mike5plus5

I purchased the van about six months ago. Looking through parts/service receipts he gave me I found that the fuel pump is a cheap Airtex E7144M purchased by former owner from Rock Auto March 2017.
The pump always wines but the whine increased one day last month and turned on the check engine light within a few seconds, setting code P0171 System Lean bank 1. I replaced the inline fuel filter and cleared the code. It hasn't set the code again but since then it has been having occasional intermittent miss at idle as well as while accelerating. I checked the fuel pressure today which was 42lbs (Specs are 58 +/- 5lbs). Could this low fuel pressure be causing the intermittent miss.
I use my friends Matco Maximus 3.0 HD Diagnostic scanner to look through the data stream but can't find anything suspicious. No DTC's. Misfires are detected intermittently across all 6 cylinders at idle but not stored in misfire history. Engine doesn't idle roughly though. Miss under load is more noticeable but not detected/recorded by scan tool (weird).
I took it to the local shop and they also scanned it and experienced the same symptoms but were unable to give me a diagnosis.
Any ideas before I spend over $300 to put a Denso fuel pump in it which I really can't afford (I'm former industrial equipment mechanic/electrician but since 2014 I'm a 1 arm/1 leg amputee with a disability check to live on).

dodgem880

It sounds like you found your problem or at the very least a problem (cheap pump out of spec). What does your long term fuel trim look like? As rule of thumb more than ±10% should be investigated.

mike5plus5

https://www.dropbox.com/s/bb1zkfo5ux...54403.mp4?dl=0

dodgem880

dodgem880

Unfortunately I only see short term in your video. Somewhere there should be long-term, possibly for both banks. If your having a fuel delivery issue, long term fuel trims should reflect that (+10%).

It also sounds like the regulator is part of the fuel pump module.... so it's just as cheap as the pump.

mike5plus5

Thanks dodgem880! 42 lbs fuel pressure looks like the most likely culprit trying to supply a system which requires 53-63 lbs.
New pump ordered. Denso Pump #953-3037

mike5plus5

The new Denso fuel pump / filter did not help. Still intermittent miss, worse when cold and worse at idle or light acceleration. Misses still not being counted by PCM.
Today I noticed IAC stuck at 255 but idle speed is within reason. Does this indicate the valve is stuck in the wide open position which I'm thinking would cause a lean condition even if it is metered air? I hope I can correct this by cleaning the IAC valve tomorrow.

Long term fuel trim runs around 14% at idle, drops closer to '0' when at higher RPM (sometimes quickly, usually slowly).
I can't find a vacuum leak with carb cleaner spray or with smoke machine although I couldn't get the van totally away from a light wind.
02 sensor looks good (only 1 primary 02s on this V6 motor mounted after the 2 manifolds 'T' into 1)(no 'Bank 1' / 'Bank 2' sensor).
Long term trim
Short term trim
02s voltage
RPM
IAC steps
Intake air temp F

Video in link shows scan tool in generic OBD mode.
https://www.dropbox.com/s/4wrqx0aexd...0post.mp4?dl=0

RacerHog

No missing count means the ignition system is in good shape....
Looks like you could be headed to installing new Injectors.... Also Check for a Pinched Fuel line, and check the return line if it has one?
As for the IAC, We have never had good luck with cleaning them, if we did clean them they seem to came back in a short amount of time stalling and needing to be replaced....

mike5plus5

Yep that's what it's looking like. I'm going to hook to a Snap-On scanner rather than the Matco Wednesday to see if it has any different / additional data. I replaced the IAC but it's still hi (223). That's the only thing that seems out of place with a set of dirty, misfiring injectors.
I found a set of OEM Siemens injectors for a decent price that I'll order contingent on the scan Wednesday. Also ordering a new injector harness, upper and lower Felpro intake manifold gaskets and valve cover gaskets too. I figure I'll replace that leaking rear vavle cover gasket while I'm there. And I've got some new heat shielding to give the new harness a couple of extra layers of protection from the manifold heat too.
We shall see. Wish me luck!

RacerHog

Sounds like a plan....
Good that you are replacing some of those gaskets, Could find a Vacuum Leak!!! Clean the Mass Air Flow if this one has one...
When you hook up to the Snap-On, When you look at the miss fire count, If you don see any, Look down further and look at the Total Miss Fire Count and see if its counting? I don't know what the significant meaning is for that count is, But I've been curious to know at times....Fingers crossed you find the issue

mike5plus5

FIXED, after some parts cannon action with plugs and wires, which were not needed but suggested by a shop owner after they failed to make a diagnosis, and a coil pack, my decision today.
But the old Pump @ 42lbs needed replacing. New Denso pump (55lbs) works well and is not noisy. The original in-line (on top of tank) fuel filter had never been changed, had ruptured filtration medium, and had long ago needed replacing and was likely the cause of the bad original fuel pump, the replacement Airtek pump going bad, and original injectors as well as injectors that had been replaced by the previous owner (which were cheap online parts anyway, but any injectors would have fouled with the ruptured filter). The new Siemens injectors now work fine with clean filtered fuel (BTW, I installed a new injector wiring harness also although the original was not bad or melted). These parts made it run better with better gas mileage but It still had an occasional intermittent miss.
The miss was much worse yesterday after a rain storm when the humidity shot high on the weather scale. I know from experience that ignition secondary high voltage misfires can be affected negatively by high humidity.
So against my judgement based on the data with the Matco scan tool (no misfire detected, real-time or recorded in misfire history), I changed the coil pack this morning. Now the motor runs good and after some driving today to relearn the LT fuel trims and, so far, some of the fuel/timing map tables, which will continue to make fine adjustments for the better, it runs very well with good WOT power - no misfires!
1 question is bothering me - why did the $5000 Matco scan tool never detect a misfire, real time nor in ''Misfire History'? Does it have something to do with the configuration of the 3 coils for 6 cylinders fed by 4 primary wires (1 power supply, 3 separate control grounds to the PCM)?

RacerHog

Not sure the last question... I would have to refer you to Matcos Tech Trainer to see if he could get you an answer for that.
Note: This from me is not a sales add !!!! But if you are looking to broaden your abilities? here is a couple of courses you could look into....
https://ataautomotivetraining.com/
and
https://atgtraining.com/

Good to hear you got it running better.... Coil pack, Plugs, Fuel pump and Fuel filter, Injectors and your good to go, Thats a big fix... Keep us posted.... Cheers

mike5plus5

Yes it was a big fix considering all of the fuel system problems could likely have been prevented if the former owner, or owners mechanic had changed the inline fuel filter at some point. And I suppose the idiotic location where Chrysler engineers put that inline filter could be where it all started.
I try to stay up to date on the vehicle that I own and that of a few friends that request my help on their vehicles from time to time, but my brain is getting a little old (63yrs) for learning a whole lot of new stuff these days. As I stated in my first post, I only have 1 arm and 1 leg left so I'm pretty slow (unemployable) at repairing anything professionally any more so I couldn't justify spending much money on training, especially because my income is so limited. I had to borrow a few hundred to go with what I had to get this job done so I hope this van will run trouble free at least until I can get some more funds saved for next time it breaks.

RacerHog

Well Mike, all i can say to that is, You have done a hell of a job with your limited resources and abilities. "My Hat is off to you"!!!!
Awesome job, and hope its all fixed and serves you well for all your hard work.
And i would agree, that engineering has a lot to be desired, Getting harder to work on these vehicles...
Cheers

Iowan

Great job!!!