2.4 TwinCams with Bosch Platinums = Bad!

[Dallas_95GT]

For a long time, I've been having problems with my girlfriends 96 Cavalier (2.4 Twincam) studdering at idle speeds. It would happen 3 or so days out of the week, the car would act like it was going to die, but never would. It seemed like no matter what I tried, the problem would not go away.

Quite a while back before this all started, I replaced the plugs with Bosch Platinums. A month later, the whole stuttering problem started. I never thought the plugs would be the problem, I have them in my Grand Am and they are perfect.

I finally asked some guys on j-body.org about the plugs. They pretty well told me these plugs are crap in the TwinCam's and to change them out. I put some regular Autolites in the car, and the problem is FIXED! Do any of you other guys have these plugs, and if so are you having problems?

Here is an explanation from one guy on why the plugs don't work in TwinCams...
The plugs have a higher resistance and the car has to push to get the spark. Idle is so low, that in some cases the car has symptoms like I had......
-hard to start sometimes
-rpms drop when you let off the gas
-rpms go from 1,000 to 2,500 rpm very easy
-car runs hotter, this is probably due to higher resistance of plugs.

I thought this was interesting and let all you TwinCam guys know. Let me know what you think!

[martopg]

Do you think that AC Delco Dual Platinum plugs might cause the same problem. A short while back, I got my ignition module, coils, ignition housing, etc, etc replaced cuz the module and the coils were fried. The shop replaced my old shitty Autolites with these brand new AC Delco Dual Platinum plugs (part# 41-942).

Anyhow, ever since this repair, I've been having the following problems:
-Car doesn't start unless i press down on the gas pedal quite a bit while starting
-Once car starts, the idle is very rough for a while
-Often, when going ~60, I will try to accelerate to 70 and the car will start to stutter/shake lightly. RPM will be sitting at ~2100. Only after I press down on gas pedal hard does the car start to move up to 70, and at this point the RPM makes a sudden jump from ~2100 to ~3500...

Do you think it could be the spark plugs causing this. I have fixed just about everything else on the car :rolleyes: If not the plugs, anyone else have any ideas?

[jayhawk]

Originally posted by martopg
Do you think that AC Delco Dual Platinum plugs might cause the same problem. A short while back, I got my ignition module, coils, ignition housing, etc, etc replaced cuz the module and the coils were fried. The shop replaced my old shitty Autolites with these brand new AC Delco Dual Platinum plugs (part# 41-942).


I have the AC's in my car also. Runs like a champ. May be a sensor acting up. :idunno:


jay

[martopg]

Hmm... I've heard elsewhere that it may be a fuel problem... I had the fuel filter checked a little while ago and they said it was fine. Anyone else know what this could be?

[p8ntman442]

Fuel pressure regulator!

[pstuttge]

I just put in some Bosch Platinum 2's. No problems so far, although I only have about 500 miles on them. I'll keep everyone posted if I encounter any problems with the way the car runs.

pstuttge

[MacAWM]

I installed a set of Bosch 4+ Platinums in my 98 and I am seeing an improvement over the original ACDelco plugs. Will update if problems occur.

[Phantomus]

Hmm... I've heard elsewhere that it may be a fuel problem... I had the fuel filter checked a little while ago and they said it was fine. Anyone else know what this could be?

Check your fuel pressure just to make sure their is no problems there.:)

[martopg]

Hmm... how would I go about checking the fuel pressure? The problem is getting worse and worse... Yesterday I had to do it like three or four times before it finally started, and even then it felt like it was gonna die. I'm not likin this one bit :(

[Turbodreams-se]

I've done some experimenting on my car and with bosch plat +4s if you put in premium gas they run alot better than with regular gas... I am not sure about the AC Delco's because mine were not in too good of shape when i took them out.


Edit: Sorry to ressurrect this old thread... I thought the information was pretty useful though.

