P0171/4 code issue, tried to fix

Help!

I've been getting the lean codes, CEL, etc.

I ordered the parts to do this fix a while back. I just got around to doing the project. I changed the upper intake plenum gasket-the 6 individual ones, new isolator bolts, new valve cover and new pcv valve. It still idles like crap. I undid what I did and reinstalled it thinking I might have screwed up a gasket or something and same thing. I've double checked all my vacuum lines, etc.

Any suggestions on what to do/check? I pretty much followed this site to the t:
http://leckemby.net/windstar/windstar01.html

Did you swap out the seals and gaskets between the lower intake and the heads/block? Its rare, but they do fail.

No, I didn't swap out the gasket that's below the lower intake...

help! what should I do/check next? replace the lower intake gasket?

Well, first I would plug off the vacuum tap that feeds the vacuum manifold on the firewall ... and also the hose that feeds the brake booster. Then see if the engine runs better or not. The idea is to make sure some vacuum leak away from the engine is not getting to ya.

After you are pretty sure the vacuum system is pretty sound, then I would consider removing the lower manifold. It ain't a big deal ... but the first time you do it, it seems like one.

BTW, what year model are you working on ? If not '99 or later ... forget all I've said.

It's a 2002. So, the hose that comes off the throttle body back to the fire wall, plug it on the motor side and the one coming off the brake booster? What will this isolate?

All the ac/heat door motors and controls, etc. ... and of course, the brake booster ... which can be a sleeper.

I plugged those two big vacuum lines and it still is idling crappy. Lower IM gasket?

Well, if you are pretty sure you've eliminated all the hoses ... and PCV hose included ... my next guess would be the "lowers".

Do your research first. You will find plenty on-line. Bolts should be tightened in sequence. Invest in a 1/4" beam torque wrench if you don't already have one.

Be prepared to do some extra things ... draining/replacing coolant. Cleaning injector inlets. Replacing IMRC link retainers. Etc, etc.

You can also carefully spray carb cleaner around the intake to see if there is a change in idle. If there is than you have found the source of your vacuum leak.

You did check to see if the MAF sensor is clean?

Good point about the MAF sensor.

What after the lower gaskets and seals if the leak persists? Well, the engine front cover and the oil pan are possibles .... You may want to check just to make sure these bolts are not loose now.

k, thx for the suggestions. would starter fluid work as well as carb cleaner?

i'll try cleaning the maf, I haven't done that yet. any suggestionS?

ok, an update.

I cleaned the maf, no change. however, when i hit the accelerator really quickly, there's a loud suction noise and then it goes away. it's very instantaneous. just a suction sound then gone. what could that be? I've check every friggen vacuum line. i sprayed carb cleaner, nothing.......help!

Make sure the front cover and oil pan are not loose. Are the links in place on the IMRC actuator?

where is the IMRC actuator?

The front cover, as in the front valve cover? I'll double check that.

I'll also double check the oil pan.

The IMRC actuator is on the front of the engine ... on the front end of the lower intake manifold. If you've never dealt with this, it may be your problem.

The front cover is what the serpertine belt runs very near ... IIRC, the belt idler and take-up are mounted on the front cover. The water pump and oil pump & filter are mounted on the front cover.

the IMRC seems to be ok. the linkages are intact and I sprayed carb cleaner by the bushing when the car was running and I didn't hear any change... next I guess is to check the oil pan. help!!!!!!!!!!!!!!!!!!!!!!!!!!!

Just check to see the bolts are not loose ... don't have to reach all of them, just most. Don't overtighten, just snug-up. Frankly this is a long shot ... but we just need to cover all bases.

well, it can't be the oil pan.

i can't pin point it. but when I hit the throttle real quickly, it sounds like an air swoosh right before the rpm goes up...it's hard to explain. it sounds like a sucking noise very briefly, but loud.

I can't imagine the lower gaskets leaking enough to give you that much sound ... something has been missed. A split in the upper manifold? A missed hose connection? A split in the intake bellows? ...??

yeah, something can't be right with what I've done. is the bellows the plastic part that has the individual plastic ports for each cylinder on the top part of the upper intake?

