Sudden loss of power at roundabout

[steambao]

So, I have a 2007 ford focus zetec and recently installed a cold air intake. Testing the effect of the CAI, decided to drive my car hard. All good so far, 1 litre per 100km fuel saving!

However, I reached a big roundabout and went through it at 60 to 70km/h. After straightening up I pushed on the accelerator only to hear my car go into that max 60km/h mode. Turned the car off, turned it on and was even worst. Pulled over to the side again, popped the bonnet. Everything was fine, no warning codes. And then the car worked fine.

I googled it and heard about something called PSP which cuts power if your vehicle corners at a speed enough to cause loss of traction. Is this true? I have a model with ESC though.

[DeKa]

The first thing ESC does is cut the power, then uses differential braking on individual wheels to pull the car back into line if necessary. I'd say you went too fast, exceeded available grip, and the ECU activated the ESC. If you had have waited a fraction of a second, you would have had normal power return.

[marg99]

There should have been a warning light come on in the instrument panel to show the ESC was operating There is one on the LT I have and if I turn a corner with a drainage grate in the road the tyre slips and triggers the ESC

[steambao]

Originally Posted by DeKa

The first thing ESC does is cut the power, then uses differential braking on individual wheels to pull the car back into line if necessary. I'd say you went too fast, exceeded available grip, and the ECU activated the ESC. If you had have waited a fraction of a second, you would have had normal power return.

Sorry Deka, I made a mistake. I have a car WITHOUT ESC

Originally Posted by marg99

There should have been a warning light come on in the instrument panel to show the ESC was operating There is one on the LT I have and if I turn a corner with a drainage grate in the road the tyre slips and triggers the ESC

Pretty sensitive! Do you notice the ESC affect your car after you straighten up?

[DeKa]

Originally Posted by steambao

Sorry Deka, I made a mistake. I have a car WITHOUT ESC




Pretty sensitive! Do you notice the ESC affect your car after you straighten up?

If you have ESC, and end up in a situation in a roundabout as described, you will find that the ESC straightens the car up before you even have a chance to do anything.

In your case however, I can't comment why you lost power as you don't have ESC.

[AndrewR_AUII]

May be worth checking all fluid levels - particularly Trans Fluid.

I say that as it reminds me of an issue I had with my AU Falcon after fitting trans cooler- no drive on/after cornering. (Auto) Trans Fluid level was low, so going around corner was enough so that pickup was 'dry'.

[BlackLS]

Get yourself a bluetooth scan tool and Torque Android app. Read the scan code.

Last time I had reduced power mode is when the TPS went under warranty

[steambao]

Originally Posted by BlackLS

Get yourself a bluetooth scan tool and Torque Android app. Read the scan code.

Last time I had reduced power mode is when the TPS went under warranty

A What? Just did a search on OBDKey... This looks awesome! Online looks expensive, where did you buy yours from?

[marg99]

They seem to go under $100 for the plug in versions not Bluetooth however

http://www.chinavasion.com/car-diagnostic-tools/

[steambao]

Ok. So a few months later, all seems well. I recently bought a OBDKey and leave it in my car. So today, low on fuel (61km left on tank), on the way to petrol station, take a regular corner, REV hard after straightening up and BAM. Torque gets limited to 2k. Speed limited to 60km/h also. However, going up a hill speed limited at 15km/hour because Torque limit to 2k comes first (all gears).

I thought, maybe it is because im low on fuel. Manage to crawl to petrol station (thank god its 12 midnight). Pump her up to half (nice BP ULTIMATE). Start car, still limited. Struggle up another hill, for 5 minutes, still limited. Stop my car, have a look around, wait 5 minutes. Turn car back on again and it's back to normal.

However, during the limited time, using my OBDKey, I checked for ECU code errors - nothing. My Short Term Fuel trim is -15% (Intake manifold preasure 4.7psi). I'm not sure if that is the reason why I got speed limited, or whether it is suppose to happen when ur car is in limit mode.

Weird cos I got no ESC on my car, and took the corner slowly this time.

[DBourne]

I'd be taking it to get looked at mate.

You might have an issue with your gearbox, throttle sensor, anything really.

[Russ]

I was just reading a post on another forum from someone with a Jeep Cherokee with the same problem (or at least the same symptoms). They said they replaced the throttle position sensor (TPS) and the issue was resolved. It might be a worth a try and apparently was an easy job as well (on the Jeep at least)

It can be tested for faults, try the link below .....

http://www.ehow.com/how_4489318_trou...ps-sensor.html

[steambao]

If its near the throttle body, then I have a feeling I might have knocked it when installing the CAI. Will check it on the next weekend im free, a long with replacing my thermo sensor!! So much to do and so little time :(

Thanks guys for the help!

[DZFord]

Yeah, its easy to do, make sure the electronic connection into the throttle body is secure and clipped in all the way.

[Russ]

This is the only pic I could find of what the TPS looks like, this pic is with the throttle body dismantled, but it should still give you an idea of what to look for