[RXmar2]

I have Split Fires --- The Platinum +4 sucked -- I clock my plugs when I put them in -- so that the arm is facing away from the intake valves so that the incoming air and fuel doesn't have to pass the arm before it hits the electrode so that there is no pre-ignition.
I heard about this tip from the old Hemmi's -- and since the 2.4 has a somewhat of a hemispherical cumbustion camber -- I figured I'd try...

But I've heard that the Platinum +4 has way too much turbulance to get to the electrode...

Besides -- Platinum is for peeps that don't want to change the spark plugs every 15 to 20 thousand miles.... But performance minded peeps don't mind getting the most out of the engine -- so why scrimp on the plugs...

[Quantum]

Originally posted by MacAWM
I installed a set of Bosch 4+ Platinums in my 98 and I am seeing an improvement over the original ACDelco plugs. Will update if problems occur.

How many miles do you have on these plugs. I've got bosch platinums, and I have a slight stutter every 5 secs or so when the car is idling in the driveway. I would love to get this solved.

Quantum

[SilverStreak]

I put Bosch platinum +2 in my old 2.2 cavalier. It is having the same problems Spitting & sputtering. Just running like crap. This is after running them for about 6,000 miles. I'm gonna change them and see if that is the problem.

[CGann]

I wanted to thank you guys for this post! My fiance's 2.4L grand am was having these similiar symptoms and I had just put bosch platinums in it a couple months ago. I just switched them out with some ac/delco plugs and so for so good. Definetly a good warning/tip for anyone with this motor. Stay AWAY from those Bosch plugs.

Chris

[jayhawk]

Originally posted by CGann
I wanted to thank you guys for this post! My fiance's 2.4L grand am was having these similiar symptoms and I had just put bosch platinums in it a couple months ago. I just switched them out with some ac/delco plugs and so for so good. Definetly a good warning/tip for anyone with this motor. Stay AWAY from those Bosch plugs.

Chris


Somtimes the original is still the best. Thanks for the info! :thumbup2:

[NickPalmer15]

Bosch are bad, mine were running VERY hot, I changed them out for some copper plugs and my rough idle went away.

[Toutsuu]

Platinum plugs, bad period.

[litdevil316]

i've had lots of ppl even the autozone boys telling me to stay away from the Bosch plugs, so i stick with the ac plats and got no proble. then again i am one of those guys that change plugs yearly.......

[AeR0]

so what kind of plugs should i use on my 2.4 twin cam?

ac delco platniums?

[litdevil316]

yea, the ac delco plats have been recommended by alot of ppl i know and trust. and as i said last time, no problems yet, tho i changed them like yearly.

[pstuttge]

Update on Bosch Platinum 2's in '98 GA.

I got about 20,000+ miles with no problems. My GA now has over 100,000 miles.

One thing I did notice that I learned from a S-10 Blazer that I had. Every oil change I run a bottle of some total fuel system cleaner through. Cleans out any carbon build up. Helps keep the plugs clean too.

On my blazer, there was a valve in the exhaust manifold that would get carboned up making it run like crap. Took it in and the dealership manually open and closed the value and ran fine again for a couple months and then the same thing. Dealership wanted install a new value ($300 + labor to tear the thing apart). I said no and dumped a bottle of fuel system cleaner in and half a tank of gas later it was running fine.

[litdevil316]

i dunno if yours is one of them fabled freak motors (stock motor that runns diff and more power then reg stock), but i dont know personaly if anything other then the ac delcos is bad. they bout the same price and my car has 80k+ on it. but since the price is bout the same, if ya want to use them ok, never said ya had to, just everyone i know recommends the ac delcos for the 2.4L

[AeR0]

could anyone link to me to where it tells me how i can remove my spark plugs my car has 150,000KMS on it now and ive never changed the spark plugs and this weekend i want to could u guys direct me to how to do it.. pics would be nice and what will i all need?

help me plz
thanks
Aaron


cuz if i take it in to my gm dealer they are guna put new plugs in than soak me for like 100buxs canadian....

