Fiesta WS 2010 stalling, rough idle, rough drive

jb1212 · 13-10-2018, 12:06 AM

I am having issues with my car

Issues I get are:
* Stalling at lights sometimes
* Not holding a constant idle, going to 500 then 1900 often when out of gear
* Driving at 60kph in 5th gear the car seems to jump a little forward sometimes then want to pull back a little sometimes

Issue started around time I serviced it when I:
-Put new plugs in
-New air filter
-New aux and timing belts
-Adjusted valve clearances with new tappets

To troubleshoot I have checked:
-Air filter is not causing this (I ran car with/without air filter for a few seconds and it has the same problem both ways)
-No obvious cracks in air hoses
-Went to Supercheap Auto to check for error codes (I was not impressed with the outcome as they told me my car had lots of errors but could not give any error codes - I will go there again tomorrow and try another store)

Any ideas to further troubleshoot by process of elimination?

From reading lots of post in this forum I think it could be:
-Faulty throttle position sensor
-Faulty speed sensor (Ken_AUXR8 suggests this is not my issue so I will look at this as a last resort)
-Faulty sensor

Thanks for any help!

**russellw** · 13-10-2018, 08:54 AM

You are really going to need the codes.

raceteam · 13-10-2018, 10:12 AM

Yep, as per your posts in other threads, get an OBD2 ELM or similar and a copy of Forscan (Windows, iPhone, Android available). Read the codes, and go from there.

jb1212 · 13-10-2018, 04:05 PM

Quote:

Originally Posted by raceteam

Yep, as per your posts in other threads, get an OBD2 ELM or similar and a copy of Forscan (Windows, iPhone, Android available). Read the codes, and go from there.

Thanks guys. I got a tool and the app and it just so happened the check engine light came on while the car was idling really rough.

The error was P2135. From reading about it and then doing some more graphing I conclude that I need to find a replacement throttle body. Below is the graph showing when I constantly hold down the throttle (blue line), the air/fuel mixture command is constant (green line) but the throttle manifold position is changing (red line).

Image

I don't know of anything else I can do besides changing the throttle body. Any ideas?

fiestaz · 13-10-2018, 06:17 PM

Had similar stuff in a 2011 fiesta. The throttle body was filthy. Cleaned it. Was never an issue again. Ford’s recommendation on air filter changes is too long!

jb1212 · 13-10-2018, 07:32 PM

Quote:

Originally Posted by fiestaz

Had similar stuff in a 2011 fiesta. The throttle body was filthy. Cleaned it. Was never an issue again. Ford’s recommendation on air filter changes is too long!

Thanks for that idea. I have made a video of what my throttle body looks like https://youtu.be/Lls2s9nkWKw is this how dirty yours was?

Some photos of the back and front of it are here: backand front.

fiestaz · 13-10-2018, 11:00 PM

Quote:

Originally Posted by jb1212

Thanks for that idea. I have made a video of what my throttle body looks like https://youtu.be/Lls2s9nkWKw is this how dirty yours was?

Some photos of the back and front of it are here: backand front.

According to the mechanic mine was black. Yours doesn’t look to bad but cleaning it is no bad thing

jb1212 · 13-10-2018, 07:33 PM

Quote:

Originally Posted by jb1212

Thanks guys. I got a tool and the app and it just so happened the check engine light came on while the car was idling really rough.

The error was P2135. From reading about it and then doing some more graphing I conclude that I need to find a replacement throttle body. Below is the graph showing when I constantly hold down the throttle (blue line), the air/fuel mixture command is constant (green line) but the throttle manifold position is changing (red line).

Image

I don't know of anything else I can do besides changing the throttle body. Any ideas?

FYI the graph above is now here on a permanent link.

jb1212 · 15-10-2018, 11:08 PM

So I got a new throttle body. $80 second hand, dealers wanted to charge from $90-$200. The revs have stabilised as you can see here. Thanks for all your help.

P.S. As you can see in the image the timing advance is jumping up and down which I will research in the forum now. Also, my cruise control is not working - I will also research that now.

P.S.S. I found the Response OBD2 reader from Jaycar for $70 here to work well. I also found the Toggle app for $5 on Google play to work well along with the Realtime Charts plugin for $4 which helped me make easy to view graphs (like the one in this post).