1999 Explorer 4.0 OHC V6 engine stalls when stopping - bad torque converter?

[ragtowne]

I have a completely stock 1999 Ford Eddie Bauer 4WD 4.0 OHC V6 with 160,000 miles. Recently the engine has been stalling when the vehicle is coming to a stop. It does not stall every time but often enough that it is dangerous to drive. It does not throw any codes. No engine check light comes on. After stalling, the engine starts right back up. The vehicle has been regularly serviced.

It has been in the local Ford dealer's shop for over 130 days. They replaced the IAC, cleaned the entire intake system, cleaned the fuel injection system, checked for vacuum leaks, done all of the checks their factory scanners and other tools will allow them to do, and talked with "Ford Senior Technicians". The dealer claims they can get the engine to stall when shifting from reverse to drive with the foot on the brake.

I thought it might be the power brake booster leaking air. I asked them if that could be the cause. They said "no, they checked it".

They now claim it is "most probably" a bad torque converter that is locking up when it should not. They state there is no guarantee that replacing the torque converter will fix the problem. If I decide to pay to have them replace the torque converter and it does not fix the problem, that's just the way it goes - no guarantee.

Does this sound reasonable that a Ford dealership can take over 130 days and only be able to "guess" at what is causing this problem? Or should I take it to another Ford dealer, or to an independent repair shop?

Any help or suggestions would be most appreciated.

 

[2000StreetRod]

Bpps

The torque converter is commanded by the PCM to lock when cruising. When the accelerator is released the torque converter may stay locked as the vehicle slows until the PCM determines the vehicle is stopping. The brake pedal position switch (BPPS) notifies the PCM that the brakes are applied. A defective BPPS can result in the torque converter staying locked and the engine will stall when the vehicle stops. An easy way to test the BPPS is to engage cruise control and then tap the brake pedal. If the BPPS is functional the cruise control should disengage.

There is a torque converter clutch (TCC) solenoid in the valve body of the transmission. The TCC solenoid can stick in the active position making the torque converter always locked. When the vehicle is slowly accelerating thru the gears to cruise the torque converter should switch from unlock to lock. It is similar to an upshift and the engine speed should drop some because there is no slippage in the torque converter.

Any shop with knowledgeable Explorer technicians should understand the above and know how to test for the functions.

 

[ragtowne]

Thanks for the quick reply

Hi Bpps,

Thanks for the quick reply. I asked the Ford service person if there was any way for them to check the torque converter lockup command from the PCM. I was told that "later models" have more sophisticated PCMs that allow their scan tools to do more, but the 1999 model PCM does not.

I will check the BPPS as that is easy as you suggest.

As for the TCC solenoid, in your opinion, are they giving me bull, or can they check the TCC solenoid operation via a scan tool or some other method?

I was thinking of first having the transmission serviced (fluid, filter) in case it was a clogged filter. I could have them put in a new TCC solenoid at the same time. It has to be way cheaper than putting in a new torque converter.

Thank you.

 

[2000StreetRod]

drive the vehicle

It seems to me that you or anyone else that can drive the vehicle and read the tachometer can determine if the torque converter is going from unlocked to locked when modestly accelerating. Actually, if the vehicle only has rear wheel drive, it probably could be done in the shop by just raising the rear wheels so they can spin and selecting drive.

There is no way I would tolerate a vehicle being kept in a dealer's shop for three weeks (let alone 130 days) even if a loaner was provided free.

 

[ragtowne]

re: drive the vehicle

There is a long story behind this which I will reserve for yelp. This is as short as I can make it.

The vehicle had a front cover leak. Brought in to the Ford dealer on 21-Jan-2015. Dealer replaced defective timing chains as well ($2900). About 500 miles later vehicle started to have the "stall" problem which got progressively worse. About 1000 miles after timing chains were replaced, the stalling got bad enough to have it fixed.

The vehicle was brought in to the Ford dealer on 5-Mar-2015. Every 2 to 3 weeks the vehicle is "ready to be picked up". The problem still has not been resolved. 1) the IAC was replaced ($700). 2) the target idle was set high now hunts between 700 and 1400 rpm. 3) target idle set to normal, but the heater/ac system has a new "noise". 4) a piece of paper was removed from the heater/ac system ($300) now it only operates on high. 5) the blower motor resistor is now broken and needs to be replaced. 6) the air intake system was cleaned. 7) the fuel injection system was cleaned. 8) now they "suspect" the torque converter needs to be replaced - no guarantee it will fix the problem.

The timing chains have no keys to index them to the crank/cams its just an interference fit. I am wondering if the new timing chains have "slipped" causing the cam timing to change?

