171 code may not be TSB related

[garync1]

I notice a lot of tsb issues for the 171-174 I have had this code 3 times so far.. every time I have replaced and cleaned the PCV valve and the tube running to the throttle body. I reset the code and its been over 3,000 miles for the last time it came on.. I notice that the grommet gets oil around it every time there for my theroy is that if a vacuum leak can cause this code the PCV valve with oil around the grommet will do it as well... My first test was done when the light came on I reset the code and did nothing... 400 miles later it came back on.. I cleaned the grommet and made sure the pcv valve sat firmly in place.. The light did not come back on until over 10,000 miles I guess.. Every time I was doing some type of work on the windstar and kept a close eye on it.
The last time was when i changed the oil around 3,000 miles ago.. The obd light came on a few days ago and the PCV valve grommet had oil all over the area all though not in bad shape I may go ahead with a new grommet. Again I cleaned the grommet and the tube and reset the code.I will keep you posted on what happens next but I dont think the light will come on for a while. But a new grommet will be purchased to see if the prolongs the light. I have pulled the intake plentum and found nothing wrong when I first got the van. So I think the PCV valve is the problem on my van at least for the 171-174 code... Hope this helps..

[DRW1000]

If it was the PCV area leaking air one would expect that you would get 174 too. However it could be on the verge of setting and that particular O2 sensor may not be as sensitive.

Why do you not think it would be the Isolator bolts as the TSB states? Perhaps yours is just starting to allow air and only to one bank for now.

BTW I think you are doing the right thing by investigating other possibilities before ripping into the Isolator bolts. Perhaps a good cleaning of the grommet and PCV valve body and perhaps wrapping the PCV body with some rubber tape might help seal it a bit better.

[garync1]

well when i first found this forum I got the 171/174 code per auto zone code scanner. Got one for my self only got the 171 and 181 after a few tries I also found out about false readings after trying a few other tricks like turning off the engine and leaving the ignition on I only got 174. Well instead of replacing the O2 sensor and doing a complete TSB I found my year van did not require certain items on the TSB so all that really left was the isolator bolts.. I first pulled the intake plentum off almost 2 years ago after finding this forum to check it out, my bolts were tight and the only thing I really found was a little oil in there and my EGR ports had a light brown glaze on them although it was very light.May clean them here soon, have not open it up to check out sence then. After finding out a vacuum leak could cause this to happen as for the 171 code on a 2001 model just wanted to share before some one got the TSB bug and started tearing it down and replacing what may have not been needed.. I wanted to be sure of what I found before posting.
So a loose PCV valve can cause a 171 and 181 and 174 reading. Why the 181 I think thats a false reading..Out of my test I had this code only twice.I pulled a vacuum line a few times and got a 171 right off the bat
reset the code after putting the vacuum line on and no engine light ever came on until my PCV valve problem came back.. So basicly when you change your oil add the PCV valve and hose and gromet cleaning to maintance schedule... just use throttle body cleaner.. Hope this helps and always thanks for all the post they help out a lot... Gary

[garync1]

Originally Posted by DRW1000

If it was the PCV area leaking air one would expect that you would get 174 too. However it could be on the verge of setting and that particular O2 sensor may not be as sensitive.

Why do you not think it would be the Isolator bolts as the TSB states? Perhaps yours is just starting to allow air and only to one bank for now.

BTW I think you are doing the right thing by investigating other possibilities before ripping into the Isolator bolts. Perhaps a good cleaning of the grommet and PCV valve body and perhaps wrapping the PCV body with some rubber tape might help seal it a bit better.

Thanks DRW I changed to 174 as well forgot to add the other codes I had pulled in the past although some were false reading as the 181...code I had pulled...

[DRW1000]

Definately any intake leak can cause 171 and 174. I am not familiar with 181.

You did say that you pulled off the top of the plenum and the bolts were tight? Just to ensure we are in agreement-It is the rubber arounnd the bolts that actually holds the lower plenum securely to the lower intake manifold. This rubber is what deteriorates with the oil. When I did mine I only replaced the bolts, the seals and the upper to lower plenum gasket. I only replaced the gasket ands seals because I had them. I doubt they really needed to be replaced. I did not replace the valve cover (because I think it is a cash cow) nor the vacuum regulator and I di not reprogramme my PCM.

I wonder if your port seals are leaking a bit - an amount that the PCM is able to compensate for but when you get a bit more "stray" air through the PCV valve it cannot compensate and flags the code.

Of course I am just guessing here. Of course if your light is off you need not worry.

[rodeo02]

Originally Posted by garync1

.. I notice that the grommet gets oil around it every time there for my theroy is that if a vacuum leak can cause this code the PCV valve with oil around the grommet will do it as well...

Gary, anything upstream of the PCV valve itself (grommet, valve cover, etc..) will have no effect on vacuum what so ever. The van should run as normal even if you have the PCV valve popped out of the v-cover grommet. Downstream of the PCV valve is a different story. If you pull the PCV valve off the hose, or pop the PCV hose off the throttle body, there is such a huge vacuum leak that the van wont run at all. It's between the valve and the t-body where a vac leak can occur.

