Looking for engine diagrams for 04 TB w/5.3

[dmartin95]

Okay, so I have a 2004 Trailblazer EXT with the 5.3 V8 (VIN code P) and I'm having an issue idling.... It's starts and runs fine for the most part... The problem comes in heavy traffic and at stop lights... My RPM's are dropping too low.... They go down to around 450-500 and it will stall if I don't toss it in neutral and manually raise the RPM's with the accelerator pedal. This problem does not show itself until the engine is warm (after about 15-20 min)... When I first start it up, it runs fine and RPM's are normal.

I've had it to the dealership now 3 times and they haven't been able to get the problem fixed.. I have new plugs, wires, MAP sensor, air filter, new battery, fresh synthetic oil and a new O2 Sensor.

I see alot of people having the same issue and they suggest cleaning the throttle body and another solution I found was to change the Cam actuator solenoid valve....

I have no idea where the CAM solenoid is and was wondering if someone could show me on a diagram...

When it comes to the variable valve timing solenoid, I'm a bit confused... I am finding some sellers that offer 2 of the VVT solenoids, one for the exhaust and one for the intake... Do I need to buy the set and where are they located?

 

[mrrsm]

Welcome to GMT Nation...

If you peruse the Article in the attached link... It indicates that your 2004 Trailblazer EXT came factory fresh with the LM4 Vintage 5.3L Aluminum Engine...which...if you look towards the very bottom of the read... states that, "The cherry on top is that it isn’t saddled with Variable Valve Timing (VVT) or Active Fuel Management (AFM) found on some Gen. 4 engines."

LM4 5.3L Engine Upgrade Guide: Expert Advice for LM4 Mods to Maximize Performance

[Editor’s Note: This LM4 engine upgrade guide is part of a series of LS engine upgrade guides assembled by a team of LS experts at Summit Racing that we’re sharing at OnAllCylinders. For …

www.onallcylinders.com

If this is true and you don't have a Later Model Engine in your SUV... those are Two Good Things and Two Less Headaches in your way to finding a solution to the problem. Here is what to do NEXT:

(1) Visit THIS Link and (Courtesy @Mooseman ...) Follow his Instructions on How To Download a COMPLETE GM OEM Digital Shop Manual for your particular Vehicle...for FREE!

Need service manuals? Get them here!

********* Please note that the FireFox browser has issues with the password handling and that these downloads are not under HTTPS, flagging them as security risks. Chrome and Edge work fine once you allow the download. ********* ATSG 4L60E Manual 4L60E Rebuild Manual 2005 GMC Envoy XUV...

gmtnation.com

(2) Use or obtain a decent OBD2 Code Reader (BLUETOOTH + Free Torque App...for example) so you can check for any PXXX Codes and alert back here for particular issues. Google and Youtube should have some Videos on How to Clean the Throttle Body...and Don't Overlook the Air Filter... if it is REALLY Clogged up... it can force the engine to Starve for Air at Idle as well.

Welcome Aboard... You are among Friends... :>)

 

[dmartin95]

Thanks for the reply MRRSM! I looked over the service on your link and none are for my 2004 TB... I have a 5.3 in mine and the 2002-05 only has info on the 4.2 and 4.8 engine... By chance have any more links?

I do have a reader... I use the Ultra Gauge EM Plus v1.2 .... I have received P0171 and P0300....

 

[C-ya]

The 4.8 chapter shows 4.8, 5.3 and 6.0. It should have what you are looking for. Only the 4.2 has the VVT solenoid and cam phaser. The V8 does not.

P0300 is random misfire as I'm sure you know. P0171 is bank 1 too lean. Both of these can cause rough running. Which O2 sensor did you replace? With that code, I would replace Bank 1, Sensor 1 as the first, easy attempt at repair. Misfires can be caused by compression or fuel injection issues, too. Just something to keep in mind. It would be nice if you had a specific cylinder misfire code to direct you.

I have an AFM 5.3 in mine, which I had disabled, and I was able to clean the throttle body very easily. I was telling a co-working with a Ranier about cleaning his as he is having the classic stumble at idle and turning into parking spots with the A/C on, and they are in a very different location on the 4.2!

It almost seems like the system isn't responding to the temp change and is using the wrong fuel map. How is the reported engine coolant temp? If the system never knows it is getting hot, it may not switch maps or make the change(s) as required - whatever this platform does.

 

[TollKeeper]

My rough idle on my 04 V8 was down to the MAF sensor. I replaced it with a ACDelco model from Amazon, and problem and MIL went away.

 

[dmartin95]

The 4.8 chapter shows 4.8, 5.3 and 6.0. It should have what you are looking for. Only the 4.2 has the VVT solenoid and cam phaser. The V8 does not.

P0300 is random misfire as I'm sure you know. P0171 is bank 1 too lean. Both of these can cause rough running. Which O2 sensor did you replace? With that code, I would replace Bank 1, Sensor 1 as the first, easy attempt at repair. Misfires can be caused by compression or fuel injection issues, too. Just something to keep in mind. It would be nice if you had a specific cylinder misfire code to direct you.

I have an AFM 5.3 in mine, which I had disabled, and I was able to clean the throttle body very easily. I was telling a co-working with a Ranier about cleaning his as he is having the classic stumble at idle and turning into parking spots with the A/C on, and they are in a very different location on the 4.2!

It almost seems like the system isn't responding to the temp change and is using the wrong fuel map. How is the reported engine coolant temp? If the system never knows it is getting hot, it may not switch maps or make the change(s) as required - whatever this platform does.

Thanks for the info.... After your reply, I opened the manual and found the info for the 5.3... Awesome!

I don't know which O2 sensor was replaced... I should be able to tell you later.. I just got off the phone with the Dealership and requested that they send me all my service records to my email.

My engine coolant temp is fine... The in dash gauge always reads good and my Ultra-gauge always reports the same temps..

One thing I should add.... It has a lifter tap... I received the trailblazer with 86,000 miles and it was tapping and she now has 156,000 with the same tap... I don't think I have a broken spring but I may need a valve adjustment... The reason I don't think it's the problem though is because it's had the tap ever since I owned it...

 

[dmartin95]

My rough idle on my 04 V8 was down to the MAF sensor. I replaced it with a ACDelco model from Amazon, and problem and MIL went away.

The Dealer replaced the MAF and used their part which I assume is ACDelco.... That was the first thing they did... Then I took it back because It was still having the same issue... That time they concluded it was my plugs and wires... So I had them replace those... still the problem persisted... Then they told me it was an O2 sensor.. NOPE, the problem is still happening.