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Discussion Starter #1
Hello everyone! I've been lurking for a while but this is my first post. I have an 05 Denali XL with 36,000mi and I am having an intermittent problem getting the envoy started. The envoy will crank but it won't start right away. Usually we have to try cranking it 5 or 6 times before it finally decides to start. On average it will do this at least once a day when starting the vehicle. Once it does start it usually stumbles for a little bit before it runs smooth, but I just chalked that up to excess fuel from cranking so much. I have had it to the dealer several time and these are the items they have replaced so far:

1. Fuel Pump
2. Oil Filter (don't even ask about this one)
3. Cleaned throttle body and injectors

At this point I think the dealer is scratching their head. Has anyone experienced the same or have any insight as to what would be causing it not to start. I've read alot on here about the ignition switch going bad, but it seems like it wouldn't even crank if that were the case. Thanks in advance.

Jason
 

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2004 gmc
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The ignition switch can indeed kill the "run" circuit while allowing it to crank. The dealer should be well aware of the high failure rate on these cheap items.

Your dealer is scratching his butt with his head - from the inside! :woot:

There are a lot of other possible causes, like intermittent opens in the wiring elsewhere or the PCM, but the ignition switch is probably going to be the consensus on trailvoy for the culprit.

Then you can tell your dealer they should be reading trailvoy forums instead of ignoring their TSBs. :cool:
 

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2004 buick rainier
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Your dealer is scratching his butt with his head - from the inside! :woot:
. :cool:
:dielaugh:

but i agree with Rodie, i would have thought that your dealer woudl have already tried the ignition switch but that could cause the problem, on my little bro's blazer when his igintion switch went we just kept trying turning the key and eventually we got it to crank and to the dealer.
 

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2002 chevy trailblazer_lt
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Hello everyone! I've been lurking for a while but this is my first post. I have an 05 Denali XL with 36,000mi and I am having an intermittent problem getting the envoy started. The envoy will crank but it won't start right away. Usually we have to try cranking it 5 or 6 times before it finally decides to start. On average it will do this at least once a day when starting the vehicle. Once it does start it usually stumbles for a little bit before it runs smooth, but I just chalked that up to excess fuel from cranking so much. I have had it to the dealer several time and these are the items they have replaced so far:

1. Fuel Pump
2. Oil Filter (don't even ask about this one)
3. Cleaned throttle body and injectors

At this point I think the dealer is scratching their head. Has anyone experienced the same or have any insight as to what would be causing it not to start. I've read alot on here about the ignition switch going bad, but it seems like it wouldn't even crank if that were the case. Thanks in advance.

Jason

OMG !!!!!!!

I just went teh same ordeal, in the end i ended up fixing the damn thing myself, It seems, and i have proof, that the fuse box under the hood after some intensive rattling and bump can become loose, just for the heck of it, take out the relay for the fuel pump, get some thin hard wire (phone wire) drop a wire in each hole, be carefull so they don't touch, re-insert the relay, you might need to fore it a bit, and start the truck, it "MIGHT" help you...i also found out that the harness underneath my fuel pump was getting severly damage, so i replaced al the wires and added some new tubing...
 

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2009 chevy
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You need 3 things to start the engine:
Air
Spark
Fuel
The air of course comes through the air filter, if it's clean the air is probably ok.
The spark need 12 volts at the coils, this comes from the ignition switch (as suggested above), these have a high failure rate. But, usually something else, that requires "key on", won't work as well. Check all things that need "key on" to see if they are working.
Fuel, needs a pump and a clean filter. If all of the above seem to be ok, you probably need a new pump. Turn on the key, don't try to crank the engine, listen for the pump running (from the rear, under the truck, it's in the tank). The pump should run for a few seconds and shut off when the pressure reaches the cut off point.
If the pump runs, it might still be fuel. You should check the fuel filter. Some years have an external filter, others have the filter in the tank.
It's a good idea to fill out the USER CP (your profile info) when you join, if the truck info is provided, we could tell you where to look for the filter.

BTW, welcome to the site.
 

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Discussion Starter #6
Thanks for all the suggestions. I also completed my profile.

