Odd P0171 & P0302

Hello Everyone,

I'm new guy here having some issues with a '99 Windstar w/ 3.8L. I have done some heavy searching here looking for possible solutions. I'm glad that I was able to find a forum that pertains to Windstars.

I just bought a code reader today due to the wife telling that the CEL was on again. This is the fourth time in the past year.

The codes I got were P0171 & P0302. I read the sticky pertaining to the TSB concerning the isolator bolts/ports seals. I'm fine doing this procedure myself as I have worked on cars quite a bit. However, I just wanted to get some input from other to see if it would fix the problem.

When we first bought the van at 107,000 miles (now 130K), I put in new motorcraft plugs and wires and also installed new air and fuel filters. About a month after that, the van started running very rough and had little power one day out on the highway. I stopped a local auto parts store, got code P0302 (No P0171 present at this time). I turned the van off and erased the code. The van drove just about perfectly for several months and then again, out of the blue it started running rough and missing. I disconnected the battery to reset the computer and all was fine again until a few months later and same thing again!

This time when I disconnect the battery or use the code scanner to erase the codes, the problem persists. After I erased the codes and then drove the van for a bit the codes have not come back yet, but it still runs rough.

It seems to me that if this problem was the same as in the TSB it wouldn't come and go like this. It certainly wouldn't clear up after erasing the codes.
I haven't seen the wires or coil pack arcing.

Any ideas about what else it may be? The thing that confuses me the most is that the misfire symptoms went away whenever I cleared the codes for it. :banghead:

Well after doing about another 3 hours of reading here, I have decided to just go ahead and replace the O-rings and isolator bolts since it would appear that they would need to be done anyway.

While I have it apart, I'm going to inspect the EGR ports and clean them if necessary and the fuel injectors. I also clean the MAF sensor and check all the vacuum lines for leaks.

The plugs and wires were just changed about a 25K miles ago with Motorcraft parts, but they are suspect as well. I'll post back later this week after I have had time to do all this with my results.

Fordguy81

Welcome to AF's!

I've done some thinking about your two error codes. The p0302 and p0171 are codes both refering to the same side of cylinders. I'm leaning (pun intended) to a possible fuel issue being the fuel injector for cylinder #2 not giving the cylinder fuel and causing a lean issue and then the code 171.

Thoughts from anyone else?

Regards

Dan

Dan,

Thanks for the welcome!

I got home from work and started working on the van. Here is what I did:

Removed the wiper cowl from the van. Wow, what a difference in room!

I replaced the DPFE sensor since I've owned enough fords to know that they're common maintenance.

Replaced the PCV valve because the one looked bad.

I ran the van for awhile and got code P0171 only(no CEL on).

Took the van for a short drive and on the way back CEL came on. I got code P0302, but NOT code P0171

Shut the engine down, erased the code & swapped plug wires 2 & 6 on the coil pack. Restarted the van and shortly after-wards got code P0302.

So, it would seem that both codes 302 & 171 are intermittent. Sometimes I get both, other times I get one of the two. I haven't found any external vacuum leaks.

I'm starting to lean towards a dirty fuel injector as well. Right now I'm waiting for the van to cool down to take a look at the #2 plug. Will post back.

Ok I checked the #2 spark plug and it looked normal.

Here is the Freeze Frame Data I got from my scan tool:

Code P0302

RPM: 671

Load Value: 34.5%

Coolant Temp: 167°

Short Term Fuel Trim 1: 18.7%

Long Term Fuel Trim 1: 9.3%

Short Term Fuel Trim 2: -4.9%

Long Term Fuel Trim 2: 2.3%

Short Term Fuel Trim 3: -17.4%

Long Term Fuel Trim 3: -28.4%

Speed: 0 mph

Fuel System 1: CLSD (closed?)

Fuel System 2: N/A

Does this data help determine the source of the problem?
Any thoughts?

Thanks,

Bill

... so you haven't done the isolator bolts and egr jet cleaning?

