: 2002 Deville Multiple codes, rough idle, surging at high RPM



Deltamaster
07-01-10, 08:52 PM
Hello All!

I have been reading many discussions regarding these problems and much points to the plenum but I wanted to run it past to find out your thoughts.

Vehicle = 2002 Deville
Unknown maintenance history. Check Engine light on for last two (at least) years (appx 8000 miles). Driven by 80+ year old man that should not have been driving anyway. I inherited it after his death.


I retrieved the codes thanks to the info found here.

B0429 = Aux rear temp air door.
I understand this is a common code and not worth messing with.

B1004 = Keep alive memory.

B1327 = Device Power Circuit low.
May have been triggered by the battery??? Had to charge battery at one point when there was not enough power to turn over starter motor.

I guess none of these really means much and likely has nothing to do with engine performance but I wanted you all to have all the data I have.

__________________________________________________ __________

Now the interesting codes:

P0101 = Mass air flow sensor.
From what I have read on these forums the sensor may be bad but is not as likely as if there is a vacuum leak after the sensor.

P0171 = Fuel Trim Lean
?????

P0174 = Fuel Trim Lean
?????

P0300 = Engine misfire detected
Bad spark plugs? Bad coil? Bad Wires?

P0741 = TCC stuck off
Torque converter problems? No problems shifting noted.

P1189 = Engine oil pressure switch circuit.
When I inherited the car I took it to Tire Kingdom for tires and they checked the oil and found it was very low. Maybe so low that the pressure was below spec at some point and left the code in the computer?

P1860 = TCC PWM solenoid circuit electrical.
???????

The vehicle seems to drive normally at highway speeds. The display on the dash shows average MPG as between 12 and 14 MPG.

After I acquired the car I drove it from Florida to SC with no problems (approximately 6-700 miles).

A couple months later the engine began to idle roughly.

With the transmission in park and the throttle applied, when it gets over 3500 RPMs the engine surges.

With the transmission in "D" and the vehicle stopped the engine idle falls to about 700 RPM and idles roughly... may stall occasionally.

With the vehicle traveling at approximately 30 miles per hour no throttle pressure applied the RPMs and speed gradually increase. Vehicle will not hold low RPMs or stand still while in "D". Speed will not decrease normally when throttle is released.



OK, Guys. I suspect from reading all the threads that I have found that the Intake Plenum may be the culprit. I did not have any carb cleaner to test it so I sprayed WD-40 on the plenum clamp screw with no change in RPM.

What do you all think?

Ranger
07-01-10, 10:01 PM
I still think it's the plenum duct. Spray it again and this time try flexing the bottom while spraying it.

Deltamaster
07-01-10, 10:05 PM
I still think it's the plenum duct. Spray it again and this time try flexing the bottom while spraying it.


Thanks for the response.

From everything I have read here I suspect you are right... Just wanted to make a confirmation before I consider the project. It does not look to be too bad but...

Has anyone posted instructions on how to replace the plenum?

Can it be done without removing the intake manifold?

OH,

This plenum must be a common flaw. Why has GM not addressed this as a flaw and developed a better solution for it?

Ranger
07-01-10, 10:40 PM
No, I think you're gonna have to lift the manifold, but that's not a bad job.

Yeah, the plenum duct does seem to be a rather common problem. Not sure why GM has not addressed it. Then again, maybe they have. Hope I'm not jinxing myself, but mine is 7 yrs old with 80K on it.

Deltamaster
07-01-10, 11:07 PM
OK.

I understand this is a dealer only part so I am off to find a local dealer and some instructions for removing the manifold.

I will post back when the deed is done to let you know the results.

Thanks

Deltamaster
07-02-10, 09:05 AM
Well...
I just called the local Caddy Dealer and the parts guy told me they have PLENTY of the plenums in stock. He said they get about two requests (between their service department and outside customers) for them per week!

Now to find instructions to replace the thing!

Submariner409
07-02-10, 11:07 AM
The procedure and pictures are posted in this Forum, and maybe in Discussion, Tech Tips.

There are several threads during April alone that have over 30 pictures and diagrams of the plenum, intake manifold, fuel rail, manifold seals (gaskets), and torque sequences.

