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as stated on FCO if there was exsessive back pressure from the exhuast it would blow off the DPFE hoses first .... the egr valves hardly ever fail ....
 
That's not necessary since I'm going off of the reading right from the O2. I only swapped the O2's to make sure it wasn't the O2 itself misreading. If the O2 was the problem, the bank reading lean would have followed the O2 under these conditions.

yes I know the code should of move to the other bank when you swapped the sensors, but if you didn't reset the PCM it takes time for a code to come up, unless its a hard fault then it would come up right away.
 
as stated on FCO if there was exsessive back pressure from the exhuast it would blow off the DPFE hoses first .... the egr valves hardly ever fail ....

I've never seen an EGR valve flat out fail, but I have seen them get stuck open from deposits.
 
I've never seen an EGR valve flat out fail, but I have seen them get stuck open from deposits.


good distinction, but I still would say its pretty rare to have the valve itself have a problem, but I am sure it happens

but the egr flow isn't going to go to just one bank
 
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if you have semi clogged passages it is sometimes possible for anything to happen. ask joey he ran my tune and he and i talked about it for hours. though i had codes i also had every code possible(i think) for the egr system so as far as that goes it could be a bad sensor but low and behold blocked the egr and fixed the problem.

its just my 2 cents.

i also had 140K on the engine with a p0420 for a few years which will cause a rich setting and gum up the intake and egr... this last bit was prior to my 3L

i just want to hear the verdict if that helped the situation.
 
People seem to be able to read better here so for anyone interested, it may be a while for a verdict. EGR flow is at spec according to the DPFE. I tried blocking it, just for :censored::censored::censored::censored:s, but there was no change. I swapped out fuel rails also to no avail. There are really only two possibilities left and at this point, I'm leaning toward the O2 readings being a product of the different exhaust paths, (bank 2 having a more streamlined exit from the cylinders)... which basically implies that bank 1's rich reading is a result of spent exhaust gases spending more time near the O2 - a flawed theory at best, but pretty much all I have left that fits with all the circumstances. Other than the possibility of this just being how the PCM is programmed, which I can't buy into... not when it's only one bank showing lean. So basically, I have some exhaust modifying to do before my next update.

I need to know EXACTLY why things are the way they are & happen the way they do, so I am unable to just throw in some 19lb'ers, tune & call it a day.
 
well there is only one thing that would cause a lean condition on one bank and one bank only, a vacuum leak .... as suggested somewhere put a normal, operational LIM back on the car and see what it does. Again as stated somewhere, I don't know who said it first but I agree, rule out modification first to figure it out ....

how about something from left field .... hows your wiring harness? maybe that is causing a control issue with the fuel injectors ...
 
Remember that the lean condition ONLY happens starting at high RPM. A vacuum leak is going to be more prevalent when vacuum is at it's highest, which is at idle. If this were a vacuum leak, fuel trims and O2 readings would, without doubt, be affected at idle. The affects would then diminish, as does the vacuum, with an increase in RPM. I'm encountering the opposite. I really don't want to argue but it is theoretically impossible for a vacuum leak to cause what I'm seeing on this setup.

Left field or not, I think the wiring is very worthwhile suggestion for a close inspection - thanks.
 
yeah the vacuum goes to zero at high rpm ... maybe vacuum leak was the wrong term to use

point that people are trying to get at is if there is a leak on bank 1 it will draw in unmetered air cause the a/f to go lean, but bank 2 would be fine

again I really would swap in a working and unmoddified LIM and make sure its sealed up well and see what happens. if nothing changes I would still suspect needing 19# injectors and a SVT PCM ...
 
I do understand how a vacuum leak can affect only one cylinder and/or bank. I have seen it first hand. Windstar 3.8l and Explorer 4.0l intake gaskets like to leak... and often do so very subtilely.

The bigger injectors & tune are a definite, and I don't doubt that this issue will go away at that point. My problem is that I would still never know exactly WHY this is occuring. That might be acceptable for the god of parts replacers over at FCO, but it doesn't cut it with me. I'm doing this to learn something, not to just add/change :censored::censored::censored::censored: until the issue magically goes away. I'm going to continue eliminating possible causes until I find, and can document a definitive root cause.
 
well that in itself could be the problem, injectors and tune, so if the problem is eliminated that you have your root cause since you have proved everything else out.

the members of FCO are not suggesting that you just throw parts at your problem and hope that it will be fixed. They are suggesting, as I have supported here that you swap parts that you modified to rule them out as a problem. Since no one but you can see the engine and know exactly what you changed with the LIM the best way to trouble shoot is to eliminate all modifications first then go from there.

taking things step by step and trying to learn as you go is great. What I see going on is that you are way to stuborn and don't want to take advice of people that have experience with these cars and engine, you want to hear what you want to hear.

Next you are working on small details of the whole. You keep looking at the details of one thing or another but you haven't stepped back and looked at the whole system, to see how everything interacts and works together. You keep trying to single out one tiny detail of one system. Just like the injectors and tune, thats a large scale thing that take from all the other things you have looked at.

