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Looking for Advice On Throttle Bodies


Texas Jim

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As most of you know, I have a 2006 DTS with the 4.6 Northstar.

I now have over 60,000 on it and plan on keeping it to AT LEAST 100,000 or more.

Since I have been a member of the board, I am always seeing references to cleaning throttle bodies.

My question is...when do they need cleaning?

My car runs great..so far. :D

It idles smooth, and for the way I drive, It gets excellent fuel mileage.

I have "ZERO" complaints about the engine and drivetrain.

I was just wondering if this should be part of my preventive maintenence program or ignore it until there is a problem.

I am usually of a mind that ... "If it ain't broke...don't be a'fixing on it. :D:D:D

Any and all comments welcome.

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There are folks here who will suggest that annual TB cleaning is a good PM idea. And that might be true. I don't subscribe.

I use the "as required" approach. And it has been more than 37,000 miles since required on my engine. My alarm for TB cleaning is when the the gas pedal needs a little extra 'bump' to go off-idle following a cold start (which indicates the air throttle valve might be gummed up and sticking to the cold ID of the TB).

Understand that your TB and PVC system design are not the same as my '98 model engine.

Jim

Drive your car.

Use your cell phone.

CHOOSE ONE !

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FWIW, I do mine as a spring clean up ritual. I am sure that is over kill, but clean up is a breeze as the carbon is nothing more than a heavy film. I suspect after 60K you'll do some scrubbing. It's a personal choice.

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My alarm for TB cleaning is when the the gas pedal needs a little extra 'bump' to go off-idle following a cold start (which indicates the air throttle valve might be gummed up and sticking to the cold ID of the TB).

Understand that your TB and PVC system design are not the same as my '98 model engine.

Thanks Jim,

That might have been what was wrong with my 1999 Chevy van that burned when my garage caught on fire.

Starting when it had about 125,000 or 150,000 miles on it...it had that exact same problem.

Most of the time, it needed a little extra PUSH on the pedal to come off idle and get moving. :D

(Kinda like me) :D:D

Nothing else was wrong with it, so I never did trouble shoot the little minor catch in the throttle.

I kinda figured it was the throttle cable itself...but thinking back...it very well could have been the TB instead. At the time I never even THOUGHT about the TB.

It had well over 250,000 miles on it when it burned, and never did get any worse than it was when it first started.

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The " Severe Service Maintenance Schedule" calls for the FIRST TB cleaning at 30,000 miles.

The SECOND TB cleaning at 60,000 miles...

Air Filter……………………………………….Inspect

Brakes and Traction Control…………………..Inspect

Cabin Air Filter………………………………………..Replace

Cooling System………………………………..Inspect

Coolant………………………………………...Inspect

Drive Belt……………………………………...Inspect

Engine Oil…………………………………………….Replace

Exhaust System………………………………..Inspect

Fluid-A/T……………………………………...Inspect

Fuel Supply Line……………………………...Inspect

Hinge, Door…………………………………………..Lubricate

Oil Filter, Engine……………………………………..Replace

Restraint Systems……………………………..Inspect

Steering and Suspension……………………....Inspect

Throttle Body…………………………………………Clean ********************************

A CLEAN TB insures proper function of the ELECTRONIC throttle control...*Cruise Control*

You won't "Feel" (pedal feedback) a dirty TB, with the newer Electronic system. The Cruise Control function, works best with a clean TB.

rek

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I clean mine when I get the high idle problem, that high idle problem induces a message that I think says, Idle system service needed or something like that.

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Jim, I had a '99 Silverado, well, still do sort of, and I can GUARANTEE that the issue you had with the van was exactly the same. Cleaning the throttle body on that engine brought that sticky throttle right back to new condition. The idle improved too.

I also had a 1999 STS, as most of you know. I did clean the TB on it, and it needed it badly, but never really felt the same issue with the throttle cable. I wonder why? Performance, including idle, was not improved by the cleaning, but it made me feel better.

I never thought about the "drive by wire" systems not giving that feedback on a sticky TB! I'm in that boat with the 2008 DTS. So far, nothing out of the ordinary at 10,800 miles. In fact, I think the engine has finally broken in with a steady 27.5 MPG highway!

Not to hijack this thread, but aside from a jumpy cruise control, can anybody say what symptoms might point to a sticky TB on this car? If not, I'll just clean it at 30,000 and be done with it. Really easy to do.

Never underestimate the amount of a persons greed.

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Thanks to all of you that answered my question.

DARN IT...Y'all made me get out the manual with the service intervals in it. :D:D

The manual does say to clean it every 30,000 miles.

Since I have well over 60,000 miles on it and I have had it for 2 years and 4 months, reckon I need to clean it next weekend. Weather permitting, of course.

My son is coming over with our new EFI Live Suite, tuning software, so I may have an extra pair of hands. :D

At this time, I have absolutely NO driveability issues whatsoever.

Runs good...idles smooth...good snappy throttle response...etc etc.

It has never had a SERVICE message on the DIC.

But, I have noticed that, EVERY GREAT ONCE IN A WHILE...when I set the cruise at 80...it will actually be running 79.

After a bit it will be back at 80, as it should be, and from then on, it will stay at 80.

This might be a symptom of the TB needing cleaning.

Again...

Thanks to all.

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I never thought about the "drive by wire" systems not giving that feedback on a sticky TB! I'm in that boat with the 2008 DTS. So far, nothing out of the ordinary at 10,800 miles. In fact, I think the engine has finally broken in with a steady 27.5 MPG highway!