One other thing I forgot to mention is that sometimes when it is cranking for a long time I can release the key and it continues to crank on its own until it fires. I of course informed the dealer of this and they tried to tell me that it is designed to work that way. :rolleyes:

I'll have to see if I can get the dealer to look into the ignition switch. Thanks for all the advice.
 

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2002 chevy trailblazer_ltz
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....One other thing I forgot to mention is that sometimes when it is cranking for a long time I can release the key and it continues to crank on its own until it fires. I of course informed the dealer of this and they tried to tell me that it is designed to work that way. :rolleyes:
They said WHAT??? OK, the first thing you need to do is get to a different dealer/service dept. The starter motor is designed to stop as soon as you let go of the key.....period.

If there is a vehicle that works the way the dealer told you, I wish someone would tell me.....I have NEVER heard that before.

IMO, it sure sounds like the ignition switch to me.
 

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2004 gmc
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... I can release the key and it continues to crank on its own until it fires. I of course informed the dealer of this and they tried to tell me that it is designed to work that way. :rolleyes:
On that point, they're right! You can blip the key for the shortest time, and it will continue the process. It really annoys me now in rental cars when I have to hold the stupid switch in until it catches.
...The starter motor is designed to stop as soon as you let go of the key.....period.

If there is a vehicle that works the way the dealer told you, I wish someone would tell me.....I have NEVER heard that before.
Hi! My 2004 works that way. Guaranteed. It's unusual, to be sure, but I'd be shocked if that didn't start with 2002. Try very short blips and you can notice the effect.
 

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2005 chevy trailblazer_ls_ext
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:iagree:
I remember reading a while back they started that feature (of the engine continuing to crank after you release the key) because THEY said too many people were trying to start these things with the engine running. According to GM, the engines ran so quiet and idled so smooth that people thought the engine had stalled. I think they started it in 2003 or 2004 - don't know for sure about the date - I'm only guessing. Roadie may be right it could have 2002.

I know my 05 has done that from day 1 - as has ALL the many vehicles of this platform that I've rented. (TBs, Envoys and the one Buick Rainer).
 

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Hehe. People who don't realize they have a tach staring them in the face ALL the time. :D
Exactly! I was thinking that but forget to mention it.

You were right Roadie it was 2002. Everyone check out this article from Motortrend:

" GM started with a brand-new, lightweight (407-lb) aluminum block with cast-iron cylinder sleeves and high-compression (10.0:1) pistons, attached an aluminum DOHC head with roller/follower cam actuation and variable timing on the exhaust valve overlap, fitted each spark plug with its own coil, and controls it all with a powerful new electronic powertrain control module and throttle-by-wire system. This sounds like it could come right out of a BMW, doesn't it? The engine not only produces some high-revving horses, but also makes 90 percent of its 275 lb-ft of torque from 1600 to 5600 rpm. And it's so quiet and smooth-running, GM's engineers made the ignition key's start mode inoperable, while the engine is running to avoid burning out the starter motor and damaging the flywheel teeth.

http://www.motortrend.com/roadtests/2001/112_0106_2002_ford_explorer_vs_2002_cheverolet_trailblazer/index.html
 

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Discussion Starter #12
Hello everyone! I've been lurking for a while but this is my first post. I have an 05 Denali XL with 36,000mi and I am having an intermittent problem getting the envoy started. The envoy will crank but it won't start right away. Usually we have to try cranking it 5 or 6 times before it finally decides to start. On average it will do this at least once a day when starting the vehicle. Once it does start it usually stumbles for a little bit before it runs smooth, but I just chalked that up to excess fuel from cranking so much. I have had it to the dealer several time and these are the items they have replaced so far:

1. Fuel Pump
2. Oil Filter (don't even ask about this one)
3. Cleaned throttle body and injectors

At this point I think the dealer is scratching their head. Has anyone experienced the same or have any insight as to what would be causing it not to start. I've read alot on here about the ignition switch going bad, but it seems like it wouldn't even crank if that were the case. Thanks in advance.

