2007 Ford e150 4.6L - Hard Starts, Random Shutdowns

Just in from more testing.
Cleared MIL, warmed up and ran @ 2000 RPM for about 20 min.
Vacuum gauge on brake booster hose reads 22 psi steady at idle - throttle snap almost bottoms out, but recovers quickly to about 24 psi @ 2000rpm.

Live monitor of O2 sensors show proper switching on both S1's,
Bank1, Sensor 2 is all over the place but is in the .15 to .25 range
Bank2, Sensor 2 is pretty steady in the .75 to .80 range

That's all I have right now - no codes thrown on this session, but shut down a couple times (wrench symbol). In closely listening to the exhaust at the tailpipe, there is a pretty significant but fluctuating miss - no misfires detected from PCM

One more observation, both long and short term trim values all average in the - 14% range

So the issue does seem to point to figuring out why the PCM is seeing a rich condition (all negative trim values) and basically starving the engine for fuel? I can cause the engine to shut down almost every time (while driving, not sitting still) by doing a medium to hard throttle. Just thinking out loud.

Well, have eliminated another possibility - did backpressure test on both O2 upstream outlets and detected virtually no backpressure at any rpm. BTW, no hard starts recently, but the truck has not been driven much.

So, the only clue I have right now is the constant negative fuel trim values.

Today's update - about 3 shutdowns while driving about 4 miles, codes
P061B - P0172 - P0175

Have decided to try a new MAF as I am now wondering about the Hitachi I installed a year ago. Should have it tomorrow, will install and see what happens.

Loachuck wrote: Well, have eliminated another possibility - did backpressure test on both O2 upstream outlets and detected virtually no backpressure at any rpm. BTW, no hard starts recently, but the truck has not been driven much.

So, the only clue I have right now is the constant negative fuel trim values.

OK good to hear, that would have been expensive. :blink: I was actually referring to a different test with the vacuum gauge, but the backpressure testing you did works, too.

Today's update - about 3 shutdowns while driving about 4 miles, codes
P061B - P0172 - P0175

Have decided to try a new MAF as I am now wondering about the Hitachi I installed a year ago. Should have it tomorrow, will install and see what happens.

You might be onto something? Have a close look at the air filter and ducting while you're there. This goes back to laminar airflow over the sensor, and how skewing that can trick the sensor, causing fuel control issues.

Did you have a chance to look at the wiring by the EGR pipe?

I did, the wiring harness is good & secure and about 2 inches away from the EGR tube - no sign of any chafing.

Forgot to mention the hard start showed up as well this morning

"This goes back to laminar airflow over the sensor, and how skewing that can trick the sensor, causing fuel control issues"

So I should be looking for some sort of abnormal obstruction or protrusion in the area between the filter and the MAF?

Well, what do you know. Started ripping air ducting apart to prep for new MAF and accidentally found a burned spot on the large brake booster hose! It had been routed over top of the egr exhaust tube, it was enclosed in a heat shield but had gotten through to the hose itself - not a huge opening but damaged enough so that you could pull air through by mouth.

This next part is really perplexing - had not checked PCV valve so removed and realized it was just an open tube! Everything I've looked at says this 4.6 should have a heated valve - the 5.4 shows just an open tube like I have. Am still trying to find any kind of wire to plug in and there just is none. Will continue to look while I get a good vac hose back in place.

I will now hold off before I install the new MAF to see what happens.

Allright, replaced brake booster vac hose and definitely made a noticeable difference, short term trim values much better, in the -5% to +5% range - long term values still high. Still had a few P061 shutdowns in about 12 miles.

Now, let's get to the real kick in the ass. Not only is my PCV valve NOT heated (as it should have been - even have the 5A fuse), the guts of the valve had, I guess, dropped out into the valve train area so there was NOTHING but an open, unrestricted source of "extra" air volume into the intake stream, after the MAF.

I think we may have found the problem(s)! Will find out tomorrow. It all makes sense now, thinking back to when the truck was running fine then BAM, all of a sudden this nightmare appeared out of nowhere. I do believe several other lesser issues have been corrected through this process, so I'm not going to beat myself up too bad over this.

EVERYBODY READING THIS - CHECK THE BASICS, EVEN THE SMALLEST DETAILS!

Hey, progress! :woohoo: Definitely let us know what you find tomorrow, when you (I'm guessing?) replace the heated PCV assembly.

I really hate to be a naysayer here. :lol: But I'm still having trouble linking the vacuum leaks from the PCV and the brake booster hose and your symptoms. Usually vacuum leaks cause positive trims on these engines, not negative. And I don't see why either one would cause hard starting. What are your trims like now after you replaced the brake booster hose?

Glad I didn't get my hopes up too much, but happy to have corrected the vac hose and PCV valve issue. As you mentioned, and according to my limited understanding of the fuel trims they should have been positive values. Fired up after the new PCV valve and took it for about a 10 mile spin - horrible, and worse than before. Short term fuel trims in the -15 to -20 range at medium throttle, several shutdowns, same P061b plus some others that were pending. It was so bad I went back to my old PCM, fired up and still very high negative numbers on the short term trim. Reasonable at idle but in the -20 to -25 range at higher rpms. One item I keep noticing is the voltage value on HO2S bank 1, sensor 2 drops waaay low at the higher rpms, in the .15v to .20v range while the bank 2 sensor 2 pretty much stays in the .80v range - hmmmm.

So, that's all I have right now. I have not installed the new MAF yet because after I open the package, it's mine. Don't know where to go from here.

