air charge sensor

[proc360]

Hi, I need some help. I have a 1998 STS which recently the check engine light came on and it began running rough at idle but as soon as i drive and get it over 10 mph it rides fine. Went to the local autozone and they read the codes . They said its was the air charge sensor valucraft SU176VC the problem is i cant find this sensor. Can anyone please help and guide me to the right location. Thanks

[Cadillac Jim]

"Air charge sensor?" It sounds like the IAT sensor or perhaps the MAF sensor. Or maybe the MAP sensor.

What you need to do is read the OBD codes yourself and that will tell you which sensor it is. Use the link in my signature block to see how to run the OBD codes from your A/C buttons and read them from the DIC. Write them down and post them here. Be sure and note which ones are History and which ones are Current.

[James Woods]

Best advice is from Cadillac Jim, use his instructions to retrieve the codes yourself.

Looking up the part number i

On auto zone website it's an air intake temperature sensor. Done of the northstar engines had the IAT located in the mass air flow meter and some were after the mass air flow meter and the throttle body.

[proc360]

Went to get codes. Hit yes to clear codes by mistake and drained battery while doing it. Had to jump start. Went to check the codes and the check engine went off, got codes but nothing to do with engine, runs a little ruff at idle. Going to drive it for a bit and see if check engine light comes back on. I found the IAT sensor it was located on the inlet air tubing before the throttle body. The connector is somewhat underneath. But as far as that sensor they gave me at autozone i've had no luck on locating. The weird thing about it as per there website its a part and if you look at symptoms associated with a faulty sensor its all that im experiencing. Until i get the check engine light come up again Ill clean the map sensor and any other sensors i find. Im also get a once i a while noise around the power steering pump area. I'm thinking of doing a smoke test to see if i have a intake leak. Whats your thoughts on that?????

CODES

1. DDM B1982 CURRENT
2. IPM D1341 CURRENT
3. IPM D1344 CURRENT
4. MSM B2120 HISTORY
5. RSS C1738 CURRENT

I believe these are all other components of the car which have nothing to do with engine management. Any input is greatly appreciated. Thanks

[Cadillac Jim]

CURRENT
B1982 Device Power Circuit High
B1341 Air Mix Door Two Movement Fault
B1344 HeaterDefrost/AC Door Movement Fault
C1738 Exhaust Solenoid Valve Short to GND [Ride height compressor/solenoid problem]

HISTORY
B2120 Lumbar Up/Down Sensor Failed

None of these are engine codes. The Bnnnn codes are from the air control doors for the A/C, the C1738 code is from the ride height control, and the B2120 is likely from the lumbar seat support being all the way up or down, against the stops.

The IAT sensor is on the side of the air cleaner box, which is on the left fender; follow the large flex hose from the engine to the air cleaner box. The IAT sensor is on the rear side. Find the connector and plug it back in.

[proc360]

Ok- finally got the check engine light today. Got a p0300 which is a misfire I believe. Well I started to take apart to get to throttle body to clean. Noticed oil inside intake. Removed all the spark plugs and most had oil on them. Was told the valve stem seals need to be replaced. Coolant seems fine, little blue smoke coming out of exhaust once in awhile. Looked at a couple of videos - this is something i'm willing to tackle. Thinking while i'm doing this to do headgasket also. Head gasket kit and switching bolts to studs. Any suggestions on manuals,videos or anything else. Plan to check injectors.

[James Woods]

All north star engines get oil pat the piston rings from carbon build up. It's just a part of the Cadillac ownership experience.

I would a say the valve stem seals is most likely a misdiagnosis. There are plenty of threads here about cleaning the rings and methods of doing it. Basically once you get the rings to free up the oil consumption and oil in the intake and on spark plugs will be way less.

Before my time here there was a member who was called the guru, I've been told he was on the design team food the north star engine. He posted a method about using second gear and a few acceleration runs and letting the engine brake the cat to slow it down, I've tried that method on 2 of my Cadillac not long ago so I can't tell you how good it worked until I drive more miles.

I always before used GM top end engine cleaner and followers the directions got a 2 hour soak then a drive until smoke disappears. That has worked for me greatly. Cut my oil use from 1 quart every 600 miles to a quart every 3000 miles. I hope the engine braking method by the guru works as well. Other members seem to have great luck with the guru way.

Here is good reading about the guru explaining oil usage and some things on the Wide Open Throttle 2nd method. http://caddyinfo.ipbhost.com/index.php?showtopic=44922&hl=

[proc360]

So today I decided to attach my timing gun with trigger being held on position with 12 gauge wire. Checked all spark plug wire and notice that cylinder 8 had no power and 3 was intermittent. Used a spark tester to confirm. I switched the coil pack with another to verify and the problem followed the coil. Went to local pick and pull and replaced. Car is back to normal for $5.35. Thanks again.

[rockfangd]

cant go wrong with that. Easily resolved

[James Woods]

I do like the movable coils on the earlier north stars. On my 2002 2003 Deville it's one coil pack for front bank and one for the rear. All I can do is move the whole pack and see if the problem moves to the other bank.

Glad it worked out easy and cheap for you

[Cadillac Jim]

Used coil bank for $5.35! Amazing!

Now we know what an "air charge sensor" is.

The A/C temperature control door and the ride height exhaust solenoid, you can fix at your leisure.