: I keep getting P0404 and P0441? Looking for suggestions...



sprj
07-14-06, 08:34 AM
I keep getting P0404 and P0441? Looking for suggestions...
P0404 EGR OPEN POSITION PERFORMANCE
P0441 EVAPORATIVE EMISSION CONTROL SYSTEM INCORRECT PURGE FLOW

97 Seville SLS

I recently cleaned the EGR valve (http://www.cadillacforums.com/forums/#) and it seemed to be moving freely. Also, did not see any significant carbon or any other kinds of deposits on it.

Any thoughts?

Ranger
07-14-06, 10:22 AM
I'd check the EGR valve again and make sure it is not sticking, even the slightest bit during the full range of motion.

Check the EVAP solenoid and purge valve vacuum lines to be sure they are connected and not cracked or broken. Also be sure that the fuel filler cap ceck valve is operating properly and that the cap is on tight.

sprj
07-14-06, 10:48 AM
I'd check the EGR valve again and make sure it is not sticking, even the slightest bit during the full range of motion.

Check the EVAP solenoid and purge valve vacuum lines to be sure they are connected and not cracked or broken. Also be sure that the fuel filler cap ceck valve is operating properly and that the cap is on tight.

How do I check the solenoid, where are the purge valve vacuum lines and how can I test the the check valve on the cap? I know the cap is on tight. That is not the issue.

Do you think if there was an issue with the integrity of the cap that it might trip both of those codes?

Ranger
07-14-06, 08:54 PM
The purge valve & solenoid are on the rear cam cover. You'll need a FSM for the diagnostic proceedure. A bad cap might trigger an EVAP code but I doubt that it would trigger an EGR code.

dkozloski
07-15-06, 12:19 AM
It could be your EGR valve has unlearned the zero position. Disconnect the electric connector on the valve. Turn on the key and reset the CEL. Immediately turn the key off before it can set again. Reconnect the EGR and turn the key on. It should automatically relearn the zero position.

sprj
11-02-06, 09:00 AM
I'd check the EGR valve again and make sure it is not sticking, even the slightest bit during the full range of motion.

Check the EVAP solenoid and purge valve vacuum lines to be sure they are connected and not cracked or broken. Also be sure that the fuel filler cap ceck valve is operating properly and that the cap is on tight.

Hey Ranger,

I am still having these problems (P0441 and P0404). Do you think that a bad gas cap check valve could cause the car to misfire occasionally and backfire occasionally? How about the EGR valve? EVAP Solenoid? Vacuum lines?

Ranger
11-02-06, 10:23 AM
No, a bad gas cap will not cause a misfire or backfire, nor would I suspect that from the EGR, EVAP solenoid or vacuum lines. Plugs and wires would be my first suspect.

sprj
11-02-06, 11:45 AM
No, a bad gas cap will not cause a misfire or backfire, nor would I suspect that from the EGR, EVAP solenoid or vacuum lines. Plugs and wires would be my first suspect.

Thanks for the reply Ranger. I don't know what to do with this car. I seem to have had more problems with the plugs and wires than anything. Somebody on this forum has insisted on sticking with OEM parts (may have been you). Car was misfiring when I first got it. I replaced plugs and wires with Delco plugs and Bosch Platinum wires. Couldn't afford the Delco wires. 1 year later car starts misfiring again. I got the wires replaced for free from website I had ordered them from. Car seemed to run good for a couple of weeks then problem recurred. I finally took it a mechanic I was referred to. He hooked it up to a machine, found that one of the plugs was not firing. Upon examination of that spark plug he found it had a crack in the porcelain. Plug was replaced, problem solved, this was in June. The consensus on this forum overwhelmingly seems to be to use OEM, however, in my case it appears that it was the OEM part that failed me and that the aftermarket part was fine. At any rate, I am having an occasional problem again with misfiring, more like intermittent and the car has even backfired a few times recently. I don't know if these issues are related to the two codes I keep receiving or if they are mutually exclusive. I don't know if I should change the plugs and or wires again and if so, what brand to use. Is there any practical way to test them? Have you ever heard of a bad batch of spark plugs? Maybe another of the plugs has a crack in it? I was planning on replacing the gas cap first since it is the least expensive and seeing if there is any change in how the car behaves, but I don't want to start spending money by guessing on what is wrong with this car. What are YOUR thoughts on these matters Sir?

