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Codes

tomtom123

tomtom123

New member
I have a few codes. I replaced plugs and wires just over a month ago and the old plugs were pretty rough looking. I got a few codes that came up afterwards.
P1404
"EGR valve stuck open. While monitoring the EGR valve pintle position the ECM detected the closed position sensor voltage higher than the learned closed position voltage.
Probable cause:
- Failed EGR valve
- Carbon blockage of pintle"
I cleaned the EGR today so that will hopefully work correctly now.

P0243
"Turbo/Supercharger wastegate solenoid a fault.
The ECM has detected a signal outside paramaters on the wastegate solenoid circuit.
Probable cause:
- Open or short circuit condition
- Poor electrical connection
- Failed wastegate solenoid"

P0304
"Cylinder 4 misfire.
The PCM monitors the crankshaft apeed and has detected a misfire condition.
Probable cause:
- I have a few codes. I replaces plugs and wires just over a month ago and the old plugs were pretty rough looking. I got a few codes that came up.
P1404
"EGR valve stuck open. While monitoring the EGR valve pintle position the ECM detected the closed position sensor voltage higher than the learned closed position voltage.
Probable cause:
- Failed EGR valve
- Carbon blockage of pintle"
I cleaned the EGR today so that will hopefully work correctly now.

P0243
"Turbo/Supercharger wastegate solenoid a fault.
The ECM has detected a signal outside paramaters on the wastegate solenoid circuit.
Probable cause:
- Open or short circuit condition
- Poor electrical connection
- Failed wastegate solenoid"

P0304
"Cylinder 4 misfire.
The PCM monitors the crankshaft apeed and has detected a misfire condition.
Probable cause:
- Ignition system fault-spark plug(s), ignition wires, coil
- Vacuum leak
- Injector fault
- High or low fuel pressure"

P0300
"Cylinder misfire detected- random cylinders
The PCM

P0300
"Cylinder misfire detected- random cylinders
The PCM monitors the crankshaft speed and has detected a miafire condition.
Probable cause:
- Ignition system fault-spark plug(s), ignition wires, coil
- Vacuum leak
- Injector fault
- High or low fuel pressure"
Any ideas of what the issues could be? I feel like there is something going on that if fixed will knock more than one of the above problems out.
 


I would replace the supercharger solenoid to clear that code, it seems that that is normal suspect. Wouldnt hurt to test voltage to it and figure out what the spec should be.


As for the misfires, what brand spark plugs were used?

Either the plug is bad or the coil pack is dying, you can swap the plug with one on the front and see if it moves to there or you can swap a coil pack around too, to see if it follows.
 
I used Bosch spark plugs for 99 GTP's from Autozone. They were like $8 each. I checked all my plugs last night and found 1 was eaten up, and one was crushed down, and the other one I was sorta concerned about was sort of coroding/blistering almost
 
One of the plugs was crushed? Got a pic? Normally that only happens when a piston hits the plug and then your piston has chunks missing out of it.
 


That doesn't look good at all. Might be time for a borescope and a compression test on the cylinders that those plugs came out of. I assume those are the front 3 plugs? Either way, I'd be pulling and checking all 6 of them. Methinks this isn't going to end well. Looks like you might have chipped some pistons and smacked the plug with it due to too much knock.

Been running premium (91+) fuel in it? Any mods or are you stock?
 
Stock, the flatened one was the front passenger side, the two that keep burning up is the back driver side plugs. The rear center one and rear drivers side plug. I replaced the plugs 2 months ago and they got eaten, then I put two plugs from my old '02 Grand Prix and they were destroyed after a day. Put 6 brand new Autolite 104's in and destroyed them on my first drive
 
So #1 is flat. 4 and 6 burn up.

Might want to be looking around for a used motor at this point, just to see what prices are like. And no, it's not worth the effort or $$ to rebuild the one you have. Just find a good low mile L67.
 


I took it in and found it has a leaking upper intake and EGR seems to be bad, I cleaned it and put it back on the ther night. I heard a bad EGR can cause lean conditions if it doesn't open, and if it is stuck open it could be continuously dumping hot exhaust air into the cylinder which will burn up the plugs. Now the problem is, I'm not sure which problem my EGR has. My car seems to only start burning up the plugs when I'm on the gas and get up to a higher speed. For $490 I can have the intake gasgets done, upper and lower and have I believe the metal gasget with cork put in it, t-stat replaced, oil and coolant all replaced
 
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You might have bigger problems though.

