I have a 2004 z71 Tahoe with the 5.3, I'm having issues with it starting in the morning when it's below 60 Fahrenheit. If I try starting it just turns over, the only way I can get it to start is if I mash the pedal down all the way. It idles rough for about 30 seconds at most. Threw out the day it cranks fine it's just that one cold start after sitting for more than 6 hours at minimum. I just replaced all spark plugs and wires not to long ago, if any of y'all have an idea of what it might be I'd appreciate any help possible!
2004 Tahoe rough start up
- Thread starter Tannerb
- Start date
Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.
cmc76
Full Access Member
- Joined
- Sep 5, 2014
- Posts
- 685
- Reaction score
- 314
Check for codes.
Try a throttle position re learn
Try a throttle position re learn
Would that cause it to be hard to crank after sitting and make it fine cranking threw out the day?
cmc76
Full Access Member
- Joined
- Sep 5, 2014
- Posts
- 685
- Reaction score
- 314
I thought the delayed start was the issue.
Slow crank. Start with the battery
Slow crank. Start with the battery
Z28TWITCH
Member
- Joined
- Sep 18, 2013
- Posts
- 83
- Reaction score
- 27
How long after the new plugs and wires did it start doing this? Make sure all the boots are on securely with no cracks or splits. May even want to make sure the porcelain on the plugs isn't damaged.
Check engine light on? If so pull the codes. How does it run once it starts?
I can't remember which years have it and which dont. Do you have a fuel pressure regulator on the drivers side fuel rail? If so, before your first start of the day, pull the vacuum line off it, if there's gas in the line, your regulator is bad. Start with the easy stuff and work up.
Check engine light on? If so pull the codes. How does it run once it starts?
I can't remember which years have it and which dont. Do you have a fuel pressure regulator on the drivers side fuel rail? If so, before your first start of the day, pull the vacuum line off it, if there's gas in the line, your regulator is bad. Start with the easy stuff and work up.
JetBlackNali
Full Access Member
Does it belch out the tailpipe when it starts? Almost sounds like flooding. Fuel regulator is my guess.
corvette744
2004 Z-71
I am no expert- but i was taught when you have to push the pedal to the floor to start a fuel injected vehicle.That its almost always flooded and by flooring it it shuts off the injectors from opening,Their bye letting you start the engine without additional fuel going down.So even though you have new plugs they are fouled and you should show some type of dark smoke out the tailpipe on cold start up???????? So fuel regulator is a prime suspect or something temp related like a sensor
It blows thick white smoke once it starts if I have to floor it to start. I checked the fuel pressure line the other morning and there was none in it but it also started just fine. It seems to only do it when it's cold. Tomorrow morning is supposed to be cold so I will check it in the morning again. If it's not the fuel pressure regulator what would you suspect it to be?
corvette744
2004 Z-71
I would not guess and throw parts at it-at least pay some one to diagnose it and you can fix your self most likely.Unless you have a tech 2 and a fuel pressure guage to see what it is cold-your going to waste your time and get stranded.
Have you checked your fuel pressure? Put a pressure gauge on the schrader valve and turn your key to ignition to get the fuel pump to prime. You should have 60PSI. Hard starts can mean low fuel pressure due to old fuel filter that hasn't been replaced in forever.
I am unsure if you are saying it cranks harder in the morning or it cranks fine but struggles starting.
If it cranks hard only on cold mornings your battery is showing early signs of failure.
If it cranks good but won't start very well try turning your key to "on" but not cranking the starter, wait about 10 seconds with key "on" then engage the starter.
If this makes it start normally it means your fuel pump is bleeding back into the tank overnight, holding the key in the "on" position for a few seconds before cranking gives the pump a chance to build pressure in the fuel system again before you try to light it off.
This is an early warning sign of a dying fuel pump by the way.
If it cranks hard only on cold mornings your battery is showing early signs of failure.
If it cranks good but won't start very well try turning your key to "on" but not cranking the starter, wait about 10 seconds with key "on" then engage the starter.
If this makes it start normally it means your fuel pump is bleeding back into the tank overnight, holding the key in the "on" position for a few seconds before cranking gives the pump a chance to build pressure in the fuel system again before you try to light it off.
This is an early warning sign of a dying fuel pump by the way.
bottomline2000
Full Access Member
The cold is making the Intake manifold gasket contract slightly. It's sucking in air that is unmetered. The computer is dumping fuel trying to balance it out. Once the engine heats up the gasket seals and it will run fine. Felpro has a nice thick metal reinforced gasket I highly recommend over the plastic one.
Sent from my SAMSUNG-SM-T377A using Tapatalk
00chevyHd
Member
- Joined
- Nov 19, 2017
- Posts
- 64
- Reaction score
- 100
Try cleaning throttle body mass air flow sensor and get the chevron fuel system cleaner
Z28TWITCH
Member
- Joined
- Sep 18, 2013
- Posts
- 83
- Reaction score
- 27
Did you ever get it figured out? To check if its an intake gasket, once it starts cold, spray some carb cleaner around the base of the gasket, if it changes idle at all, there's the problem. I honestly doubt it though, an intake leak large enough to cause a no start issue isn't going to fix itself after running for a minute.
bottomline2000
Full Access Member
You'd be surprised. Normally the carb spray trick doesn't work. It's hard to get the carb spray to the interior of the intake and if the leak is there the carb spray won't make a difference. Many people have had this issue including myself. My truck ran like it was cammed until it warmed up. The intake gasket was replaced under warranty and it ran fine afterwards..im curious to see what the OP has to say.
Sent from my SAMSUNG-SM-T377A using Tapatalk