dkozloski
11-02-06, 12:20 PM
Thanks for the reply Ranger. I don't know what to do with this car. I seem to have had more problems with the plugs and wires than anything. Somebody on this forum has insisted on sticking with OEM parts (may have been you). Car was misfiring when I first got it. I replaced plugs and wires with Delco plugs and Bosch Platinum wires. Couldn't afford the Delco wires. 1 year later car starts misfiring again. I got the wires replaced for free from website I had ordered them from. Car seemed to run good for a couple of weeks then problem recurred. I finally took it a mechanic I was referred to. He hooked it up to a machine, found that one of the plugs was not firing. Upon examination of that spark plug he found it had a crack in the porcelain. Plug was replaced, problem solved, this was in June. The consensus on this forum overwhelmingly seems to be to use OEM, however, in my case it appears that it was the OEM part that failed me and that the aftermarket part was fine. At any rate, I am having an occasional problem again with misfiring, more like intermittent and the car has even backfired a few times recently. I don't know if these issues are related to the two codes I keep receiving or if they are mutually exclusive. I don't know if I should change the plugs and or wires again and if so, what brand to use. Is there any practical way to test them? Have you ever heard of a bad batch of spark plugs? Maybe another of the plugs has a crack in it? I was planning on replacing the gas cap first since it is the least expensive and seeing if there is any change in how the car behaves, but I don't want to start spending money by guessing on what is wrong with this car. What are YOUR thoughts on these matters Sir?
99.99% of the time damaged sparkplug porcelain comes from a slip during installation. The correct Delco plugs and wires are the best on the maket and the rest are varying grades of junk. Delco stuff properly installed is engineered for 100,000 miles. Anything else is anybody's guess.

Ranger
11-02-06, 04:03 PM
I have to agree with Koz. You are not the first to say that they have had problems with Bosch wires. Porcelin cracks are rarely manufaturer defects. As Koz said it is usually rough handling somewhere along the line. That said, carbon tracking is frequently mistaken for a crack. Did they use any dielectric grease on the wire caps?

dkozloski
11-02-06, 05:06 PM
I have to agree with Koz. You are not the first to say that they have had problems with Bosch wires. Porcelin cracks are rarely manufaturer defects. As Koz said it is usually rough handling somewhere along the line. That said, carbon tracking is frequently mistaken for a crack. Did they use any dielectric grease on the wire caps?
It is not unheard of for there to be defective spark plug insulators but very rare. An ACDelco rep urged me to call him personally if I ever encountered one back when I was in the aircraft engine overhaul business.

sprj
11-02-06, 11:28 PM
I have to agree with Koz. You are not the first to say that they have had problems with Bosch wires. Porcelin cracks are rarely manufaturer defects. As Koz said it is usually rough handling somewhere along the line. That said, carbon tracking is frequently mistaken for a crack. Did they use any dielectric grease on the wire caps?

The gentleman who discovered the bad plug did not put any grease on that I know of. That raises another question. I didn't put any kind of grease on those wires when I put them in. Sounds like that grease may aid in that boot seating and facilitate conduction, is that correct? I have had a hell of a time getting those boots to seat on the plugs the few times I have had them off and on. I have never dropped any of the plugs, but have you ever heard of anyone cracking a plug by struggling to seat the spark plug boot?

Ranger
11-02-06, 11:59 PM
A/C Delco wires come with some type of lube already applied to the boot and specificly say not to use dielectric grease.

I have never seen anyone crack the porcelin by putting the boots on, but I have cracked 1 or 2 in my younger days installing them. :rolleyes:

sprj
11-03-06, 02:13 PM
A/C Delco wires come with some type of lube already applied to the boot and specificly say not to use dielectric grease.

