Codes 171 & 174 too lean

[DRW1000]

Cowboy,
The codes will clear after a few drive cycles after correcting the problem.

88Duke,
The TSB for the lean codes is burried less than a month into this forum. I am sure they are still active. Search for 171/174, Isolator bolts, intake leak.....

[kdstaller]

Excellent thread post and thanks for the webpage instructions pcitizen. I have a '99 with 67K miles that just started pinging the 171 and 174 codes. It had to drop below 50 degrees here in Phoenix to start seeing them.

I should have known that something like this would creep up. We had a '91 Tracer (escort in mercury clothing) which had problems with oil blow back into the intake filter box through the PVC piping(1.9l engine).

I will say, however, that the 3.8l in my '89 cougar had zero engine issues and is now over 150K miles in the hands of a different owner. My only gripe with it was that a $2 throttle kick-down bushing deteriorated and jammed the car at full throttle in rush hour traffic one day. There were over 100 NTSB reports about cougars and t-birds running away and crashing, but no warning from Ford about it.

As far as warranty coverage, isn't the emissions system covered for 10 years? The CEL codes indicate that the engine is running too lean and may be exceeding HC levels. Any car exbiting a CEL during emissions testing here in the southwest automatically fail the test. If this is a systemic intake malfunction which causes the vehicle to fail emissions, then it should be covered under the emissions warranty. This may explain why they are willing to pay for the labor in some circumstances.

[jimsaco]

Well this is what I have determined based on this and the Cartrackers forum. I just bought a 99 Windstar LX on Ebay and the check engine light is on. I have not had the codes read but from all appearances on this site I have to assume it is likely 171/174.

1. First one must determine whether one wants to do anything about this at all. I live in a state where they don't do emissions testing, the van seems to run fine, and if there is some impairment of fuel economy, how much gas must one burn to pay for what sounds to me like dismantling the whole engine. On this site and Cartrackers I have seen estimates of 1200-1400 for this repair. Or, several hundred in parts, plus my time (assuming I had the right tools)(and knew what I was doing)(which I don't).

If you have 171/174 and the van eventually dies (If it does), will it even be Worth 1200-1400 at that point. (My van has 109k, and I paid 2700 for it.)

2. OK, assume you simply Must deal with it. My reading suggests the following triage:

a) do routine maintenance -- change oil, oil filter, air filter, fuel filter, PCV valve and sparkplugs. Reset. If it comes on again,

b) replace the DPFE sensor. Reset. If it comes on Again,

c) replace the 2 oxygen sensors (front and rear?). Reset. If it Still comes on,

d) proceed with TSB 03-16-1 and have checkbook and a stiff drink at hand.


Or, am I missing something critical??

Many thanks.

[pcitizen]

Jimsaco.... 1200-1400! I am not sure where you've read that fixing the 171/174 code problem costs that much. It was closer to $100 if I recall. I think this is a relatively cheap repair and to me, worth it.

Please take a gander at http://leckemby.net/windstar/windstar01.html

PCitizen

[wiswind]

I would skip the oxygen sensor replacement....as the TSB is FAR more likely the issue. The oxygen sensors rarely fail.

You will have 4 oxygen sensors.
1 before each of the 2 catalytic converters.....which are the ones that are used for engine control....as in air/fuel mixture for banks 1 and 2.

You also have 1 after each catalytic converter.....they are used to monitor the catalytic converters to make sure that they are doing their job. They are not used for engine control.

There are a lot of oxygen sensor specific codes to tell you if there is an oxygen sensor failure.

[sprawlking]

I'm writing to hopefully provide solace for those who are perplexed by these two bewildering codes. I recently had an issue with these two codes occurring together. From the outset, I paid for a diagnosis at the service dept of my local Ford dealership. They failed to make a diagnosis. I made it clear to them that I had no intention of throwing thousands of dollars at every symptom they could come up with (...and belive me there are many variables); but apparently this had been their plan. It's inconceivable that the mechanics would have had no experience in dealing with other distressed Explorer owners--enough to know how to resolve the issue without expensive "guesses". Once I paid for a diagnosis I was determined to hold their feet to the fire--showing up at the service dept everytime the light came back on. Eventually, I gave up and begin the arduous process of elimination. I had spent approximately $300-350 replacing the (mas airflow sensor, Throttle position sensor, and the oxygen sensor). After replacing all these, the light immediately came back on. Forutnately, I took it to a trustworthy mechanic who did a thorough investigation (before my very eyes), before rendering an opinion. He said that the problem was most likely the (intake-manifold gasket). I paid him 225.00 for the diagnosis and to replace the gasket and I've been worry-free ever since. The point I am trying to make is for anyone distressed by this should first consider this before spending hundreds of dollars needlessly in replacing all the sensors. Undoubtedly, it's a money making scheme--dreamed up by the engineers at Ford.

