So I have an old handheld obd2 scanner and a new bluetooth / phone app based one.

I should add that the vehicle has been running a bit rough on cold starts, but then goes to normal around 80 degrees coolant temp. (So pretty quick)

The following data came from the first minute or so of the vehicle running. I didnt catch the CEL actually coming on, but it was within the first two mins, at around 100-120 engine coolant.

The old scan tool pulled a p0306 - which we know how to deal with, so no issues there.



However when I got the new one, pulled codes, it ALSO included:
- p0503 (Vehicle speed sensor)
- p0600 (CAN Data bus malfunction)
- p0005 (Fuel shut off valve - open circuit)

I verified they all say "Confirmed" by them, they are not archived.

So here is my freeze frame data:
Fuel System Status: Closed Loop

Calculated Engine Load value: 37.25%

Engine Coolant Temperature: 75.2 F

Short Term Fuel % trim - Bank 1: -7.03%
Long Term Fuel % trim - Bank 1: 1.56%

Short Term Fuel % trim - Bank 2: -3.9%

Long Term Fuel % trim - Bank 2: 2.34%

Engine RPM: 1144 rpm

Vehicle Speed: 0 mph

Does anything look odd?

Much thanks!

 

Can't be in closed loop at 75deg F
75deg C would be closed loop, that is 170degF
Idle is way to high for Closed loop, should be down at 750-800rpms

Fuel trims are fine

P0503 Vehicle Speed Sensor Intermittent/Erratic/High
This is from the OSS sensor on the upper rear drivers side of trans in a 2001 Ranger, unplug it and clean its connector
Replace sensor if you get the code again

Clear these
- p0600 (CAN Data bus malfunction)
- p0005 (Fuel shut off valve - open circuit)

Unless you had the key on and were unplugging modules P0600 is a glitch
P0005 is not a valid code for Rangers

 

Well, this was within 3 mins of starting up, so that temp is accurate in Fahrenheit.. at the time I was watching the temp because I wanted to see at what temp it started to run better.

so could the fact that it's thinking it's in closed loop at such a low temp be part of the problem?

much thanks @RonD !

 

Yes, maybe

At what temp did it change from Open Loop to Closed Loop
See if you can get that change over

Generally the change to Closed Loop happens when O2s start to generate valid voltages, O2's make their own voltage once heated above 650degF so it can take only a few minutes since exhaust is 900+ degF
But 2min is very fast if engine/exhaust were fully cooled down

Choke mode should lasts until coolant is above 140degF, but there is no PID for that to check it, computer can go to closed loop and still run the engine richer and higher idle(choke mode)

Closed loop is when computer starts to calculate air/fuel mix on the fly based on feedback from O2 sensors
Open loop is when computer uses tables in memory and pre-programmed air/fuel mixes

 

Well here's an update. I bolded some stuff so you can scan thru quick

I reset codes, waited til it was cold this morning, and started it up, gave it some gas and even drove it a little while it was struggling (remember it idles rough til about 80-90 degrees engine coolant)

Plugs and wires are new.

Also, remember I swapped the wires 6&2 to see if the misfire (originally on 6) follows it.

Here's what we got:

Car Scanner ELM OBD2
Version: 1.105.1/401051/GP
DTC report
Connection profile: Ford OBD-II / EOBDDate: 3/16/2024 157 PM
============================
OBD-IIOBD-II
DTCs: 4
----------------------------
P0306 [0x0306]
Cylinder 6 - misfire detected
Cylinder #6 Misfire Detected
Status: Pending
----------------------------
P0303 [0x0303]
Cylinder 3 - misfire detected
Cylinder #3 Misfire Detected
Status: Pending
----------------------------
P0600 [0x0600]
CAN data bus - malfunction
Serial Communications Link Malfunction
Status: Pending
----------------------------
P0003 [0x0003]
Fuel volume regulator control - circuit low
Status: Pending

Freeze Frame:

Freeze frame << 0 >>

Freeze Frame DTC: P03068F

Fuel System Status: Closed loop, using oxygen sensor feedback to determine fuel

mix

Calculated engine load value: 61.5686274509804%

Engine coolant temperature: 82.4 °F

Short term fuel % trim - Bank 1: -3.125%

Long term fuel % trim - Bank 1: 0%

Short term fuel % trim - Bank 2: 0%

Long term fuel % trim - Bank 2: 1.5625%

Engine RPM: 2343 rpm

Vehicle speed: 16.1556509981707 mph

Any help is appreciated, I think this is getting stranger and stranger @RonD

 

Ok I wanted to update the topic for the community:

TLDR; DPFE Sensor was toast

I researched a TON on this one. Basically, as a recap, the ranger was misfiring at cold startup, for about the first 30 seconds or so, then running fine as long as it stayed warm. This happened when it hit around 80F coolant temp.

I came across many posts by @RonD who is amazingly helpful in this community, 90% of what I read was his stuff, and I noticed he is very patient with people and takes time to explain stuff instead of just firing off a couple words.

Anyway, I got to reading basically all the posts on this forum about misfires, and some of them seemed very similar to my situation, others, not so much.

I did notice people talking about the EGR valve and the DPFE sensor, so I went out to the garage to check the hoses going to the DPFE to see if they were cracked / rotted, etc.

I gently twisted the left hose, and it BROKE OFF. The hose was fine - it was the DPFE nipple that broke off, right inside the hose.

I didn't twist any harder than you'd turn a volume **** on your stereo. Probably 23 year old fatigued plastic.

So after scouring the Atlanta area for one, I found one at NAPA for $90 or so, and went off to get it. Advance Auto had a Motorcraft listed but when I got to the store, they couldn't find it.

So I opted for Napa's premium $97 (Echlin) and headed home, installed it, and called it a day. The rest of the day I didn't notice anything different about how she drove.

This morning, in 40 degrees, she started up and purred perfectly.

So my theory is that the DPFE sensor was cracked, but once the intake manifold heated up (its bolted to it) it must've warmed that hard plastic and sealed the crack back up.

Crazy stuff.