03 Trailblazer Hard Starting Issues

[manderson7015]

New member having issues with my 03 TB. Thing has a hard starting problem but does start everytime. Will crank 5-15 times when cold before actually starting. This TB 2wd is new to our house and has been in the family for about 6 months. It has 165,000 miles on it. When i bought it i put new plugs, and air filter in it. I have ran an injector cleaner through it, and cleaned throttle body (very dirty, took off engine and did thorough cleaning.). Also changed a coil that looked to be the wrong type with a new one.
Going to check fuel pressure this weekend to look for fuel pressure bleed off.i dont want to start throwing parts at this thing unless i have to. weird thing is that this thing starts fine after it has warmed up. Only has hard starts in morning and after it has cooled off. Runs like a top other than that.
Any help on this issue would be a great help.Thanks!
-manderson7015.

 

[SmokeyMcBlazer]

what kind of plugs did you install?

 

[manderson7015]

stock auto lite plugs

 

[Mounce]

Autolite is crap and aren't designed for our motors. Stock plugs are ACDelco.

 

[dmanns67]

Autolite is crap and aren't designed for our motors. Stock plugs are ACDelco.

41-103 to be exact.

 

[manderson7015]

every plug gap was incorrect when i took out of box had to set gap on each one. they were pregapped to .060. Iset gap at .042. was that right?
I asked for ac delco but were all out. I had no idea that a certain brand of plug would make a difference. Anyways going to pull a plug and make sure it is correct and take it from there. will switch to delcos also and see if that helps.

 

[Mounce]

To be honest, I'm not sure what the gap is supposed to be but I know a well renowned guy here that took a class through autolite and they specifically said not to use them on GM coil-on-plug motors. Not trying to beat you up on this but autolites do not belong in the i6, incorrect plugs cause issues, this motor is very picky about it's parts. Just because that's what you took out doesn't mean that's what came from the factory.

 

[dmanns67]

The AC Delco 41-103s do not need gapped, at least that I have seen. Try rockauto.com, they always have them in stock. You could also use advanceauto.com and have them ship to store for free.

 

[manderson7015]

yeah im gonna change them pulled plug looks good. dry and burning clean. the plugs are autolite double platinum app 5263. im gonna change this weekend to delco 41-103 to get me back on track. will update this saturday. i hope this works.

 

[marinegrunt]

This is just a shot in the dark but I wonder if it could be the fuel pressure regulator. I've seen about 4 or 5 vehicles over the years that would turn over quite a few times but would always start. Once the fuel pressure regulator was replaced it started right up. Just something to maybe look at.

 

[Texan]

Do not try to gap the AC 41-103's. Read other threads about why you should not do it.
Do check/change fuel filter, and fuel pressure and bleed off.

 

[Mooseman]

When you cleaned the throttle body, did you disconnect the battery for 30 minutes to reset the PCM?

 

[manderson7015]

ok, changed plugs 41-103 and that didnt change a thing. just what i figured plugs are plugs.That was $43 i could have saved. Plugs are like shoes, you buy what you can afford. anyways. yes battey was disconected when i cleaned throttle body. drove thirty plus miles for pcm to relearn. but i did not clean throttle body until i started troubleshooting this hard start. going to do fuel filter next and then check pressure for bleed off. if that is okay then will probably change fuel pressure regulator. if none of that works will start looking at timing? thing is that it runs great when it starts. its only when its cold do i have the hard starts. uggghh!

 

[Mounce]

Haven't seen this asked or addressed: check engine light on?

 

[manderson7015]

Haven't seen this asked or addressed: check engine light on?

 

[manderson7015]

p1345 came on today but I attribute that to relearning mapping?

 

[Mounce]

That's a timing code. Cam-Crank correlation to be exact. Do some reading on trailvoy and gmtnation in this link or just search here on the site. Some of the more educated guys will probably chime in on it too.

https://www.google.com/#q=p1345+trailblazer


(just don't post on trailvoy, it's dead and the only good info there is the info the guys here left behind)

 

[Mooseman]

First of all, we're just trying to help you at a distance here, going on information you provide us. We know for a fact that this engine only runs well on ACDelco plugs so we started with that as it is the least expensive and easiest first try at fixing your problem. If you think $45 is a lot of money, you ain't seen nothing yet. These trucks love money!

I know the P1345 code intimately and I doubt that it has anything to do with your hard starting issues. I currently have it for the second time after replacing the timing chain and tensioner but my truck starts and runs fine. In order, these are the things I did until I fixed it:

- CPAS
- Camshaft sensor
- Crankshaft sensor
- CASE relearn
- Camshaft phaser

The CASE relearn can only be done by a dealer or shop with a Tech 2 scanner and is mandatory after replacing the crank sensor. The cam phaser wound up being the cause but had to try the cheaper and easier parts first. It's probably also the reason for the second time I'm getting this code as I may have damaged it when I changed the timing chain/tensioner, which was an unrelated issue.

For the hard starting, did you ever check the fuel pressure? Beyond that, it would likely take a dealer or shop with a high end scanner or a Tech 2 to see what is happening while the hard starting is happening.

You can either pay megabucks and have a dealer do this or try some of it yourself and possibly save some cash. it's your choice. Nothing is guaranteed.

 

[manderson7015]

all I was saying is; noticed no difference from a $20 set of plugs to a $45 set. I ended up changing fuel filter today and lo and behold started cold on first attempt. I'm not a noob been working on anything with a motor for years. first trailblazer though. been a Chevy guy forever. thing with the spark plugs was me trusting that someone here actually had problems with a certain kind of plug. oh well guess I should worry about what floor mats are best next, carpet or rubber! what do you all think?

 

[SmokeyMcBlazer]

Do some reading here, trailvoy or ofroadtb and see how many people over the years have had problems with their I6 engines because they didn't put in the ac delcos...

 

[Mooseman]

Ditto. Well documented here and the other sites. However, you are the first to solve an issue by changing the fuel filter. Either it was really neglected or a really bad batch of gas was in the tank and plugged it up.

For the floor mats, search for Weathertech. There is a discussion on those right now.

 

[manderson7015]

thought it was weird too. no other symptoms of a bad fuel filter. will read up on plugs. u learn something new everyday. thx guys.

 

[manderson7015]

so the hard start came back. i did fuel pressure check and fuel pressure was bleeding off after i shut the key off. so i pinched the line that feeds pressure regulator,which isolates the fuel pump, turned key on and off and still had bleed off. this proved my fuel pump was bad. changed out and all has been well for 5 days now no hard starting.

 

[Mounce]

Good to hear, thanks for updating with the fix, might help someone out in the future.