Focus Fanatics Forum banner

1 - 10 of 10 Posts

·
Registered
Joined
·
43 Posts
Discussion Starter · #1 ·
Hello everyone!

I have been lurking here for a few weeks and finally decided to buy a 2001 Focus Wagon SE. I found a pretty nice one with no major problems that has 96,149 original miles. The problem is that it rough idles which is more pronounced with the AC on. I took it for diagnostic and there were no codes, I also had it smogged and it passed fine. It gets around 27 MPG highway, and accelerates fairly quickly...I did notice a slight sluggishness in response to gas pedal push, and figured that my TPS might need replacing. I bought it from an older lady so I doubt much has been done except routine Oil Changes and two trans services which she had receipts for.

My question is what could be causing the rough idle? I'm not afraid to start replacing sensors and such, because I know they are probably due, but would really like to find the one making it rough idle.

Any ideas? Let me know if you need more info as this is really my first post anywhere for an engine related issue.

Thanks in advance,

Matt
 

·
Registered
Joined
·
1,073 Posts
How about this
Happened to me 2004 Zetec auto wagon
There is a formed black hose, probably for vacuum, that collapses and leaks. It is between the engine and firewall.
This hose has been commented on alot
 

·
Registered
Joined
·
43 Posts
Discussion Starter · #4 ·
Does anyone have a picture of it or a description of what it's called so I can buy one?
 

·
Premium Member
Joined
·
21,256 Posts
It's the dreaded PCV and it's vacuum line problem. PCV valves should be checked every 25k miles- roughly the same interval as the fuel filter- and replaced when failing the test. Find where the PCV vacuum line connects to the TB, and unplug it. Then blow into the line. You should feel resistance to your blowing if the valve is operating correctly.

If you hear your breath escaping, then the line has a break in it, and need to be replaced. The final test is to feel the rubber elbows and line with the engine idling to be sure that the lines aren't collapsing.

If the lines are collapsing, or you have a break, then you have several options for replacing the line. Ford sells a replacement line which will cost you anywhere from $20-40. If you're clever enough at engineering, then get yourself a sufficient amount of appropriately sized vacuum or fuel line, and some plastic elbows. Use that to connect to the PCV valve. IMO, if you have to replace the line, then replace the valve. The valve should cost about $5. I figure it will cost you about $10 to engineer your own line- maybe less.

You should verify that this is your problem before you replace it. Likewise, the IACV- idle air control valve- is what regulates idle for these vehicles. It will not throw a DTC if it fails. The easiest way to test it is to unplug it while the engine is running. If there is no change in the idle, then that's the problem. It can be cleaned and that sometimes repairs it. The IACV should increase engine idle slightly to compensate for the AC- however, on EFI vehicles vacuum leaks, like the PCV discussed above, cause low idle conditions that the IACV might not be able to compensate for. Check for the PCV problem first, and then test the IACV.
 

·
Registered
Joined
·
43 Posts
Discussion Starter · #6 ·
It's the dreaded PCV and it's vacuum line problem. PCV valves should be checked every 25k miles- roughly the same interval as the fuel filter- and replaced when failing the test. Find where the PCV vacuum line connects to the TB, and unplug it. Then blow into the line. You should feel resistance to your blowing if the valve is operating correctly.

If you hear your breath escaping, then the line has a break in it, and need to be replaced. The final test is to feel the rubber elbows and line with the engine idling to be sure that the lines aren't collapsing.

If the lines are collapsing, or you have a break, then you have several options for replacing the line. Ford sells a replacement line which will cost you anywhere from $20-40. If you're clever enough at engineering, then get yourself a sufficient amount of appropriately sized vacuum or fuel line, and some plastic elbows. Use that to connect to the PCV valve. IMO, if you have to replace the line, then replace the valve. The valve should cost about $5. I figure it will cost you about $10 to engineer your own line- maybe less.

