Vehicle: 2001 E150 Econoline 4.6L FI - vin W
Milage: 114,000
Problem: OBDII Code po175 preventing tag registration (sons work van)
Long term fuel trim = 28.10 Bank 1 -35.2 Bank 2 (from scanner info)
Whats been done so far:
O2 sensors changed (both banks - both forward and after) = no change
new fuel injectors on Bank 2 = no change
New spark plugs (all 8) = no change (old plugs looked very good)
Fuel filter changed - Fuel pressure Key On Engine Off = 40psi
Fuel pressure with engine running at idle - 32psi
Fuel pressure with engine runing and gunning rpm's = 32psi + 5psi then 32psi agian
Fuel rails hold pressure after engine off ok
MAF sensor cleaner with MAF cleaner = no change (air filter good - dry type)
Tested long term fuel trim readings with each injector disconnected:
Bank1 went from roughly 28.10 to 21.0 (cyl 1,2,3,4)
Bank2 went from roughly -35.2 to -18.0 (cyl 5,6,7) and to -23.5 (cyl 8)
Engine temp seems a bit low at 199°F
Cat test was completed before I started working on vehicle
I know evap test will not complete with error code
Tail pipe clean - no soot
don't seem to have any loss of coolant - everything looks dry around intake (very complicated intake manifold on this beast)
Didn't see any obvious leaky vac hoses - EGR test completed
The engine idles like kitten - power seems to be normal
The code po175 sets very quickly all the time.
I'm at wits end on this one - since the long term trim test was so consistant, could it possibly be the PCM in this case?
I also thought maybe the fuel pressure might be high on bank 2 - but fuel pressure tests my fuel regulator seems to be working ok.
Disconnecting vac from regulator brings pressure back up to 40psi. Drats.
Scan report attached if anyone wants to see it.


(This post was edited by MROD on Aug 9, 2009, 4:48 PM)

Looks like you've already covered a lot of the bases. The rich bank 2 code mean obviously the bank is running rich which I'm sure you already know.

The bank 2 LTFT @ -34% which will set the code but if you look at you bank 1 LTFT, its at 17 % that's borderline setting a lean code & in your post you say you had 28 % that should set a lean code. The engine load % is way too high for idle and the air flow looks low, I'm not sure of the scale measured there, usually its grams per second.

If that has dual cats on it, I would be looking at the backpressure on Bank 2 to check the cat. On readings I've seen similar to that one of the cats was plugged........


(This post was edited by Sidom on Aug 9, 2009, 6:56 PM)

As an off the wall reply---We have run into several fuel regulators that were partially blocked open and caused a rich condition. They were blocked open by what seemed like charcoal deposits. May not relate to yours, but we have run into 3 or 4 of the 4.6 engines do this. Just another fuzzy part of a dizzying puzzle.


http://www.publicsurplus.com/...owse/cataucs?catid=4 <<< Click on link and see our surplus vehicles for sale.
Being way2old is why I need help from younger minds

Thanks Sidom, I appreciate your input and I will persue checking the cat on that side.

Thanks Way2old
I first thought the regulator, which is welded to the left fuel rail was unserviceable, but it looks like it does come apart so I can easily check for any deposits.

The regulator is held into the housing with a snap-ring. After removing the ring, twist the regulator and it will come out. Good luck.


http://www.publicsurplus.com/...owse/cataucs?catid=4 <<< Click on link and see our surplus vehicles for sale.
Being way2old is why I need help from younger minds

To Sidom:

Checked the back pressure of the two cats and Bank 2 was slightly higher and the pressure needle was really buncing around - up to 4 lbs spikes. Bank 1 was a little less than 1 lbs and no bouncing of the needle at all.

Does this signal anything? - there is also some mystery welding around where the Bank 2 cat is attached to the Y pipe of Bank 1 cat. The clamp is still there so why would there be welding here? We bought it used - a plumper owned it.

I think this rich problem is why it was on the lot. I know I'll never buy another vehicle witout scanning it first. Still shying away from it being an intake problem. This engine does NOT have the plastic intake manifolds - I couldn't believe it - they actually used a PLASTIC intake manifold os alot of the vehicles of this vintage.

