2001 windstart p0171 & p0174 wits end

[mdshumaker]

I drove this Windstar as a leased car for two years prior to purchasing it, so I know it has a good history. Check engine light came on in late 2004. I drove it till Nov 2005 before getting it checked out. The intake manifold gasket had failed. My mechanic did what appear to be a good job fixing that issue. Engine purred for one week, then the light came back on. Getting lean codes P0171 and P0174. Since then they've replaced the MAF, all 4 O2 sensors, and flash upgraded the software in the computer. They did a 'smoke' test and found no other air leaks. After each repair, the van would be fine for about a week, then the light would come on the it will idle rough, especially at lights. The last four days were spent doing wiring continuity check. No problems found. The latest data from my mechanic he claims is per a Ford tech note. Basically, I need to run a higher octane fuel. 87 is too 'volitile', causing the lean codes.
What do you think? He admits he's stumped.
We are currently testing to see if higher octane makes a difference. I know it does in my wallet.

[12Ounce]

Do you know what the first set of codes were?

[DRW1000]

Originally Posted by 12Ounce

Do you know what the first set of codes were?

...and besides the CEL how was it running when you took it in the first time?

Why do you say the first repair seemed to be performed well? was it simply because the light went out? Did you ever have FORD look at it?

[mdshumaker]

The codes have always been the same. By November 05, the van had begun to idle rough, especially when you'd stop at a light. After the rework on the intake manifold gasket, the van idled as smooth as it had when it was new. One the light came back on, the idling went rough again. We when through two MAF's till the mechanic installed a Fork OEM one. The problem returned and then we replaced all four O2 sensors. (I think running it for so long with the intake manifold leak, damaged them) We thought we'd nailed it with the O2 sensors, it ran ok for about two weeks. Currently, the MAF and O2's are reporting proper feedback numbers, so the thought was that maybe there was a intermittent connection that was causing the computer to loose a signal. That's why the mechanic did the point-to-point check. That produced no results, and now 88 miles after they added the octane booster, the light is back on. So far the idle is OK. I'm seriously considering the black electrical tape the hide it.
Marc

[mdshumaker]

Per you question about whether Ford has looked at it. No, not yet. I'm debating how much more I'm willing to spend.

[DRW1000]

Originally Posted by mdshumaker

Per you question about whether Ford has looked at it. No, not yet. I'm debating how much more I'm willing to spend.

The reason I asked is that there is a TSB that addresses 171/174 codes. Ford would presumably follow this TSB unless they had reason to believe the cause was due to something else. Normally they consider the codes and no drivability issues to be the trigger to perform the TSB. Perhaps your mechanic is unaware of this TSB.

It sounds like your mechanic has played some "hit-and-miss" with your van. I am not too sure they should have replaced as much as they did without a bit more thought - but then again it is your money they are spending.

171/174 are lean conditions on banks 1 and 2. Lean conditions are reported by the 02 sensors (although only 2 of them and not all 4). Lean conditions occur for a variety of reasons including faulty or dirty MAFs and failing 02 sensors but these are not all that common. The most common reason for these 2 codes are intake leaks. The MAF reports a volume of air entering the intake stream and the PCM introduces the "correct" amount of fuel for this volume and at the end of the combustion cycle the 02 sensors provide feedback to the PCM to adjust the air/fuel ratio. If it cannot compensate it assumes a failure somewhere and sets the code(s).

It sounds like during the repair the CEL was turned off (easy to do) and you left thinking the problem was fixed. However after seeing the fault a couple of times the PCM commanded the CEL back on.

Replacing the same part twice (MAF) seems like questionable trouble shooting unless he had a good reason for believing the first replacement was faulty out of the box. Why he would think that both banks would have faulty 02 sensors at the same time also seems questionable. Although certainly possible I would have thought he would look elsewhere. I also do not believe that the rear 02 sensors have anything to do with the Lean reporting.

There is a TSB that involves replacing the port seals and Isolator bolts on the upper intake plenum. If this is what he replaced when he mentioned intake gasket then he either told you incorrectly or you misunderstood or he did indeed replace the intake gasket which could cause the problem but obviously was not the issue. Ford would have known about the TSB but like yourself and many others I would not go to Ford for a repair as a first choice.
You can read up on the TSB in this forum buy searching under 171/174.

I tend to beileve that you have a vacuum leak. Since your vehicle is not running well it may be a bigger leak than the port seals can offer. Perhaps a hose is cracked or loose or you have a combination of leaks.

[road_rascal]

I would also question any mechanic who says you need to run higher octane fuel in these engines. 87 too volatile ...

[mdshumaker]

As for the sensor replacements, the first two MAF's were aftermarket units. When the CEL came back on, the monitor showed that the signal from the MAF was out of "spec". The final and current unit is a Ford OEM part. I was told that it was calibrated properly and seems to be holding it's own. After the MAF replacements, then the mechanic told me that the O2 sensors in both banks were not "toggling" the way they should. Their way of telling me that the feedback was not right. I was advised that since the car had been running with too much unmeasured air in if for so long, that the O2 sensors were probably damaged. It was my call to do all four. Better now while it's on the rack that later.

