Running lean after 10psi

[eski]

Hi all

Today I did find a problem from my 91 spirit (2.5T). When accelerating and boost goes over 10psi A/F meter starts dropping to lean. And it drops quick to lean. (Max boost 13, using boost controller). Engine had run 13 psi several months withoug problems.

I did check vacuum lines, plugs look normal, no codes. I did change TPS, because I find one thread about running lean at some throttle position. I think MAP-sensor is propably broken, but some advice is it really broken. It is little expensive and I do not want to buy it for nothing.

-Esa

[toddipoo]

Most likely not the map.
Does your engine give any codes?

I would check the fuel pressure and maybe replace your fuel filter.

-toddi

[eski]

Hi

No code in this time mean codes 12, 33 and 55. So no codes Fuel filter was changed last spring.

But.. I am lazy as human can be.. rather buy new easily replaceable part than check fuel pressure.. Fuel pressure was idle at 40psi (vacuum connected). Changed it to 45psi (vacuum connected). I have 804 injectors and adjustable FPR from Gary. I did set fuel at idle to 45psi last spring, but I should have check it. Now I only need to test how it works now..

-Esa

[eski]

Hi

Problem still exist. I even raised fuel pressure to 50psi (vacuum connected). No help at all. It goes rich between 1-8 psi of boost. After that it drops fast to lean.

Do you have any good ideas what to test or replace?

-Esa

What octane gas are you running?

[eski]

I'm running 95, but when I convert it to US system it is 90.
(95 RON+85MON)/2.

-Esa

Unless your throwing a code for the MAP sensor that's probably not it, when mine was bad the car would barely even run but worse yet is that it ran really really lean and nuked 3 pistons. I can't think of anything else right now. Sorry

[glhsken]

Pump is wearing out and can't handle the higher pressures and flow required.

[eski]

Hi

Yeasterday I was driving and O2 sensor totally died. It show only lean or very lean. Today I started car and O2 only shows very lean.. car did run pretty crappy. I was driving to dealer to get new O2 sensor and when I was driving all information from A/F meter was lost. Then I got check engine light on and code 14.

I did send mail to Gary about new O2 and MAP. It comes cheaper to replace both that get O2 from local dealer. It cost 194e and that is something over 200usd.. nice...

Still I do not think that is fuel pump, yet.. even car has 270tkm on meter.

Thank you for help.

-Esa

[eski]

I'm back..

If someone is interested that problem is fixed now. New O2 and Map from Gary..

Now I'm running little rich on idle.. little bit tuning with AFPR should fix it...

-Esa