Thanks for your interest and input.

Yea it looks like you got something going on there on bank 2. Anything over 2lbs is a little high. Anything higher than what you recorded & you would probably start noticing a drivability problem.. The welding could of possibly been done to seal a leak but who knows.....

With the fuel trim readings that you were getting, about the only single problem to give those readings that I have seen would be a restricted bank. Not saying that there couldn't be 2 or 3 things happening at the same time that would cause that but less likely...

Fuel trims are a good tool to find out what's going on when & where.

What's going on with yours, is say you have 100 grams of air coming thru the MAF, (I'm just making these numbers up) now comp knows it needs a 5ms pulse width from the injectors to hit the stoichiometric (sp) air/fuel ratio of 14.7 to 1 for both banks and on a good engine 50 grams goes down both sides, it gets its 5ms pulse & everything is good and the trims hover around 0 like they should. But if you have a restriction on one side. Now only 30 grams of the 100 goes down bank 2 but comp is still hitting it with a 5ms pulse so the air/fuel mixture is too rich and in turn the fuel trims on that bank go negative in attempt to compensate. So that means bank 1 gets 70 grams and still only a 5ms pulse, that isn't enough for 70 grams so that mixture is too lean and the fuel trims go way positive in attempt to compensate. Now the computer has probably been compensating for this problem for a while and as long as it can hit stoichio and keep the trims in range there will be no light. Once it gets out of range and in my experience thats in the 20 to 25% range, neg or pos, and it throw its hands up & turns on the light, saying it's got too bad & I can't adjust it anymore.......

I don't know if that helps any but you seem know your data so I figured I'd bore ya for a bit....

Lets us know how it works out for you once you find the problem & fix it.........

To Sidom:

Update:
I undid the manifold coupling to the cat which left a little gap for exhaust to excape. The scan readings went to a lot to the plus side with the gap open and as I closed it up, the trim readings gradully went back to zero and then on to the negative side as I closed the gap even more. I think you are spot on. I now feel comfortable enough to get a replacement cat and install - looks fairly easy and access is very open under the truck.

I'll report back when I get it replaced - probably not for a week or two or three.

Thx 4 keeping us updated on your progress....Did you happen to notice if that brought the trims down from such a positive reading on bank 1?

Sidom:

Yes it did.

Now I have another REAL problem. I seached the web and NOBODY offers an exact replacement cat for that darn thing and Ford wants like $800.00 + your first born - that is absurd.

I'm hoping that someone can point in the right direction here on this. I didn't expect this to be a road block. I WILL NOT spend that kind of money for a cat. Eastern offers cats and thier typ price is about $300.00.

It really depends on where your at and the particular smog laws for that state. I'm in CA and with some new laws it's got pretty crazy. If you're in a state that allows universals someone here might have a good link where you could get one..... Pros & cons with those, the price is good but I've seen new ones set a P0420 within months of being installed..........

$800 for an older Ford is kinda nut tho....got to agree with ya there............

To Sidom

Update 08-23-09

Well, I finally used my eyeballs today and the reason for the welding at the cat Y connector on bank 2 is becuase IT HAS BEEN CHANGED!!! Dork faces welded it in - thank you very much. Many years ago I started to tell muffer people NOT to weld anything in place . . . . . Also, checking the EGR system and I cannot get it to open at idle with vacuum pump - valve will not hold vacuum. The "smart" PCM has told me it passed the "Ready Test" - I guess you can't always rely on the masterfull, all powerful PCM.

Still tracking down an aftermarket Cat (if anyone has any leads please let me know) (Cato and Eastern don't seem to offer a drop-in replacement) - apparently there were not too many 4.6L engines used in the mighty E150 Econline series. I'm thinking that maybe the defective EGR system may have attributed to the replacement cats early demize - or ir could be the replacement cat was not the right one in the first place.

Update:

For those few who might be interested . . . .

