Flooding on cold start...

[Keitha]

Help!
1991 Suburban
383 w/ Holley TBI
16147060

Motor has been running a bit rich but otherwise fine and has started right up and run well even cold (first thing in the morning). For the past week it has been running richer after cold starts to where is stumbles a bit until closed loop kicks in (WB around 9.5:1 - 10:1). After closed loop kicks in it is fine.
Yesterday morning I attempted to start the motor and it fired then quickly died with a cloud of smoke out the tail pipe. Eventually I got it fired and was able to feather the throttle long enough to keep it running.
After work yesterday, same thing. I could not start it as it was totaly flooded. I looked under the throttle blades and gas was pooled in the intake pluenum. I unplugged the injectors and it started and burned off the gas, then I was able to again feather the throttle and keep it running long enough to get to closed loop (where it ran fine).
The injectors do not seem to be leaking but obviously something is wrong. I have a spare ECCM and tried that this morning with the same bad result. The chip I am using has been good for months but I did try another.
Once warm I can shut it down and it fires up no problem.

Any guidance?

 

[Thunder]

Holley TBs are well known for flooding problems and running rich. Usually bad/ leaky injectors or regulator problems. Your injectors may be slowly leaking down after the ignition is turned off.

 

[dyeager535]

Whats the ECM think the coolant temp is when "cold"?

 

[Keitha]

Holley TBs are well known for flooding problems and running rich. Usually bad/ leaky injectors or regulator problems. Your injectors may be slowly leaking down after the ignition is turned off.

While I do not disagree with the assesment of the Holley, This does not seem to be a leaky injector problem. Even when I pulled the injector wires and fired the motor it burns off the gas in the intake but does not solve the problem. When I rehook up the wires it does the same thing again and runs really rich until I get into closed loop.

No Service Engine Soon light.

 

[Keitha]

Whats the ECM think the coolant temp is when "cold"?

I will look at this this afternoon when I get home from work.

 

[Stomis]

What kinda of ignition you running?

My truck with stock tbi and a stupid crap aftermarket chip did the same thing constantly until I put an MSD coil on it. Now it only does it in certain weather conditions.

Seeing as how its a custom TB/ecm cant you just tune it to run a tad leaner between a certain temp?

 

[Keitha]

What kinda of ignition you running?

My truck with stock tbi and a stupid crap aftermarket chip did the same thing constantly until I put an MSD coil on it. Now it only does it in certain weather conditions.

Seeing as how its a custom TB/ecm cant you just tune it to run a tad leaner between a certain temp?

MSD coil, stock distributor.
I don't know if I could tune it out, but it just started out of the blue so something is causing it.

 

[sweetk30]

talk to brian and read his stuff at www.tbichips.com

 

[Keitha]

Update: I am pretty sure it is/was the CTS. I data-logged about 30 seconds once getting the Suburban started this morning. I did not review it untill I got home from work but the temp showed 3 degrees Fairenhieght. I did not drive the Sub to work today but when I got home I plugged the computer in to read the sensor before I started it and it read 74degrees (normal). It started right up as normal. For now I will keep an eye on it. I burned a CTS-fail-safe chip that moves Crank cold collant temp AFR to 6:1 and Open Loop cold temp to 11:1 bellow 60degrees.
I will keep an eye on the sensor and replace it if I need to.
thanks for the help,

 

[Stomis]

Update: I am pretty sure it is/was the CTS. I data-logged about 30 seconds once getting the Suburban started this morning. I did not review it untill I got home from work but the temp showed 3 degrees Fairenhieght. I did not drive the Sub to work today but when I got home I plugged the computer in to read the sensor before I started it and it read 74degrees (normal). It started right up as normal. For now I will keep an eye on it. I burned a CTS-fail-safe chip that moves Crank cold collant temp AFR to 6:1 and Open Loop cold temp to 11:1 bellow 60degrees.
I will keep an eye on the sensor and replace it if I need to.
thanks for the help,

Glad you found it. CTS is one of those things I dont even bother testing for if I'm anywhere kinda sure thats my problem. I mean the thing is only like $9 right?