You should verify that this is your problem before you replace it. Likewise, the IACV- idle air control valve- is what regulates idle for these vehicles. It will not throw a DTC if it fails. The easiest way to test it is to unplug it while the engine is running. If there is no change in the idle, then that's the problem. It can be cleaned and that sometimes repairs it. The IACV should increase engine idle slightly to compensate for the AC- however, on EFI vehicles vacuum leaks, like the PCV discussed above, cause low idle conditions that the IACV might not be able to compensate for. Check for the PCV problem first, and then test the IACV.
Awesome detailed answer. I ought to replace both since I'm sure they haven't been done. One question...what's a DTC...looked on google and got all sorts of funky answers.

Cheers to you and everyone else! [cheers]
 

·
DTC P0606
Joined
·
3,364 Posts
Awesome detailed answer. I ought to replace both since I'm sure they haven't been done. One question...what's a DTC...looked on google and got all sorts of funky answers.
DTC = Diagnostic Trouble Code
A code stored by the PCM (Powertrain Control Module) to indicate an engine problem. Usually lights the CEL (Check Engine Light) on the dash to indicate the need for servicing.

DTCs listed here: http://www.focusfanatics.com/forum/showthread.php?t=59286
 

·
Registered
Joined
·
43 Posts
Discussion Starter · #9 ·
Well with your help, ([ffrocks]) I changed the PCV valve (old one still rattled) and tubing today, flushed the radiator, and changed the thermostat since I was removing the housing anyhow...I also changed the lower radiator hose, a hose that went from the valve cover to the air-filter box, the breather filter, and installed a K&N Air box filter. I did an oil change and installed a Wrench off K&N Oil Filter.

The engine runs much better but still runs a bit rough during idle. I looked at four auto parts stores for an IAC and none had it...I even went to Ford and nothing. Oh well...I decided not to take it apart as 1. I'm not quite sure where it is, 2. what if I hose it up...still have to drive it on Monday [wiggle]. Anyone know for sure where it is located on my DOHC?

I was amazed at how hard the friggin PCV hose was to get off the metal tubing...crikey! It was melded (not melted) to the steel tube...the bottom bolt of the Thermostat housing was childsplay compared to that stinking hose! It took me 45minutes just to get that blasted hose off!!! i finally cut it off with my razor knife, but what a pain!

What else could be causing the rough idle other than what I replaced above? BTW...the CEL is not on...It comes on during ignition sequencing but fades off with all the other warning lights. I asked at Autozone but my local one doesn't check codes for free, so I'll look elsewhere.

Any other ideas?

Thanks everyone!

Matt
 

·
Premium Member
Joined
·
21,256 Posts
You need to verify your idle, and do a tune-up. These are the basic things that I recommend doing to any new-to-you vehicle. To verify the idle use the electronic odometer trick in that link to find the idle speed. You can also do this trick with the engine off- key ON, and then start the car. The odometer will remain in test mode until the key is turned OFF.

1) spark plugs: check, clean, re-gap or replace if needed
2) spark plug wires: if lifetime warranty wires, replace for free, if not get some if needed. There are 2 tests for bad plug wires. The first is turning the AM radio to a frequency where there is no radio station. Turn up the volume and listen for pops in the sound of the engine as you rev or drive it. Second is to spray down the wires with a household cleaner like Fantastic, and start the engine at night. Look under the hood, and if you see sparks popping in time with a miss in the engine- replace the wires.
3) MAF: clean with spray MAF cleaner.
4) Air filter: inspect or replace
5) Throttle body: clean with carb cleaner and a rag
6) Idle air control valve: remove, clean with carb cleaner and Q-tips so the shaft is clean, replace with new gasket: $1
7) Reset A/F ratio: Remove the neg battery terminal for 10 mins. Replace the terminal, start the engine. Allow the engine to idle for 7 mins or so until the idle drops down to normal. Expect the idle to be high around 1k rpm, and will be fluctuating slightly. On a completely cold engine that has sat all night, this test might take longer. The actual test starts as soon as the engine is at a certain cylinder temp, and lasts for 5 mins. If you touch the accelerator during the test it will restart the test.

You can check the idle before or after to see if you've done anything.
 
1 - 10 of 10 Posts
Top