I have never seen anyone crack the porcelin by putting the boots on, but I have cracked 1 or 2 in my younger days installing them. :rolleyes:

Maybe I cracked a plug or two putting them in. I am usually pretty conscience about tightening the plugs, but you never know. I think I am going to replace all the plugs even though they are only a year old. I don't know what else to do. What gap do you recommend on the Northstar? I put a new gas cap on last night, so I am waiting to see if the P0441 code bears itself again and if/and when I get the P0404 again I am going to take the EGR off again when I replace the plugs and clean it again even though it did seem to be moving freely and did not seem to really be fouled up at all. That EGR is kind of expensive, so I don't want to replace it wrongly if it is not the problem whether that means a cleaning or misdiagnosis. If,after that, I keep getting the P0404 code do you think it is safe to say that I would be doing the right thing by spending the money on a new EGR valve?

Thanks for the advice. I am not real savvy with auto repair and my budget is challenging right now. I really appreciate all the information I have gotten on this forum in the last year. It is a tremendous help to me.

Ranger
11-03-06, 04:21 PM
A/C Delco dual platinum plugs for the Northstar are spec'd at .050 gap.

If the EGR fails or is sticking, it should set a DTC. Don't replace it without a DTC set. Even then, a good cleaning will usually fix it.

sprj
11-03-06, 05:00 PM
A/C Delco dual platinum plugs for the Northstar are spec'd at .050 gap.

If the EGR fails or is sticking, it should set a DTC. Don't replace it without a DTC set. Even then, a good cleaning will usually fix it.

What is a 'DTC'? Is P0404 a DTC?

Ranger
11-03-06, 05:16 PM
Yes.
DTC = Diagnostic Trouble Code

sprj
11-03-06, 05:28 PM
Yes.
DTC = Diagnostic Trouble Code

I'll clean 'er again. Toothbrush and carb cleaner, keep 'er upright so the cleaner doesn't get inside, right? Any tips for effectiveness?

Ranger
11-03-06, 05:48 PM
You got it. :thumbsup: Just be sure when you're done and you push on the pintle, it moves freely through out its range and does not stick anywhere.

sprj
11-03-06, 06:24 PM
Thanks a lot Ranger.

sprj
11-03-06, 11:39 PM
The purge valve & solenoid are on the rear cam cover. You'll need a FSM for the diagnostic proceedure. A bad cap might trigger an EVAP code but I doubt that it would trigger an EGR code.

Still getting the P0441. I figured a gas cap would be too easy to get off the hook. I need to get an FSM. Field Shop Manual, right? I looked online a bit with no luck. Any suggestions where I might find one of these? Will it have the vacuum line diagrams? Are Chilton's, Hayne's, those types of books considered FSM's or is the FSM something totally different?

sprj
11-04-06, 03:04 AM
Originally Posted by Ranger
I'd check the EGR valve again and make sure it is not sticking, even the slightest bit during the full range of motion.

Check the EVAP solenoid and purge valve vacuum lines to be sure they are connected and not cracked or broken. Also be sure that the fuel filler cap ceck valve is operating properly and that the cap is on tight.


Hey Ranger, I think you were right about the EGR. It's late, but I got anxious thinking about this so I went out to the garage and took it apart. The EGR was showing some carbon around the inlet, more than I remember last time I took it off. Anyway, I brought in the house and upon inspection in good light I could see a ring of carbon around the inlet and on the inside wall of the inlet that the valve seats in. This time rather than carb cleaner I used the edge on a pair of scissors to scrape the deposits off as they were very hard. I can tell the valve is very smooth now. I didn't think there was any resistance on it before, but comparatively in retrospect there was. Hopefully I won't hear anything about the EGR again. I looked at all the vacuum lines I could see. I couldn't find anything disconnected or cracked. On Rock Auto.com it looks like the solenoid and purge valve are one part? Are either of these what you were referring to?:
Vapor Canister Purge Solenoid (http://www.rockauto.com/catalog/x,carcode,1027831,parttype,5148)
Vapor Canister Purge Valve (http://www.rockauto.com/catalog/x,carcode,1027831,parttype,4936)
If so, I might just replace it. It is only about $20. What do you think?

