I have a 1991 Sierra RS Cosworth 4x4 and it has the following upgrades:-

• 3 bar map sensor
• Stage 2 sue collins chip
• Light Green Injectors
• -31 Auctuator
• Cone Air Filter

But my car is running very lean when it comes up onto boost. I have recenly changed the fuel filter and a full engine service including plugs, can anyboady give some advise on how to cure this problem. Thanks

 

What AFR's is it making on boost?

What fuel pressure are you running?

What boost are you getting up to?

 

it is making 16.1 at 16psi

fuel pressure is 2.8bar on idle and rises to 3.4/3.5 bar on load

it peaks at 18psi and drops to 16/15 psi

 

So your fuel pressure with half a bar or so of vacuum is 2.8 bar, and with 1.1 bar of boost is 3.5 bar?

If so, I would say that you have a problem with your pump or pump wiring, or possibly even the diaphram in your regulator, as if its 2.8 on idle, it should be 4.5 or so when running 16psi of boost!

 

thanks for your information i am very greatfull.

 

No problem, obviously I would STRONGLY advise you dont keep putting your foot down with it till this is sorted!