Sometime you have to give up fighting a problem on your own and take the help of others. While you have been here asking for help you have only heard what you have wanted to hear and gone down solution paths that you wanted to take. So your not really taking the help from others.

Its time to realize that some of this is beyond your knowledge or capability to learn/understand at the moment, as it is for me, and take the advice of those with more experience, no matter how it comes across, ie friendly or blunt.

one last thing to keep in mind, if you continue to ask questions and not follow any of the suggestions that you have received your going to stop getting any help in the future. We had a member previously like this, he would ask questions and we would answer and he would never do what was suggested or requested to help him out. It got to the point that no one bothered to help him anymore because it was like talking to a brick wall or a pile of dirt, just a wasted effort. You have already alienated the members of FCO ... ones with good knowledge to boot, you might not want to do that here or you will have no where to turn when you really need help in the future ....
 
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well that in itself could be the problem, injectors and tune, so if the problem is eliminated that you have your root cause since you have proved everything else out. the members of FCO are not suggesting that you just throw parts at your problem
Sorry, but adding ANYTHING at this point is throwing a part at it because I still do not know the root cause. Okay, the injectors are too small, but how will that cause only one bank to go lean at high RPM? I cannot theorize a how to answer that question, given the troubleshooting I've already done, so I pose it to anyone reading. Until a possible theoretical "how" is established, it's not a possiblity. Inadequate injector size is not a possible root cause of this particular issue.

Many people are focusing on the "why" when I am actually asking if anyone can theorize "how". Just like the vacuum leak theory, people said it was a vacuum leak. I posed the question of how a vacuum leak could possibly cause this particular issue because I couldn't rap my head around it. Instead of a valid counterpoint that everyone could discuss, there came disrespect and ignorance, and yes at that point, I certainly gave back some disrespect... which makes me, and only me, an ass? :shrug: When someone who should know what they're talking about offers a possible solution that doesn't seem theoretically possible in my mind, I ask how it is possible in hopes of learning something I didn't know. Doesn't that make sense?

What I see going on is that you are way to stuborn and don't want to take advice of people that have experience with these cars and engine, you want to hear what you want to hear...if you continue to ask questions and not follow any of the suggestions that you have received your going to stop getting any help in the future
I explore valid possible root causes of this issue. When anyone, even the "people that have experience" are blaming an impossible root cause, even after numerous attempts at trying to explain why it's not possible to be the root cause, it DOES tend to discourage me from listening to them continue to argue the impossible.

Seriously, I would not be where I am now without the help of many who knew much more than I and even some who didn't know quite as much. But I also would not be here had I not taken ideas and proved or disproved them. Time is money for me, so when a customer has a problem with their car or truck that I've neve come across or can't figure out I consult other techs. I toss out the recommendations that are not theoretically possible, and move on to those that are. It would be a waste of my time to check oil pressure to diagnose an ignition misfire. Therefor, I would not explore that possiblity unless a plausible theory was presented with the recommendation.

It all makes complete sense to me, but makes ME, an ass to some... I feel like I'm taking crazy pills!
 
Inadequate injector size is not a possible root cause of this particular issue.

Probably correct here, but it may be a contributor to a possible root cause. You are running borderline duty cycle at high rpm high load on the 17# injectors, and some normal variance between the banks, either in harness signal strength, or PCM signal or whatever, may just be enough to cause control issues on one bank. Either way, you're running out of fuel, and that's a problem you should fix.

I posed the question of how a vacuum leak could possibly cause this particular issue because I couldn't rap my head around it.

I think you are getting hung up on the term "vacuum". A lot of people use the term to generically refer to any leak on the intake tract, (probably incorrectly so, but what are ya gonna do?) not just for leaks in the vacuum lines. If you had a leak in the lower intake manifold, it is possible that a leak could get more severe as rpm increases. Static vacuum pressure in the intake may drop as the throttle opens, but local dynamic pressure changes are still evident because of the fast moving air. Think about how the fast moving air in the venturi throat of a carb sucks fuel into the airstream, and increases the amount of fuel drawn as the air moves faster . . . The same effect can occur on a bad, or poorly supported gasket in the lower intake area. Your gutted lower manifold (IIRC its gutted, right?) could have some sealing issues under the dynamic pressure difference. This is what most people are referring to as "possible vacuum leaks". I've seen it happen, and I've seen people make it happen on purpose.



which makes me, and only me, an ass? :shrug:

I dunno, I freely admit I'm an ass quite often. Some people are just scared to call me out on it . . .

When someone who should know what they're talking about offers a possible solution that doesn't seem theoretically possible in my mind, I ask how it is possible in hopes of learning something I didn't know. Doesn't that make sense?

Sometimes people do know what they are talking about even if you don't understand it fully at the time . . . Wasn't Galileo imprisoned for awhile for his theory that the world wasn't flat?


Seriously, you're at the point where you need to narrow down where the problem is coming from, even if you don't understand it exactly yet. If you narrow the scope of the problem further, by swapping some parts around, it will help you understand what is going on better and perhaps get through your current impass of understanding.
 