Ranger
11-04-06, 10:52 AM
FSM = Factory Service Manual. If you can't find one on Ebay, Helm is running a 1/2 price sale on manuals up to 2001. http://www.helminc.com Haynes & Chiltons are virtually worthless for any serious trouble shooting. THe Helm manual has every electrical schematic, diagnostic proceedure, torque spec, and much more than you will ever need and in some cases, understand, but it is worth it's weight in gold.

The solenoid and purge valve may be one part. I can't remember for sure but compare it to the one on your car. I would not replace it yet. You may have solved the problem. Wait and see.

sprj
11-04-06, 12:47 PM
FSM = Factory Service Manual. If you can't find one on Ebay, Helm is running a 1/2 price sale on manuals up to 2001. http://www.helminc.com Haynes & Chiltons are virtually worthless for any serious trouble shooting. THe Helm manual has every electrical schematic, diagnostic proceedure, torque spec, and much more than you will ever need and in some cases, understand, but it is worth it's weight in gold.

The solenoid and purge valve may be one part. I can't remember for sure but compare it to the one on your car. I would not replace it yet. You may have solved the problem. Wait and see.

Thanks for the info on the manual. I will look into it. You think that the EGR carbon may have been trigger the EVAP EMISSION CONTROL code (P0441) too?

sprj
11-04-06, 01:16 PM
http://www.storesonline.com/images/site/common/en/image/imagewrap.img?picture.image.url=http://www.storesonline.com/members/573683/uploaded/GMP97EK1-2.jpg&picture.width.max=200&picture.height.max=0 I found this picture on another website. I want to make sure this is the right manual before I order it from Helm. The manual is $67.50 on Helm. I looked online a bit and that looks like a real good price. Is this the book I'm I want?

Ranger
11-04-06, 03:52 PM
That be it.

No, I don't think that the EGR would cause an EVAP code. Two seperate systems and issues.

Caddyshack100
11-05-06, 09:23 PM
This might help you until you get your fsm. Keep in mind though that any time you clear a emission code such as 0441, it will have to stay clear for at least 7 to ten days, to confirm that the fix has worked. GM evap codes work in strange ways.
DTC P0441 Evaporative Emission (EVAP) System No Flow During Purge

Object Number: 13018 Size: MF
Click here for detailed picture of above image.
Circuit Description

This diagnostic test is used to determine if the Evaporative Emission (EVAP) purge control solenoid is open when the PCM is commanding it open (energized). The PCM does this by monitoring the Evaporative Emission (EVAP) purge vacuum switch which is a normally closed switch mounted in the vacuum line between the EVAP canister and the EVAP purge solenoid. The switch opens when vacuum from the engine draws the evaporative emissions from the EVAP canister through the EVAP purge solenoid and into the throttle body. The PCM monitors the state of the EVAP purge vacuum switch to determine if the EVAP purge solenoid is open and passing vacuum. The PCM accomplishes this by monitoring the amount of time the EVAP purge vacuum switch is continuously open or closed during purge. When the test conditions are met the PCM starts a timer, which will be reset when the switch transitions open to closed or vice versa. If the switch remains closed for 9 seconds continuously, DTC P0441 is set. If the switch remains open for 2 seconds continuously, the test is passed.
Conditions for Setting the DTC

* Test Conditions DTCs P0101, P0102, P0103, P0107, P0108, P0122, P0123, P0401, P0506, P0507, P1441, P1508, P1509 and P1645 not set.
* IAT at key ON is greater than -25°C (-13°F).
* IAT remains below 99.5°C.
* ECT at key ON is at least 30°C less than previous key OFF ECT reading.
* ECT is less than 125°C (257°F).
* MAP is between 29.9 and 60 kPa.
* Throttle position between 0 and 81.6 degrees.
* Engine speed between 500 and 6375 RPM.
* EVAP purge solenoid duty cycle at least 60%.
* BARO at least 72.
* Engine vacuum at least 12 kPa.

Failure Condition

EVAP purge vacuum switch closed for 9 seconds and the EVAP purge vacuum switch has not been open for 2 seconds at any point during the test.
Action Taken When the DTC Sets

* The PCM will illuminate the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
* The PCM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records.

