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2001 Deville
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Discussion Starter · #1 ·
Hi, I have a Deville 2001 with northstar. ive had this car 3 months. ran great until I power washed the engine. Now it spits and sputters very bad. I cant find anything wrong. No power and horrible gas mileage. Can anyone help me? t, Thanks, Vic

Hi, I posted a thread in the wrong area I think. I have a 2001 Deville. Ran great when I bought 3 months ago. Now it runs terrible with a p0300 code. Everything I check seems ok. I have a lap top with ScanXLPRO on it and I was going to check paramiters and all values were jumping all over the place, Can anyone steer me to the right direction? The problem seemed to start right after I power washed the motor.
Thanks,
Vic
 

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Get somebody electrical contact cleaner from the part store and then also get some dialectic grease and after you have cleaned everything put a little bit of dialectic grease on and plug everything back together and hopefully that will solve your problem if not you may have caused a vacuum leak somewhere..

Roy
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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Now you know - NEVER power wash a Northstar. It's all done with brushes, rags, and patience.

The engine can easily stand up to normal road and rain splash but not power washing.

The valley under the dry intake manifold is wide open. The starter may now be flooded. Same for the injector and ignition wiring and connectors. The two ignition coil cassettes may also be wet, as well as the plug connector boots.

Welcome Aboard - study all the sticky threads, marked with a push pin, in the Deville, Seville, and Northstar forums.

Starter & Knock Sensor.jpg


coil-boot-plug 1.JPG


Intake silicone seals2.JPG
 

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2010 DTS
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88,310 Posts
Start it up and let it idle until it gets to operating temperature. The longer it runs at operating temperature, the better chance of evaporating moisture.

WD40 (Water Displacement). Spray some on the injector connectors and the ICM connector. That may help as well.
 

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2001 Deville
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Discussion Starter · #5 ·
Thank you for the advice. I will try this. Its been doing this for about 6 weeks now.
 

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2001 Deville
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Discussion Starter · #6 ·
I forgot to post another weird problem. With car running, I disconnect the rear coil pack, motor stalls immediatly, If I disconnect the front coil pack, the rpms drop and then the pcm or something compinsates and motor returns to its normal rough running. Is this a clue to something?
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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It's running on 4 cylinders only - the right (rear) bank is firing; the left (front) is not.

P 0300 is the catchall "misfire detected" code; parts store and handheld scanners will give you the actual cylinder number in which the misfire(s) are detected - P 0302, P 0304, P 0306, P 0308, etc..

Using my picture, remove the left (front) coil cassette and plug boots. You may find moisture in one or more boots as well as in the ICM connector - and that ICM comes out to reveal another connector to the cassette itself.

Use a smear of silicone dielectric ignition grease inside each plug boot tip and coil area. Dirt cheap at any parts counter.

You will find some oil in one or more plug wells - normal. The O-ring seals weep over time, and oil is an insulator . . . .
 

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2000 Deville Base, 2019 Corvette GS
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Instead of going back and forth here just get the damn car read at one of the auto parts stores and they will tell you WHICH cylinder is misfiring. Forget disconnecting this and that, you got a misfire code with a specific cylinder, start there and then work your way around.
 

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Discussion Starter · #10 ·
Instead of going back and forth here just get the damn car read at one of the auto parts stores and they will tell you WHICH cylinder is misfiring. Forget disconnecting this and that, you got a misfire code with a specific cylinder, start there and then work your way around.
RON93, I have a laptop with a scan tool on it. All it says on my laptop is P0300, No cyl codes, just that. The ironic thing about this is I have been a mechanic my whole life but that was mostly heavy equipment, Then I became disabled. The program I am currently using is Scanxl pro. I wish it would tell me specific cylinder isn't firing. I am just at my wits end with my car. Thanks for the advice. I have a wide verity of Snap-On tools tools so no issue there.
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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Once again, have the car scanned. THAT will give you the specific cylinders affected. Your scan tool/program probably won't (and many aftermarket "scanners" won't) tell you which cylinders are logging misfires - the parts stores will. . . .
 

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RON93, I have a laptop with a scan tool on it. All it says on my laptop is P0300, No cyl codes, just that. The ironic thing about this is I have been a mechanic my whole life but that was mostly heavy equipment, Then I became disabled. The program I am currently using is Scanxl pro. I wish it would tell me specific cylinder isn't firing. I am just at my wits end with my car. Thanks for the advice. I have a wide verity of Snap-On tools tools so no issue there.
We could go all day and get nowhere(as we are) with a generic 300 code. Does your car drive? Get it to a auto parts store and have it scanned. This is just wasting time saying you have a 300 code without the specific cylinders. I use a cheap $40 code reader and it tells me everything. Emissions, live data, codes and their meanings etc..Get yourself one.
602099
 

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I took off the front coil cassette and pulled the plugs. I noticed 2 different brands, ACDELCO and DENSO. I put it all back together after cleaning everything. Fired it up and still ran rough but when I pulled the codes I get a P1106 code and the P0300 code which points to a map sensor, where is it? Thank you....