12ounce

No, I haven't done those things yet. It will have to wait until the weekend when I'll have enough daylight to complete the project. I have purchased the isolator bolts and new O-ring seals. We bought the van last year and I was unaware of the isolator bolt issues until I found this forum a few days ago. Great forum!! The job doesn't seem all that much more involved than my ranger. I had leaking valve cover gaskets and had to remove both upper and lower intakes to get to the valve covers.

I'm begining to think along the same lines as Dan is. That the fuel injector is clogged up causing a lean condition and a misfire. I figure since I have to take off the intake to get to the fuel injectors, might as well replace the isolator bolts/O-rings, clean the EGR ports, and anything else that I may see. Plus, it would seem from reading that even if the isolator bolts are not the problem now, they eventually will be. I will report back with what I come up with.


Also, can I use brake cleaner to clean the plastic intake manifold or will I need something else? What part of the plenum are people using RTV on and what for? Is it the black RTV? I've read several posts alluding to this, but I didn't see why or how.

Thanks,

Bill

All will be "revealed" as you open up the plenum. Once you see the inner construction of the plastic upper intake ... you will see the opportunity to use RTV for some vibration dampening.

I would not concerned myself with the injectors until you have dealt with the EGR jets. Too much EGR being dumped into one or two cylinders can cause some misfires. You could, however, swap some injectors around (say bank 1 to bank 2) to see if that causes a different set of codes later on.

Brake cleaner should be just fine on those plastic parts ... but soap and water will work also.

Thanks 12Ounce for the reply.

Good to hear that I'll see it when I open her up. I'll post back in the next few days when I get project done. I had asked about the brake cleaner because I wasn't sure if it would harm the plastic or not. I'm a little leary about plastic engine parts, maybe in the furture we'll have plastic connecting rods and pistons :grinyes: !!

Has anyone ever replaced the lower intake gasket as part of this (the one between the heads and lower intake)?

Thanks,

Bill

I may have been one of the first to replace the isolator bolts ... not having much history to benefit from, I also replaced the lower intake gaskets and seals ... propably did not one bit of good!

And since then, I have rebuilt the engine totally ... and had another opportunity to replace the lower gasket.

I don't think you need to include that task at this time.

Ok so as not to start a new thread, I'm going to post my questions here.

Since I'll be tearing into the van this weekend, I thought I might as well flush the fluid from the PS and tranny. I bought the tranny filter kit and 18 quarts of Merc V fluid at Napa. That stuff is like gold! $5.29/quart! Both procedures seem straightforward enough, however, I just have a few questions.

Regarding the return line to the tranny, is there a special tool that I need to remove the lower line?

Does the van need to be level when I'm flushing either system? I was planning on setting it up on jack stands. Never flushed either system before, so that's why I have the questions.

I checked the fluid in the PS reservoir and it was reddish-brown, but not too brown. Made me feel better that it wasn't black. Also, the tranny fluid was still a translucent red, so that's good.

Anyway, thanks for all the help thus far. Any thoughts or comments are always appreciated.

Bill

I don't think being a little out of level will affect the tranny flush very much ... you intend to drop and clean the pan in the process .. the final top-off/check should be done on the level.

You need to look at the hoses before starting ... most just have hose clips securing them in place since this is low pressure fluid ... but not all have the simple clips.

I don't think being a little out of level will affect the tranny flush very much ... you intend to drop and clean the pan in the process .. the final top-off/check should be done on the level.

You need to look at the hoses before starting ... most just have hose clips securing them in place since this is low pressure fluid ... but not all have the simple clips.

Thanks, 12Ounce. That's what I was thinking about the tranny being level. I really haven't looked at the hose connections to the tranny yet, so I was wondering if I needed anything before I started. Good to know that Ford uses different parts depending on the day of the week the car was made still to this day.:lol:

The P0302 code, I would guess the EGR port is crudded up. The P0171 is from the vacuum leak in the manifold area, if I am not mistaken? Too much air in the mixture and the MAF doesn't know about it!

