Rough idle, dying when cold, runs fine warm

[rp23g7]

Hey Guys, got a issue with my 99 Eddie Bauer.

Its a 99 EB, with a 4.0 SOHC

Bad idle when cold, rough and dies without your foot on the gas. When ambient temp is warmer when the car is cold, i.e. over 75, it is better at idle. When warmed up it runs fine.

This leads me to believe it may be the coolant temp sensor.

I have replaced, the IAC, the upper intake manifold gasket, cleaned the MAF, that was exciting, the car blew white fuel exahust for 20 min.

None of these had any effect, still idled bad when cold. The engine light was on, i did a code check, i have forgotten them now, but i think they were the bank 1, 2 lean codes.

I failed a emmision test once, with the light on. When warm the light didnt come on, so i went home, reset the computer and went out and tried again and passed.

The only thing i havent changed is the ECT sensor, which i have not been able to find for some reason, i looked for anything that looked like one when i had the upper intake off, couldnt see it, ARRGG

Where is this on the engine? Some say its by the thermostat, i cant see anything that looks like it by the thermostat.

I have a small coolant leak too, which also leads me to believe the sensor may be cracked or bad, which i cant find either.

I have a small leak that drips off the lower rad hose, i replaced the clamps and hose thinking it was bad, it still has a small leak coming from somewhere.

Any ideas??

 

[Xplorer82]

as far as the coolant leak.... i had the same coolant leak. was always on the lower hose, sway bar, ect. it was my water pump. leaking from the weep hole. after i swapped that and the thermostat out for new ones, NO Leaks anymore. check the water pump good with a bright light near the weep hole..

check my thread out for pics if you want.
http://www.explorerforum.com/forums/showthread.php?t=259950

 

[rp23g7]

as far as the coolant leak.... i had the same coolant leak. was always on the lower hose, sway bar, ect. it was my water pump. leaking from the weep hole. after i swapped that and the thermostat out for new ones, NO Leaks anymore. check the water pump good with a bright light near the weep hole..

check my thread out for pics if you want.
http://www.explorerforum.com/forums/showthread.php?t=259950

Thanks, I will have to take c closer look down there. I have 160,000 on it, its probably about time for it to go bad.

 

[Xplorer82]

Thanks, I will have to take c closer look down there. I have 160,000 on it, its probably about time for it to go bad.

your welcome.

yeah, most likely that is where your leak is coming from. it is hard to see, but the best spot i found to look from while everything is still attached is crawl under the front and look right above the crankshaft pulley. you will see the water pump/pulley, look behind that near the engine block with a good light you wont be able to see the actual weep hole at this point, but you should be able to see all the antifeeze built up on the pump and also some on the hose(s).

i got tons of pics that i took of my leaks and of the replacement process if you need/want to glance thru them.

 

[2000StreetRod]

ECT sensor location

More than likely the gaskets on the bottom of your lower intake manifold are leaking. I just replaced mine and it solved my problem. Many others have done the same thing. The ECT sensor is next to the front driver side upper chain tensioner. You have to remove the upper intake manifold to replace it. You can replace gaskets and sensor at the same time. See this thread for my experience replacing mine with a link to step by step instructions.

 

[rp23g7]

More than likely the gaskets on the bottom of your lower intake manifold are leaking. I just replaced mine and it solved my problem. Many others have done the same thing. The ECT sensor is next to the front driver side upper chain tensioner. You have to remove the upper intake manifold to replace it. You can replace gaskets and sensor at the same time. See this thread for my experience replacing mine with a link to step by step instructions.

Ewww, lower intake manifold, as in the actual device that is attached to the heads? Hmm dont know if i am in the mood to do that till it warms up. I must be blind or something, when i had the upper off i didnt see anything like that next to the tensioner. I will have to look again. I will check out your thread too.

Thanks

 

[rp23g7]

On post number 9 on your thread, the 2nd and third image, is that the sensor on the lower right? I cant really get a reference on the location. I see your upper radiator hose, but it looks like it may be routed different maybe.

 

[2000StreetRod]

Already removed

No, the ECT sensor has already been removed in those 2 photos. The connector for it is still there. The sensor came from the open hole. The one in the photo is the engine temperature sender for the instrument panel. Look at the second photo in Post #6. The ECT sensor is directly below the side hole in the EGR tube.

 

[rp23g7]

No, the ECT sensor has already been removed in those 2 photos. The connector for it is still there. The sensor came from the open hole. The one in the photo is the engine temperature sender for the instrument panel. Look at the second photo in Post #6. The ECT sensor is directly below the side hole in the EGR tube.

Cool, thanks, i will look for it tonight.

 

[Fordfixer32]

Hey Guys, got a issue with my 99 Eddie Bauer.

Its a 99 EB, with a 4.0 SOHC

Bad idle when cold, rough and dies without your foot on the gas. When ambient temp is warmer when the car is cold, i.e. over 75, it is better at idle. When warmed up it runs fine.

This leads me to believe it may be the coolant temp sensor.

I have replaced, the IAC, the upper intake manifold gasket, cleaned the MAF, that was exciting, the car blew white fuel exahust for 20 min.

None of these had any effect, still idled bad when cold. The engine light was on, i did a code check, i have forgotten them now, but i think they were the bank 1, 2 lean codes.

I failed a emmision test once, with the light on. When warm the light didnt come on, so i went home, reset the computer and went out and tried again and passed.

The only thing i havent changed is the ECT sensor, which i have not been able to find for some reason, i looked for anything that looked like one when i had the upper intake off, couldnt see it, ARRGG

Where is this on the engine? Some say its by the thermostat, i cant see anything that looks like it by the thermostat.

I have a small coolant leak too, which also leads me to believe the sensor may be cracked or bad, which i cant find either.

I have a small leak that drips off the lower rad hose, i replaced the clamps and hose thinking it was bad, it still has a small leak coming from somewhere.

Any ideas??

Ok i had the exact same problem it was the lower intake manifold gaskets were bad after replacing it runs like new also fixed the coolant leak it was the seal under the thermostat housing do it while you have the intake off because you have to remove the upper intake to replacing this seal good luck