460 Ford FI stalling problem

[cb1000rider]

I don't know the specifics of this Ford, but I can tell that you that it's pretty common in EFI tuning to command more timing at lower-than-idle RPM - it's a bit of a fail-safe to catch where the IAC failed to react.

All I have tuned is speed density, but I haven't worked on any factory speed density systems in a long time.

Not interested in a contest on EFI knowledge. I do not know OBD-I - and the 460 Ford, I'd just like the OP to have as much information as possible... It's very likely that people know this system better than me.

If I was in his shoes, I'd be checking mechanical fuel pressure. I had an 1999 V10 that gave me it's first indications of bad fuel pressure by dying at idle... And I'm running manual tests on the IAC. IF there are better ways of doing things, I completely accept 'em...

OP: I'm impressed.. Lots of work here... Keep us in the loop.

[Geocritter]

I set the dynamic ignition timing to 10o BTDC with the SPOUT removed and I did it before I installed the radiator, fan and timing belts so that I’d have a clear view of the timing marks with the timing light without having to worry about losing fingers and hands. I double checked the timing again after I’d tightened down the distributor clamp. So the initial engine timing should be exact. One thing that’s interesting, a few days earlier, right after I finished putting the engine back together, I drove the rig a few miles through San Marcos traffic to have it safety inspected and it ran flawlessly the entire time. It wasn’t until the next time I drove it that the stalling problem reappeared.
Steve

[cb1000rider]

Steve, I'm still suspicious of those new parts. Do you have a test procedure for the IAC? Sometimes those reman'd parts aren't reman'd so well. They IACs are typically stepper motors, but they can have different designs.

Your timing with the sprout back on should be advanced of that 10 degrees.

Have you ever put a fuel filter on the thing? The V10 is a hog, and 10k miles on it is probably like 50k in your Honda... And the tanks are typically much crappier.

[mpaton]

Originally Posted by RLS7201

No assumptions or suggestions

But Richard, you must remember these suggestions of yours:

Originally Posted by RLS7201

I suggest that subford is correct.
I disable my IAC for better engine braking when descending a mountain. If I forget to re-enable it when stopped, the engine will go to 450 RPM in gear or 500 RPM in neutral, which is what the mechanical idle stop was set to at the factory. Which suggests that the timing is not being adjusted to gain idle speed.

Richard

Aside from the fact that I know your conclusion to be in error, I do not see the logic in your inference. Therefore in my opinion it is your assumption.

Originally Posted by RLS7201

It's a fact that the ECM doesn't change timing to correct a IAC failure.
Richard

And I did not say that it did.
That sentence is your own interpretation.

What I did say is that both ignition timing and Idle Air Control settings are changed to maintain a desired idle speed.

I know this because I have extracted the code from my ecm, I have disassembled it, and I understand what it is doing. I have modified my code, and I have obtained the results I expected from those modifications. So, yes it is interesting to have my own version of "facts" challenged.

Should anyone wish to observe the ignition timing changing, they need only use a timing light or a scanner to see the timing, while the engine idles (foot off throttle). Changing the load on the engine by turning the AC on and off will cause timing changes (followed by IAC changes) in order to maintain engine rpm.

Michael

[Geocritter]

Originally Posted by cb1000rider

Steve, I'm still suspicious of those new parts. Do you have a test procedure for the IAC? Sometimes those reman'd parts aren't reman'd so well. They IACs are typically stepper motors, but they can have different designs.

Your timing with the sprout back on should be advanced of that 10 degrees.

Have you ever put a fuel filter on the thing? The V10 is a hog, and 10k miles on it is probably like 50k in your Honda... And the tanks are typically much crappier.

I'm also concerned about the IAC and will check it out. As for the fuel filter, I replaced the filter 4,400 miles ago so it should still be okay.

Steve

[Geocritter]

I have to wonder. I’ve been the habit of disconnecting my RV engine battery with a large battery isolator switch. Though I did this for over a year and 5,617 miles on my Grand Western North American Tour and Shakedown Journey without ever having a stalling problem. The problem began a few months after my return but has been persistent since it began. After reading a book about Ford FI I have to wonder if the problem stems from my inadvertently wiping the engines computer memory clean every time I disconnect the battery. I got into the habit because of a concern over parasitic power drains.
Steve

[subford]

The only problem with doing that is you lose the running self test codes.
I always disconnect my chassis with the disconnect switch that my RV came with every night and never had any problems. Maybe for the first 10 miles or so it may run a little different but after that it will run with the sensor values the sensors are sending to the PCM Computer if they are of a believable value for the Computer. If not the Computer will operated on a value in its table for the running condition.