Misfire would be intermittent as you get to the point where there is not enough air in the mix on that cylinder, but could just as easisly be the injector not putting the fuel in too. I agree, you need to do the isolator bolt fix any way, so do that and watch closely for any other gasket problems as you disassemble. When I completed the repair, the gaskets were all good, but the isolator grommets were relatively hard and not flexible anymore. After cleaning everything and reassembling, all has been well aside from a recent DPFE failure.

Nothing special required for removing the hose off the tranny, but words of advice from a person who didn't do it right; make sure you check level on the tranny when it is WARM. I had to keep adding for quite a while afterwards to get it right. It was as if it was eating it or something, and you aren't kidding about liquid gold. In Canada, the Mobil 1 Synthetic ATF is $9 a quart!!!

Andrew1941,

Thanks, you made some good points about the intermitent misfire. After doing A LOT of reading here I came upon this post:

http://www.automotiveforums.com/vbulletin/showthread.php?t=756904&highlight=flutter

Here, this member actually mentions that his van had a 'flutter'. This exactly describes how the van acted up to time before having this issue. You could feel it in the drivers seat as the van was idling. It was subtle, but it was there from time to time. We actually bought the van that way and when I replaced the plugs and wires shortly after, it was even less noticeable. The 'flutter' would go away or become so minute as the RPMs/vehicle speed picked up, you couldn't tell at all it was there. So it was ignored, as I just chalked it up to the van's 'character'. I'm going to replace the coil pack first, just to see if that's it before tearing into the isolator bolts, EGR, etc. Whatever it is, I hope to get to the bottom of it tomorrow.

For tomorrow:

Fix isolator bolts/O-rings
Clean up EGR ports
Check & clean fuel injectors
Clean MAF & IAT sensors
Replace coil
Flush PS
Flush tranny & install new filter
Change oil & filter

It's going to be quite alot to do in one day, but the wife needs the van ASAP.

Bill

Update

Today I worked the van, but didn't get as much done as I wanted to. I ended up having to tear the the intake of twice. First time, I noticed that someone had already replaced the isolator bolts. I cleaned up the EGR ports, wiped down the intakes, installed new plugs, wires, and coil pack. I also removed the fuel rail and checked out all the injectors. They looked fine, but I swapped #2 injector with #4. I buttoned everything up and went for a drive. Sure enough, I code another misfire code, this time for #4 cylinder.

Faulty Fuel Injector!

Went and bought a new injector and installed it. Van runs better than it ever has. My wife took it for a drive to the store and called to tell me that she needs to get used to the new power, lol.

Anyway thanks everyone for all the help you have provided.

Bill

Fordguy

I've very glad that you found the problem to be a bad injector! Way COOL! Now you need to tell your wife to watch out and be careful not to speed. All of that power!


Dan

Thanks LeSabre,

You nailed it being a fuel issue. Even my wife, who doesn't know much about cars, had said 'may its a fuel injector'. Those EGR ports were REALLY cruddy, #6 had a little mound of gunk over the hole. The others were pretty bad. Now I just have to change the oil and flush the tranny.

Never really noticed how much the van lacked until I cleaned up the EGR ports and replaced the failing injector. It still puzzles me that after clearing the misfire code, the van would run like nothing was ever wrong with it. I mean we put ~25K on the van with it like that.

Bill

Congrats on your find and repair. Moving the injectors, as well as plugs and wires, around after a misfire code to see if the misfire "moves" is a good technique.

The time to use injector cleaners in the fuel is before there is a misfire! If used during a misfire, and the misfire is not immediately cleared, there is a danger of the cleaner passing on thru the engine to the oxygen sensors and catalytic converter. Not good! Best to use this stuff sparingly and as preventive, not remedial, action. I add a few ounces of clean motor oil to a tank fillup ... when I think to do it. This seems to keep my injectors clear ... but this is my own "experiment" ... I'm not recommending it to others. I've never had to replace any injectors ... but once, on an Escort, I convinced myself I should replace them. So, lets say, I invested some money in education!

