GT/CS Guy

Hey everyone, new to the forums. I need help.

Ok. Here's the deal. I've got a 2009 GT/CS with a 4.6. I've got a 2.3L Whipple blower with a bunch of other mods. After getting it tuned at the local dyno shop to 449rwhp, when the car has been sitting outside in 40 degree temps or less, once the engine has cooled down, it takes 15-20 attempts to start it before it finally starts and stays running. A few times, it will blow white, really rich fuel vapor out of the back (this also happened with the stock tune from Ford that came with the blower kit).

However, if I leave the car in my climate controlled garage, it can be there for days on end sitting untouched and fire right up on the first turn and run like a champ, so it's NOT an issue of the motor sitting without running (i.e, leaky injector). It's TEMPERATURE related. I went digging into the installation instructions for the blower kit and it tells you to disconnect the engine coolant temp sensor, relocate the harness behind the passenger head, and then hook it back up. Thinking it might be unplugged (even though I don't have any codes currently), I went hunting for it and found that it WAS in fact hooked up (PIC 1)

But in doing so, I found this little guy (PIC 2/3) and I have no clue what it's supposed to hook to. There's nothing back there. I would REALLY appreciate it if one of you fellow 4.6 peeps could help me out and see if yours is hooked up and if so, where it runs to. Thanks!!

Any ideas, comments, suggestions would be appreciated. Thanks everyone for your time!

GT/CS Guy

Here are some reference pics of the setup if that helps....

CPTCO

If I remember correctly, the plug that is unplugged is the stock CMCV (I have no idea off the top of my head what that stands for) when I installed my Roush, it stated in the instructions that it would no longer be used. So I think you are good there.

I too get a brief puff of white smoke when starting on cold mornings, but mine fires on the first attempt.

GT/CS Guy

Cool. Thanks. Yeah, before I installed my x-pipe and long tubes, using the tune from Ford that came on the tuner with the kit, I had the white fuel vapor (smoke) and it always started on the first turn, except that it was a little sluggish and hesitant to start, but it always started on the first turn. After I got my x-pipe and headers installed, I had it dyno'd and tuned at two different facilities, thinking the first one screwed up, but now it's MUCH worse needing up to 20 times of turning the key before it will stay running.

Again, it's only when I leave the car out in the cold. It starts and runs fine when I keep it in the garage. I'm stumped. I have NO codes to point me in any direction.

CPTCO

Well don't quote me in that being CMCV. It's some acronym anyway.

That's definitely not right though, I don't know where you are in Ks, but you will get some freezing temps. Is the car even going to start then? What happens if you reload the ford tune? I know it doesn't match up with your headers, but at least you would know where to start.

GT/CS Guy

Yeah, I thought about that, but the problem was happening even with the Ford tune, although not at bad. I called my dyno shop and I am going to drop the car off tomorrow after work, they are going to let it sit outside overnight and do some live monitoring in the morning when they try to start it to see what they can find. I'll report back if they find anything.

GT/CS Guy

Well. It looks to be a timing issue. I took the car to the dyno shop for live monitoring/data logging. They brought up the table that shows the timing at different temperatures. From 0-40 it's -34, or something like that. From 40-60, it's -6. From 60 and up, it's -34. Only problem is, they couldn't duplicate my issue because after letting the car sit outside all day, the motor ended up being below 40 degrees when they started it, so it acted and started normally. It only acts up between 40 and 60 degrees, which just happens to be the range of higher (dealing with negative numbers here) timing.

So tomorrow, they are going to monitor the motor temp and when it hits 50 degrees, they are going to try and start it to see if they can duplicate my problem. If they do, they are going to adjust the timing for those temperature ranges and it SHOULD fix my problem. Stay tuned.

GT/CS Guy

FIXED!!

It all started with the Ford tune that came on the tuner with the blower kit. The timing for the cold start parameters (temperature wise) for 40-60 degrees was way out of whack. Freezing to 40 and 60 to 200 were all the same settings, but 40-60 were all messed up. That's why it starts perfectly in the garage, but not when it's outside. My local Dyno shop was able to duplicate the cold start problem today and after 3 times of trying to get it to start, they went in and fixed the timing parameters for the 40-60 degree settings. After that, it fired right up!

Anyway, that was the fix. Thanks for everyone's input and time!!