Conditions for Clearing the MIL/DTC

* The PCM will turn the MIL OFF after three consecutive drive trips that the diagnostic runs and does not fail.
* A Last Test Failed DTC will clear when the diagnostic runs and does not fail.
* A History DTC will clear after forty consecutive warm-up cycles with no failures of any diagnostic test.
* Use a scan tool to clear DTCs.
* Interrupting PCM battery voltage may or may not clear DTCs. This practice is not recommended. Refer to Clearing Diagnostic Trouble Codes in PCM Description and Operation.

Diagnostic Aids

Notice

Do not apply voltage to the EVAP vacuum switch. The voltage supplied by the PCM is of a low current design. The EVAP vacuum switch may be damaged if jumpered to voltage without this current limiting feature.
EVAP System Charcoal Contamination Checking Procedure

1. Remove EVAP Purge solenoid and the EVAP vacuum switch. Refer to R&R Procedures .
2. Lightly tap both components on a hard surface.
3. Check for the release of charcoal from either component.
4. If charcoal contamination is present replace the EVAP Vapor canister, EVAP Purge solenoid, EVAP Vacuum switch and clean the EVAP purge hoses. Refer to the EVAP Purge Hose Cleaning Procedure .

Test Description

Number(s) below refer to the step number(s) on the Diagnostic Table.

3.

Ensuring correct vacuum line connection and checking if fault conditions are present.
4.

Checking if fault is vacuum or switch.
5.

With a properly operating system the vacuum gauge can fluctuate rapidly while the solenoid is commanded On until 100% duty cycle is reached, at which point the vacuum should indicate the value specified. If the vacuum gauge indicates manifold vacuum immediately following 10% commanded On duty cycle then there is a restriction in the line or canister.

Step


Action


Value(s)


Yes


No

1


Was the Powertrain On-Board Diagnostic (OBD) System Check performed?


--


Go to Step 2


Go to A Powertrain On Board Diagnostic (OBD) System Check

2


Is DTC P1645 also set?


--


Go to DTC P1645 Evaporative Emission (EVAP) Vent Solenoid Contorl Circuit


Go to Step 3

3


1. Ensure correct vacuum line connection to EVAP Purge Solenoid.
2. Turn the key ON.
3. Start engine.
4. Raise the engine RPM slightly and using the scan tool command the EVAP solenoid ON (100%).

Does the Evap. Vacuum SW. display Purging?


--


Fault not present


Go to Step 4

4


Disconnect EVAP vacuum switch connector.

Does the Evap Vacuum SW. display Purging?


--


Go to Step 5


Go to Step 12

5


1. Reconnect the EVAP switch connector.
2. Disconnect EVAP vacuum switch vacuum hose (solenoid side).
3. Tee a vacuum gage between hose and switch and reconnect vacuum hose (with tee) to EVAP solenoid.
4. Measure the vacuum with the engine running and the EVAP control solenoid commanded ON (100%).

Is the vacuum the same or more than the value specified?


4 HG


Go to Step 6


Go to Step 7

6


Replace the EVAP switch.

Is the repair complete?


--


Go to Powertrain Control Module Diagnosis for Verify Repair


--

7


1. Disconnect EVAP control solenoid vacuum hose (intake manifold side).
2. Connect vacuum gage to vacuum hose and measure the vacuum with the engine running.

Is the vacuum the same or more than the value specified?


4 HG


Go to Step 8


Go to Step 9

8


1. Reconnect vacuum hose to EVAP control solenoid.
2. Disconnect EVAP control solenoid vacuum hose (EVAP switch side)
3. Connect vacuum gage to EVAP solenoid port.
4. Measure the vacuum with the engine running and the EVAP control solenoid commanded ON (100%).

Is the vacuum the same or more than the value specified?


4 HG


Go to Step 11


Go to Step 10

9


Repair blocked or leaking vacuum hose between intake manifold and EVAP control solenoid.

Is the repair complete?


--


Go to Powertrain Control Module Diagnosis for Verify Repair


--

10


Replace the EVAP control solenoid.

