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F150 5.4L 3V tech in Chit Chat


Well-known member
May 22, 2020
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Here is a chance to show that the new Irate is smarter than the lesser 4x4 site!!!!!1

Anybody got any advice to help me fix my truck. 2005 F015 5.4 V8 with about 171K miles. About a week ago it started running rough on the way home from work. Checked codes and there was a P0172 system too rich pending code. I am not a master mechanic but do know a bit about this engine. Replaced coil packs with known good ones and no change. Then replaced spark plugs with new Motorcraft spark plugs. No change and now throwing a P2196 Bank 1 rich.
At this time at hot idle:
STFTb1 -4% STFTb2 around 0
LTFTb1 -11% LTFTb2 +10

So I clearly have a fueling issue on bank 1. O2 sensors also both reading rich on bank 1 ~.9V. 2005 inparticular had an issue with fuel injectors sticking open (I was on my original injectors) so I ordered up a new (not rebuilt) OEM set of injectors. While I waited on them I had a couple parts on the shelf I decided to throw on to see if anything changed. MAF and Throttle body and no change. I also had a couple new Bosch O2 sensor. I replaced one bank at a time with the new ones and noticed no changed on how it ran or the fuel trims.

New injectors come in the mail and I am sure that is my issue. I put them on and it runs better and not throwing codes but still a bit of a rough idle. I know the 3v 5.4 don't idle all that smooth to begin with but this is a but worse than normal but also not terrible. I reset the fuel trims and now fuel trims at hot idle are:
STFTb1 around -2% STFTb2 around 0
LTFTb1 around -6% LTFTb2 +10
So fuel trims got about half way better on bank 1. Now I try to pull some more data to see what is effecting bank 1 and not bank 2 since they do share many of the same sensors. At this time I notice that at hot idle timing advance on bank 1 is +11.3 and bank 2 is 0. Ok so this gives me something to go with. Still no codes and running ok, but not great. I guess the timing on bank 1 is throwing the fuel trims off. When driving the timing advance of each bank mirrors each other more or less. I still have original cam phasers and VCT solenoids in the truck. I am religious about maintenance and when I pulled the valve covers off a couple years ago the top of the heads were in excellent shape with no sludge. I unplugged the VCT solenoid an the timing stayed the same on each bank. So I pulled the VCT solenoid off bank 1 thinking the screens came off and jammed it or the piston was stuck in the bore. Neither was true screens still intact and when I dissembled it the piston came out easily. I put it back on and still have the timing not equal between the banks at idle. I have a OEM VCT solenoid on order and should be here in a few days. Also I confirmed no exhaust manifold cracks on either side so rule out one side missing exhaust before the O2 and then over fueling that side. Compression is excellent 180 or more on each cylinder.
Like I said I am not some master mechanic but I did load up the parts cannon and throw a few at the truck. I haven't tried the new O2 sensors since AFTER the new fuel injectors since they didn't do anything with the old injectors and seemingly the cats/O2 sensors are working. While I wait on the VCT solenoid to come in the mail anybody else have any ideas I should look at besides the VCT solenoid? Any ideas of what other data to check on my scan tool?

So would the wonky fueling cause the computer to adjust the timing to compensate some way OR would the wonky timing throw off the fuel trims. Someone suggested I may has so much slack in the timing chain that it is throwing off the timing. At cold start up when it has sat for a day or two it often has a rattle that lasts about 1 second or less. I always figured it was the timing chain and that the tensioner just leaks down over time when sitting. Otherwise no noises from the timing chains/VCT when running at any RPM.
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