Look through past pages here and in Deville - stuff like Plenum, Intake Manifold, various P codes, rough idle, etc.

All the job takes is simple hand tools and time. The plenum is held on by 3 long bolts through the throttlebody casting: the "nuts" on the Plenum are welded on. Manifold torque is only 7.5 ft/lb - 89 in/lb......be careful or you'll crack the composite plastic bolt bosses.

Deltamaster
07-02-10, 01:30 PM
Well...

I bought the plenum... $35.00 at the local Caddy dealer. I wanted to replace the intake manifold gaskets but they wanted over $7.00 each for them so I opted not to spend the $58.00 for rubber gaskets. The original ones were in pretty good shape and still pliable so I should be OK there.

I took everything apart which was not too bad (as you mentioned), only needed one socket and a flat screwdriver to do the job. Problem was when I was removing the injectors from the fuel rails one of the blue rubber "O" rings popped off and flew out in to neverland. Dealer did not have them in stock and wanted $75.00 for the kit which included the eight blue upper and the eight black lower "O" rings... WOW!

Advance Auto parts was able to order the uppers for a little over eight bucks total (came in sets of four so I bought two sets).

Am waiting for them to come in now... should be here in about two and a half hours.

Sure enough, though... when I pulled the old plenum there was a tear on the bottom where the rubber meets the metal plate about one inch long.

Sure hope this solves the problem!

Deltamaster
07-02-10, 01:35 PM
There are several threads during April alone that have over 30 pictures and diagrams of the plenum, intake manifold, fuel rail, manifold seals (gaskets), and torque sequences.



Seems to me that if this is such a big problem General Motors needs to develop a solution (better engineered part) and replace them free of charge.

Submariner409
07-02-10, 02:39 PM
That has about the same chances as restitution for '97-99 blown head gaskets from head bolt hole thread failure: slim and none.

When you drop the fuel rail back in, oil the upper and lower fuel injector O-rings - use a smear of your engine oil around each - it will make your life much easier.

When it's all buttoned up, before you try to start the engine, turn the key ON for 10 seconds, OFF for 30 seconds, twice. This will prime the fuel rail again. Start 'er up and use a flashlight to snoop for fuel leaks at the injector/rail connections.

For future use, buy a cheap Walgreen stethoscope, remove the chest diaphragm, and substitute an 18" length of proper sized vacuum hose (Help ! rack). Use the rig to snoop for vacuum leaks and mechanical ticks and squeaks.

Deltamaster
07-02-10, 02:59 PM
I used WD 40 on the lower "O" rings and popped the injectors in to the manifold already. Figured I would do same for uppers when I got them.

Good thing you told me about how to prime the fuel rails/system. I would likely not have done it that way.

Right now I have everything back together except the fuel rails. I just need to pop them on and bolt them down. I figure another 15-20 minutes (after I get the new "O" rings and I will be up and running again.

Thanks for all the info.

Deltamaster
07-02-10, 09:26 PM
Got the new "O" rings. They are not blue, they are black.

Hooked everything up, checked it all out OK. I went for a drive and kept smelling fuel. Went home and checked it out and one of the injectors was spewing gas. Disconnected everything and reconnected to the fuel rails and then a different injector started leaking... Juggled and twisted the problem injectors and eventually the seals seated and the fuel stopped flowing.

Now all is good, car runs fine and smooth!

Still have the SES light on due to the P1860/0741 TCC issues. I have found on the forums that this is a problem that is (as noted) a $50.00 part buried in a $2000.00 repair! WOW... must drop the engine/tranny about 8-12 inches to get to the access cover and effect replacement of the solenoid.

Fortunately from what I have read here the only disadvantage to not repairing this is a loss of about one mile per gallon of fuel economy since the torque converter will not lock up... SO... I guess this goes on the deferred list until my ambition level rises enough to try dropping the engine/tranny myself.


Thanks for all the help and encouragement in replacing the plenum. Local dealer wanted $300.00 to do the job and total time involved for me was about one and one half hours... maybe two with cigarette breaks and all!

