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2004 chevy trailblazer_lt
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I believe you are referring to Techron Complete. Techron Complete is a great fuel injector cleaner - better than Berryman B-12. However, Berryman B-12 is better at dissolving varnish and crud than Techron Complete. Different chemistries involved for each cleaning process.

I have not run across a DTC for the fuel gauge, but that does not mean there aren't any for these beasts!
 

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2004 chevy trailblazer_lt
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Thanks!
 

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2004 Chevy Trailblazer LS RWD
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Discussion Starter · #144 · (Edited)
Found a fuel level sensor on eBay for $15. Ordered it for just in case. Looking at wiring diagrams to see if I can find easy access to the circuit to dummy in a substitute resistance to see if the gauge indicates right with a good signal.
 

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2004 chevy trailblazer_lt
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Allegedly for the empty reading the ECM sees 40 ohms. For the full reading it sees 250 ohms. Those numbers are from Delphi for their FG0387 fuel pump assembly for 2004 TrailBlazers non-EXT. The numbers are in a chart at rockauto.com.
 

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2004 Chevy Trailblazer LS RWD
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Discussion Starter · #146 ·
There's been some discussion here about piston slap and/or cold carbon knock, as the source of a knock that goes away as the engine warms up. Seems they're saying not to worry about it much.
I have such a knock. It sounds like bearing knock to me, nothing like ping or detonation from low octane fuel.
I hear it on a cold start. It goes away completely in a few minutes, maybe 1 or 2. So it goes away when it's just starting to warm up.

I plan to at some point get an oil analysis done. I want to take the sample when the car has been in use, rather than when it's been sitting around for weeks.
The last oil change was by the previous owner in October of 2019, almost a year before I bought it. We have not yet reached the mileage on the Jiffy Lube oil change due sticker.
Yeah, at some point the oil should be changes after so much time. I'm choosing not to, yet.
 

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'05 Chevy TB EXT
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Jiffy Lube --- huh?

I guess yez takes yer chances.

I personally wouldn't stop in there to be urinated upon if I was on fire ... but you can do as you see fit.

Your noise is probably piston skirt slap from a partially collapsed piston (or two). Once it warms up and expands to fill the roundness of the cylinder, the noise will abate.

Pistons can take that kinda abuse for a while --- but the constant expanding-contracting and you driving away while it's still making slapping noise --- will eventually shove a rod through the cylinder wall and outside the block.
 

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Discussion Starter · #148 · (Edited)
Well that's encouraging. It usually stops the noise before I start driving, certainly before I make it out of the driveway. It's not immediately noticeable if you're not listening for it. But sometimes I just listen too close, I can always hear something.

It was the previous owner that took it to Jiffy Lube.
 

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'05 Chevy TB EXT
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Well that's encouraging. It usually stops the noise before I start driving, certainly before I make it out of the driveway. It's not immediately noticeable if you're not listening for it. But sometimes I just listen too close, I can always hear something.

It was the previous owner that took it to Jiffy Lube.
It's realistic really --- noise when cold is a clearance issue that semi-resolves when things get warm and expand.

Take it for real or snidely --- but eventually you're gonna pay for it.
 

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Discussion Starter · #150 ·
It is what it is, or it isn't. I'm not gonna start worrying about it unless it gets worse.
You could buy a newer car and end up needing a repair that cost more than all I have in this one.
 

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Discussion Starter · #152 ·
Tried to record the engine start and knock sound for you, but this time I couldn't hear the knock. Tried to attach the audio file here and it wouldn't allow the file type. Nothing to hear anyway. You can hear the fast fan on startup that quiets down in about half a minute. It was about 78 degrees out. Maybe it has to be colder out for the knock. It hadn't been started since yesterday. I didn't realize it don't knock every time
 

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2004 chevy trailblazer_lt
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Well, the operation of the radiator fan sounds normal.

Regarding the knock, just for the heck of it, remove the serpentine belt and using your hand spin the pulley on the alternator. It should be nice and smooth. If it feels rough, the bearings are going bad. A few weeks back another gent on here who said it he a knock and was concerned it could be rod knock. Well, he found out that it was the bearings in the alternator. New alternator and the knock was gone.

While you are at it, check the other pulleys and you might as well check the water pump shaft for play as well.

Good Luck!
 

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Discussion Starter · #154 · (Edited)
I decided to try to suck some of the nasty ATF out through the dipstick tube. I measured the amount extracted with a digital luggage scale. I got out about 2.9 qts, I replaced the same amount by weight The old atf looks brown opaque in the milk jug. It doesn't smell so good either. I've smelled worse on a known burned up transmission. A drop on a paper towel spreads out to a lighter brown. I did it cold. With 2.9 qt of new in it, hot after a 2 mile drive, the color didn't change. The drop on a paper tower, if anything, looked darker, probably cus it was hot. By my fuzzy math it's 25% new atf and 75% old. I can't get to my lift to do this right yet
 

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Discussion Starter · #155 ·
The GD ground hog or one of his family has struck again. Damage to the wiring harness of my minivan in several places under the hood. Surprised it still ran. Now I gotta work on that. I'm still setting the trap.
 

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Good luck with eradicating them!
 

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Discussion Starter · #159 ·
I've mentioned the ground hog problem before. For more animal stories, we saw a ugly turtle on the road today, a baby deer in a field by itself, and another deer resting next to someones driveway.
After the 2nd ATF extract & replenish through the dipstick, the fluid drop an a paper towel is starting to look red. There was another thread here about changing trans fluid this way. I'm able to pump more out than that other person was. I bet it's cus I'm doing it cold and more fluid had drained back to the pan.
My rough calculation says when I have done this 4 times, I will have replaced 71% of the original ATF.
 
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