EGR system did checked out to be OK. System checks out just fine (using vacuum gage) with the exhaust venturi tube disconnected from the EGR valve. However, with it connected, it does not create enough vacuum to open the EGR valve pintal. I suspect it is due to the partially blocked catalytic converter on Bank 2. The exaust tube cannot create enough vacuum to trigger the sensor due to the restricted exhaust flow. We shall soon see on this one.

I had a locate shop quote replacing the two cats and they wanted like $700.00. No way - I told the man to his face that it was way too high because I know the price of replacement converters after visiting every possible site on the web. I have ordered two OEM grade converters from Magnaflow (front and back) and will bulldog them into place myself, one way or another.

Thx 4 the updates M, we do appreciate it. A lot of time once someone gets it fix they just leave us hangin so it's nice to see how things are going, whether its something we suggested or not...

You do seem to have a lot of patience sticking with it this long...maybe I'll hire ya work on my truck once you get done (I hate workin on my own stuff )....

09-08-2009 Update

Well, the cats are in and NOTHING has changed. Still showing -36% Long Fuel Trim on left bank 2. Did the scan before I connected the wye pipe connecting to the right Bank 1 cats.
I was sickened when I looked thru the old cats and seen lots of daylight. Ever try to cut & butt weld two cats into place using the old O2 sensor pipes - especially when your MIG welder is about 2 days old and you dont have any welding talent to speak of? Good thing I don't drink anymore otherwise there would have been a 2 day blackout.
Job looks pretty good tho I must say.

Only two things left before I go get some C4.
1. Intake manifold (which I don't think it really is)
2. ECM -would reflashing or getting a replacement be a fix? Is the fuel trim info in that flash memory? With a -36% trim correction you would think the engine could not run - but it seams to run OK and idles just fine.

This is turning out to be a very tough one and I need input. Is a visit to the Ford dealer in order (Gerrrr)?

I really doubt it's the intake manifold either.... If anything that would give you a lean code.

This is definitely a strange problem... The backpressure reading you had taken earlier would support a problem in the exhaust.

In order to get the reading you are getting there would have to be 2 very different problems going on in each bank. One side causing a rich condition the other side causing a lean condition. I went over your 1st post and there is a lot of stuff you have already replaced that could possibly cause those problems. Ford does have problems with their MAFs that sometimes cleaning doesn't fix but then again, you would have 2 banks with lean codes.... I really don't like to say never because anything is possible but I have never seen a MAF fail that makes one bank rich and the other lean.....

Have you cleared out the KAM (learned adaptives) and driven it? If you've cleared it with your scanner try disconnecting both battery cables, touch them together and turn the lights on. Then hook the battery back up and drive it....

I seem to remember checking TSBs but took a look again and didn't see anything about a reflash for this problem....

10-02-2009 Update

Well, it's still in my driveway.

After replacing MAF sensor from the zone it ran like crap and they would not refund me my money (or even sell me my old core back) - they have nice racket going there. I will not be getting into the zone again.

Bought one on sale from Ford dealer for $210.00 - now runs like it did before and still have -36% LTFT. Also replace the EGR diff sensor (also on sale from Ford) - still -36% LTFT on Bank 2.

Going to replace the fuel regulator tommorrow - Motorcraft replacement. I will be able to work on this engine blindfolded pretty soon.

Question
There was a large u-shaped peice of fairly thick plastic which was mounted inbetween and around the back side of the upper and lower intake manifolds. It looked like a shield of some sort, but it was all broken up and I had to take it out in small peices. Anyone know what this was for? I hope the lower manifold is not made from the same material.

That's a bad deal with AZ. Most parts house won't refund electronics & comp stuff that's been installed just because of when it doesn't solve the problem people try to refund it. Your case was different where it made it run worse (has happened to me on reman stuff). I'm surprised they didn't exchange it for you or at least give you your old one back for the core price (if they still had it).

I'm drawing a blank on that piece right now (probably due to the stuff the doc has me on right now) but if you could post a picture, that would help.