G/luck
Joel

[wiswind]

The air that flows through the PCV valve.....is replaced by air that flows into the opposite valve cover.....through the breather......which comes through a plastic tube that connects to the fexible air hose that goes from the air filter / MAF to the throttle body. The air that flows in to replace the air pulled out through the PCV valve has come through the MAF....and as such....is measured.

If the PCV valve is out of the grommet, or air leaks into the crankcase through another path (loose dipstick), that is air that is not measured.....and the computer does not know about it.

[garync1]

Thanks for all the replys... Low and behold after all my testing. my findings!!
I do believe now is bull !
Just this morning at 8:00 am my wife tells me CEL is back on just a few days ago I thought I found the answer. This morning i went out and got this time. 3 codes 171 181 and a 497 what is 497 my book does not even have that code. I turn off the engine and keeped the ignition on and only got a 171-174. I did however could hear the intake plentum doing its knock that I have not heard sence I got the van. So this week end I am going to replace this isolator bolts and port seals. SO there's mud on my face for my findings although the times I cleaned the gromet and the vacuum tube I did not see the 171-174 code for a long time. So too see if I can put this issue to rest for me I will be working on the windstar this weekend. I will also clean the egr ports while I am in there.
Again thanks for the replys and sorry for the confussion.. I do think my code reader is misreading some codes 181 fuel temp sensor can not be found on the 2001 any one know what a 497 is ?? Thanks,Gary

[lewisnc100]

181 is listed for my 2000, but 497 is not listed.

[garync1]

Originally Posted by lewisnc100

181 is listed for my 2000, but 497 is not listed.

181 fuel tempsensor but never could find and no one seems to know were it located... reset the light yesterday came back on today.. so its time to take care of it I guess...

[lewisnc100]

I can't find a diagram either, but according to Ford it's right near the injectors.

"The EFT sensor measures the temperature of the fuel near the fuel injectors. This signal is used by the PCM to adjust the fuel injector pulse width and meter fuel to each engine combustion cylinder"

[garync1]

Originally Posted by lewisnc100

I can't find a diagram either, but according to Ford it's right near the injectors.

"The EFT sensor measures the temperature of the fuel near the fuel injectors. This signal is used by the PCM to adjust the fuel injector pulse width and meter fuel to each engine combustion cylinder"

I Did find out 2001 does not have a EFT the dealer gave the the print out and there is no EFT on it.I got every part number to everything on this van with the fuel and intake area.. so it must of been a false code.. Vans fixed now.. thanks... any one like a copy pm me..

[garync1]

My final thought on this TSB.. After completion of this problem I wonder if the port gaskets were really the issue here.. seems like to me you could have pulled the isolator botls out and added tread lock to them.. replace port seals and torque bolts back down.. The reason I say this a guy at work had a ford sport trac and they only replaced his port seals with the new thicker ones. Sound like what i got. The seals looked a little bigger than the old ones.... hmmmmmmm... My isolator botls did not seem really loose to me only one was easier to remove than the rest . I only got seven to tighten beacuse I broke the one.. But the thing runs better than before. Almost a week and no CEL...knock on wood...I ask my wife every day.. How the van running...

[DRW1000]

I did not notice the replacement port seals to be any different than the originals. I beleieve they are replaced when the Isolator bolts are replaced simply because dirt builds up on the sealing surfaces due to air being drawn in from the outside through them.

I don't believe the bolts themselves actually loosen in the threads but rather it is the force that the rubber exerts on the lower plenum that is compromised due to the rubber wearing. Imagine a bolt with a lock washer tightend to a specific torque. Then imagine that the lock washer could be magically removed. The bolt-thread relatinship remains the same but anything that the bolt and lock washer was holding down will be loose. The bolts would not retain it's torque because it is the contact of the head that creates the torque. If there was locktight on the threads it would still be there securely holding the bolt threads.

[garync1]

Originally Posted by DRW1000

I did not notice the replacement port seals to be any different than the originals. I beleieve they are replaced when the Isolator bolts are replaced simply because dirt builds up on the sealing surfaces due to air being drawn in from the outside through them.

I don't believe the bolts themselves actually loosen in the threads but rather it is the force that the rubber exerts on the lower plenum that is compromised due to the rubber wearing. Imagine a bolt with a lock washer tightend to a specific torque. Then imagine that the lock washer could be magically removed. The bolt-thread relatinship remains the same but anything that the bolt and lock washer was holding down will be loose. The bolts would not retain it's torque because it is the contact of the head that creates the torque. If there was locktight on the threads it would still be there securely holding the bolt threads.

OK !! Good point!! it squashed the puppies... As far as the port seals when I held them side by side, they were a llittle thicker..But that also could have been under the same,those puppies were squashed as well... so they looked a little thicker... Thanks for your reply..