Recall that this van ran for probably a year with that intake manifold gasket leak, which he told me was quite serious by the time we took it in. He said that the intake ports were practically closed off from the screwed up fuel mixture and the there were parts of the gasket ready to be sucked into the engine. ( I figure that's were the rest of the gasket went anyway ).

All the feedback I'm getting is that there has to be air getting into this engine other than what come through the MAF. The mechanic has done three "smoke" tests, looking for a leak with not results. How good is a smoke test? I tend to think it would not find a hose leak of any other crack that is not on the engine, but off on some other connected piece. I may have to get under the hood and just start looking for something like a cracked hose.

As for the 87 being to volatile, that was the way he explained what he said was a Ford tech note of some sort. The the higher octane fuel burned slower and were less volatile.

Right now the light is on and the van seems to run fine. It's idling smooth and has plenty of pickup.

The mechanic mentioned something about the fuel intake in the tank possible getting blocked and causing a low fuel pressure situation. It could suck up scale in the bottom of the tank. He said he'd have to drop the tank and pull the pump to check into that. Can low fuel pressure possible cause a lean condition.

[jgattian]

No where in any of your posts do you mention that the isolator bolts were replaced. If your mechanic re-used the old (black in color) isolator bolts then the intake manifold will not seal and cause the CEL to come back on with the 171/174 code.

Do as was mentioned by DRW1000 . Do a search in the Windstar forums for the 171/174 codes. In those threads you will find an actual copy of the Ford TSB regarding this issue. Print it out and ask your mechanic if all of the parts as specified in the TSB were replaced.

Also while the intake is off it is always a good idea to clean out the EGR ports in the lower manifold. If these plug it will cause a lot of the symptoms you have described you are experiencing such as rough idle.

This link has the TSB in it.
http://leckemby.net/windstar/windstar01.html

[mdshumaker]

Thanks for your input. I did find that TSB last night and have printed it. Your point is well taken, if they did not replace all the parts specified, the issues can occur. From the looks of this TSB, I feel I can get in there and do this to save the $$. Of couse, I may be able to talk him into a warranty repair. We see.

Again, thanks for all your feedback.
Marc

[HarrisClub]

I've joing the unlucky club with this problem. My follow-up question is do only Ford Mechanics have access to the TSBs or all. I usually bring my cars to my "Big O" Mechanic who up to now I've trusted to do the best in my interest also. Reading the threads however it seems the problem could be so many different things it might be worth going to a Ford Dealership who has the TSB also. My goal is to go from the least expensive to the most expensive.
Thanks for any feedback
Sincerely
HarrisClub

[DRW1000]

TSBs are available on line for a fee. (I can't remember the site). I too would not want to take my car to Ford for servicing either. I recommend that you post questions here. More than likely any TSB or other tricks will probably already be known.

[mdshumaker]

DRW1000,
I had a discussion with the mechanic today about this TSB. I had printed the copy and he and I reviewed it. It is the same TSB that they followed. The only thing that they did not do is replace the isolator bolts. The mechanic said that he never has and he's done the TSB dozens of times.
Mainly, because it's not called out in the TSB.

This mechanic is real high on the smoke test machine that they have. He's well aware of the possiblity of those six seals leaking and was careful to look there during the two subsequent smoke tests that were performed after the initial repairs. (that's actually where he found the fiirst leak). He's confident that there is no issue with the seals between the bottom of the clam shell and the top of the intake manifold.

I drove the car for 250 miles this past weekend. It runs like a top and only has a slight idling issue when it's still cold. The mechanic does not feel that there is any air getting into the system. He's wondering if the "flash" upgrade to the PCM that Ford did for them didn't take completely. He's seen the progress bar on the flash process read 100%, but still have an "incomplete" message elsewhere on the computer screen.

I'm of the mind right now to just ignore the light and drive the van. If it starts acting up, I can have it checked out again. I may get on ebay and see if I can get a code reader cheap. One that can also reset the CEL.
Any recommendations on a make and model??

Thanks for your help.

[pitteach]

You might want to check out the TSB again it is listed at the end of this website http://leckemby.net/windstar/windstar01.html. The TSB specifically says to replace the isolator bolts. Originally they had a black seal attached but were re-designed with a green seal-those are the ones you want. Could be the source of the problem.

[mdshumaker]

You are correct. I missed those links to the actual TSB that is at the very end of the article. I've printed and reviewed it and it does clearly call out the replacement of the isolator bolts. Now my challenge. My mechanic was using this exact TSB. I'll have to call him on the carpet and see if he's willing to go back in and replace these, since he didn't follow the TSB to the letter.
(interesting also that the TSB advises against using smoke to locate the leak. Any reason you know of as to what the down side of smoke is? The TSB explains only carb or brake cleaner)

Can you explain what is wrong with the original isolator bolts.