Jason

Update: The dealer finally decided to replace the ignition switch after talking to technical assistance. Unfortunately, this does not appear to have fixed the problem either. :confused: In fact, when picking it up from the dealer we got in start it and it took a couple of tries cranking it before it started. I needed the vehicle, so we took it for the weekend to see what happens. So far it has cranked excessively 3 or 4 times before eventually starting. Next time it does it I think I'm going to mess with the relays and see if that helps any. Any other ideas out there since the ignition switch didn't do the trick?

Thanks
Jason
 

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This is just thinking out loud so bare with me. Did they replace the fuel filter when the replaced the pump? I would hope they would but this is a dealership we are talking about. If the fuel filter is partially clogged then it may take a while to prime the system. This would be why it would only do it occasionally. Maybe after it set a while or whatever. Now you would think if it was plugged like that it would have issues running or would set some kind of code but like I said I am just thinking out loud.
 

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Discussion Starter #14
I am not sure if the filter was replaced when the pump was or not. I know the ticket stated that the part was a fuel pump kit, so I don't know if the filter was part of the kit or not. I may give them a call to find out if they did or not.
 

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This is just thinking out loud so bare with me. Did they replace the fuel filter when the replaced the pump? I would hope they would but this is a dealership we are talking about. If the fuel filter is partially clogged then it may take a while to prime the system. This would be why it would only do it occasionally. Maybe after it set a while or whatever. Now you would think if it was plugged like that it would have issues running or would set some kind of code but like I said I am just thinking out loud.
Does the 05 5.3 have a fuel filter? From 05 on the I6 engines do NOT have an external fuel filter. The filter on 05+ is the "sock" on the fuel pump assembly.
 

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I thought it was an actual replaceable filter in the tank. Again, I was just searching for ideas and I am still learning the Trailblazer so I could be wrong.
 

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Fuel filters are notorious for causing fuel starvation. But, this usually occurs are road speeds or higher. Generally, a dirty filter will let the truck start. It sounds to me like a flooding problem or a bleed down problem.
Try turning the key on and listen for the pump. It should run for a couple of seconds, if it runs longer than that, you could be loosing fuel pressure in the lines. Note, this is hard to tell with your ear.
One thing that could cause both of these problems is an injector that is leaking.
To test, you need to connect a pressure gauge to the fuel rail (there is a port for this purpose).
Sometimes the injectors can be cleaned, sometimes they need to be replaced.
 

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Okay, when I did a Google search this came up showing that the 2005 actually had an external filter. Did it change mid year?

http://www.car-stuff.com/carparts/chevrolettrailblazer20022005framahg93441.html

All the other hits I got shows it external also.
Many of the parts guides are wrong. We have discussed this a lot on this forum over the last 3 years or so. I have an 05 EXT with the I6 - it was made in November 04.
I crawled under this thing and checked - there is NO external filter. They changed the design in 05 on. A member who used to post here and has a pretty good knowledge of cars in general stated:

"2005+ 4.2's have pretty much a completely different fuel system than 2002-2004's. 2005+ use a variable speed fuel pump with no return line and no fuel pressure regulator. I believe they call it a 'pulse width modulated' fuel pump where the PCM regulates the voltage to the pump based on engine load. With different plumbing and hardware, I'd have to say the filter is different as well and probably in the tank somewhere"

http://forums.trailvoy.com/showthread.php?t=15960&highlight=fuel+filter

As has been pointed out in other posts - even some of the owner's manuals are wrong. My cousin (who has the same year TB I do) noticed it first. The manual said to change it every 25,000 miles. :weird:

The easy way to tell if you have the "new" system or not is to check and see if you have a fuel pressure regulator under the hood.
http://forums.trailvoy.com/showpost.php?p=208549&postcount=21
 

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2002 chevy trailblazer_lt
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Did you try the relay connector, i assure you I HAD THE SAME SYMPTOMS, they tried everything, fuel filter fuel pump when they started saying it was teh ignition switch i just laughed and left, after taking the the fuel thank apart and following the fuel connector wires with a tracert i saw that some pins of teh relay were becoming loose

just try it....add a longer lenght of wire to the fuel pump relay and squeeze it in, if it works you will know it's the fuse box connectors
 
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