spark plugs

[umina]

So i'm trying to figure out my power issues with 01 regal LS. In the back of my mind I htink the converter is bad (though no SES, no converter rattle), but figure i should try the cheaper stuff first. I pulled a spark plug yesterday to have a look, and noticed that it looked odd. I'm not sure what the double platinum OEM plugs should look like so this is why i'm posting. What should they look like? These ones looked like there was an electrode on the arm and in the center. Not sure that makes sense, but the little L arm on the plug is not clean/smooth, it has a bump on it that coresponds with the elctrode on the plug. Is this normal? Someone on here had posted pictures of their plugs and they looked just like mine, but I can't find the post. Google turned up no results either, so maybe this is bad?

I replaced my MAF, which made no difference even though i swear it runs better with it unplugged. This sorta makes me think its a fuel problem. The MAF came out of my Grand Prix (same part number) which runs great, and i put the buick one in the GP and it is fine there too. I've got 140k miles on the car, so some things are gonna need replaced. The plug wires look old, but there was grease inside the boot on the plug, and anti-sieze compound on the threads, so i think they've been replaced by the previous owner, though they said all they did was drive it. I dont wanna throw money at plugs if these are correct, they did not look horrible, just out of the ordinary. Let me know, thanks!

[HotZ28]

The plugs are more than likely an Iridium plug, ACDELCO Part # 41101 with recommended replacement @ 100K. If they are original, you are pushing the limit @ 140K! If they were replaced, you should be fine with plugs. BTW, they should have a “bump” on the ground strap of the plug, so what you are seeing is normal. (See pic below)

Have you checked fuel pressure, or changed the fuel filter & air filter? If the wires are original, they should be changed using MSD, ACDelco, or Belden wires. The cheap wires will not work well with the high voltage DIS ignition system!

[umina]

I replaced fuel and air filters last week. Havn't checked fuel pressure, its one of the few tools I don't have. The "bump" is the same size/length as the elctrode on the other side of the gap, it doesn't look like that picture much. Car runs good, just seems like accelleration, even moderate, has a large flat spot. Each gear will get you going, then power falls off/flattens out, then picks up and shifts, then same thing again. You can floor the car, and it takes few seconds before it decides to downshift, and when it does, there is no power. No check engine lights (except when I unplug the MAF), and no stored codes. Maybe the TPS is bad....

I just checked again, and no loose vacuum hoses. Car just had UIM replaced before I bought it (less than 500 miles ago). I'm gonna throw it up on ramps this afternoon, and disconnect the downpipe before the converter and see if it gets its gusto back (even though it'll be freakin loud!!)

[umina]

UPDATE:
I replaced front 3 plugs today (I happened to have some Bosch Platinum plugs, bad i know, laying around from my old lumina). The iridium plugs i pulled were kinda white and crusty, possibly originals. Anyways, car fired up super fast, which was a change, but when driving ,still no power and lots of random hesitation. So I pulled over and unplugged my MAF. Bang, drives like a new car.

Trouble is, I swapped the MAF from the regal with the one on my GP with no difference but the GP drives great, even with the buick MAF installed. So since neither car had a CEL, is it safe to assume the MAFs are fine, and the trouble is elswhere? Does the MAF control something else, or make the car run rich when its not plugged in? I know it controls air/fuel mixture but since the car runs like crap (though it idles fine, and is great once you established your driving speed) when accellerating only, maybe a fuel problem? How bad is it to keep driving with the MAF unplugged, other than the CEL that will come on as a result? Also, the car will start, then die out frequently with the first turn of the key, then it starts up and runs great, or if you start it and tap the gas a bit, it stays running. Oh, and i'm getting plenty of exhaust out the tailpipes, so i don't think the CAT is clogged for now....

[BNaylor]

Are you sure you have iridium spark plugs? You could if they were replaced but GM did not deliver 2001 Regals either LS or GS models with them. The OE plugs are supposed to be AC Delco 41-921 double platinums and good for at least 100K miles.

What are the numbers on your spark plugs?

[umina]

yes, they are 41-921 plugs. What should those look like, I can't seem to find any pictures, but these do not look like ordinary plugs.

[BNaylor]

Here is a pic of an AC Delco 41-921 which is double platinum. The unique part is the ground electrode has the platinum tit. Plus the center electrode is platinum. Also, you can check the gap which should be .060" but technically you are not supposed to adjust the gap on these due to the tit and possibly breaking it off or cause a misalignment between the electrodes. The platinum material is what gives the plugs the long life versus single platinum or copper core types. GM claims up to 100K miles.

[wtijr]

Originally Posted by umina

UPDATE:
... Does the MAF control something else, or make the car run rich when its not plugged in? I know it controls air/fuel mixture but since the car runs like crap (though it idles fine, and is great once you established your driving speed) when accellerating only, maybe a fuel problem? ....

I have read that the when you disconnect the MAF sensor, the computer falls back to a default, factory configured data set instead of using real-time data. So your problem could be with one of the other sensors that provide real-time data to the computer.

[umina]

So tonight I replaced the IAC (swapped from my GP, cleaned before installing), and TPS. No difference. This is starting to drive me nuts, what else can I look at? With the windows down if you accellerate, the car goes, then bogs down badly, and you can almost hear a wooshing noise coming from the secondary air pump thingy on the drivers side behind the headlight. Though hard to say thats it since thats the only area that can be heard with your head sticking out the window :o). Once again, unplug MAF and works like a charm, though hard to start (cranks alot before catching). With it plugged back in the car starts then immediatly stumbles and dies. Then I can restart it and its fine. Happens nearly every time unless i give the gas a nudge just after it fires over. Does this sound like a fuel problem, or maybe an Oxygen sensor maybe? No codes in the computer other than from having the MAF unplugged. In park, cannot reproduce the bogging down. Your thoughts appreciated, thanks!

[BNaylor]

Best thing to do if you suspect a fuel supply related problem is test the fuel pressure at the Schrader valve located on the front fuel injector rail. 48-55 psi.

Based on what you are saying it sounds like a bad MAF sensor since driveability returns when disconnected.

Also, do you still have the original CAT converter?

[umina]

I swapped MAF sensors with my other car and no difference. plus there is no check engine light. right now i'm thinking O2 sensor, fuel pressure reg., fuel pump, or bad computer. when the car doesn't start if I turn the key and wait for the fuel pump to preddurize before cranking it starts every time. if I don't it runs rough for a bit before smoothing out. Does the MAF give more fuel when unplugged? I may just drive it unplugged for awhile while I look at my control arm bushings popping. Gotta do one thing at a time and tired of working on this with no fix . let me know what you think.