I have left the vehicle at the dealer so they cannot claim someone else did something to absolve them of any responsibility for putting in parts and doing work that did not fix the problem.

AND they refuse to give me a loaner car.

Thanks for your suggestions. I will bring this up with the Ford dealer.

 

[drdoom]

Streetrod I believe is correct, just watch the tachometer. And yes you can easily pull up the solenoid state on a scantool, smartphone, or laptop, as well as the BOO switch, TPS, and other sensors. I will concede that the electronic & hydraulic circuits related to lock-up are rather complex. In a way it really sounds like an IAC pipe is disconnected or even a cracked PCV elbow. Shot in the dark I know, but just a couple simple things to check & eliminate.

 

[ragtowne]

Those are good ideas to check. I will bring them up with the Ford dealer. If all else fails, I am inclined to have them service the transmission (filter,fluid) and replace the TCC solenoid first before having them replace the torque converter.

Thank you.

 

[drdoom]

TCC solenoid fault should pop a code(s). If they are dropping the pan, and the converter is fragging, you'll see the tailings in the pan. BTW 160K is right on for a converter failure. Be advised, if it is fragging, you will need a rebuild.

 

[ragtowne]

When they told me about replacing the torque converter, I thought to myself the labor cost of removing the exhaust, transfer case, etc. and the transmission would justify replacing the entire transmission rather than just the torque converter.

Since the PCM is not throwing any codes, I thought dropping the transmission pan first to check for any signs of clutch or other material present would help make the decision on what to do. If there is any material present I have been told it can clog up the transmission cooler as well.

Thanks for the information.

 

[96eb96]

the target idle was set high now hunts between 700 and 1400 rpm.

Is this resolved?
What is the percent IAC at idle? I think it should be around 30%.
I guess fuel trims are around +-5%?
What is the BARO reading on the MAF. Does it correspond with altitude?
Try disconnecting the MAF and see if there is any improvement.
Hows fuel pressure?
Also, the intake gaskets on these are notorious for failing. I didn't see that checked or addressed.

I'm really shocked at Ford that they can't find this problem. There are breakout boxes that can activate any solenoid if the IDS can't. I don't have a 99 but there is no * on the IDS screen for my 96 TCC PID(can't be activated). TCC sticking could cause that symptom.


I'm thinking maybe disconnect the TCC wire? See if they can get it to stall then. Not sure if you should drive it like that, but it seems like a diagnostic step. maybe discuss it with them.

 

[ragtowne]

I talked with their "senior" tech. I asked if perhaps the replacement IAC could be defective. He admitted they tried two IACs, so they knew the vehicle was not fixed when they told me it was ready (and a USED IAC was put back in stock as new...)

The tech also admitted that setting the target idle "high" was not the correct fix for the engine stall problem. I had them reset the target idle back to "normal" and the engine idle no longer hunts. The engine stalling problem is still present.

The questions you raised are good - I am making a list and am going to go in to the dealer on Monday with that list.

Thanks to everyone for taking the time to help me out.

 

[ohfugit]

In case someone comes upon this in a search. I had this happen on my 2003 sport.
The bracket that holds the solenoids in place was broken off by the tcc solenoid.
I replaced the bracket, the tcc solenoid and the epc solenoid and it is not stalling out anymore.

 

[ragtowne]

Interesting... in January 2015 I had the Ford Dealer do a 150,000 mileage service. Among other things, they removed the transmission oil pan, drained the transmission, replaced the filter, reinstalled the transmission oil pan, and filled the transmission with the proper Ford fluid.

The Ford dealer continually promises to get back to me but never does. I have to leave several messages and drive to the dealership personally to get attention. I believe they do not want to work on the vehicle any more and this is their way of making us "tired of them" and take the vehicle away. IMHO this is a bunch of malarkey. Just tell me "We do not want to work on your vehicle".

We decided to get the vehicle back from the Ford dealer and have an independent repair shop do their own diagnostic testing to see what they come up with. A good friend of mine with over 30 years of experience works there and he will tell me the truth about what he finds. Tomorrow I am going to go to the Ford dealer and pick the vehicle up regardless of what they say or do.

I have been going to this particular Ford dealer since 1995 and have never had this kind of problem until now. I have no idea why they would act they way they have.

Thank you for your suggestion. I will add it to the list of questions I have.

 

[chefduane]

The torque converter is commanded by the PCM to lock when cruising. When the accelerator is released the torque converter may stay locked as the vehicle slows until the PCM determines the vehicle is stopping. The brake pedal position switch (BPPS) notifies the PCM that the brakes are applied. A defective BPPS can result in the torque converter staying locked and the engine will stall when the vehicle stops. An easy way to test the BPPS is to engage cruise control and then tap the brake pedal. If the BPPS is functional the cruise control should disengage.