[litdevil316]

i could tell you how to. not hard. take off the piece over the motor that says "2.4L twin cam" but you need to disconnect the plug that goes into it. then use a spark plug socket with matching breaker bar or ratchet. the plug socket should be the smaller one. most tool kits come with two plug socckets. pop old ones out. aplly some thread grease (parts store usually askes if you want to buy some, less then a us dollar). it is recommended that you get a torque wrench set to 13lb-ft (or what it says on the cam cover). pop new ones in with thread grease on threads. pop cover back on, remember to re-connect the cover plug or car wont start. that should cover it all. but one thing... if ya plan on being a weekend worrier and fix your own car, get a Chiltons manual for your car.

[AeR0]

what if i dont have a torque wrench could i still do it?

5/8" socket?

[litdevil316]

i dont use a torque wrench b/c i dont have one my self. you just have to becarefull. it doesnt take much to break a spark plug. i've broken enuff before back in school. if i remembered the 13lb-ft right, then 13lb-ft is not really that much. it easy for most ppl to tighten it down more then 13lb-ft. and i think it is the 5/8" socket.

[AeR0]

ok so there is no wires on my 2.4L i dont understand how this works lol..

your telling me i undo the 3 or 4 wires that are plugged in undo the 5-6 screws take the 2.4 twin cam cover thing off and 4 spark plugs are right there?

also is ac delco the best to use what about champion or ngk ?

[RocketFast321]

ac-delco 41-963. I did not want to spend 5.99 each so i got ac-delco rapidfire 14

[AeR0]

what plugs are 5.99 each?

[RocketFast321]

ac-delco 41-963, they are what's in your car now

[AeR0]

nobody has still yet answered me tho where are my spark plug wires timing belt or chain and why doesnt my car have this stuff

lol
:roll2:

[mthegodfather]

No need for the spark plug wires because of where the Coil Packs are located. The spark is sent directly thru Spark Boots to the plugs.

[mthegodfather]

I looked up the part number for the Rapidfire plugs for my 1998 2.4 and they said it was the Rapidfire 12s.i saw where someone said they used the 14s??????????

[AeR0]

well kinda work in progress as im speaking.. ive got the 2.4L cover off and now i just have to pull those rubber boots off???????? and put the new spark plugs in


right?

[AeR0]

hey everyone well i got it done and they work nice i paid 42.00cad for my plugs i just had some trouble getting the 2.4 twin cam cover back on.. those rubber things i didnt know if they were best left on the spark plug than put the cover on or leave them attached to the 2.4 cover.. i loosened off those aluminum 1/2 metal lines that are near so i could get the one wiring clip thing plugged in.. and it gave me more room to work with.. anyone else do this

and thanks to everyone who helped me!

[Brad97GS]

On my old GA with the Quad 4, it was always easiest to plug the boots into the coil housing and then drop the whole thing onto the plugs. That engine didn't have the metal lines going over the top though, so maybe it affects ease of reinstallation.

[RocketFast321]

Originally posted by mthegodfather
I looked up the part number for the Rapidfire plugs for my 1998 2.4 and they said it was the Rapidfire 12s.i saw where someone said they used the 14s??????????

That what the autozone computer told me. Ac delco 12 and 14. I going to pull em tomarrow and see how that are looking.

[litdevil316]

ok, sorry i wasnt here for a while. Iraq doesnt let you get online that much sometimes. but yea, the boots ($20usd) are your plug wires. and i usualy leave them on the cover while i put the cover back on. wiggle it a bit and it should pop on down. and all motors have timing belts. ours is under the 'black' cover on the left side (passenger side) of the motor. and you shouldnt have needed to loosen those lines up. just wiggle the cover into place under the lines. those lines are fuel lines if i am correct.

[AeR0]

well everything worked out good for me...

thanks for the help though eh

[azeniskid]

quad's dont' have a timing belt, it's a timing chain..... low maintanence piece.

if you're cool though you can drop 30lbs from the car by being smart and converting to a belt.

[litdevil316]

ok, my bad. true true. it is a chain not a belt. but it still does the same thing, and all motors have a timing belt(s)/chain(s).