problem with "cold" starting

[joeblow55]

You guys are awesome. This is really good info to have. Now, I am thinking that if it is a bogus resistance reading from the coolant temperature sensor, wouldn't it also affect "warm up" ? In other words, why wouldn't it run really bad until everything is warmed up...As it is right now, once the engine fires and runs for more than 5-7 seconds, it smooths out and then seems to run normally. Or is the ECM only looking at the CTS to tell the injectors how much fuel is needed to start the car, and that's it. Trying to understand how it's supposed to work. I will see if I can locate the CTS and read the resistance with an Ohmmeter, and record the values...let you know what I find out. Thanks again for your replies. I really appreciate everyones help !

[petrified.rabbit]

that is getting into mapping of the ecu. And "circuits" it uses at different points.

[joeblow55]

not sure I understand what you mean by mapping of the ecu & "circuits" it uses at different points. Can you clarify ?
I can't seem to get it out of my head that a bad coolant sensor reading that affects starting when cold would also affect
engine running conditions until "warmed up"...but like I said earlier, I am still learning this computer controlled stuff.
There might be a perfectly good explanation that I am just unaware of because of my lack of familiarity with the systems in play.

[waynek20047]

The coolant temperature sensor (CTS) could be the problem with cold start problems. It was on my 2005 Aveo LT. Had terrible time starting when cold. Actually hard to start after sitting 8 hours or more in 70+ degree weather. I tried several things before I found the actual problem. A defective sensor does not set a code. So for me it was try this and then something else.

As it turns out the CTS was the least expensive part to buy but the hardest part to get access to on my Aveo. Forget about testing it. If you get to it, replace it. I could only access it from below the car when it was jacked up. The CTS screws into the back side of the engine block below the intake manifold, between the engine and the firewall. There is an engine brace which is in the way and must be removed. It has 4 bolts in it. The bottom two bolts are #14 metric the top two are #13 metric. The top ones required me to use a short extension to remove. Once the bracket is moved to the left side of the car you can access the CTS. There is a clip on the two wire connector which must be released. This is tricky using only one hand. Once the wire is removed you can access the CTS.

Remove the pressure cap on the water inlet tank. When you remove the CTS water/anti freeze will come out of the hole. You may want to drain the coolant first. I did not. You will need a 3/4 inch SAE deep-well socket to remove/reinstall the CTS. It comes out easily once loosened. Good Luck, sorry no pictures were taken.

[Chhonker]

Please help me to solve this problem i am also facing such issue in morning

[ramquez31]

Just my 2 Cents, I am currently having this same problem, I even had my mechianic looked at it and he didn't seem to mind this obvious problem on the Air Cleaner Intake Hose or ACIH (Picture Attached), The inside was full of grease, dirt and other stuff that went into the Main Throttle Idle Actuator (MTIA) and clogged the holes in it with the same black grease and dirt...sight.

I'll buy the new ACIH have my mechanic clean up all this parts, replace the air filter and I'll post back after all this is done. And maybe get a new mechanic afterwards.

Hope it helps!

PD
I was ready with my soap and water just to check for punctures or leeks and found this!

[KevinA]

Just my 2 Cents, I am currently having this same problem, I even had my mechianic looked at it and he didn't seem to mind this obvious problem on the Air Cleaner Intake Hose or ACIH (Picture Attached), The inside was full of grease, dirt and other stuff that went into the Main Throttle Idle Actuator (MTIA) and clogged the holes in it with the same black grease and dirt...sight.

I'll buy the new ACIH have my mechanic clean up all this parts, replace the air filter and I'll post back after all this is done. And maybe get a new mechanic afterwards.

Hope it helps!

PD
I was ready with my soap and water just to check for punctures or leeks and found this!

When mine did that I thought I had a bad muffler.. Now I've got the cold start issue when it is 35 or lower, sounds like I'll buy a sensor then spend some time under the car, at any rate at least I can fill my gas tank without it taking 30 minutes now that I replaced the EVP canister and valve.

[KevinA]

The coolant temperature sensor (CTS) could be the problem with cold start problems. It was on my 2005 Aveo LT. Had terrible time starting when cold. Actually hard to start after sitting 8 hours or more in 70+ degree weather. I tried several things before I found the actual problem. A defective sensor does not set a code. So for me it was try this and then something else.

As it turns out the CTS was the least expensive part to buy but the hardest part to get access to on my Aveo. Forget about testing it. If you get to it, replace it. I could only access it from below the car when it was jacked up. The CTS screws into the back side of the engine block below the intake manifold, between the engine and the firewall. There is an engine brace which is in the way and must be removed. It has 4 bolts in it. The bottom two bolts are #14 metric the top two are #13 metric. The top ones required me to use a short extension to remove. Once the bracket is moved to the left side of the car you can access the CTS. There is a clip on the two wire connector which must be released. This is tricky using only one hand. Once the wire is removed you can access the CTS.

Remove the pressure cap on the water inlet tank. When you remove the CTS water/anti freeze will come out of the hole. You may want to drain the coolant first. I did not. You will need a 3/4 inch SAE deep-well socket to remove/reinstall the CTS. It comes out easily once loosened. Good Luck, sorry no pictures were taken.

I had purchased a Vapor Canister Purge Solenoid Valve along with a vent valve and Vapor canister but had not installed it due to its location, right in front of the brace that blocks access to the CTS. If anyone knows of any means to remove the tube 'clips' without breaking them please speak up! I think if the vehicle was on a lift it would not be so bad but laying under the vehicle with only one handed access at 27F with a drop light is not fun at 73. When I finally pulled the CTS out the antifreeze started running out, I got the new one installed but not before the antifreeze had hit the drop light which became a drop dark. After everything was reassembled I still had a few seconds of blah when II started it, I warmed the car up and topped the antifreeze off. 5 hours later at 29F I just tried to start it, works great again.

The Vapor canister, vent valve and Vapor Canister Purge Solenoid Valve solved my having to spend 15 minutes hand filling at a trickle the gas tank, been doing that for three years before it dawned on me there might be something wrong.... The canister was full of dirt.