1990 5.7L TBI Flooding at Freezing Temps on Cold Start?

[89Suburban]

Silvy has been having an issue this fall. This is the first time I had this new to me Burb in these conditions: Overnight temps dropping to freezing and below.

In the morning after a cold night like that, she will crank and not start. I open up the throttle blades just a tad, she fires right up. No engine light when this happens. No raw fuel smell. Have not pulled the air cleaner lid to investigate because it usually happens on my way to work. No change in the oil level, no symptoms of any severe flooding. Just won't start unless I crack the blades open. Happens every couple a days on the coldest mornings.

Thoughts? Tips? Where should I go from here? Not a huge problem, just something else to tinker with.

 

[Jims86]

Silvy has been having an issue this fall. This is the first time I had this new to me Burb in these conditions: Overnight temps dropping to freezing and below.

In the morning after a cold night like that, she will crank and not start. I open up the throttle blades just a tad, she fires right up. No engine light when this happens. No raw fuel smell. Have not pulled the air cleaner lid to investigate because it usually happens on my way to work. No change in the oil level, no symptoms of any severe flooding. Just won't start unless I crack the blades open. Happens every couple a days on the coldest mornings.

Thoughts? Tips? Where should I go from here? Not a huge problem, just something else to tinker with.

Doesn't really sound like a flood, more like starving for air. Black smoke when it finally fires?
Can you hear the fuel pump priming? I have heard of fuel relays freezing. I am assuming you have cleaned the IAC Passage, and made sure the Pintle is clean, and not burying its self into the passage.

 

[89Suburban]

I have not touched the IAC at all. No black smoke that I can tell. What is the correct procedure for checking the IAC?

 

[Jims86]

I have not touched the IAC at all. No black smoke that I can tell. What is the correct procedure for checking the IAC?

Just unscrew it and make sure its clean, tip and passage. just snug it back down so you dont strip or crack the casting. Do you let the pedal back down, or do you have to hold it open till the temp comes up a little?

 

[89Suburban]

Just unscrew it and make sure its clean, tip and passage. just snug it back down so you dont strip or crack the casting. Do you let the pedal back down, or do you have to hold it open till the temp comes up a little?

I will do that this weekend. No I just give a little bit of throttle, crank it and it fires up fine and I immediately let off the pedal. I will watch for black smoke the next time it does it.

 

[Jims86]

I will do that this weekend. No I just give a little bit of throttle, crank it and it fires up fine and I immediately let off the pedal. I will watch for black smoke the next time it does it.

try to fire it up without pedal tomorrow, see how long it cranks before catching.

 

[89Suburban]

Ok I will have to try that. You don't think a low voltage would be the cause of this do you? Weird how it only happens below freezing.

 

[Jims86]

Yeah, it could. Take enough power to crank the starter, and you wont get a hot enough spark. But cracking the throttle open to start makes no sense. I know its cold, but maybe hook up a known good battery and jump it....If it works, get a batt tray for the drivers side, and run doubles.

 

[89Suburban]

That would be a good mod, especially with the 100 amp alternator setup. Food for thought. Anyway I will update this as I can think of it and appreciate the help Jimbo.