05 trailblazer running very rough

towdriver

Original poster
Member
Oct 20, 2012
25
My wife has a 05 that she got about 5 years ago. A few years ago the battery went bad due to to much subwoffer use with truck shut off. I pulled the spare (brand new) battery out of my jeep and put in the trailblazer. Ever since then is would stall in the drive thru with the heater or a/c on. I figured it was just to much draw on the electrical system and never did anything about it. Over the last summer while towing our 25' camper it has gotten worse and I started asking other mechanics about it. Being a heavy diesel Mechanic I did not know what it could be but would be dammed if I was going to pay someone to do something I could do my self. I heard many times it could the intake throttle valve due to carbon build up. After watching MAY03LT very well done video on YouTube I removed and cleaned the throttle valve. Thanks to MAY03LT. It was very built up and required the use of a brass brush to clean. I tried a tooth brush like in the video but it didn't work. Once I was done truck idled smother. Now the issue have is when taking off from a stop it misses bad and almost quits. I'm sure it needs new plugs as they haven't been changed since center new and have almost 200000km on them. Found new ones in stock by work and I'm picking them up tomorrow. I also have codes p0410, p0442, p0128, p0014 and p0300. Form what I have read here I'm guessing that the p0300 will be fixed by replacing the plugs. I also know the cooling fan hub is shot but don't have the $500 for a new one right now and suspect the thermostat to be bad as well as the truck takes forever to warm up. I checked for a video on what to do about the code p0410 for the air purifier with no luck and need help and finding the problem. Also have no clue what to do about the other codes. Any help would be great. Thanks again to MAY03LT and everyone else who can help.
 

CaptainXL

Member
Dec 4, 2011
2,445
Hello and welcome!

Sounds like you got a lot of work to do and nothing has ever been done except maybe tires and oil change. Well you have come to the right place. But first can you give us a hodown on what maintnenace has been done up to this point other than oil changes and tires? In your opinion has this vehicle been neglected from a preventative maintenance point of view?
 

towdriver

Original poster
Member
Oct 20, 2012
25
Until lately the truck has been really good to us and not needed much. It was bought new by a rental company then was rented for a trip to Florida and left at the rental place down there till it was brought back to Canada when it was traded in on a new on. That's when we bought it. About three years ago we had to replace the transfer case. Other then that it's had tires and two sets of brake pads and one set of rotors. I change the oil and filter every 5000km regardless of what the oil change light says. Change the air filter every second oil change and grease what fittings there are at every oil change. Both axles had fluid changed when t case was replaced. That's all that I have done since we got it. I don't know what was done before we bought it and can't remember how many km were on it when we got it.
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
P0128 is indeed the thermostat sticking open. Deferring its replacement is not a great idea because it makes the engine run rich, wasting $$ in fuel and abusing the catalytic converter whose expensive lifetime is being shortened.

P0300 is the plugs most likely, but you should only use Delco 41-103. Other plugs have had reports of additional misfiring.

Early transfer case failures are often due to neglect, since the fluid change interval is a surprisingly short 50K miles. Keep up on that now you have a new one.

P0410 is the Secondary Air Injection System (SAIS). There's a turbine pump that sounds like a shop vac mounted to the frame rail under the driver's seat that should run for 30 seconds only after a cold start. Do you hear that? There are about five things that can go wrong with this system, from water in the hose that goes from the pump to the solenoid valve on the exhaust manifold, to electrical problems with the pump or solenoid valve, or a mechanical problem with the valve, and ending with a sluggish upstream O2 sensor.

Of the O2 sensor has never been changed, then slap in one of those when you do the plugs. Use Delco as well. The post-cat O2 sensor almost never fails, but the upstream one in the exhaust manifold can get old and slow and you can see that in the data stream with a good enough scan tool.
 

towdriver

Original poster
Member
Oct 20, 2012
25
I got the plugs today at Canadian tire and installed them just now. Not sure if it was a good price for the plugs or not ($10.09 each) but I needed them today as wife has to have truck tomorrow and Canadian tire was the only place that had 6 AC Delco 41-103 in stock. After watching the video by MAY03LT on YouTube I set up some lights and spent a hour changing the plugs. I'm sure I could have had it done sooner but my 4 year old son had to know what I was doing too. Fired it up when I was done it ran way better. I did find water in #4 as I have read it a known issue. From what I have read on here they were still the factory plugs. I guess I lucked out by making it 198000km before changing them. After getting good a owners manual online I now find out that I have missed a lot the required services that need to be done to these trucks. Guess I know what I'm doing this weekend. As soon as I figure out how to load pictures from my BlackBerry PlayBook I will post the pictures of the water and plugs
 

towdriver

Original poster
Member
Oct 20, 2012
25
Okay I have another issue now I think. After cleaning the intake and removing the fuses for 20 minutes when I started throwing truck it when right to 2000rpm the climbed to 2500 and slowly when down to 700. I thought maybe I had not had the fuses out for long enough so I pulled them for over a hour tonight and had the same result except it only went as high as 2000rpm tonight. Any ideas what is going on? I'm lost as to what's happening.
Oh I also cleared the codes after cleaning the throttle valve and so far only the p0410 has come back on but have only driven around the block so I'm sure the rest will be back soon.
 

towdriver

Original poster
Member
Oct 20, 2012
25
Thanks for that info. I plan on doing the thermostat and troubleshooting the air pump this weekend. I wasn't sure if there might be another thing causing the high idle. I will change the thermostat and try that. Thanks
 

WarGawd

Member
Sep 2, 2012
468
CaptainXL said:
The bad thermostat is gonna play havock with your idle. I would do that next.