Wasn't Galileo imprisoned for awhile for his theory that the world wasn't flat?
I thought it was for saying that the Earth wasn't the center of the universe but either way, they DID put his ass in jail... crazy to think about. I realize you were not comparing him to me, but I can relate to being misunderstood and ridiculed. Allthough, it's almost good to know where to find a monkey that will just start thowing :censored::censored::censored::censored: at you when he doesn't understand your words, or you disagree with him.

I understand about the vacuum leak. It's just an air leak at a point where there is a measure of vacuum, and it can be anywhere that vacuum is ever present, i.e. a vacuum line, intake mani gasket, cracked intake manifold. I have had the intakes off 4 different times now since this started. The first time I just checked the gaskets and corresponding marks left on their sealing surfaces - all good. The second time I did a pressure check in the runners of the LIM, (yes it's gutted), looking for any possible leakage from runner to outside, and cylinder to cylinder, or possible cracks in the manifolds, then just for good measure, new gaskets. The other two times only got a visual because I was satisfied of the integrity of the manifolds and gaskets. Worse case scenario, I WILL put the stock stuff back on, if for no other reason than just to verify my sanity.

Seriously, you're at the point where you need to narrow down where the problem is coming from, even if you don't understand it exactly yet. If you narrow the scope of the problem further, by swapping some parts around, it will help you understand what is going on better and perhaps get through your current impass of understanding.
No doubt. There are definitely still things for me to check/eliminate/swap. The intellectual part of me just won't let me move on until I find the root cause. I'm glad I'm that way though... otherwise I'd just be another :censored::censored::censored::censored:-throwing monkey.

Thanks for the input.
 
ok one thing that i just noticed while reading is that the lean condition is normal and it seems you think that is a problem. what i think you need to look at now is your fuel delivery system. somehow your are getting more fuel in bank 1 than you are supposed to.

both banks should be lean at 5K rpms and higher with the 17# injectors. there is an explanaion of this by warmonger somewhere i might have to find that for you.

your problem seems to be not a lean condition but a rich condition.

i cant remember who said it but it is probably what you need to look at next. your fuel delivery is somehow puting in MORE fuel than you are supposed to be getting.

check your wiring and you might swap a pcm... wait and listen... just a pcm to see if it is possibly the computer malfunctioning.

if that doesnt change anything then you have officially eliminated the computer. next i believe some of the older tours had wiring harness issues. you might try and find out exactly what those were and check your harness...think you are already doing that

next pull all your injectors inspect them carefully though i dont think it could be them i would do it anyway. you might take off and clean the UIM as the 3L needs as much air as possible so any obstruction will probably show up.

have you cleaned the MAF? it probably has nothing to do with your problem but it is always a good thing to do.

... im running out of ideas... just try everything you can think of. even if it doesnt seem to have anything to do with the actual problem.

any more details about the car you can give? anything random. doesnt matter. just to get you thinking.

hope this helps.


ok i just confirmed my own thoughts. you are having trouble with bank 2 being lean correct? bank 1 is getting mor fuel than expected...

well at the peak of the injectors capabilities im wondering if the average fuel pressure (at max injector capacity) is allowig the bank 1 injectors to produce more flow vs the bank 2 injectors. to prove this theory... the fuel rail runs 3,2,1,6,5,4 correct or 3,2,1,4,5,6 however it is but what i am saying (this is all theory) is the the average fuel injected from injectors 3,2 and 1 is higher than the average of the fuel injected from injectors 4,5 and 6 possibly due to the fact at MAXIMUM possible injection given the slight drop in pressure between the 2 banks that bank 1 is recieving a little bit more fuel than bank 2.

this theory cant be proved or disproved unless you get the exact fuel messurement for each injector or you can get the numbers off of a set of 19# injectors in your car running at a more normal pulse width. do you see what i am saying? this may be a normal condition that no one has noticed before because they havent tested it as expensively as you have... and/or the right person has not chimed in yet...

just a theory but it might be worth some investigation into if you cant find anything else.
 
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your problem seems to be not a lean condition but a rich condition.
That's why the EGR theory made so much sense to me. I'm still exploring the possible issue of an over-rich condition, AND the possibility of the O2 just reading that way because of the more-restrictive exhaust path for bank one. Back pressure test and exhaust-less datalog are next.

you might swap a pcm... to see if it is possibly the computer malfunctioning.
Definitely a good idea. Parts swap of PCM and possibly wiring harness are after my exhaust checks.

next i believe some of the older tours had wiring harness issues.
That's why the other techs here couldn't believe that I was driving a Contour of my own free will. There were chaffing issues and even some wire insulation issues. The vast majority of them included a CEL, but I'm still going to check the wiring very closely.

next pull all your injectors inspect them carefully
Yeah, I did that when I swapped banks.

have you cleaned the MAF?
Yep. I made an air inlet tube and removed & cleaned the MAF before making use of the new tube. To answer the next question, yes the stock MAF is in the stock MAF housing. :cool:

Thanks for the input.

I'm hoping to get back at it tomorrow so I'll give updates as I get them myself.
 
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