Something you may not have thought about....

[DryCreek]

So, while we all enjoy the extra peace of mind given to us by our steering dampeners (Steer Safe, TruCenter, et. al.), I was rudely reminded that there is more to think of last weekend.

To kinda' build the scenario here, I want to mention that on the 3V Triton 6.8L V-10's, they no longer have an IAC Valve. The entire throttle is now "fly-by-wire". As such, the function of the IAC is performed by the stepper motor controlling the throttle body butterflies. Early model F-53 3V versions do not come stock with a "learn" feature to reprogram closed throttle idle position. So, after carbon starts building up and obstructing the idle air path, the volume of air admitted when your foot is off the accelerator is diminished - resulting in a slower and slower idle. This can sometimes cause the idle to fall below the point where the engine will keep running. This happened to me as I was passing through a small town (Glen Rose) at low speed. I was entering a sharp curve in town on a narrow two-lane road and let off of the throttle. The engine died. When that happens, power steering is lost.

Now, back to my point. When you lose power steering in a turn, at low speed, do you know (I mean KNOW, not guess) how much effort it is going to take to keep the motor home in its lane? Now imagine having to fight a device that is constantly exerting 150 lbs. or more to the drag link - trying to straighten out your wheels! Luckily, the oncoming lane was open and I could get the transmission in neutral and engine restarted before anyone else came along. It was an eye opening experience.


I have thoroughly cleaned the throttle plates and gone through the re-learn cycle for idle speed. I also have a whole new (well, rebuilt) throttle body on order for an experiment. I am going to drill two 1/16" holes (top and bottom) on each of the two throttle plate butterflies. This should give me enough of an induced vacuum leak to prevent that from happening again in the future. You may be wondering why I just don't go and get Ford TSB 08-18-2 flashed to my ECM. Well, I have a Banks tune loaded. So, if I go and have them reflash the ECM, it will overwrite the Banks tune. I may have a problem fixed, but I will still have the sluggish shifting and the engine won't be able to take advantage of the Banks exhaust and intake. The only issue I can predict (other than higher than normal idle speed) may be P-2195/2196 for an O2 sensor stuck lean condition. That typically sets after extended idling (such as when levelling and then running slides out) with a vacuum leak. That's how this all started for me. I was getting the occasional CEL and code P-2195. After replacing both O2 sensors it still persisted, so the fuel filter was next. Fuel rail pressures were never low, but it was a shot in the dark. Still no cure, so I went looking for vacuum leaks. I found the hose for the fuel vapor canister purge valve had been rubbing up against the bottom of the doghouse and was worn pretty thin. It feeds into the intake manifold on the passenger side - which also happens to be Bank 1. After replacing the hose, my idle woes began - until it finally choked out with closed throttle. Unfortunately I was in a turn at the time.

So, the two lessons I learned last weekend, and which I have chosen to share with y'all are:
1 - clean your throttle bodies!
2 - if your engine stalls and you have a steering stabilizer, be prepared to go straight.

ETA - the Ford TSB I mentioned adds a "learn" feature to the ECM to adjust idle speed as carbon builds up in the throttle body. I think it was standard after 2010 or so.

[Bosunmate]

Thanks for sharing this info. If I’m reading it correct, newer (I have a 2017) V-10’s are good to go?

Patrick

[Dav L]

instead of drilling the throttle plates...doesn't the throttle body have a minimum airflow adjustment screw (idle stop)?
The AIS (Automatic Idle Speed) motor is supposed to keep it from dieing like that.
Note: I haven't messed with a V10 injection system.

[DryCreek]

Originally Posted by Bosunmate

Thanks for sharing this info. If I’m reading it correct, newer (I have a 2017) V-10’s are good to go?

Patrick

As I understand, yes. That is based on this:

This article supersedes TSB(s) 08-5-13, 07-23-12 and 06-25-8 to update the Service Procedure.
ISSUE:
Some 2004-2006 4.6L and 5.4L F-150 (excluding F-150 Heritage), 2006 5.4L Mark LT, 2005-2006 6.8L E-350 / E-450, 2005-2006 6.8L F-Super Duty (F-250 to F-550), 2006 6.8L F-53 Motorhome Chassis, 2006-2007 4.0L Explorer 4 dr, 2007 4.0L Explorer Sport Trac, 2006-2007 4.0L Mountaineer, 2006 4.0L Mustang, 2006 - 2007 4.6L 3V Explorer / Explorer Sport Trac / Mountaineer, 2006 4.6L 3V Mustang, and 2005-2007 Crown Vic / Grand Marquis / Towncar vehicles may exhibit one or more of the following symptoms: drive-away hesitation, loss of RPM on deceleration, difficulty starting, and/or idle RPM less than desired. Malfunction indicator lamp (MIL) may be illuminated with diagnostic trouble codes (DTCs) P0506 and/or P0505. These conditions may appear after battery disconnect, dead battery condition, or keep alive memory (KAM) reset. The symptoms may be due to engine deposits in the throttle leading to airflow less than desired.