Johnny,

I too never thought about the drive by wire not giving you any feedback on the accelerator pedal.

That is something I will have to keep in mind.

Your mileage is great. Glad you finally got it broken in. :D:D

I never get anywhere near that good. :(

But mine has a lower gear and is turning more RPM at the same speed.

Best I can get, is around 23 if I keep it down to around 75.

At 90/100 it drops to a hair below 20.

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Texas Jim,

Considering the velocity that air has whistled thru your DTS's throttle body, I would venture to say it might need a little metal "BUILD UP", as opposed to any cleaning of deposits.

Only point in reference is our 94' DeVille with nearly 214,000 miles and nary a wrench turned on the engine/tranny. (period)

No mouse hole tinkering, no TB cleaning or top cylinder hosing. Nothing but a few oil changes and a fewer coolant changes, but a whole lot of WOT spanking of fundamentally good engineering.

Good luck,

Add power to leave problems behind. Most braking is just - poor planning.
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I have never cleaned my TB and it is time on two of my caddy's. It looks pretty simple but should I be prepaired with a new O Ring or any other parts for reassembly? Thanks.

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Here is the GM procedure but it does not mention if you need to replace any O rings or gaskets.

Throttle Body Service

Removal Procedure

Notice

Do not damage the MAF sensor screen. A damaged screen could restrict airflow and lead to a driveability concern.

Remove the MAF sensor bolts and intake air duct as an assembly.

Notice

Do not use any solvent that contains Methyl Ethyl Ketone (MEK). This solvent may damage fuel system components.

Inspect the throttle body bore and throttle valve plate for deposits. It is necessary to open the throttle valve to inspect all surfaces.

Clean the throttle body bore and throttle valve plate using a clean shop towel with GM Top Engine Cleaner, P/N 1052626 or AC-Delco Carburetor Tune-Up Conditioner, P/N X66-P, or equivalent product.

Installation Procedure

Notice

The outlet of the air cleaner assembly and the MAF sensor inlet duct must line up when completely installed. Misalignment may cause incorrect airflow readings resulting in MIL illumination or a driveability concern. An improperly installed inlet duct assembly or air cleaner assembly may cause misalignment.

Install the MAF sensor and intake air duct as an assembly.

Notice

Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

Install the MAF sensor bolts. Tighten

Tighten the MAF sensor attaching bolts to 8 N·m (71 lb in).

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Best I can get, is around 23 if I keep it down to around 75.

At 90/100 it drops to a hair below 20.

My mileage is reported with the cruise set on 71, rolling reset, Ohio flat. BIG difference!

On a side note, this thing COASTS with the taller gearing. It's nothing to pick up 5 or 10 mph on a small downhill grade. With cruise set on 71, it runs 72 most of the time, which is perfect for the 65 speed limit around here. Maybe that's part of the drive by wire effect, but I think it's mostly a combination of the coasting ability and the less agressive throttle action progammed into the cruise control.

No tickets yet. :D

Never underestimate the amount of a persons greed.

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can anybody say what symptoms might point to a sticky TB on this car?

You'll feel the pedal stick and need a little extra pressure to free it up.

Could someone share with us the procedure to clean the TB, and the cleaner used?

I've heard it said to use TB cleaner and not carb cleaner, but I still have Gumout and use it till it's gone. Just remove the intake duct and block the throttle plate wide open. Get a toothbrush and a rag. Spray, brush and wipe until the TB bore and the back and perimeter of the throttle plate are clean.

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No tickets yet. :D

Wish I could say that.

Got one in Mississippi the other day. Darn it.

Need to run by the bank and get a $212 dollar money order and send it to them.

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No tickets yet. :D

Wish I could say that.

Got one in Mississippi the other day. Darn it.

Need to run by the bank and get a $212 dollar money order and send it to them.

They didn't make you pay the ticket on the spot? 17 or 18 years ago, I got a ticket in Wisconsin (41 in a 25...) and the cop made me follow him to the police station in order to pay the ticket.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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Ranger, I understand how to clean the TB but my car must be different then yours. I believe that I need to remove the MAF sensor to get to the TB. I "ASSUME" there is an O-Ring or gasket of some sort. My question is "is this reusable or should I purchase the part prior to disassembly"? Thanks

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My daughter used to have a '99, but I forget exactly how it was set up. IF you do have to remove the MAF sensor (I did on my '97, but not on my '03) I am sure you can reused whatever is there (o ring). I never bought on for her car or mine. It may be built into the MAF sensor.

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can anybody say what symptoms might point to a sticky TB on this car?

You'll feel the pedal stick and need a little extra pressure to free it up.

Ranger, exactly why would that be the case? Doesn't drive by wire eliminate pedal feedback, effectively isolating you from "feeling" the pedal, or is there some kind of feedback circuit built in?

Never underestimate the amount of a persons greed.

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Just to make sure, i checked the TB today. No sign of throttle cable whatsoever! Scary really, but it sure works nice.

Never underestimate the amount of a persons greed.

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Just to make sure, i checked the TB today. No sign of throttle cable whatsoever! Scary really, but it sure works nice.

Yeah...I understand the scary part.

If for some reason the throttle STUCK OPEN...you couldn't put your toe under the accelerator pedal and pull it back up.

The way I understand about how it works is...there are "TWO" sensors on the accelerator pedal.

When you mash it to give it gas...they have to agree with each other, or no signal is sent to the throttle body or the injectors for increased fuel.

Default for ANY malfunction in ANY of the sensors is "NO ACTION TAKEN" at the injectors or throttle body.

It will idle, but if you press the accelerator pedal...it won't go anywhere.

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