Bad ECM (?) 1999 Expy 4wd

[joyfulheart]

I have a 1999 Expedition, Eddie Bauer 4wd.

175000+ miles on it
No extras or customization on it...

Check engine light is on all the time.
about a 9 months now it has had hesitation, bucking and multiple random misfires
Burning alot of oil too (at least hubby is complaining)

The spedometer on the dash keeps going out at random times-- Hubby took apart and re-soldered, but that doesn't seem to fix the issue permanently.

Hubby changed every spark plug and fuel filter.
Codes keep changing on it, lately it's been bank 3 and 7.
Replaced ALL of the thingies on banks (can't remember what they're called, but will edit this later with the name of those things)

Hubby is a handy guy, but is SOOOO sick of chasing down the issues on this truck has declared himself DONE and refuses to work on this issue any more.

Took it to my local mechanic, who says that it's the ECM and wants me to take it to the dealer.
Phone call to the dealer says they want to charge $900 for the ECM/labor. OUCH!

I have a few questions:

I found an online place that sells programmed (specific to my vin, mileage) ECM's for $199. They promise I can do it myself.

However, IF I do it myself, I have read online that I might have trouble with starting the car due to PATS on the keys. and if it wont start, I'll have to tow it to the dealership and have them program it.

Is there a way to do it myself at home? Or am I stuck going to the dealer?

Also, will this fix the spedometer issue or do I need to replace that too? Do I have to replace the whole dash?

Please speak to me in kindergarten terms. I don't know alot but I'm trying very hard.

 

[FordandPolaris]

It is most likely an annoying problem with what is called the GEM (Generic Electric Module). It sits behind the fuse box underneath the dash.

Have you ever had the windshield replaced? There was a problem with the original windshields having their seals begin to leak water slowly. It would leak down and drip directly onto the GEM. We have two first gen Expeditions in my family and both have had problems with this. It controls all sorts of functions, and most likely is the cause of the dash issue. This link will help you with that.

http://www.expeditionforum.com/f16/what-all-does-gem-control-18616/

Are the "thingies" he has replaced the Coil on Plugs (COP's)? If so then I would check the fuel injectors to make sure they are clean and possibly replace those. If he has replaced the injectors, but not the COP's, replace the COP's on the misfiring cylinders.

It would be worth doing a compression test as well. The testers usually are not too much, and it is easy to do. Just youtube compression testing and there is plenty of how-to's. Hope this helps.

It could be the ECM but I would not replace that first.

 

[joyfulheart]

Thanks!

I believe he's changed the COILS on each bank (7 or 8 of them if memory serves me right)

This GEM part will also fix the sluggish jerky driving and my check engine light too? (with code reading problem on bank 7)???

Any source for an affordable (reliable) part?

Or are we talking two separate problems here? (hoping not! LOL)

Not sure which problem I should fix first, the GEM or the ECM?


Thank you very much for taking the time to help me-- I truly appreciate it!

 

[FordandPolaris]

The GEM does not control anything with the engine that I know of. I would say unfortunately you have two different problems. It would be most helpful if you can post the specific code(s) you get from the check engine light. It sounds like you have had them read before, but in case you paid for them to be read, here is a useful tip. Most auto parts stores have code readers they will let you use for free. If you knew that, then ignore that part. If you have a multimeter to check voltage, make sure you are getting power from the plug that connects to the COP. I would also look at the fuel injector. I have never had one go bad, but it is possible, and no fuel in the cylinder would mean a misfire condition.

As for which one to fix first, worry about the misfire condition. If you can, find out from him exactly what he has replaced. The GEM will cause weird things to happen occasionally, my driver's side window used to roll down in cold weather for no apparent reason, and my mom's expy tries to use 4x4 high at 70 mph (had to disable the 4x4 completely haha), but it is not imperative to the basic running of the truck.

 

[stamp11127]

If I remember correctly the pcm (powertrain control module) is located near the battery. You should gather the facts concerning the engine, they will point you in the correct direction.

1) I would disconnect the battery, clean the posts and terminals, unseat the plugs to the pcm, inspect and reconnect them.
2) Same deal with the ground strap to the engine.
3) Read, record and clear codes
4) Read fuel pressure at idle and at around 2500-3000 rpm
5) Run engine and scan for codes
6) Post results

This may not help but at least you would know you have good connections to start with.

The speedo dropping out may be caused by multiple things. One to look at is the VSS (vehicle speed sensor). Others are the electrical connections to and from the pcm for the VSS and instrument cluster.

How is it going through oil? Burning or leaking? Blue/white smoke at startup?

You can check the injectors with a mechanics stethoscope with the engine running. You'll hear a difference in the bad one compared to the rest of them.

How did your local mechanic determine the pcm is bad? One way to tell is to try and flash it with a new program. That is one of our trouble shooting methods we use at work. Unfortunately your spending $ in the process.

 

[Duane Wong]

I have a 1999 Ford Expedition Eddie Bauer 5.4L that shuts down intermittently when driving and shows '-------' when it does.

The dealer changed the TPS which was throwing a code, but it happened again after that.

The dealer suggested an $18 Relay for the PCM, but that would not explain why the vehicle starts up immediately and has numbers on the odometer and runs fine for miles until it shuts down, again.

I bought a lifetime warranted remanufactured PCM from Flagship One for about $171-$5 online discount=$166.

Hopefully that will repair the problem.

All the previous forums say the pcm Relay or grounds could cause the problem, but have read four or five posts saying they tried that and the problem returned.

Getting the dealer to replicate the problem has been difficult and time consuming.

Duane Wong

 

[Yupster Dog]

I have a 1999 Ford Expedition Eddie Bauer 5.4L that shuts down intermittently when driving and shows '-------' when it does.

You need to start your own thread on this,
This will help you do that,
https://www.expeditionforum.com/threads/correct-way-to-start-a-thread.47954/

Welcome to the forum

 

[tekrsq]

I have a 1999 Ford Expedition Eddie Bauer 5.4L that shuts down intermittently when driving and shows '-------' when it does.

The dealer changed the TPS which was throwing a code, but it happened again after that.

The dealer suggested an $18 Relay for the PCM, but that would not explain why the vehicle starts up immediately and has numbers on the odometer and runs fine for miles until it shuts down, again.

I bought a lifetime warranted remanufactured PCM from Flagship One for about $171-$5 online discount=$166.

Hopefully that will repair the problem.

All the previous forums say the pcm Relay or grounds could cause the problem, but have read four or five posts saying they tried that and the problem returned.

Getting the dealer to replicate the problem has been difficult and time consuming.

Duane Wong

Not trying to high jack an old thread, but did you get this resolved ? I'm having almost the same problem with my 99 EB 5.4.