[DryCreek]

Originally Posted by Dav L

instead of drilling the throttle plates...doesn't the throttle body have a minimum airflow adjustment screw (idle stop)?
The AIS (Automatic Idle Speed) motor is supposed to keep it from dieing like that.
Note: I haven't messed with a V10 injection system.

I can't find any reference for setting idle speed by setting a throttle stop. On the 2-valve Triton engines, they do have a throttle stop. but then again, you also have a throttle cable to control the butterflies. In the past, I've always compensated for a plugged/malfunctioning IAC by adjusting the throttle stop on the throttle body. The newer Triton 3-valve engines are completely electronic - the accelerator pedal is just a rheostat that adjusts current/voltage going to a stepper motor that drives the throttle plate position. The AIS, (otherwise known as an IAC Valve) is not used on the drive-by-wire setup. The stepper motor is supposed to hold the throttle plates in a fixed position once the "idle learn" is complete. When the throttle (accelerator pedal) goes to zero, the stepper motor returns to its known minimum value position. Until the computer flash is made, the programming just assumes that position is suitable until it is told to relearn idle position by a loss of power to the KAM (Keep Alive Memory) or directed by a scan tool. The newer algorithms will compensate for carbon buildup on the butterflies by monitoring idle speed and keeping it within a target value. If you have a vacuum leak and the KAM is reset, then the Throttle Body (TB) learns a new minimum idle position. If the vacuum leak is fixed, or carbon builds up around the throat of the TB and restricts airflow at minimum setting, then you will a lower idle speed until you go back through the "re-learn idle speed" procedure. The idea behind drilling holes in the throttle plate are based on the concept that the carbon buildup typically occurs at the TB throat - where the butterflies (throttle plates) close off. If you have an alternate path more towards the center of the throttle plate, it is less likely to become carbon fouled. If the idle speed is just unacceptably high, then you can block off pairs of holes (one on each side) with self-tapping screws without having to remove the TB from the intake.


My issue is that I have a very infrequent loss of power to KAM. It usually occurs while I'm driving at slow speeds, coming to a stop. Since I immediately restart the engine after shifting to neutral, the TB doesn't get to go through the relearn cycle and uses its default value. Carbon buildup exacerbates the condition. My goal before our next trip is to tighten every chassis power connection, clean the battery terminals, remove the knife switch from the negative terminal and run a new ECM ground. I have already done the "wiggle test" to all feeders going into the ECM and couldn't recreate the power loss to the KAM of the ECM.

[Fiesta48]

The OP is a rare breed today. Most will never clean the throttle body. No one will understand the instructions he laid out. Not his fault.
Many have installed a steering stablizers.
But thanks for the info.
And me I upgraded to a diesel that has its own problems. Had two V10s.

[Dav L]

Drycreek, don't forget to do something so those screws (if you need them) won't find their way into the intake...

[DryCreek]

Originally Posted by Dav L

Drycreek, don't forget to do something so those screws (if you need them) won't find their way into the intake...

Red Loctite goes on anything that could be ingested into an intake manifold. It's worth the pain to remove (heat gun) for the peace of mind.

Just got the replacement TB yesterday. Despite reassurances from the manufacturer, it did not come with the gasket. Looks like I'll be heading to East Texas with the old (but much cleaner) one still mounted.

[DryCreek]

OK, since I received the replacement throttle body without gaskets, I decided to take our short trip this week on the old (but much cleaner) throttle body.

Ran like a charm. No issues at all. I watched the RPM's as I came to a stop each time, and they never fell below minimum idle speed (about 650 rpm). Every. Single. Time.
And, we went through several smallish towns - Meridian, Hillsboro, Corsicana and Palestine. The idle had smoothed out so much that we wife kept looking over to see if it was still running!


But, it looks like I drifted my own thread! Sorry.

The most important takeaway is that if you have a steering stabilizer, be prepared to exert Herculean forces to guide your rig if you lose power steering! I mean, it was unbelievably hard to turn the wheel. It took me leaning into it to keep from hitting the curb when the engine stalled.