[Geocritter]

I finally braved the oppressive summer heat today and took my RV out for a test drive. I drove it for 21 miles up and down SH 80 with numerous stop lights, several stop signs and highway speeds up to 60mph. As luck would have it the engine performed flawlessly (of course!).

Upon my return I hooked up my new code reader and first ran a key on engine off (KOEO) test followed by a key on engine running (KOER) test.

During the KOEO test I retrieved the following codes (and their definitions from the manual)

334 – EGR valve closed voltage high.
BTW yesterday I removed the EGR valve and, being careful not to hit the electronics, I cleaned the carbon buildup out of the valve assembly with chlorinated carburetor cleaner. I also checked the EGR’s diaphragm for vacuum leaks and didn’t find any. Inserting a narrow piece of plastic rod into the exhaust end of the EGR valve I could open and shut the valve with hand pressure.

542 – Fuel pump secondary circuit fault.
I haven’t a clue, I do know that some previous technician installed a fuel pump on/off toggle switch and appears to have connected the fuel pump directly to the battery since the only way to turn the pump off is with the toggle switch (though long before my current problems started the engine shut down once when I pulled off too fast on a rough turn-out, I suspect triggering the inertia crash switch)

During the KOER test I retrieved the following codes (and their definitions per the manual)

311 – Thermator air system/fault during engine run self-test.
No surprise, since I recently removed the air pump and associated plumbing when I installed my new long block engine assembly.

334 – EGR valve closed voltage high
See above in KOEO

The fact that I couldn’t get the engine to act up is very frustrating. As for the fuel pump, I replaced the fuel filter about 4,500 miles ago and I did have some problems early on during my recent 5,600 trip last summer. However these were long before the current stalling problem started. Twice the engine shut down, the first time on a grade on I-10 outside of Benson AZ (afterwards I replaced the fuel filter) the second time on SH99 outside of Bakersfield CA cruising at 60mph (with my speed control on) on a flat surface during 80 degree temps. Several people suggested that I replace my fuel pump but in lieu of that to never let my fuel drop below half full. I did the half-full work-around for the remaining 3,600 miles of my journey and had no more problems.


BTW this problem seems to be a carry over from my former engine as it first began to plague me shortly before I replaced my former engine with a factory rebuilt long block assembly.

I certainly hope someone has some ideas.

Steve

[subford]

You did not say if you had any CM codes. The 542 could have been either a CM code or a KOEO code. I would think either code was from the installed a fuel pump on/off toggle switch. This I would get rid of because of the fire hazard involved.

If it was a CM code only then I would think about replacing the fuel pump but this code can also be generated by grounding pin #6 of the self-test (DLC) connector to check fuel pressure. Then not clearing the codes when done with the fuel pressure test.

You may also have a bad sensor on top of the EGR valve.
DTC 334 in Key On Engine Off (KOEO) or Engine Running (KOER) Self-Test indicates the EGR valve and/or EGR Valve Position (EVP) sensor may not be fully seated in the closed position. The EVP sensor voltage is greater than the closed limit voltage of 0.67 volt. Because of the preload on the installed EVP sensor, it is difficult to determine whether the EGR valve is seated or the EVP sensor is in contact with the EGR valve stem.
Possible causes:
-- Poor continuity in EVP sensor harness.
-- Non-seated EGR valve.
-- Damaged EGR valve.
-- Damaged EVP sensor.
-- Damaged EVR solenoid.
-- Damaged Powertrain Control Module (PCM).

If the inertia crash switch shuts the engine down the engine will not start again until you reset it by pushing the button on top of it down.

[Geocritter]

I'm afraid I don't know what CM means, I googled it but didn't find anything obviously meaningful regarding the acronym. However, I received the 542 code only during the KOEO test.


I've been wondering about the EGR valve because that's one of the things listed in a trouble shooting guide I have. However, though I took it off, cleaned out the carbon buildup with carburetor cleaner and tested for vacuum (by sucking on the diaphragm) I don't really know what a healthy EGR valve looks like. However, though they're hard to find on the internet they are available and it looks like it may be time to replace it.