LOL, at some point I'm sure you're gonna get the impression I'm picking on you, but I'm not - just wanting clarification (take it as me paying attention to what you're saying :biggrin:}.

I'm guessing you really mean idle after warmup? Otherwise I don't see what role a bad t-stat can play in idle speeds @ cold start. Could you expand your thinking a bit for my benefit, if not for OP and others?

Thx again
(btw I appreciated your quick reply last nite...gave me a chance to cancel and explore a few other options)
 

CaptainXL

Member
Dec 4, 2011
2,445
towdriver said:
Thanks for that info. I plan on doing the thermostat and troubleshooting the air pump this weekend. I wasn't sure if there might be another thing causing the high idle. I will change the thermostat and try that. Thanks

Ok. Just make sure the thermostat is a 195 F stat. ? Celcius. Ac delco is best match. The pcm is a bit picky at what temp range the engine runs.

Also it Would be a good time to flush radiator with some water and prestone flush. Also inspect radiator for obstructions. Fill radiator with 50/50 prestone Dexcool. Its pinkish/orange in color.

Also wouldnt be a bad time to change the upper and lower radiator hoses and pressure cap if they are showing age. Replace belt also if its over 100k.
 

CaptainXL

Member
Dec 4, 2011
2,445
There should be tsb for it. Alldatadiy or chiltondiy.com should have the specifics. Prior to 2002 models used to have a ton of problems with water and the pump.
 

towdriver

Original poster
Member
Oct 20, 2012
25
So far it only has the high idle issue on cold start. Once it's warm it only goes up to about 1000rpm on start then down to around 750-800.
Thanks for the temp on the thermostat. Form what I have read on here so far I have decided to only go with the good parts and get AC DELCO parts instead of buy what's cheap. Better to do it right once then do it wrong many times.
 

CaptainXL

Member
Dec 4, 2011
2,445
towdriver said:
So far it only has the high idle issue on cold start. Once it's warm it only goes up to about 1000rpm on start then down to around 750-800.

This is normal. Im assuming you didnt see this before because there was a problem and now its fixed.

On a cold start (depending on outside temp and coolant temp) the idle will be fast for a time. It should settle down to about 700 rpm when the coolant gets to about 170 F.

If its really cold outside and the coolant is having a hard time getting up to operating temp (especially if the rear heater fan is on for the XL/EXT) the pcm will increase the idle to about 1000 rpm until its correct. You might notice this on a really cold night when idling at a fast food drivethru or something. Usually if its only a few miles or so away when the coolant doesnt have enough time to heat up.

Again, a scan tool would verify if the coolant is at the proper temp and the rpm is right.
 

towdriver

Original poster
Member
Oct 20, 2012
25
Is it normal for it to rev to 2500 or just the 1000. When the truck is started cold it goes to 2500 but one the coolant is warm and truck is restarted it only goes as high as 1000.
 

CaptainXL

Member
Dec 4, 2011
2,445
Well. Let's take a look at Roadies chart. If the truck is warm it should idle at about 800 before settling down to 700. This chart is for sustained idle. Not startup idle. So to answer your question. Yes you should see a rather high 2500 rpm or so startup idle when its cold outside and your engine is cold but it should stabilize to the idle speed as indicated in the chart below within a few seconds. Startup idle has nothing to do with warmup idle which is shown below. The colder it is outside the higher your initial idle will be.

View attachment 24064
 

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CaptainXL

Member
Dec 4, 2011
2,445
WarGawd said:
LOL, at some point I'm sure you're gonna get the impression I'm picking on you, but I'm not - just wanting clarification (take it as me paying attention to what you're saying :biggrin:}.

I'm guessing you really mean idle after warmup? Otherwise I don't see what role a bad t-stat can play in idle speeds @ cold start. Could you expand your thinking a bit for my benefit, if not for OP and others?

Thx again
(btw I appreciated your quick reply last nite...gave me a chance to cancel and explore a few other options)

Well if the engine doesnt get up to the proper operating temp within a certain amount of engine run time the pcm will increase the idle speed to try and warm up the engine faster. First hand experience here. This type of scenario could be classified as loop because the original problem never gets solved.
 

towdriver

Original poster
Member
Oct 20, 2012
25
Okay I get it now. I will change the thermostat this weekend and see if that helps it get to the required temperature and then idles better when warm. The cold start does follow the chart. Thank you.
 

CaptainXL

Member
Dec 4, 2011
2,445
towdriver said:
The cold start does follow the chart. Thank you.

I know what youre saying but thats not what i was talking about. Anyway. Good to see you are changing it. Keep us updated or if you need more help.
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
WarGawd said:
Minor comment for future reference roadie - I like when you elaborate a bit on the code definition - I know it saves me the time of having to go look it up many times, and I assume others would benefit as well....
Many, but not all, acronyms like that - if they appear with an underline - are auto-explaining. Hover your cursor over them and they pop up the phrase they are made from. There's a bug we haven't found in a year of looking that not all of the acronyms in our look-up table appear with their expected underlining - but try it on a few and see how the process works.

For instance: OS, SAIS, IMHO, TV, TB
 

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