
>Where do they fail in your testing?
>
>What type of testing did you subject them to?
>
>What is it, exactly, that makes them inferior to other spark plugs?

I don't know what wrong with them but I DO know that they will cause a
misfire that can be fixed by doing absolutely nothing other than
putting NGK or Denso plugs in the car. I have heard many reports of
this and was sceptical until experiencing it myself a few times.

Don
www.donsautomotive.com

Why no Bosch?


"Don" > wrote in message
...
> On 26 Aug 2006 16:41:00 -0700, "Wei Hu" > wrote:
>
> >Hi,
> >
> >Today I replaced the six spark plugs of my 94 Ford Taurus.
> >However, when I stop for red lights, the car shakes every one or two
> >seconds.
> >Does anybody know the reason?
> >Could it be that I didn't adjust the gap?
>
> Your car will miss at idle if the spark plug gaps are too close.
> Also, if you put in Bosch take them out.
>
> Don
> www.donsautomotive.com
>
>
> >
> >Thanks,
> >Wei
>

"*" > wrote in message
news:01c6c9dc$a5ce8100$da96c3d8@race...
>
>
> jeffcoslacker > wrote in article
> >...
>>
>>
>> I'll cocurr with the others...cracked insulator or damaged plug wire
>> most likely, gap not so much so, but possible...if they were platinum
>> plugs with the preset gap, they are rarely ever wrong...the electrode
>> is tough as hell and doesn't bend easily..
>>
>> I agree also, Bosch Plats are crap, I'd throw them away if that's what
>> you got, get Motorcraft or Autolite for it...
>>
>>
>
>
> I, for one, would be interested in hearing what, exactly, is "crap" about
> the Bosch plugs.
>
> Resistors? Metallurgy? Ceramic composition?
>
> Where do they fail in your testing?
>
> What type of testing did you subject them to?
>
> What is it, exactly, that makes them inferior to other spark plugs?
>
>

How about personal experience. Customer brings vehicle in complaining
about poor idle, miss under load, hard starting, poor mileage, etc.....
Customer states vehicle had tune-up anywere from one week to six months ago.
Tune-up looks good except Bosh plugs were used. Replace Bosh plugs with
quality plugs and driveability problems are gone. I have seen this happen
dozens of times. Bosh plugs are JUNK!!!!

On Mon, 28 Aug 2006 00:06:54 GMT, "Mike" > wrote:

>
>"*" > wrote in message
>news:01c6c9dc$a5ce8100$da96c3d8@race...
>>
>>
>> jeffcoslacker > wrote in article
>> >...
>>>
>>>
>>> I'll cocurr with the others...cracked insulator or damaged plug wire
>>> most likely, gap not so much so, but possible...if they were platinum
>>> plugs with the preset gap, they are rarely ever wrong...the electrode
>>> is tough as hell and doesn't bend easily..
>>>
>>> I agree also, Bosch Plats are crap, I'd throw them away if that's what
>>> you got, get Motorcraft or Autolite for it...
>>>
>>>
>>
>>
>> I, for one, would be interested in hearing what, exactly, is "crap" about
>> the Bosch plugs.
>>
>> Resistors? Metallurgy? Ceramic composition?
>>
>> Where do they fail in your testing?
>>
>> What type of testing did you subject them to?
>>
>> What is it, exactly, that makes them inferior to other spark plugs?
>>
>>
>
> How about personal experience. Customer brings vehicle in complaining
>about poor idle, miss under load, hard starting, poor mileage, etc.....
>Customer states vehicle had tune-up anywere from one week to six months ago.
>Tune-up looks good except Bosh plugs were used. Replace Bosh plugs with
>quality plugs and driveability problems are gone. I have seen this happen
>dozens of times. Bosh plugs are JUNK!!!!

That's exactly right! WHY they don't work I don't know.

Don
www.donsautomotive.com

WOW,

AM i glad i read this post this morning.

I just installed Bosch platinum plugs in my 1995 Buick Century 3.1

a week ago, and it is at idle, doing a little "sputtering"..

It is drivable (other than my new problem of power steering fluid
leaking on the drivers side underneath coming out pretty
good...........not sure yet what it is...havent had it checked out...i
mean the reservoir and pump and main hoses are on the passenger side,
and now the leak drippings are coming down on the DRIVERS side...?

When i can i am going to buy some other plugs.

But i am getting about a half quart to about 10 miles of powersteering
fluid right now!

Shep > wrote in article
>...
> Plat Bosch's in a 97 Lumina 3.1, replaced OE plats at 70k, at 22k Bosch's

> began misfire under load, pulled em out the center electrode had eroded
> below the insulator, put oe's in another 70k no problem, field test
seemed
> to indicate they wouldn't work in this car.


So, you're absolutely sure that it was the plug - not the ignition system's
inability to deal with the resistance of the Bosch Platinum plug???

Mike Romain > wrote in article
>...

>
> Don't know what is wrong with the suckers, but if you put them in a Jeep
> 4.2 carb engine and in most Jeep 4.0 FI engines, they will work for a
> few miles, then they carbon up and the engine starts running like crap,
> especially at idle. Pull them out, put some real plugs in like Champion
> and bingo, the engine runs well again.
>
> I have seen this well over a half dozen times in the last few years and
> the fix is always to toss the plugs out.
>

These were the actual plugs recommended for the application by Bosch in the
Bosch catalog?

Or were the plug applications determined by cross-referencing from one plug
manufacturer to Bosch?

Carboned-up plugs suggest two things to me......

Bad fuel system - which I would feel safe in eliminating since it would
appear that other plugs did not carbon up in the same application.

OR - wrong heat range for the plug....plugs running too cold for the engine
application.

Carboning up on a single plug MIGHT suggest one bad plug......

......but carboning up on ALL plugs suggests fuel system or parts
application problems.

In article <01c6caaa$fc162a80$a492c3d8@race>, * > wrote:
>Shep > wrote in article
>...
>> Plat Bosch's in a 97 Lumina 3.1, replaced OE plats at 70k, at 22k Bosch's
>
>> began misfire under load, pulled em out the center electrode had eroded
>> below the insulator, put oe's in another 70k no problem, field test
>seemed
>> to indicate they wouldn't work in this car.
>
>So, you're absolutely sure that it was the plug - not the ignition system's
>inability to deal with the resistance of the Bosch Platinum plug???

I have never used the Platinums, but I have been using the usual $2
Bosch plugs for thirty years and never had a problem. They're a little
more expensive than Autolite or NGK but they seem reliable.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."