Is the repair complete?


--


Go to Powertrain Control Module Diagnosis for Verify Repair


--

11


Check for vacuum leak in system between EVAP control solenoid and the vapor canister, including the switch.

Was a leak found and repaired?


--


Go to Powertrain Control Module Diagnosis for Verify Repair


Go to Step 13

12


Repair short to ground on the EVAP vacuum switch input circuit.

Is the repair complete?


--


Go to Powertrain Control Module Diagnosis for Verify Repair


--

13


Replace the vapor canister. Refer to EVAP Canister Replacement .

Is the replacement complete?


--


Go to Powertrain Control Module Diagnosis for Verify Repair


--

sprj
11-10-06, 12:46 PM
Ranger,

Still waiting on my FSM, should arrive today. I noticed on your posts it says 'MODERATOR'... What does that mean? Are you or have you been a professional tech? You seem to be extremely informed? I was talking to a GM Tech who was at the parts store I was at the other day. I was talking to him about my issues with the plugs (crack). He was telling me about potential issues with the ratchet touching the top of the plug on a standard spark plug socket and putting a sideload on the plug when tightening causing a crack. I replaced my plugs yesterday and was extremely careful installing them. I bought a very deep socket so the ratchet was no where near the top of the spark plug in the socket. The ignition issues I was having were very sporadic, so I will give it several weeks before I feel confident that she is running smooth, but it does seem to be running a little nicer and I am hoping that will be the last of my ignition concerns. I am learning slowly here. The gentleman that I spoke with was telling me about some procedures regarding the EVAP situation including pressurizing the gas tank with compressed air and spraying the vacuum lines with soapy water to look for a leak and pressurizing the gas tank with smoke to visibly locate a leak...? Have you heard of these procedures? I feel like this one may be over my head, but I am going to review the manual when it arrives and make a decision. I also was looking at some of the general posts in the technical discussion and I saw a couple that got my attention that you had replied to regarding changing coolant and trans fluid. My car has 92,000 miles currently and I have had it for almost two years now. I have not changed either of those and I don't know when either of them have been changed if ever, so I think that may be in order. What are the ramifications of neglecting those maintenance items? The doorbell just rang... the FSM has arrived! By the way, how is your DHS? How long have you had it and what has your maintenance and repair history been like with it and how long have you been driving Cadillacs?

sprj
11-10-06, 12:48 PM
Caddyshack100,

This looks intimidating to me. I am assuming this is from the FSM? I feel like this issue may be beyond me, but my FSM just arrived so I am going to review the information. Thank you for taking the time to post this information. It is greatly appreciated.

Ranger
11-10-06, 01:44 PM
Ranger,

Still waiting on my FSM, should arrive today. I noticed on your posts it says 'MODERATOR'... What does that mean? Are you or have you been a professional tech? You seem to be extremely informed? I was talking to a GM Tech who was at the parts store I was at the other day. I was talking to him about my issues with the plugs (crack). He was telling me about potential issues with the ratchet touching the top of the plug on a standard spark plug socket and putting a sideload on the plug when tightening causing a crack. I replaced my plugs yesterday and was extremely careful installing them. I bought a very deep socket so the ratchet was no where near the top of the spark plug in the socket. The ignition issues I was having were very sporadic, so I will give it several weeks before I feel confident that she is running smooth, but it does seem to be running a little nicer and I am hoping that will be the last of my ignition concerns. I am learning slowly here. The gentleman that I spoke with was telling me about some procedures regarding the EVAP situation including pressurizing the gas tank with compressed air and spraying the vacuum lines with soapy water to look for a leak and pressurizing the gas tank with smoke to visibly locate a leak...? Have you heard of these procedures? I feel like this one may be over my head, but I am going to review the manual when it arrives and make a decision. I also was looking at some of the general posts in the technical discussion and I saw a couple that got my attention that you had replied to regarding changing coolant and trans fluid. My car has 92,000 miles currently and I have had it for almost two years now. I have not changed either of those and I don't know when either of them have been changed if ever, so I think that may be in order. What are the ramifications of neglecting those maintenance items? The doorbell just rang... the FSM has arrived! By the way, how is your DHS? How long have you had it and what has your maintenance and repair history been like with it and how long have you been driving Cadillacs?

