Engine runs rich

[OleH]

Hi all,
I'm having issues with my Sunny :sad:

This is the engine:
- 400+ bhp
- thicker headgasket than standard
- front mounted big intercooler
- LINK ECU
- Garret 3071R turbo
- 1.5 bar turbo pressure
- sharper camshafts fitted
- ported headers
- thicker wires from the battery back to the fuel pump
- 3" exhaust from turbo and back

These are the symptons:
- The spark plugs get black after very few miles (500 at most)
- Fuel pressure is 4-4.5 bar, maybe even higher under heavy load
- Air/Fuel ratio is 11.4 on idle, even richer under load
- Engine runs very sluggish, power only kicks in when the turbo kicks in
- The exhaust spits small black drops
- There's a definite smell of gasoline

This is the troubleshooting I have done:
- Compression test. The figures were fine
- Changed the spark plugs, new ones also get black after a short while
- Pressurised the vacuum system. It held 2 bar without leaks
- Changed the oil and filter. It has not used any oil the last 750 miles
- No bubbling in the coolant expansion tank = headgasket is fine
- Ohm'ed the leads (the are standard leads)

Where do I start troubleshooting now?

 

[vss irvine]

Does it run a maf or map sensor?

You need to look at the management and associated sensors.

Who mapped the car?

 

[PobodY]

I'd be looking at the mapping too.

 

[fubar andy]

Check your injectors are not stuck open too.

Listen to them when the engine is ticking over (put a screw driver on to the injector and the put your ear on the butt of the handle and you will hear a ticking noise)

 

[campbellju]

Can you read the MAF idle voltage to understand if it's in the right range?

 

[PobodY]

Check your injectors are not stuck open too.

Could that be more of a problem if you're running them at higher fuel pressure? - If it's 4-4.5bar at idle, and the boost pressure is 1.5bar; that's 5.5-6bar at full boost.

It just occurs to me that if the injector is designed to take 4-4.5bar at peak pressure (i.e. 3bar+1-1.5bar), maybe it's not coping with that at idle.

 

[OleH]

Does it run a maf or map sensor?

It runs a map sensor:
http://www.linkecu.com/products/InstallationAccessories/Sensors/mapsensor

You need to look at the management and associated sensors.

I have no error codes, and all sensors are functioning as far as I can tell.

Who mapped the car?

A garage in Norway ;-)

 

[OleH]

Check your injectors are not stuck open too.

Listen to them when the engine is ticking over (put a screw driver on to the injector and the put your ear on the butt of the handle and you will hear a ticking noise)

Thanks for the tip

 

[OleH]

Can you read the MAF idle voltage to understand if it's in the right range?

Not sure what the range is supposed to be?

 

[OleH]

Could that be more of a problem if you're running them at higher fuel pressure? - If it's 4-4.5bar at idle, and the boost pressure is 1.5bar; that's 5.5-6bar at full boost.

It just occurs to me that if the injector is designed to take 4-4.5bar at peak pressure (i.e. 3bar+1-1.5bar), maybe it's not coping with that at idle.

And the fuel pressure is regulated with the manual pressure regulator? Or is it done with the LINK system?

 

[PobodY]

Fuel pressure is regulated by the manual regulator, but it's not meant to be that high. - If Andy is suggesting there's an injector stuck open, I'm just wondering if it's because they can't take the fuel pressure.

Are they standard injectors or larger ones?

 

[Fusion Ed]

What fuel pressure reg and injectors do you have?

 

[OleH]

What fuel pressure reg and injectors do you have?

It's a no-name universal type: https://www.google.no/url?sa=i&rct=...bHR1wNkRqnjE_QQO7Yp1DzXA&ust=1382875147902498

The injectors are 700cc

 

[OleH]

The guy who tuned the car 3 years ago, said I should change out the small fuelfilter that's under the car to a bigger filter. Can anyone explain where it is, as I've not found it yet??

Also, the fuel pressure was 3bar at idle 3 years ago after I got the car back from mapping. Now the pressure has creeped up to 4 bar... Bad fuel pressure regulator??

 

[OleH]

Fuel pressure is regulated by the manual regulator, but it's not meant to be that high. - If Andy is suggesting there's an injector stuck open, I'm just wondering if it's because they can't take the fuel pressure.

Are they standard injectors or larger ones?

If I adjust the fuel pressure, do I have to adjust anything in the map?