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Ford Windstar - fixing PO171 and PO174

25 messages,  Last post on Feb 13, 2013 at 11:35 AM

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What is this discussion about? Ford Windstar, Van

Messages Page 2 of 3

#5 of 25 Re: HELP needed [diclemeg] by autodr

May 01, 2008 (7:42 pm)

Replying to: diclemeg (May 01, 2008 6:28 pm)
Disconnect the battery for a few minutes. Reconnect, drive it and see if that seems to fix it. If it does, test the battery.
 
What kind of vehicle? I'm assuming something in the Ford line.

#6 of 25 Re: HELP needed [autodr] by diclemeg

May 01, 2008 (9:52 pm)

Replying to: autodr (May 01, 2008 7:42 pm)
yes, a 2003 ford windstar

#7 of 25 did I find my high idle problem ????? by diclemeg

May 04, 2008 (6:16 pm)

I finally attached a scan tool.. .... and here is what i found..... .the "absolute throttle position" reads at 18.4% without touching the pedal, and goes up from 18.4 if I do touch the pedal. If I disconnect it, it reads 0%. The short and long fuel trims were -1% and 3% and varied but never got above 6%...
 
recall that i already changed the TPS sensor a week ago.
calling all experts, please advise here.

#8 of 25 Re: did I find my high idle problem ????? [diclemeg] by autodr

May 04, 2008 (7:36 pm)

Replying to: diclemeg (May 04, 2008 6:16 pm)
Does your scan tool give you the TPS in volts also? Or is it only generic scan data.
 
If your scanner won't give you the voltage, use a DVOM directly at the sensor and measure voltage on he signal wire and the ground. There should be no voltage on the ground wire. TPS voltage should be around .8 If the signal voltage is higher than that with no voltage on the ground, inspect the throttle plate stop screw... maybe someone adjusted it up. If not, then suspect the wrong TPS or a poorly made one. If the voltage is correct with the absolute TPS value reading that high, disconnect the battery... reconnect after a minute, and see if the absolute TPS is now correct at zero. If it is, test the battery,

#9 of 25 Re: did I find my high idle problem ????? [autodr] by diclemeg

May 05, 2008 (6:10 pm)

Replying to: autodr (May 04, 2008 7:36 pm)
Hi autodr,
the scan tool does not have volts. however, get this.. when the tps sensor is attached to the throttle housing, it actually has to open and turn a little bit, which is causing the 18.4% reading. i know this because i took it off with the computer in front of me and it went to zero. then i put it on half way and it read zero and in order to seat the screws, i had to turn it to the point that it read the 18%. The flat plastic knob that is attached to the throttle plate and what turns the tps sensor at closed position is not at 0 degrees like this " -- " but titled downward like this " \ " (but not that exagerrated). I guess the question is whether the pcm knows that the downward tilt is absolute zero and accounts for it.

#10 of 25 Yeah... but.... by autodr

May 06, 2008 (4:03 am)

Absolute throttle position is NOT a measured position. It is a learned or calculated position. It is the position that is in reference to the lowest measured TPS voltage. You need to know the measured voltage. That phantom 18% may be coming from an incorrectly learned closed TPS position. If you have a volt meter, try measuring the vltage at the TPS and let me know what you read. There are 3 wires there, One is a 5 volt reference, one is a a ground which will only have a couple millivolts on it... and the other is your signal wire. It will start around .8 volts closed and raise up to about 4.8 at wide open throttle.
 
You have only generic level scan access then.... which is better than nothing at all. But, you have to remember that you are not seeing "actual" TPS position on that scanner... you are seeing more of a "virtual" TPS position. The position displayed is relative to the lowest measured voltage that the PCM saw.
 
You can also try disconnecting the battery for several minutes then reconnect. That will clear out the lowest measured TPS voltage from the PCM's memory. And unless the TPS is at a ridiculous high level... like more than a volt, it should accept that first key-on TPS voltage as the new "closed" TPS voltage.
 
It may be that the TPS they gave you is the wrong one. I'm assuming you went to a part's store rather than the dealer, which doomed you to get the wrong one early on. At the part's store, they ask you year. make, model, and engine and hand you the only one they list for it because they do a "one size fits most" thing. Whereas there may be 2 or 3 different ones for that vehicle depending on the vehicle's calibration code which the dealer will use to get the correct one.
 
However, some TPS's are under slight tension when installed so that test you gave may or may not prove anything. I really would like the voltage to get a better idea of where that TPS is sitting at at closed throttle position.
 
Another quick test here would be to unplug the IAC valve. If the engine idles down to the point of near stall, or does stall, then it is likely that the phantom TPS position is the only problem. When the PCM sees the TPS open, it cranks the IAC open to anticipate "dashpot" mode when you let off of the gas.

#11 of 25 Windstar IMRC Problem by gregwrench63

Oct 05, 2008 (11:24 am)

I have three MIL codes , 2 lean banks and a EGR flow code . I replaced the EGR and EGR flow sensor . Then , I found that the linkages to both IMRC 's had fallen off . I need to know 2 things , 1) does anyone know where to get the linkages and retainers besides from Ford and ,2) could this be throwing lean codes ? I am assuming that the rough idle is associated with the IMRC being inop . It acts sort of like a vacuum leak but I cannot find one and that is what is leading my this way . Help and thank you.

#12 of 25 Re: Windstar IMRC Problem [gregwrench63] by autodr

Oct 05, 2008 (12:22 pm)

Replying to: gregwrench63 (Oct 05, 2008 11:24 am)
The little white plastic bushings are available at the dealer for about 7 dollars each.
 
If a linkage is missing, then you are in big trouble. The linkages are not available separate and do not come with a new IMRC unit. In order to get new linkages you have to buy an entire lower intake manifold... but the lower intake manifold might be your source of your lean codes anyway because the IMRC shafts leak vacuum there anyhow and the seal in the shaft that leaks is not availble without buying a lower intake manifold anyway.
 
I keep the old IMRC linkages when I replace a lower intake because I know you have to buy a 3 hundred and something dollar lower intake to get them. It is likely that a tech at a local Ford dealer near you will have a few in his tool box too for the same reason.
 
Lean fault codes have the largest list of possible causes out of all of the fault codes, second only to rich codes. That engine has a few intake leakage sources, like the upper intake seals and bolts, pcv valve lines, and lower intake IMRC shaft seals are all common causes, but other possibilities are possible. It should be checked out by a qualified tech. Otherwise, you might through a LOT of expensive parts at it attempting to fix it. Paying to properly diag the problem and fix it right the first time is cheaper than guessing.
 
BTW... there is also a reflash for the PCM that "hides" much of the vacuum leakages. It doesn't fix the cause, but helps cover it up and might keep the light out. If you take it to a dealer, you might find it can be fixed with only a reflash.

#13 of 25 IMRC Fixes by gregwrench63

Oct 08, 2008 (4:52 am)

I want to thank autodr for the great suggestions with respect to my IMRC misery . I did however , find a way to beat Ford at it's own game by manufacturing new linkages from 4mm welding rod . I did use new bushings but , instead of Ford linkage , I bent "Z" bar style linkages and they are not falling out any time soon . I was unaware that the IMRC rods leaked vacuum. How much , roughly , does an intake manifold cost ? The replacement looks fairly straightforward .

#14 of 25 Re: IMRC Fixes [gregwrench63] by autodr

Oct 08, 2008 (6:49 am)

Replying to: gregwrench63 (Oct 08, 2008 4:52 am)
*prices may vary
 
The last time I had to get one (a year + ago) I seem to remember $365.00 as the price. Plus the gaskets.

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