New to TRS, but not new to Rangers - The dreaded P0102 Code on new to me 1996 Ranger

[flying_root]

Been a lurker for years as we've owned a 1994 2.3 5spd, 7ft bed Ranger for 10+ years. Love that truck, just passed 285k miles, over 100k put on myself.

Recently purchased a 1996 Ranger Splash 3.0 Auto 4X4 with only 141k miles on it. The overall condition is very nice. I bought with the dreaded P0102 MAF low voltage code. Other than idling a little high (1100rpm), the code didn't scare me as I was almost certain it would be a vacuum leak between throttle body and MAF. Welp, after checking a number of lines and even some wires, not finding a smoking gun.

Did wind up swapping out the MAF (I know, don't start throwing parts at it), no change, CEL still triggers after a few miles.

New PCV valve and grommet, needed it anyway.

Last night while checking more for vacuum leaks I noticed a piece of electrical tape over the little hole on the butterfly valve in the throttle body. Oh crap, someone's been dealing with this for a long while.

I've read threads and know I need to start testing more of the harness to ensure wires aren't broken etc.

Looking for possible advise from any other 3.0 owners who've had to tackle the P0102 code. Ranger runs and drives out good. I do smell a little extra CAT out the tailpipe which would make sense if the MAF isn't sending a proper signal.

I do have an ODBII reader on the way. I have a scanner, but it only shows codes. The reader will allow me to see real time data.

Sorry for my first post being a question and thank anyone for any tips or places to look.

-Dan

 

[franklin2]

Air filter looks perfect?

 

[flying_root]

Filter is new. Bought a reader and not seeing the MAF move at all. Stays at 0.06lb/min. Don't see any other data for it.

Getting 5volts from red wire, black is a good ground. Scratching my head on this one.

MAF is not Motorcraft. Maybe the issue?

 

[franklin2]

Could be. New parts are pretty lousy.

 

[flying_root]

Have another MAF on the way, still not Motorcraft (Can't seem to find one). Continuing to check things as I can, TPS voltage is good at .6 closed. I have a Motorcraft IAC on the way. Have a slightly high idle and the hole on the throttle plate is taped up. I want to get all that sorted as it may have some impact on the MAF?

I'll post results here.

 

[flying_root]

Here's a picture of the tape covering the hole in the TB. Frustrating someone did this to "fix" a high idle.

 

[Blmpkn]

Have another MAF on the way, still not Motorcraft (Can't seem to find one). Continuing to check things as I can, TPS voltage is good at .6 closed. I have a Motorcraft IAC on the way. Have a slightly high idle and the hole on the throttle plate is taped up. I want to get all that sorted as it may have some impact on the MAF?

I'll post results here.

Seems like Delphi, hitachi, Bosch & NTK all made Fords MAF's for them at one point in time.. is one of these the one you purchased?

Probably the most important thing I've learned during my time here is that Fords REALLY REALLY WANT the brand of electrical components that they left the factory with. If the MAF you bought isn't from one of the above companies.. id honestly send it right back and buy one that is.

That being said.. it'd do you good to buy a scanner capable of live data. I bought the one I have at HF probably over a decade ago.. 120$ IIRC.. CEN-TECH is the brand.

 

[flying_root]

I did buy a reader just last week, $150. So nice to see live data. It's how I learned the MAF wasn't doing anything. Same .06lb/min reading all the time. Good power and ground.

Thanks for the brand tip, I'll have to look what brand I got from Oreily's.

 

[Blmpkn]

I did buy a reader just last week, $150. So nice to see live data. It's how I learned the MAF wasn't doing anything. Same .06lb/min reading all the time. Good power and ground.

Thanks for the brand tip, I'll have to look what brand I got from Oreily's.

Right on.. idk how I missed that but my bad lol. Been a long damn day.. a glass of bourbon and my bed are calling me

 

[flying_root]

Rebuilt MAF arrived yesterday from carparts.com (said it came from JC Whitney of all places due to supply shortage). There isn't a brand or even a part number on anywhere I can see, but it came in the aluminum housing which was nice. Swapped it out and presto! I could watch real-time ODBII data and changing values from MAF as engine was running with rpm changes. Cleared the code and 65 miles into it, still off.

The New part I put in to start was "Blue Streak" from Oreilly's. It read .06lb/min and would never change.

My solution to the dreaded P0102 code was actually a bad MAF, then a bad out of the box MAF part. I'll see if Oreilly's will take the Blue Streak part back. I'll bring my Carparts.com receipt to show I'm not buying parts just to "test".

Still have a bit of a high idle, but believe cleaning the TB around the IAC and installing a Motorcraft IAC (should be here today) will resolve that. Spent some time replacing a number of vacuum hoses, elbows, PCV valve and grommet so I feel like the intake is sealed up.

I did pull a P0172 this morning, but watched the live ODBII data and didn't see anything crazy. Cleared the code and hoping the ECU is simply re-learning after having run with a bad MAF for so long.

 

[flying_root]

Welp, Ranger decided to throw the book of codes at me:

P0175 - System too rich bank 1
P0135 - O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 1)
P0141 - O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)
P0155 - O2 Sensor Heater Circuit Malfunction (Bank 2 Sensor 1)
P0172 - System too rich bank 2

That's pretty much every O2 code I think? Stuck my head underneath and noted both O2's looked new. Likely more parts cannon action trying to resolve the original P0102 MAF code.

I went to test fuel pressure, but my kit doesn't have a small enough adapter. Ranger uses one looks like the size of a tire valve. I'll see if a local parts place has an adaptor.

Could this be cheap O2's, not compatible parts? I can't tell what brand they are.

Sigh.



Screen shot of ODBII Reader at idle.

 

[Blmpkn]

Welp, Ranger decided to throw the book of codes at me:

P0175 - System too rich bank 1
P0135 - O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 1)
P0141 - O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)
P0155 - O2 Sensor Heater Circuit Malfunction (Bank 2 Sensor 1)
P0172 - System too rich bank 2

That's pretty much every O2 code I think? Stuck my head underneath and noted both O2's looked new. Likely more parts cannon action trying to resolve the original P0102 MAF code.

I went to test fuel pressure, but my kit doesn't have a small enough adapter. Ranger uses one looks like the size of a tire valve. I'll see if a local parts place has an adaptor.

Could this be cheap O2's, not compatible parts? I can't tell what brand they are.

Sigh.



Screen shot of ODBII Reader at idle.

Again, if the o2s are Amazon specials I wouldn't be surprised if they're crap. I bought the cheapest full set of o2s I could back in the day (from ebay) when I owned a crown vic and they worked just long enough for me to get an inspection sticker. Started throwing O2 codes literally the day after.

NTK is the way to go for o2s

 

[flying_root]

NTK, exactly what I was looking for, thanks! I'll swap all 3 out and report back. Cleared codes and after about 20 miles, threw the 3 heater codes again. I'm with Blmpkn, likely junk O2's.

 

[flying_root]

Installed 3 new NTK's O2's and same errors continue to pop up after a bit of driving. Checked 15amp fuse in engine bay for power to O2 heaters and that's good.

Uncommon, but maybe a bad ECU?

I need to start testing pinouts. Which means I need a Haynes Manual.

 

[franklin2]

Try for pinout info here. https://charm.li/