2002 ford explorer 169000 runs crappy

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#1
I replaced all the chains and guide in the motor , bought all the lock down tools for the job, runs ruff after warmup I pulled the valve covers to recheck the timing thinking something may have slipped but she is still in place & in time.. so from there I bought a new scan tool with live data. Fuel trims @ 2000 rpms +20 bank 1 & -19 on bank 2 . Not being familiar with a scan tool data not sure where to go next. Iv cleaned & check injectors, sprayed the engine for vacuum leaks... not sure where to go from here... thanks for any help....bob
 

billr

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#2
Is this engine a 4.6l V-8 with VVT?
 
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#3
We have both worked on Ford engines where the exhaust valves closed early to eliminate the need for an EGR valve leaving combustion chamber gases in for the next cycle or so called variable valve timing. Ha, all I can remember, had to be awake while doing this.

A connector can be making good contact, but the act of disconnecting and reconnecting it with corrosion on the inside can prevent good contact creating more problems. Also can be the problem, the contacts have to be clean.
 

nickb2

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#4
Your thread prompted me to post a new thread on stoichiometry. See my thread in FAQ's and tips.

Now seeing +20% on bank 1 and -19% on bank 2, I need to know if these are long term or short term readings. The distinction is very important.

Can you please post back if your new scanner displays STFT and LTFT? And also please provide engine calculated load.

Also, can you post a screenshot of live data and post it here?
 

nickb2

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#5
+20 on bank one indicates a lean mixture, and -19 on bank two indicates a rich mixture.

If I was you, I would erase the keep alive memory to restore fuel trims to default and do a drive cycle and then look again at live data to see if trims are the same.

I will post your particular drive cycle for this explorer. I will assume you have a 4.0l since you have not told us yet which engine you have.

I attached a timing chain R and R for a 4.0l

Seeing that you have opposite fuel trims, I am maybe thinking you timed your cams wrong. Again, all depending on which engine you have.

I also posted for a 4.6l timing R and R. See ace 6

Btw, can you tell us why you felt the need to replace chain and guides and tensioners?
 

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this is a 4.0, sorry for leaving out so much info guess I was frustraited @ the time lol... I rechecked the info on the scantool today and it reads as follows @ idle (740rpm). LTFT bank1 +10 LTFT bank2 -9 STFT bank 1&2 switching from -1 to +2
2000 rpm LTFT bank1 +22 LTFT bank2 -18 STFT bank1 +8to10 bank2 -8to10
I did pull the front sensors today to check back pressure , test show converters are good with no 0 back pressure. sure looks like I have the timing of from right to left cams. when I pulled the valve covers to see if timing slipped or something everything was still as I placed it....
with no.1 pistion @ tdc the lock down cam tools still fit easly on both cams..... Im sure its right but this is my first experiance with a ford 4.0.
also I don't think this is vvt , it does have an egr valve.....
 

nickb2

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#8
I am extremely surprised you do not have a lean code seeing bank 1 long term is at 22% and bank2 is +19%.

You should be coding a P0171 or P0174 and for rich mixture a P0172 or P0175.

Go to this site, http://www.aa1car.com/library/what_is_fuel_trim.htm

Since I hate ford flow charts, I posted one here for you for a P0172 code in the hope that you will not get discouraged. 8)
 

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#9
Is a SOHC engine, ha, this is two less cams to worry about getting out of time. My stupid question is, why can't Ford use timing marks like everybody else? Let's leave this in the stupid question section.

When changing a belt or chain, just like install enough crap back on to do a compression check to make sure this is okay. If not done then, a hell of a lot more crap to put on that would have to be taken off again if he compression is not right.

Typically when cylinders run lean, means some others or just one are running rich. Why they designed "all" engines this way is beyond me. Can be a plugged injector, ignition, or even low compression. Never put that much faith in codes, but look for the problem. Automotive diagnosis is the cheapest they can make it, no secondary references. Just go back to the basics, compression, fuel, ignition, and timing. Really don't need codes to tell you your engine is running like crap. But a tad helpful is a sensor is completely opned or shorted, but this isn't very common. Way out of tolerance is, no codes for this.
 

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#10
Well, see here Nick. With the advent of adaptive learning, one can have a major issue with spark, fuel and air and not know it cuz the control unit is set up for limp mode and adaptive memory will keep it alive. That is where knowing how to interpret live data comes in handy.

Often a condition is hidden and knowing why in this case, a 2002 ford 4.0l, is showing +22% bank 1 and -19% bank 2. When this guy tells me it runs crappy, I sure as hell believe him. I think he has a major vac leak but I could be wrong. A dirty MAF sensor could also send both banks out of whack.

I made a mistake in my last post, I typed +19% when in fact the op was seeing negative. So lean on bank one and rich on bank two.

I am trying to wrap my head around this fact, what can cause an engine to be rich on one side and lean on the other? I want to ask the op why he changed the chain? What prompted him to do so @ 169000mileage. Was it running crappy before? Is it worse now? Have basics checks been done such as compression and vacuum test.
 

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#11
I don't want to muck-up this thread because of my ignorance, but I did a bit of reading on this 4l V-6 engine. Am I right in thinking it has "variable intake length" and three valve-timing chains? Two chains at the front, one from crank to jack/balance shaft, then one from that shaft to one of the cams. Then, in the rear, another chain driving one cam from the other. I see lots of possibilities for one bank to run different than the other here.
 
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#12
Ha, this electronic BS is less than 30 years old, which translated, was already seven years old than you are now at the time, before we even had toys to deal with stuff like this.

Ever hear of a cylinder balance test? Still the same old engine from over a hundred years ago. Just using a lot more crap to do the same thing.
 

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#13
Billr, that is exactly what I am trying to say to op. He says his timing marks are spot on. I am not at my house right now, so posting proper schematics is no go for now.

Me being a huge fan of ford, that was sarcastic BTW, I am not sure if the 4liter is VVT. I know the 4.6 is and comes with dual and single OHC and high output. If you call a few Hp's high output.

I will have to do a bit of google research, but I don't know by heart if it is varaiable . I don't think so, but cannot with a sound mind say it is.


First picture is a dual vvt 4.6l I think, and second a SOHC. quite different.
 

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nickb2

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#14
Ok, did some research, pretty sure the 4 liter is not VVT. I could be wrong, have been before.

At nickd, how was a cylinder balance test was done before all the electronic BS? Here is video of an old 1986 crown vic. My first car BTW. Was 16 when I bought this with my paper route. https://www.youtube.com/watch?v=jVjvgnLUBzE

I am serious, how was that done back in the day? , cuz the only other non electronic BS cars I have touched were point ignition or feed back carbs (which still had electronics) and for me, a cylinder check was checking compression, vacuum and spark strength by eye with a screwdriver.

This being an explorer, I think it is a sport trek, I think they were the only ones with a 4 liter. They did have variable intake manifold runners. Most often the clips to the runners broke or the runner motor stripped gears. They caused lean codes galore.