No, I was referring to that rubber flexible piece that goes from filter to throttle-body.

But, that other thing that you mentioned ... that inner-manifold inside the upper manifold. Was it removable or fixed?

I know you've covered it. But the rough idle and a sucking noise. The most likely culprit is a vaccum line. Either not on snug or a line has a split.

Did you check that the air intake (filter housing, rubber fresh air tube, etc) are all buttoned up properly?

Stepping back. In your first post, you said "it still idles like crap". Is the idling worse than before you fixed the lean code? Or os the idle/misfire the same?

Other things I would check or replace :
Fuel filter,
clgged or bad Injectors,
Fuel pressure/fuel pump
MAF connector (is it on snug)
Replace the spark plugs
Check the spark plug wires (arcing, routing, all snug?)
Check all ign wires connected to the correct spark plug?
Stick with OEM spark plugs, some aftermarket plugs cause problems.
Bad ignition coil
Bad MAF sensor

Are there any codes?

We have a 2000 w/ a 3.8L and even with the 171/174 codes (before or after the fix), it didn't idle rough.

if someone turns the steering wheel while you listen under the hood do you hear the same "air" sound? I know that when the power steering pump (for example) is running there is an increase in idle that sounds like a sucking, woosh, air sound for just a second. This sound is normal. If this is the same sound you're hearing just as you step on the gas it may just be normal. Now this doesn't help with the 171/174 codes but maybe you're chasing a normal sound? Do you have any friends who happen to have a windstar that you could listen to? Too bad this site doesn't have a sound bit capability so that we could hear what your sound is....


I agree with previous posters though. There's gotta be a split line, elbow that's leaking, something isn't correct with the vac. Do you have a vac gauge?
P

No, I was referring to that rubber flexible piece that goes from filter to throttle-body.

But, that other thing that you mentioned ... that inner-manifold inside the upper manifold. Was it removable or fixed?


The inner manifold has the 6 hard plastic ports on the top half of the upper intake manifold.

Stepping back. In your first post, you said "it still idles like crap". Is the idling worse than before you fixed the lean code? Or os the idle/misfire the same?

Other things I would check or replace :
Fuel filter,
clgged or bad Injectors,
Fuel pressure/fuel pump
MAF connector (is it on snug)
Replace the spark plugs
Check the spark plug wires (arcing, routing, all snug?)
Check all ign wires connected to the correct spark plug?
Stick with OEM spark plugs, some aftermarket plugs cause problems.
Bad ignition coil
Bad MAF sensor

Are there any codes?

We have a 2000 w/ a 3.8L and even with the 171/174 codes (before or after the fix), it didn't idle rough.

It idles the same, maybe a little worse that before. It idled like crap before I did the work.
I just changed the plug wires, the plugs looks ok, they were changed about 30k miles ago.
There are no codes now. I cleaned the MAF a few days ago with some MAF cleaner spray.

if someone turns the steering wheel while you listen under the hood do you hear the same "air" sound? I know that when the power steering pump (for example) is running there is an increase in idle that sounds like a sucking, woosh, air sound for just a second. This sound is normal. If this is the same sound you're hearing just as you step on the gas it may just be normal. Now this doesn't help with the 171/174 codes but maybe you're chasing a normal sound? Do you have any friends who happen to have a windstar that you could listen to? Too bad this site doesn't have a sound bit capability so that we could hear what your sound is....


I agree with previous posters though. There's gotta be a split line, elbow that's leaking, something isn't correct with the vac. Do you have a vac gauge?
P

It definitely sounds like a vacuum noise, but it goes away real quickly as the RPM revs. I don't have a vac gauge. I spray a hole friggin can of carb cleaner around trying to find it, never did.

without touching the throttle letting the van simply idle turn the steering wheel. If the vacuum sound is the same and lasts the same amount of time I don't think that you have vac leak. Doesn't help the 171/74 but I think you may be hearing a normal intake sound resulting from the increased rpms. Incidentally, turning the steering wheel causes the engine to idle up a bit which is why I've asked you to do this as a simple test.