Thanks for the heads-up regarding the inertia switch. As soon as I find a good wiring schematic (and either the relentless TEXAS summer heat is gone, or I'm gone from Texas) I'll properly rewire the fuel pump. It seems like I spend half my time on this rig correcting inadequately done work by others.

Steve

[subford]

The CM codes are lost if you unhook the chassis battery after driving the F53.

To check for stored CM codes you run the KOEO self-test and after the KOEO electrical test codes read out twice you will get a space code (10) and then the CM codes will read out. If there are no CM codes you will get another "111" readout twice.

CM = Continuous Memory: The portion of KAM used to store DTCs generated during Continuous Self-Test.

Continuous Self-Test: A continuous test of the EEC system conducted by the PCM whenever the vehicle is operating.

KAM: Keep Alive Memory, A portion of the memory within the PCM that must maintain power even when the vehicle is not operating.

DTC: Diagnostic Trouble Code.

Sounds like you EGR valve is OK but you might have bad sensor mounted on top of it or bad wiring to the sensor. The sensor is a separate part.

[subford]

Originally Posted by Geocritter

As soon as I find a good wiring schematic (and either the relentless TEXAS summer heat is gone, or I'm gone from Texas) I'll properly rewire the fuel pump.

/

[cutlooselily]

Fwiw...

I've had very similar problems of past that are described here on many efi OBD I & II power plants.

One was on a 95 F350 chassis cab 4x4 with FI460. Ended up being fuel pressure related. Defective new pump(s) was the reason...two of them!

After reading this entire thread, I still suspicion a fuel delivery problem as not having been factually eliminated from the "diagnostic tree".

Either fuel psi regulator, fuel pressure regulator supply vac, fuel pump, fuel pump to sending unit attachment rubber line, fuel pump wiring/voltage/ground and/or fuel filter usually relate to said stalling problems.

Looking at fuel trims and/or live data on OBD I doesn't give all the proof in diagnostics.

The only way to eliminate the fuel delivery as a culprit is to use a schrader valve adapter @ the fuel rail, a short section of either efi rated rubber hose or preferably, an aftermarket s/s #3-4 braided/teflon lined line and an aftermarket mechanical fuel psi gauge.

I personally use an Autometer brand mechanical gauge and their 6' ss mechanical gauge line kit. I temporarily mount the gauge (outside the vehicle) with a couple of zip ties to the windshield wiper arm with the supply line running under the hood to firewall rubber seal or through the cowl vent.

This allows, in real time, to watch the rail pressure through the driving/throttle transients and either see a substantial loss or gain of line pressure when any negative situation arises.

Popular to contrary belief, an overly rich decel condition can stall an engine...only seen that one twice on OBD II's with a lot more rail/fuel pressure....

Under full engine vacuum the pressure will be the lowest and under wide open throttle, obviously higher.

High 20's~ Low 30ish psi idle, High 30's~ Low 40ish with fuel pressure reg vac line disconnected or WOT is the norm on early generation OBD I Fords with sound fuel systems.

To this day, even with OBD II, I have not found a more proper way to diagnose common EFI fuel related problems.

Just be glad you aren't dealing with a newer Chevy Camaro V6 with direct cyl injection. 2000+psi is the norm.

Oh, and diesels! Ooofff!

Good luck

[Geocritter]

In my ongoing efforts to root out my engines intermittent stalling problem I replaced my EGR valves Delta Pressure Feedback EGR (DPFE) sensor. Below is a photo of the EGR valve with the old DPFE mounted on top and hi-lighted with an oval.

[img]http://i.imgur.com/K6AOS4s.jpg[/img]

Just in front of the DPFE is a green vacuum line. After installing the DPFE sensor I started and ran the engine while parked (I’ll test drive it later this week). What I’m curious about is the fact that, on a whim I disconnected the green vacuum line while the engine was running and it didn’t appear to have any vacuum on it. I don’t know if it’s supposed to always have vacuum pressure or not.

I’m sorry I have so many questions but I’m not that knowledgeable about FI and I’m trying to climb the learning curve as best as I can.

Steve

PS cutlooselily, at a friends urging I purchased an inexpensive fuel pressure gauge a while ago but I haven't gotten around to checking the fuel pressure with it yet. Texas is currently in the midst of hell (which the locals quaintly call "summertime") and it's hard for me to do much of anything having to do with a hot engine. Once "summertime" is over I'll do more work on rig.