I don't need a scanner I use my laptop.

My laptop has a very powerful diagnostic software that I bought. I only use the pc for troubleshooting OBDII systems. I am a horrible typer but RON(#, we could exchange phone numbers if you want. Mine is 414-460-1728. I need my afternoon nap so I'll be back.......
 

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I don't need a scanner I use my laptop.
My laptop has a very powerful diagnostic software that I bought. I only use the pc for troubleshooting OBDII systems. I am a horrible typer but RON(#, we could exchange phone numbers if you want. Mine is 414-460-1728. I need my afternoon nap so I'll be back.......
How powerful can it be if it can't tell you what cylinder is mis-fireing. Here is where your MAP sensor is. I'll show you on my car. Until you tell us WHAT cylinder or cylinders are misfireing this thread is sort of use less
602101
602102
 

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Yeah, I figured that out. My nap won me over and woke up at 10pm I didn't do anything to the car but when this first started, I did take it to an auto parts store and they hooked their OBDII scanner and got the same results as my laptop. It just won't tell which cyl is misfiring but I saw some evedence on the plugs that were black. I think it was 8 and 6 were the black ones, front bank pass side. At least it is starting to show more codes.

OH, I was a member of this site about 15 years ago but can't find my old login info. Yeah, that sensor took a good bath.

Is your IAC plug ripped out?
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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The original spark plugs in our - our - cars were branded either AC Delco or DENSO - the 41-987 (2000 - 2005 Northstar) is the same double platinum plug, all contract-sourced from DENSO, Japan.

DENSO = PT16EPR-C13
AC Delco - 41-987

My owner's manual gives the DENSO plug number - other model year manuals give the AC Delco numbers. Read the fine print on the boxes. My spare set of "AC Delco" 41-987 plugs are marked "Made in Japan". (All our parts are contract-sourced from all over the world) The plugs in the picture in Post #3 - Made in Japan - by DENSO.

P 1106 for GM translates to MAP circuit high voltage. Not the sensor itself.

Butt plug & air box 2.JPG
 

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Yeah, I figured that out. My nap won me over and woke up at 10pm I didn't do anything to the car but when this first started, I did take it to an auto parts store and they hooked their OBDII scanner and got the same results as my laptop. It just won't tell which cyl is misfiring but I saw some evedence on the plugs that were black. I think it was 8 and 6 were the black ones, front bank pass side. At least it is starting to show more codes.

OH, I was a member of this site about 15 years ago but can't find my old login info. Yeah, that sensor took a good bath.

Is your IAC plug ripped out?
This is the IAC ,perfecrly fine. Your still wasting everybody's time until you post which cylinders are misfireing.
602118
 

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Discussion Starter · #18 ·
Even though the pcm isn't saying what cyls are misfiring, I would say front bank the 2 cyls on the pass side. I pulled the plugs and examined them and those had no color and stunk like rotten exhaust. I looked down the spark plug holes and those 2 cyls, the tops of the pistons looked all wet. Maybe that is a clue?
 

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Even though the pcm isn't saying what cyls are misfiring, I would say front bank the 2 cyls on the pass side. I pulled the plugs and examined them and those had no color and stunk like rotten exhaust. I looked down the spark plug holes and those 2 cyls, the tops of the pistons looked all wet. Maybe that is a clue?
You refuse to find out what cylinders are misfiring and just constantly post hypothetical situations, for that reason I am out of the conversation. $30 scanner like I have will tell you everything about the car, always good to have for the future.
602186
 

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That's cylinders 2 and 4. Wet piston crowns usually means fuel but no ignition. Based on your earlier power washing description I'd guess the cassette is cracked and has water intrusion, the ICM inner or outer connector is wet, or the plug boots/plug wells are wet.

Disregard the pre-2000 coil numbering -

Northstar firing order & coils.gif


The cassettes crack around the coil connector tower/insulation area - where the spark plug boot slides onto the cassette.

Cassettes at junkyards - both are identical save for color.

When you remove the cassette look for carbon tracking -

2011-07-09_100054_carbon_tracking.jpg


DSCN0192.jpg
 
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