Minor issues

rah^ · 15 Dec 2015 at 21:32

So after earlier faffing this year to have a section of exhaust cut out and a new bit welded in (thanks to a custom exhaust company!) my cars now run into another issue

Being its only a fiesta 1.25 petrol (now done best part of 80k miles) its starting to run a little rough

Its had new plugs / leads / coil pack and runs no different with or without the lambda sensor plugged in. It also has no codes stored so "making the assumption" as yet its a sensor thats not running right but not bad enough that its throwing a code anywhere

In short it idles a little rough, it hesitates under acceleration, makes no difference if its hot or cold, on the very rare occasion when starting it can be really rough running for 10/20secs then all is back to its usual sorta rough running

I am looking at the "MAP" sensor as my next option to swap out but I suspect it could be numerous amounts of sensors or injectors etc? so any ideas?

Frozennova · 15 Dec 2015 at 21:35

It will be MAF sensor rather than a MAP sensor on a fiesta.

The easiest way to test this is to see if the car runs any better with it disconnectedness, it will be located between the airbox and throttle . Coolant temperature sensors are also known to cause running issues as they are directly used to calccalculatre required fuel aswell

rah^ · 15 Dec 2015 at 21:48

From my understanding (and physical looking) there is no MAF its a MAP sensor on mine? I maybe wrong? but the airbox is connected directly to the throttle body nothing on it

swinnie · 15 Dec 2015 at 23:07

What age is the car?

rah^ · 16 Dec 2015 at 07:56

Oops that might help I guess! It's a 59 plate (2009!)

LEK-89 · 16 Dec 2015 at 11:49

Have you also considered the fuel filter? This could cause general rough running - as can the coolant temperature sensor in the engine block if it's on the way out as well (the engine is getting incorrect temperature readings which therefore is either under fueling or over fueling the engine).

If I am right anything like the MAP or MAF sensor would bring up the engine warning light as well?

Liam.

swinnie · 16 Dec 2015 at 12:50

Fuel Filter is a good shout. Also, perhaps a dirty throttle body?

rah^ · 16 Dec 2015 at 13:32

LEK-89 said:
Have you also considered the fuel filter? This could cause general rough running - as can the coolant temperature sensor in the engine block if it's on the way out as well (the engine is getting incorrect temperature readings which therefore is either under fueling or over fueling the engine).

If I am right anything like the MAP or MAF sensor would bring up the engine warning light as well?

Liam.

I couldn't for the life of me find a fuel filter anywhere to fit the car - even eucat website doesn't show one!

A dirty / underperforming MAP wouldn't until the readings were out of range but I'll take the advice and check the coolant sensor aswell.

swinnie said:
Fuel Filter is a good shout. Also, perhaps a dirty throttle body?

I did take the throttle body out and clean it however to be sure I'll take it back out and do it again.

rah^ · 17 Dec 2015 at 20:32

So on this I did manage to hunt the map sensor down.. looked clean no issues and no change.

Throttle body back out and cleaned again no change.

I've decided to just drop it back into a garage tomorrow afternoon explained the problems etc and the guys going to give it a once over