[mtherr]

Thanks for the response... Nothing to do with oxygen sensors. Someone on the forum mentioned the technical service bulletin TSB 03-16-1. Look for it. It explains the procedure to solve the problem. This was a design flaw, for which Ford, I guess, decided that it is up to the customer to pay to have it fixed. There is a kit available with all the required parts (valve cover, a piece of hose, and some bolts with a rubber seal and intake manifold gaskets. The parts cost 300$ and the garage wanted 800$ to do the job... saying it is very complicated to do....

So, being anything but a mechanics... I took my intelligence out of me and did the job by myself. First time I dismantled parts in a car that I would need to get to work the next morning. Well, I started at 6pm and finished at midnight, and the TSB, being clear, it was easy to do. I suppose that somebody with a bit more experience would have done it in half that time.

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[DamnDummy]

Can anyone advise what to do now that I've snapped two of the bolts off? I am not sure how to completely remove the lower plenum to gain easy access but the bolts are located in the front, adjacent to each other. I know I'm not the first to have done this. They have the green sleeve and are new. Can I leave them in and add a gasket sealer just under the top of the bolt? Anyone know what other people did to fix their snapped off bolts? it is pallius@gmail.com if anyone can help.

Thank you!!

[12Ounce]

Originally Posted by DamnDummy

...... I know I'm not the first to have done this. ...... Can I leave them in and add a gasket sealer ......? Anyone know what other people did to fix their snapped off bolts? .....i.

Yes, you can be sure that others have had the problem of snapping these bolts. Part of the problem is the "units of torque measure" that was choosen ... few folks don't notice that it is 89 inch-pounds (not " foot-pounds"). 89 inch-pounds ... that's not much torque!... (about 8 foot-pounds) ... many of us can twist a screwdriver with more torque than that!

And some folks think that some extra added torque will help seal a leaking bolt. NOT SO!! Once the center-bolt-head draws down tight against the inner steel sleeve ... that's all the sealing you are gonna git!!!

And many folks don't obtain and use a small torque wrench. 1/4" drive beam torque wrenches are available ... just a bit hard to find.

There is no short cut that will work ... the old bolts must be removed and new ones added. You may find yourself having to remove the lower metal intake manifold to avoid getting drill shavings down into the engine. This also is not that difficult ... but it must also be done correctly or you will have even greater issues.

Good luck!

[pcitizen]

I recommend cleaning the mating surfaces with acetone. Then covering the intake ports with blue painters tape.

Use a center punch dimple the center of each bolt. It is important that your dimple is in the center because once you start drilling you don't want to drill into the female threads.

Then drill it with a 1/6 inch carbide tipped bit. Drill about 1/2 to 5/8" in to the screw. Then drill it with a 3/32 or 1/8 inch carbide bit.

Use EasyOuts. These are reverse, tapered, screw-like items. As you screw them in (counter clockwise) they should bight into the broken off screw and remove it easily. They work great. Most auto parts stores sell them but I would buy a high quality set - Craftsman or similar.

I do not recommend using gasket sealer to remedy the problem. In fact, the mating surfaces don't require gasket sealer at all thanks to the presence of space-age, heat resistant, highly fantastic, super elastic, rubber seals.

Be patient and you;ll have good success.

PCitizen.

[pcitizen]

I am not saying the problem couldn't be the intake manifold gaskets, but it seems this thread needs refreshed.

The 171 and 174 codes are very likely related to the bolts used to hold the intake manifold on. At least that was the cause in 2000 Windstars and similar year automobiles with 3.8 engines.

Ford, and others, sell kits to remedy the problem; e.g., oil destroyed the shoulder bolt seals. Ford made new bolts, and found valve cover needed replaced too.

Check out http://leckemby.net/windstar/windstar01.html for a tutorial on the fix.

PCitizen.

[Lamorake]

Just today I performed the "Pcitizen Special". Walkthrough was amazing and handy... especially since the most I've ever done in the past is change my own oil.

So, at the very end of the process I was putting on all of the vacuum tubing/hose and when I was re-attaching one of the tubes to the DPFE Sensor (the black polymer one) it tore on me... I started up the Windstar anyways, which thankfully it did run, but had a very rough idle I'm assuming is from the torn tube.

I took it off the van and headed to Auto Zone. They couldn't find anything to 100% match so they sold me a 1/4 in. fuel injection hose. It looked good at first but the tubing is just too stiff to attach.

I've tried many different searches but just can't find the right hose for the job... anyone know what I should do next?

EDIT: Advanced Auto Parts had the hose I needed. I repaced the hose, but the rough idle still exists! I didn't have this rough idle before I did the valve cover replacement / isolator bolt job. Any thoughts to this? Maybe another vacuum leak?


Joe

[pcitizen]

Many hoses these days are molded types. I recommend buying an exact replacement.

[Lamorake]

I figured out the rough idle... one of the last things I did was to re-plug in the spark plugs. After close examination I had attempted to plug the connector into an extended bolt that was close to the spark plug.

FYI, bolts don't give the same results as spark plugs. :P

After the rough idle was settled, the engine runs MUCH smoother. Now on to the next thing - replacing the idler pulley and belt tensioner to hope it solves the whining sound I'm hearing.