There is a torque converter clutch (TCC) solenoid in the valve body of the transmission. The TCC solenoid can stick in the active position making the torque converter always locked. When the vehicle is slowly accelerating thru the gears to cruise the torque converter should switch from unlock to lock. It is similar to an upshift and the engine speed should drop some because there is no slippage in the torque converter.

Any shop with knowledgeable Explorer technicians should understand the above and know how to test for the functions.

Yikes!! I would NOT want to be a Certified Ford Tech and mess with 2kSR!!

"Uhh... Yes sir Mr. Streetrod, I uh.. think that's correct, Sir."

 

[ragtowne]

140 days in the hole is enough for me...

Something is terribly wrong with this Ford dealer. I asked for an estimate to replace the transmission and the engine rear timing chain. They continued to play the "do not call the customer back" game.

I called today and got the standard "but we left you a message" bit. I said it was clear they did not want to work on my vehicle and I was going to pick it up. The only response was "OK"...

After 140 days, I would have preferred the truth - "we still cannot figure out what is wrong with your truck and do not want to work on it any more".

I picked the vehicle up and took it in to an independent repair shop where a good friend of mine works. I included all of the suggestions everyone has given to me on this forum. If anything turns up I will let you know.

Thanks to everyone for their suggestions.

 

[gatzdon]

I think it's time for a formal complaint to Ford. Don't expect much from Ford, but 130 days in the shop and $4k in charges without a definitive diagnosis is ridiculous.

Even in pristine condition, this vehicle might be worth $6k, but realistically it's $5k.

Don't know what Ford Corporate can do at this point, but you need to make a stink.

Also, keep in mind and be honest about any/all services that they recommended, but you declined. It may not make a difference, but if the complaint goes anywhere, that will be brought up.

 

[gatzdon]

Also keep in mind, typical OBD software only pulls OBD codes. There are many more places in the vehicle that diagnostic trouble codes can be stored.

With Forscan (free software) and a good OBDII reader (~$100 to $150), you can access and view most all of the codes stored. When viewing all the stored codes, keep in mind that not all of them are indicative of a real problem.

 

[chefduane]

You need to find out the individual who is the Zone Manager in that area for Ford. The ZM is the FoMoCo corporate rep that oversees/monitors the dealerships in that designated zone. Dealerships DO NOT like to get questions about service and support from Zone Managers and are typically very responsive to complaints fielded through the ZM. The ZM has the power to sanction dealerships and in extreme cases, can even shut down dealerships if offenses are particularly numerous and grievous.

 

[ragtowne]

And the answer is....

It took the vehicle to an independent shop where a very good friend of mine, who has been repairing vehicles professionally since 1977, took less than 30 minutes to figure out the problem. He started the vehicle and drove it. He heard a noise while driving. He put the vehicle up on a hoist, and with a Snapon mechanics stethoscope (~$30) determined it was the main transmission output bearing. He removed the transmission oil pan and it was full of metal debris. He recommended replacing the transmission and transmission cooler, and a complete flush of the transmission cooling lines. He said he could hear no unusual noise from the timing chain areas of the engine.

I asked my friend how could the "factory trained Ford technicians" miss such an obvious thing? His reply was "they are basically code readers and parts replacers - they no longer teach mechanics how vehicles work, and how to diagnose problems without the help of a scanner".

When I picked the vehicle up from the Ford dealership, besides saying it was their "guess" it was the torque converter, I was told "the technician heard a noise and believes it is the front timing chains going". Wrong on both counts. Had I allowed them to replace the timing chains and torque converter, it would not have fixed the problem, and probably damaged the replacement torque converter in the process. I called the Ford dealership service manager and told him the findings. He basically had nothing to say.

This same Ford dealership did the 150,000 mile service (which included changing the transmission filter and fluid) 500 miles before the vehicle started stalling. They made no mention of any debris in the transmission oil pan. Makes me wonder if they used the wrong fluid or some such?

I am definitely going to contact the Ford Zone Manager for the area.

Thanks again for your help.

EDIT: my friend told me he first smoke tested the engine while cold, and checked all of the vacuum hoses and accessories such as the brake booster - the original PCV valve was still installed and "full of crud" - it should have been replaced at one of the major services performed by Ford.

EDIT-2: 1000 miles ago Ford performed a "Flush transmission fluid & replace filter". There is no comment about any debris found in the transmission oil pan. The invoice has "14 QT BULK-MERCON MERCON-OIL" . All on-line references state that the 5R55E is supposed to have "MERCON-V" fluid.

Could this have caused a problem?