MODERATOR, just means that I help out moderating the forum. I can move a post to another section if it was posted in the wrong place, lock it if it gets out of hand (flaming). Traffic cop so to speak.

I am not a professional tech. I have driven Cadillacs for 33 years. Won't consider anything else. Most advice I give is just a culmination of expirience, reading FSM's (had one for every car) and knowledge picked up here and at caddyinfo. I have learned a lot from our old Guru and professional techs like Ewill3rd. You'll notice that there are some posts I don't touch, and a few others that I have been wrong on and learned some more.

You are correct about sideload cracking plugs. Cracked a few in my younger days.

I have not heard of pressuizing the gas tank, but I am sure it would work. I suppose you'd need a modified gas cap to connect an air line to though. Likewise with the smoke proceedure. I have used soapy water on other pressure lines before. It works great.

The ramifications of a neglected cooling system is head gasket failure. Green coolant should be changed every 2 years/24K (pre '96). Dex should be changed every 5yrs/100K ('96 on). If in doubt, change it.

Trans fluid should be changed if it is brownish, smells burnt, or is used in "severe conditions" per the owners manual. GM says it is good for like if driven normally. I change mine at 100K regardless. Others do it sooner.

The DHS is great. I just bought it last July in Dallas Texas with 17K on it and drove it home. I met mtflight when I was down there and he was kind enough to put me up for the night. We had dinner with Bruce (owner of caddyinfo). Made for a pleasant evening before I hit the road the next morning. No real maintanence issues or history as it only has 22K on it other than the crossover manifold I just had replaced under warranty due to a very minor coolant leak.

sprj
11-10-06, 01:45 PM
Ranger,

I noticed last night on the highway when I accelerated aggressively that I let out quite a bit of carbon from the exhaust and my exhaust tips seem to have a good amount of carbon on them too. The old plugs I took out were gapped wide. I don't recall where I had gotten the info, but someone had told me .060 so I am guessing that may have been causing some unspent fuel before, but everything is up to spec now and I still noticed the smoke when I accelerated after the 'tune up' last night. What are some reasons that this thing is blowing out smoke when I step on it. Is this normal or is this indicative of something that needs to be addressed?

By the way, what is DEX and where do I find it?

Ranger
11-10-06, 02:03 PM
Carbon on accelleration indicates that the cylinders are badly carboned. It needs some tender loving WOT treatment. Take it out and, as our old Guru used to say, "Drive it like you stole it". Whoop her, beat on her, stand on that throttle til she quits blowing carbon. Go to the top left of this page, click on Technical Archives and read up on "Full Throttle Accelleration".

Dex = Dex-Cool antifreeze. Should be available anywhere you get coolant.

sprj
11-10-06, 02:21 PM
Thanks Ranger.

sprj
11-11-06, 10:49 AM
I got the FSM's. I can not find a vacuum or EVAP diagram anywhere in either of these books? Do you know if that is something that should be in there? Here is the problem that I am having... When looking at the Vacuum Purge Switch in the book (reference diagram), it is showing a line coming off each side and nothing else. I noticed a very different picture under my hood as shown in the attached picture. If you will see, there is nothing coming off the right side and there is an 'elbow' fitting coming off the front of the switch, but it is not connected to anything? I have disconnected the electrical plug in this picture for visibility, but that is the only change I have made and I cannot find any loose hoses under the hood. If I had a diagram of the system, at least I could find where that open side should be connected to and see if there is a hose there that is disconnected or missing altogether?

24910
24909

Ranger
11-11-06, 03:37 PM
Yeah, something looks amiss. The 90 degree elbow at the bottom of the pic is a vent I believe. Sure looks like a line is missing on the right though. I am sure there is a vacuum routing diagram in there somewhere. That manual is not the most user freindly manual I have seen. If I still had my '97 I could check and see where that line runs to. I'm sure my '03 is a little different.