Cold Start Problems.....

[Justawajz]

So the past few months my Mountaineer has had some starting problems. In the morning it will start.. then run really ruff.. sounds like a real lobby cam or somming and after about 5 seconds stall's out. Then I'll crack it over again and it starts right up with no prob.... So I searched around the fourm and found the coolant temp sensor can cause this so I repaced it. Next morning still stalled out. Then I cleaned the IAC valve as somone in a thread stated it may help.. didnt help.. So I forked out $120 at ford for a new one... Started it up the next moring.. Stalled again.. Now one thing I was thinking was fuel pump mabey.. I did replace the stock one with a walbro 255 a few months back before winter. Could somthing with that cause the stalling??? Anyone... Anything.....????

 

[97sprt4x4]

do you hear the fuel pump whine when you put the key into the on position? i would check you're tps as well,
http://www.explorerforum.com/forums/showthread.php?p=2349296

Justin

 

[Justawajz]

do you hear the fuel pump whine when you put the key into the on position? i would check you're tps as well,
http://www.explorerforum.com/forums/showthread.php?p=2349296

Justin

Yeah I can hear the whine when I turn the key to Ign.. Thanks though I'll have to test the tps sensor. I didn't even think of that, I'll have to break out the DMM and check it out tomorrow at work.

 

[Justawajz]

do you hear the fuel pump whine when you put the key into the on position? i would check you're tps as well,
http://www.explorerforum.com/forums/showthread.php?p=2349296

Justin

Alright so I tested the tps just now and mine rest's at .991, and at WOT I read 4.66 so it seems to be ok.. It gradually increases with the opening of the throttle. Dosnt jump or spike at all. Another thing i was thinking was a vacuum leak mabey.. If if there was why would it start right up the second time around...???


Edit: I also tested the reference voltage wire(brown/white wire) and it was sitting right at 5.0 volts.

 

[BuckeyeSlim]

vacuum leak is where to start. its very common for the plenum gaskets to leak when cold but when they warm up they expand and seal. new gaskets should solve the issue... however i recomend performing a smoke test to pinpoint any vacuum leaks. do the test in the conditions where the poor idle occurs. (stone cold, cold dryer ambient temp if possible.)