TCCoA Forums banner

1 - 4 of 4 Posts

·
Registered
Joined
·
295 Posts
Discussion Starter · #1 ·
I have been experiencing hard starting only when really cold, like less than freezing, and only after sitting long enough to cool off to ambient. Didn't have any issues during the recent heatwave of 40-degree temps. It tries to catch, but only stumbles. After as many as 4 tries, it will finally catch, running really rough at first, and smoothing out quickly after that, but I have to feather the throttle to get it to stay running initially. Performance and fuel economy are as good as ever.

Yes, I waited to hear the fuel pump run and shut off, and it does. I checked he hoses, PCV, etc. I took out the 2 year old Autolite copper 22C's and put in a new set of Denso 1T16's to see if any change. None.

Looking at the results of The Search, a lot of votes seem to say crank position sensor. I have over 150,000 miles on it, and the CPS has never been touched. In fact, since I bought it in 1999, the only things that have been touched emissions-wise are the 4 O2 sensors. I haven't seen a check engine light since the O2 sensor replacement 2 years ago, and never prior to that. I haven't cleaned the MAF since I ditched my K&N for a stock paper filter a year ago. The plug wires are 6 year old Motorsports, and the coil packs are original. One thing that happened two years ago, though, is that my tachometer went weird, and finally quit altogether, so that brings me back to possibly the CPS again, if it inputs to the tach through the ECM (???).

So, how does cold weather affect starting? My Fiero (2.8 MPFI V-6) has a cold start injector, but these things don't. Is there something else like that on the 4.6?
 

·
Registered
Joined
·
5 Posts
Unfortunately I don't have any answers for you. I can, however, relate. I am having pretty much the same problem when it is very cold. The thing with my cougar is that it only has 75000 miles on it and it catches right away. After it catches, it doesn't want to stay running. I just posted the issue in the general tech forum. Keep an eye on that forum to see if somebody posts something over there and not here. Hopefully we'll find something out...
 

·
Registered
Joined
·
1,747 Posts
check your idle air control valve. Mine did the same thing, so i just cleaned it out with carb cleaner. It will do it from time to time now, and i just hit the IAC with something and the idle will go back to where it should be when first starting the car
 

·
Registered
Joined
·
295 Posts
Discussion Starter · #4 ·
Picked up an IAC valve today, and the dealer gave me the wrong part. No air supply tube connection, but it was open to the throttle body in both holes, and the plug connector faced down instead of up. Maybe it's a a 94-95 part? Same problem happended when I tried NAPA. He finally had to go to the 96-up Mustang screen and plug in the p/n to find the correct IAC, and of course, it wasn't in stock at the dealer or NAPA. Autozone carried the correct part for under $50, but the dealer wants almost $115, NAPA around $85.

So, I hit mine with carb cleaner and put it back on. Seemed to start fine after sitting for 2 hours in single digit temps, but the real test will be tomorrow morning. Is the valve supposed to let fluid pass through it when it is removed (de-energized), or is it supposed to be closed? Mine lets fluid pass through it.

Thanks for the ideas. Now, if I could just figure out how to make my tach work again...
 
1 - 4 of 4 Posts
Top