You know, I'm having a real had time with those trim & backpressure readings you posted. It all points to something going on in the exhaust on the left bank. Obviously I'm missing something. Now there is a bunch of scenarios for those trims if you have 2 different things going, but alot of that stuff, you've already replaced..... Then I come back to the high bp reading on B2 that spikes to 4 lbs....... Make me think of a no start Chevelle I had about 25 years ago that drove me crazy. End result was the inner wall of the exhaust had come apart & rolled up completely sealing the exhausted, the pipe "looked" good from outside.

I'm gonna have to ponder this some more. This one is driving me nuts as well...

   

After I installed the cats on bank 2 I did not weld that side back to the Y connector right away and ran the diagnostics again - still -30+ on long time fuel trim reading.

The plastic part I'm talking about what so broken up, I could not even tell what it looked like in one piece. I'm toying with the idea (if the fuel pressure regulator is not it) to drop the exhaust manifold on bank 2 for a peek.

There are ecm's out there for like $350 and they say to provide mileage and vin number so they can "crank that into the module. I have tried e-mailing these folks (two different ones) and they will not answer me when I ask if the modules are "drop-in ready", not requiring a Ford dealer to program anything into them. Curious. It's really neat how Ford mounts the ecms - they pull out like a dvd drive in a computer.

Changing regulator now. Sorry for the length of this thread.

Later

Update 10-04-2009

Changed fuel regulator and didn't get out of the driveway before it threw the po175 code. This engine is running fairly well and I becoming more and more convinced it is the ecm. I think it has had a stroke in the area controlling fuel trims.

It's not throwing the lean code for bank 1, but it has got to be close to doing so. You would think there would be idle and drivability problems if bank 2 was really that rich. The original cats and bank 2 sure didn't show any signs of it.

Any comments in changing out the ecm would be appricaited. Maybe at this point I should just throw in the towel and take it in. If it is the ecm, obviously, I will never find the problem.

It's possible but if this was just a fuel trim problem with the PCM they can normal fix that with a new flash. I did check and didn't see any but maybe check with Ford service to be sure (not like I've never missed something )

Out of curiosity, I switched the front o2 sensor connections (cables were long enough) and cleared kam. Interesting results. BOTH sides now indicate a -24% STFT. Engine still running just fine, idles good. Doing this did not seem to effect how it starts, idles. I can also gun it without a stall or miss. I did not road drive it this way.

1. ECM bad - needs flashing? Is flashing writing to a ROM chip (different than kam) ?
2. Did you indicate that this ECM CANNOT be flashed? Can a Ford dealer flash the ECM only if I take just the ECM in - or are they not into that just out of principle $$$?
3. The IAC valve was not extremely dirty, but the resting position of the valve could be pushed back and forth a bit freely. Seems to me there should NOT be this play (slop) in the normal resting position.

Thanks for your comments - finding a replacement ecm is not easy for this 4.6L. Since 60% of the 2001 E150 workvans out there have 4.6l W engines, I would think they would be more plentiful - maybe there is a reason why they are in short supply?

The PCM can be flashed but would have to be done in the vehicle. Some parts houses that sell PCMs have the equipment to flash them out of the car but any shops equipment does it in the vehicle......

I was actually thinking about a possible crossed O2 last night.......funny you already tried it...
Getting the rears crossed is more common due to how close together they are, the newer Fords actually have a code now to indicate this problem.....

I would go thru and disconnect them one at a time and on your scanner verify that the position is correct. Disconnect B1S1 and verify that that PID is dead on your scanner, then B1S2 & so on.........

Sidom:

I crossed the two front o2 sensors on purpose just to see what I would get. I got 2 rich banks (originally I had Bank2 rich and Bank1 lean). I figure this should not have happened and since I have checked and changed just about everything else possible, the ECM is my next target.

I have ordered a Cardone ECM from Rockauto and am having them program it (flash it). Also replacing the IAC valve becuase of valve play (maybe the play should be there - replacing it anyway).

I will post the results of the new ECM. Hopefully, this will bring this to a close and my final comments.

My son has been very understanding. I have spent a lot, but I have also learned a great deal.