Low Power

[cw212010]

Hi all,

I'm working through all the problems bit by bit and I'm stumped with the next one.

Symptoms: Low horsepower, slow acceleration. Would liken power to a 1.4l engine, not a 4.6.

- Moderately rough idle at times
- New plugs
- All cylinders appear to be firing, however hard to test
- New air filter
- New fuel filter
- EVAP Purge valve pulling a vacuum on fuel line
- Fuel cap sealing
- No leaks
- All fluid levels ok
- Exhaust system fully operational
- No fault codes showing

The ONLY fault code in the car is the EGR valve.


What the hell can be causing this?!

 

[Hugh Janus]

let me guess - EGR valve?

 

[apenland01]

Lot's of things could be causing this.....

Is this new to you, or did you just start working on it recently?

I would reset the PCM and force it to re-assess the current status of the air, fuel and spark systems. If it is still isn't throwing a code after driving it for a bit, then start with air (MAF, TB, EGR - all can be cleaned for free/cheap), then dump a large bottle of Techron in the tank and clear the fuel system/injectors, then re-seat each boot on each plug and double check each connector to both the COP's and injectors.

 

[cw212010]

I've tried all except the PCM.

Is it simply a case of disconnect the battery and hold the two connectors together for five minutes, reattach and then drive the car gently for a while?

 

[apenland01]

No, go to youtube and watch the re-learn process from makuloco2000. It's specific to force the PCM to re-learn idle and shifting values. Basically make sure everything is turned off before disconnecting negative (lights, stereo, AC, etc). disconnect neg and jumper for 5-10 mins, then reconnect. turn key to "on", but don't start it, let the PCM do the sweep (30-45 seconds). You'll hear stuff stop moving when the sweep is finished. Then start it with your feet off the pedals and let it idle for 10 minutes. Then take it out and "gently" drive it through all the gears for a few miles to learn initial shift points. It will continue learning during the next week or so, but it will start throwing codes based on it's reset baseline.

 

[apenland01]

The reason you want to reset the PCM is because if you recently cleaned the throttle body, it's using old data and trying to compensate because it thinks it's still all gummed up, when it's actually like factory again. Resetting the PCM can a fix a lot of silly issues, or at least, force it to identify the real problems based on the original factory settings.

 

[imp]

The reason you want to reset the PCM is because if you recently cleaned the throttle body, it's using old data and trying to compensate because it thinks it's still all gummed up, when it's actually like factory again. Resetting the PCM can a fix a lot of silly issues, or at least, force it to identify the real problems based on the original factory settings.

Ford Shop Manual has a highlighted warning not to clean the throttle body, as it has a special coating, they claim. I cleaned mine with LPS-2 and a rag. Definitely ran peppier with small throttle opening especially. But the P-2106 TAC Forced Limited Power still keeps coming back.

Many repair sites state P-2106 is only thrown due to Throttle Actuator Control problems. I have a recurring ABS problem, and suspect (but not certain) Ford uses P-2106 to discourage using the vehicle with faulty ABS. Any thoughts would be deeply appreciated! imp

 

[Semperfi96]

I would start with changes in the egregious first

 

[imp]

I would start with changes in the egregious first

Huh? imp

 

[Semperfi96]

Huh? imp

Typo sorry. Egr valve

 

[cw212010]

No success, engine is still low on power. It's now popped off another stud on the front hub. This car is just never ending.

 

[Semperfi96]

No success, engine is still low on power. It's now popped off another stud on the front hub. This car is just never ending.

We'll the studs and easy fix. Don't give up yet. Is you catalytic converter making a bad smell or seemed to be stopped up?

 

[cw212010]

Cat makes no smell, I have a thermal imaging camera at work (Fire dept) so I will have a look tonight to see if one is getting hotter than the rest.

The wheel studs is a whole new bearing which is just more money!

 

[Semperfi96]

Cat makes no smell, I have a thermal imaging camera at work (Fire dept) so I will have a look tonight to see if one is getting hotter than the rest.

The wheel studs is a whole new bearing which is just more money!

That's awesome you have access to the good tools let me know what you find out also resetting the computer if you know how as mentioned above could benefit you as well

 

[cw212010]

Computer has been reset to no avail.

 

[Semperfi96]

Computer has been reset to no avail.

Well damn...... lemme think for a while and go thru some shop manuals I have

 

[Semperfi96]

You could have a bad ecu too

 

[cw212010]

Would this be the ECU in the bulkhead on the passengers side? I have a charging light/message showing with a good alternator and I know this can be attributed to a bad ECU.

 

[Semperfi96]

Would this be the ECU in the bulkhead on the passengers side? I have a charging light/message showing with a good alternator and I know this can be attributed to a bad ECU.

Yes that's it

 

[Semperfi96]

It's a possibility