P

My suggestion is to own a vacuum gauge w/ the hose, and make tests. It'll easier to find the problem. Now you're wasting a lot of time and energy for small results.

Back to the spark plugs... I had a rough idle and it was a cracked plug. Took quite a while to find it because it was really not very obvious. It was cracked on the side of the ceramic part of the main body and was a faint hairline crack. Once I put new plugs in, she ran like new. Maybe worth double checking the plugs?

Another thought is to check the EGR valve is not stuck open partially. It is unlikely, but if you have exhaust going back when you shouldn't, you will get rough idle and/or stalling. While idling, put vacuum to the EGR valve supply line and see if the engine stalls. If it does, valve is probably just fine. If it doesn't change the engine condition immediately, then the valve is stuck. I used the vacuum line from the heater controls to connect to the EGR line just by holding them together with my fingers and that was enough to stall the engine. Worth a try if you have eveything open anyway.

Hi Andrew, thanks for the post.

I'm ready to torch the POS! I'm obviously pretty frustrated. I took the upper IM off again this morning and looked everywhere for vacuum lines. I redid everything one more time, I reassembled the upper IM. I seems like it's missing. I have no codes, so it's possible I fixed the lean code issue and now have another issue? The engine shakes a little bit. It idles even, but it has a little shake to it. I put new spark plug wires. I pulled a couple of the plugs, all the ones in the front and one in the rear. They looked "ok". Not real bad, just a little carbon buildup. My next guess is to pull all three rear ones and change them on suspicion?

If I still had the vacuum problem due to the isolator bolts, wouldn't I probably have a code by now? If changing the plugs doesn't fix it, is my next guess to change the lower IM gaskets?

also, when I had the upper IM off again, around the egr ports and on the lower IM surface, there was some oil... this mean anything? It was probably around 1 tsp.

Well Good News! I changed the spark plugs, bam! Runs smooth as a babies behind! It was the rear 3, I started it up after I changed them and it didn't help, I changed the front 3, fixed! No more codes, no more missing... whew! Thanks Guys for everything!

Well Good News! I changed the spark plugs, bam! Runs smooth as a babies behind! It was the rear 3, I started it up after I changed them and it didn't help, I changed the front 3, fixed! No more codes, no more missing... whew! Thanks Guys for everything!


Just to clarify, was the front 3 or the rear 3 the ones that were causing the miss. Your post was kind of ambiguous.

Also curious since you had stated earlier that these plugs were only in for about 30k miles. What brand / type were they? Did you notice anything physically wrong on the set that was replaced (cracked or excess carbon)? I have 53k original miles on my 9 year old 2000 SE with the original plugs / wires / coil backs and still starts / idles just fine.

Anyway, sure glad you have your Winnie fixed and that you posted back the final remedy.

It's all of them.
Anyway, they are in serial. So if the front misfires, the rear will do it too.

I found one with a hairline crack in the white porcelein. They were bosch plugs, I replaced them with autolite from Schucks...

Damn! When I suggested plugs it was because I had a suspision that you had the asme things I had! You had EXACTLY the same thing! I had Bosh Platinum plugs (4 prong) that were about 40 to 50,000 km old and the #3 on the back had a hairline crack in the procelain. I missed it the first time I pulled the plugs and then found it the second time. What a relief to find the problem and have her run smooth again! Congrats and the good find.

Best to stick with Motorcraft or Autolite double plat's.
Several folks have had similar problems as mentioned with Bosch plugs.
I understand folks trying them.....they put such a impressive display in the auto part stores.
They may be good for some applications....but not so good for the Windstar.

I believe Bosch plugs tend to be a bit fragile, and will not withstand overtorqueing. I used to use Bosch, but became disinterested when they came out with all these extra firing tips. What's with that? They're up to four now with no end in sight ... perhaps a continuous circle/hole with the electrode in the center??