Did some electrical double checking on the MAF and according to the ref values in PC ED, voltage at idle should be .78 volt. This one hovers around .62, live data shows up/down responses as expected, except all lower values than ref. WOT sitting still jumps it up to around 2.75v

Took a test drive w/old PCM - ran better and observed much better short term trims, -10 to +5. Did have one shutdown (P061B) - almost always occurs at exactly the same place, light throttle around 40 mph into a slight incline - I can almost predict it's happened so many times.

So, that's it. All I have is the MAF lower than spec voltage and the HO2SB1, S2 that drops very low on higher rpms - observed as low as .08v, usually down to around about .15v. Equalizes to the other one (about .80v) at idle. Seems odd. Still have to decide if I want to go ahead & try the new MAF. So far, I'm not convinced enough to try another $100 part. Thanks.

6/1/18 - Replaced air filter, installed new MAF. Started right up, idle perfectly for 20 min took a test drive about 7 miles, ran perfect but O2 sensors stayed offline and threw the P2196, P2198 and of course, 1 shutdown resulting in P061b. Switched over to newer PCM with same results - was never able to get the O2s going, so I just shut it down for the night thinking the PCM just did not like the Delphi MAF.

6/2/18 - Cleaned and installed older Hitachi MAF, left newer PCM in. Fired right up, monitored O2 Sensors and they kicked in properly. Drove about 40 miles - ran very well with a few P061b shutdowns (of course), monitored short term trim values - they were excellent, in the -5 to +5 average. However, as I got back close to home, the O2 sensors stuck rich again, so now I'm left with the usual P061b, plus P2196 & P2198.

As much as I hate to think of it, (especially since it's a crap shoot where you spend a lot of $$$ with no guarantees) I'm wondering if a programming session at the Ford dealership might be necessary.

Loachuck wrote: 6/2/18 - Cleaned and installed older Hitachi MAF, left newer PCM in. Fired right up, monitored O2 Sensors and they kicked in properly. Drove about 40 miles - ran very well with a few P061b shutdowns (of course), monitored short term trim values - they were excellent, in the -5 to +5 average. However, as I got back close to home, the O2 sensors stuck rich again, so now I'm left with the usual P061b, plus P2196 & P2198.

Are you able to save scan data from your test drives? I'd love to look at it if possible. Mostly looking for anything that may have changed around the same time that the trims started taking a nose dive (which they would be if the O2's were stuck rich.

I wonder if you're encountering a false rich condition, causing the PCM to suck all the fuel away. Still not sure how the P061B ties in.

The other thing that occurs to me is a sticking purge valve, or Vapor Management Valve in Ford-ese. They can stick open and cause rich conditions, and also allow unmetered air in depending on the charcoal canister content. Next chance you get, try unplugging the VMV and go for another drive. Fingers crossed.

I will get what FF data there is and post.

Also, just came across the purge valve issue relating to the P061b discussion, so I will pursue that as well. Thanks

Just checking in! Any luck with the purge valve?

I did not do the purge valve plug test - yet. Maybe I should today as I had made an appointment at the Ford dealer for tomorrow.

Just found this thread, and eagerly followed(until it just ended with no apparent resolution)as I have the exact same issue with a 2005 E-150 4.6L. I've been banging away at this for a few months, with similar if not exactly the same symptoms and efforts to fix.. P061b code only. Researching this endlessly, the usual suspects are Air intake path and Throttle Body/drive by wire system. Parts replaced:

Throttle Body (ford factory new compete assembly with TPS)
New Accelerator Pedal assembly
Several different MAF's
New connectors on Throttle body and new wire bypassing harness
New PCV Valve
New Cam Position Sensor
Fuel Filter (was very dirty)
Reconditioned PCM
I have new EGR coming tomorrow as well as coil set and plugs.

Just recently ordered and received today and new Air intake horn with the MAF housing and was surprised it was complete with new air filter, clamp, and new MAF already installed, and new MAF wire harness and plug. Pretty good deal at 150$, considering factory MAF is around 100$. Looks great when you open the hood, but didn,t clear the problem. Which is pretty much the same as Loachuck. Sometimes it will run for 10 -20 min fine, then and always skip into limp mode. I can reset rolling in neutral, but lately it takes 2 or 3 tries . Usually happens on firm throttle press, (which I am doing to see if I can trip the code.)

I have been able to dive for a distance by very gentle throttle modulation (which usually irritates the car behind me).
I only have Forscan, using Bluetooth and iphone or Ipad. It does read most of the Ford PiD's and will do live data readout as guage or graph, that can be saved and emailed. I have monitored many of the parameters discussed here, but nothing jumps out when it happens.

One part of Loachucks post caught my attention regarding the CAT's. about 3 weeks before this started, I was getting a horrible metallic rattle just aft of the engine, seemed like a loose heat shield or I thought maybe the CATs where disintegrated . That noise stopped and hasn't come back. Not sure how to test CAT system.
Also, 3 weeks ago I took it to independent shop that had it for 10 days and got nowhere. Didn't even charge me. I think they were glad the van was gone. Then a week ago I broke down and took it to ford dealer, and they had it for 4 days. Tech reprogrammed/updated PCM and test drove and said it did not throw the code, so i was hopeful (but not really) that maybe it was fixed. It failed barely out of the parking lot. So at least I know it's up to me to solve (Unless there is a ford savant in the area)

The frustrating thing is, the van runs great until limp mode pops. But it is a worthless hunk of metal with this problem unresolved, as it is pretty dangerous driving, not know when it will shut down. And it has no resale value as is, other that salvage. This is my first Ford, coming from working on my own BMW's, and I thought,"American made, and easy to work on, and parts must be easy to source" Wrong on all counts
I guess at this point, probably my last Ford, unless I can fix this thing. Ok rant over. Just wondering if any thing became of the other folks who had the same problem