Need help with Ford 5.4 misfire

4x4_Welder

Active Member
Location
Twin Falls, ID
Ok, assuming you have an Android phone, get Car Gauge Pro from the play store (it's around $8) and get a Bluetooth v2.1 elm327 adapter off eBay. The tiny cheap ones are junk, usually the $20 range ones are good.
If you have an iPhone, pick up a cheap Android phone too. I have not found a program that will reliably work and connect with a car either with Bluetooth or wifi on an iPhone.
I use the stuff I recommend in a professional environment, I've been running this stuff for four years now with very good results. I got my setup to diagnose an "unfixable" 6.0 Ford that even the regional engineer condemned. Turned out to be a poorly installed crank sensor, and a shorted injector.
 

TRD270

Web Wheeler
Location
SaSa Sandy
I ordered the OBDLink MX+. Little more expensive, but works with my devices and it includes the app so it will save me some money in the long run. Has good reviews, everyone's biggest complainant about them was having to pay for the "enhanced" features for different vehicles. They are all supposed to be included now.
 

DAA

Premium Member
Supporting Member
I have been using an OBDLink LX with Torque for a long time. But on older OBDII stuff, no CAN. Has always worked great. Except, for whatever reason, the app that came with it has always had trouble connecting to the device. But Torque has always connected with no drama. So I've never really used the app that came with it.

- DAA
 

TRD270

Web Wheeler
Location
SaSa Sandy
Okay data is in. I don't know what to do with it but I logged some for those of you willing to help. So this was done tonight with the super wind in full force. Trip one for the most part was with the wind, trip two against.

Confirmed watching my misfires happen that almost none (comparatively) happened on the surface streets. And boy were they happening fast with minimal load at freeway speed with the wind pushing me (4x more than the same trip home with extra load on it with the headwind) I could also see the misfires spike every time I was on a slight downhill where the load was reduced.

I need to delete some data being captured, feel free to look at the logs and tell me what you think or if you would like to see any other parameters being captured.

Edit: it won't let me attach the excel files so sorry for the crappy pdf
 

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4x4_Welder

Active Member
Location
Twin Falls, ID
How are your fuel trims? Short term and long term added together need to be under 10%.
Watch the trims just prior to the misfires, I wouldn't be surprised if they start climbing.
 

TRD270

Web Wheeler
Location
SaSa Sandy
How are your fuel trims? Short term and long term added together need to be under 10%.
Watch the trims just prior to the misfires, I wouldn't be surprised if they start climbing.

I'll add that to the log, but I do have the freeze frame showing that

118599
 

TRD270

Web Wheeler
Location
SaSa Sandy
So this trip was my post top end cleaner run. Giving it the beans a lot to clean out intake. So not the same circumstances. But after a few minutes almost no misfires. Also added the fuel trim to this log
 

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4x4_Welder

Active Member
Location
Twin Falls, ID
Yeah, it's spiking up a bit. Ford went to a returnless system sometime in the early 2000s, and that system had a computer controlled fuel pump. The ECM would send a signal to the fuel pump driver, and the driver would vary the pump speed. The signal to the driver would only be 20-50%. If the PID for fuel pump shows 100%, then it's the old system. You would also have a PID for fuel rail pressure, and instead of a traditional fuel pressure regulator the rail would have a little electronic device that also had a vacuum line to it.
The fuel pump driver on most Fords is on the frame crossmember above the spare, and frequently fails due to corrosion.
 
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TRD270

Web Wheeler
Location
SaSa Sandy
Yeah, it's spiking up a bit. Ford went to a returnless system sometime in the early 2000s, and that system had a computer controlled fuel pump. The ECM would send a signal to the fuel pump driver, and the driver would vary the pump speed. The signal to the driver would only be 20-50%. If the PID for fuel pump shows 100%, then it's the old system. You would also have a PID for fuel rail pressure, and instead of a traditional fuel pressure regulator the rail would have a little electronic device that also had a vacuum line to it.
The fuel pump driver on most Fords is on the frame crossmember above the spare, and frequently fails due to corrosion.
I turned all the fuel rail PID's on and none of them read anything. The fuel pump one only showed on or off.
 

4x4_Welder

Active Member
Location
Twin Falls, ID
Generally, the computer expects to have a certain amount of fuel available, and if there is less it'll start cranking up the trims trying to get more fuel in there. Usually they'll give a P0171 lean code first, but my Explorer didn't give that code until it started stumbling a bit.
Check the pressure, I've driven with a fuel pressure gauge taped to the windshield on a few cars to try and find an odd pressure issue. If you have pressure well within the spec range at idle but dropping under load, I'd start with a filter.
 

TRD270

Web Wheeler
Location
SaSa Sandy
Generally, the computer expects to have a certain amount of fuel available, and if there is less it'll start cranking up the trims trying to get more fuel in there. Usually they'll give a P0171 lean code first, but my Explorer didn't give that code until it started stumbling a bit.
Check the pressure, I've driven with a fuel pressure gauge taped to the windshield on a few cars to try and find an odd pressure issue. If you have pressure well within the spec range at idle but dropping under load, I'd start with a filter.
I bought a filter while I was buying MAF cleaner tonight so that will be first on my list tomorrow. Then tracking down a fuel pressure gauge
 
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TRD270

Web Wheeler
Location
SaSa Sandy
I wish I knew more about what I was looking at here. Went on my loop again post cleaning just to see. More of the same. Interesting soon as it gets settled into overdrive on the freeway the misfires start. Soon as it downshifted for a hill and gave it some RPM it goes away, or if a little more throttle is needed to hold speed.

I'll do the filter in the morning see what happens
 

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4x4_Welder

Active Member
Location
Twin Falls, ID
On another forum I'm on, the cure all for odd problems is a thorough "stage 0". Basically a major tune-up, plus standard wear items like water pump, idler, belt, and tensioner, brake pads, suspension bushings, then work on making the heavy slow car fast.
 
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