Heck, I could charge half that much and make good money all day long on that job!

Deltamaster
07-02-10, 09:30 PM
For future use, buy a cheap Walgreen stethoscope, remove the chest diaphragm, and substitute an 18" length of proper sized vacuum hose (Help ! rack). Use the rig to snoop for vacuum leaks and mechanical ticks and squeaks.

Great idea. I still have my Litman from my USAF EMT days that I could convert like that. If I save the parts I could use it for people and cars BOTH!:yup:


Oh, BTW, what is this "casino cash" thing on the right side of each of my posts?

Ranger
07-02-10, 10:38 PM
When I converted my stethoscope I used a 12" length of copper tubing in place of the chest diaphragm, then added a rubber cap and drilled a hole through it to prevent noises when probing. It helps greatly when getting into tight or hard to reach places.

Submariner409
07-03-10, 10:20 AM
Go up in the blue bar ^^^ and gamble.

While you're at it, go further up to the black bar and read the entire Cadillac Technical Archive.

Deltamaster
07-03-10, 09:31 PM
I found the technical archive. Some interesting info there... especially the WOT info. I remember back in the days of carburetor engines and NO COMPUTERS that the old timers would tell you to get out on the highway and romp on it to clear out the "Cobwebs". When I went to vehicle maintenance tech school in the Air Force I was told this was an urban legend and not really advisable.

I sure can understand a performance engineered engine would need a little "Exercising" from time to time... like a good race horse. Especially when the majority of the people buying/driving these cars are old codgers (at least in Florida they were) that never drive them over 50 mph and take 20 minutes to get up to speed from a stop light! (hehe)

The only reason I have this one is because my old codger passed on to the great reward, did not need it any more and left it for me to struggle with the small problems.

So far I have had to replace both rear window regulators (which has now tossed a window position code).

Replaced all the tires due to dry rot... had good tread but GIANT creacks in the sidewalls!

Thought I had a problem with engine oil consumption until I read the archives!

Repaired the bumper and grill from when the old man ran in to God Knows What... and how many times.

Abandoned the plan to buff out all the scratches since there are so many... from scraping the garage door frame and running grandma's wheelchair in to the body panels.

Now I had to do this Plenum thing and still have the TCC solenoid problem (which I will let pass).

Other than all that she runs great and rides like a dream. Really comfortable to ride in. A joy on the freeway. A darn sight more comfortable (but less practical) than my overloaded 97 Dodge Dakota!

2001_Seville_SLS
07-12-10, 04:41 AM
Still have the SES light on due to the P1860/0741 TCC issues. I have found on the forums that this is a problem that is (as noted) a $50.00 part buried in a $2000.00 repair! WOW... must drop the engine/tranny about 8-12 inches to get to the access cover and effect replacement of the solenoid.

Fortunately from what I have read here the only disadvantage to not repairing this is a loss of about one mile per gallon of fuel economy since the torque converter will not lock up... SO... I guess this goes on the deferred list until my ambition level rises enough to try dropping the engine/tranny myself.


The In the event that you decide to replace the TCC PWM Solenoid Valve, there is no need to pull the transaxle or hang it on all threads. The valve can be replaced with the engine and transaxle in their original location. I posted a how to in Tech Tips.

http://www.cadillacforums.com/forums...741-p1860.html (Malfunction Indicator Light with P0741 and P1860)

2001_Seville_SLS
07-12-10, 01:08 PM
Here is the correct link:

http://www.cadillacforums.com/forums/cadillac-tech-tips/203046-malfunction-indicator-light-p0741-p1860.html

babyb
04-19-13, 09:30 AM
Hi i have the same problem with my Cadillac .i live in Cleveland Ohio. I changed the massive air flow and the throttle .but the problem still continued. So i took thr car to Firestone had it put on a diagnostic test and the guy ssid it is the intake manifold and he said it will cost me $665.00 $325.00 for the intake snd $200 for labor plus taxes. Than i read the comment ftom Deltamaster and he was saying it was the Plenum and it fixed the problem .so im not sure what to do. It is now 2013 and this thred was 2010 but i hope yall can help me please .is anyone in Cleveland?