Vacuum line???

[marquis00]

There is a vacuum line that comes out of the throttle body has two 90 degree bends in it. then travels down and connects to a solenoid. trying to find out what the solenoid does. i have a rough idle and have replaced spark plugs, plug wires, coil. the hose has damage to it.

[shorod]

What year is your Explorer and which engine does it have?

-Rod

[marquis00]

2001 explorer sport with the 4.0L SOHC. i just can't figure out this rough idle. i have tried the carb cleaner, test the coil and it was bad so replaced it. also new plugs and wires. i replaced the vacuum line i was discussing about in previous post. i would like to know what this line is for and what the solenoid does. i am out of ideas? please help.

[carlos80]

After the elbows is it plastic lines? Perhaps a green and red? If they are they control the egr valve.

[shorod]

If you still have the vacuum diagram on the emissions label under the hood, that will indicate where each vacuum lines goes and what it connects to, such as the EGR valve.

-Rod

[marquis00]

it is a large line (3/8 in.). it does not show on the emissions sticker or in the manual. i have purchased an elm327 scan tool, have any of u used this. car does drive bad, only at idle, it is rough. the scan tool says that the engine rpm is at 660 and flucuates about 15 to 40 rpm. is that normal?

[carlos80]

Yeah that fluctuation is normal. Try disconnecting the MAF.

[carlos80]

What else can u see with this scan tool? O2 sensor readings? MAF? IAC? Fuel trims? TPS?

[marquis00]

here are some of the vaules i got from scanmaster.

http://aycu22.webshots.com/image/237...5692762_rs.jpg


http://aycu30.webshots.com/image/260...9685862_rs.jpg


now the intake air temp seems low. i live in florida and its 90 degrees out.
and the engine coolant temp is at 86 degrees and i was driving it for about 25 minutes before the scan.

[shorod]

Have you used this software before and achieved realistic numbers for both parameters?

-Rod

[marquis00]

no just got it. didn't come with a manual. maybe someone would know if the parameters are right or off. gonna try it my brothers car.

[shorod]

The numbers certainly seem off, but without baseline data to know that the ELM software is reading your car properly, it's hard to say either or both of those sensors are faulty. You could measure them with an ohm meter and see what temperature the resistance corresponds to and determine if that is consistent with what the ELM tool is reporting.

-Rod

[Chad79]

I know it may seem weird, but, check your transmission fluid level. If it's low, it's your modulator valve. Just replaced it in my '93. Pull one plug out at a time and see if one of them look horrible. It fouls usually one plug of the 6.

good Luck,
Chad

[marquis00]

fluid is at the proper level.

[carlos80]

Originally Posted by Chad79

I know it may seem weird, but, check your transmission fluid level. If it's low, it's your modulator valve. Just replaced it in my '93. Pull one plug out at a time and see if one of them look horrible. It fouls usually one plug of the 6.

good Luck,
Chad

Newer vehicles no longer have the modulator valve.

Is there any way that you can get the parameters to display in voltages. I don't know if you MAF(air flow) reading is correct. Both MAF and Intake Air Temp IAT sensor are one assembly if ones off the other could also be faulty. The MAF reading should be at around 1 volt, at idle and climb as vehicle moves(accelerates), if you are able to get them to read in Voltages.