BTW, I have about totally eliminated the problem of EGR jet foul-up by glueing the lower horn extentions, six of them, that stick down into the air intake spacer. The idea is to keep the oil puddle on top of the spacer from going down into the area of the jets and fouling them. I've covered this some on another post.

Thanks 12Ounce,

Normally, I use an entire can of seafoam through the PB vacuum line at every other oil change, or at least 3-4 times a year. I also use seafoam about every month or two in the tank. From reading posts on this site I just bought the Berrymans fuel cleaner. I'll see if that works better, plus its cheaper.

Also, has this ever happened to anyone else? When I was putting the plenum cover back on the second time, one of the bolts would not tighten and I couldn't get to back out either. I know I didn't cross-thread it. I deduced that the threaded metal insert(s) in the plenum had broken free, thus I can't tighten the bolt or remove it. Any idea how to get it out should I need to?

Thanks,

Bill

Some other posters have had the problem. Probably caused by overtightening somewhere along the way ...

I would suspect a small grinder, with a cut-off disc, could be used to remove the bolt head ... and go from there.

So tonight I went to the store and decided to check and see if there were any pending codes since I did the work about a week ago. The CEL is not on, but the codes are pending.

Even though the isolator bolts had been replaced by the PO, I went ahead and replaced them, along with the O-ring gaskets, anyway. I did not torque the bolts, but I made them snug. EGR ports were throughly cleaned, and all vacuum lines on the back were reconnected. Other than a slight shudder from time to time, engine runs great.

Is there anything else to cause both these codes? Would these codes cause a shudder from time to time? Will these codes harm anything until I get time to look into it more?

Thanks,

Bill

Can you explain about the isolator bolts? Where are the bolts located and what is the problem they cause? I have the same codes 0171,0302.

Can you explain about the isolator bolts? Where are the bolts located and what is the problem they cause? I have the same codes 0171,0302.

The isolator bolts are located between the two halves of the plastic upper intake manifold. It is best to remove the wiper arms and the plastic cowling at the base of the windshield before attempting to remove the upper intake. There are quite a few threads on this forum relating to the isolator bolts and how to fix them.

You must realize that the isolator bolts are only one probable cause for code P0170, which is a Bank 1 (I think) Lean code. This means there is shortage of fuel or an unmetered air source (vacuum leak) somewhere on bank 1. Fixing the isolator bolts may or may not fix the P0170 code.

I was not having an issue with the isolator bolts when I replaced mine. After a lot of testing trying to figure the source of my misfire, I decided to tear off the upper intake to get to the fuel injectors. The isolator bolts had to come off to get to the fuel rail, so I just replaced them then.

P0302 is the code for a misfire on cylinder 3. In my case, I had a faulty fuel injector that was not firing causing the cylinder to misfire and trip the P0302 code. I spent quite a bit of time tracking down the source of the misfire. Only by moving the #3 fuel injector to cylinder 5 and seeing the code change to 0305 that I determined that the fuel injector was bad.

Besides a faulty or clogged fuel injector, the misfire code can also be caused by a faulty sparkplug, sparkplug wire, coil, or bad communication between the ECU and the fuel injector. A commpression leak at the indicated cylinder can also cause a misfire.

Had same codes and problem with my 2000 Windstar w/ 3.8. This discussion definitely help me determine the problem and fix it. Switched wires 2 & 6 with no change. so then bought a new injector and changed #2's and it's running fine now.

I also found this site that had some helpful trouble shooting info for this problem and others.

http://troubleshootmyvehicle.com/ford/3.0L-3.8L/how-to-test-the-fuel-injectors-1

So I checked the resistance of the new and old injector when cold and they were pretty much the same. However my rough running didn't happen from a cold start, it took 4-5 miles of driving before it started, I thought maybe my injector was ok until it got hot. I considered swapping the suspect injector with a different cylinder but I didn't want to have to assemble everything to test and then disassemble a second time to replace it if it was the problem so I just went ahead and replaced injector #2.

Luckily that did fixed it, and even better I had a cold beer or 6 waiting!