Them bosch plugs are arent something to run in these cars either, ac delco plugs (non plats) are the best for stock cars.
 
What do you all think of this situation? I replaced spark plug for cylinder 3 and now its running smooth again for now. What should I be concerned about? What steps should I take?
 
How does cyl 3 factor into this??? From your description above #3 was ok. Did you replace all 6 plugs? From the pic of the 3 plugs you posted it looked as though they were irridium which is the factory plug. I agree with FFDP as Bosch plugs are usually not a great idea in these motors. Most stick with AC delco, NGK irridiums or Autolite coppers.

There is no metal gasket with cork in it that I'm aware of for the LIM. It's aluminum and silicone for the updated ones. The stockers were black nylon. For doing the LIM, S/C gasket, new T-stat, coolant replacement/bleeding cooling system properly and oil change with labor I'd expect it to be much higher than $490 considering most shop markups on parts.

I'm still confused on how you managed to smash the electrode shut on #1, and burn off the rear one and somehow have it run smooth again just by replacing #3 plug :th_scratchhead:

You are running premium gas in it right?
 
I have been having issues with random cylinders, not just one or two specifically. The first time I replaced the plugs was about two months ago, I replaced all 6 plugs and wires, two plugs were broken, but I didn't think much of it. A few days ago I had issues and misfires so I replaced the 2 plugs that were bad with some Ac delcos from my other Grand Prix until I could buy a new set yesterday. I put in 6 new Autolite copper 104's. The car is running lean for some reason. Today I had a problem with the plug that was in cylinder 3 so I put in another Autolite 104. The one I pulled out of that cylinder was pushed closed. I put a new Autolite 104 copper plug in that spot and it is running smooth so far. The fuel trim is around 16.6% when idling. I know it's running lean but it doesn't seem to just be 1 specific cylinder that misfires every time. I was running premium when everything started freaking out, yes.

I just posted a picture of the plug out of cylinder 3, and the quote I got today on the gasgets.
 
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Hmm, well it's possible that pre-detonation (knock) is pushing it closed. Hopefully the EGR is just fubar. The ICM could be suspect as well assuming all the coils check out ok. If a coil cracks it can make the ICM do weird things and possibly kill it. The P0300 could be an indication that. Do you have a spare ICM laying around you could try?

Might want to also check the ground to the ICM.

Didn't mean to harp on the premium fuel question, but I've read about owners putting lower octane fuel in when 91+ gets "expensive" and then have issues.

Have you checked for vac leaks? The "T" under the S/C snout is a common place to have a leak. Even if it looks ok bend it a bit and see if it's cracked. The accordian pipes on the EGR also like to crack and not be visable. Might be time to start spraying carb cleaner around all the vac lines/fittings to see if there is a leak somewhere causing it to run lean.
 
I don't think I have a spare ICM lying around, unfortunately. Tomorrow I'll try to check the ground for the ICM and post on here about it. I was plannong on getting some carb cleaner today but forgot when I went to take my girlfriend home and instead of letting me take off wanted to sit in the car and talk my ear off for some reason o.O so I'll have to get some of that in the morning as well and spray it around all my vac. lines. I appreciate the help! I don't like taking my cars in and paying tons of money on things I can do myself =P
I'll post once I find out a bit more
 
Sprayed carb cleaner everywhere and no revving occured. Under supercharger snout, under/around throttle body, around the vacuum lines and no revving so I'm guessing there's no leak there
 
So I found that my boost bypass solenoid was bypassed. The line coming from the fuel regulator/supercharger snout was unplugged and it had a plug in it. I believe it was bypassed because the bypass solenoid is bad. I plugged it back in and now it isn't destroying the plugs, but it also only builds up to 4 blocks of boost on the boost gauge. But I think cylinder 3 has a bad injector or leak or something, the plugs from 1 and 5 are fine but the plug from 3 was darker, not really dark, but noticeably dark. I'll put a pic on photobucket for the link I gave earlier
 
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