diff --git a/opm/material/eos/PengRobinson.hpp b/opm/material/eos/PengRobinson.hpp
index 6512c41b3..8559e6be0 100644
--- a/opm/material/eos/PengRobinson.hpp
+++ b/opm/material/eos/PengRobinson.hpp
@@ -191,10 +191,13 @@ public:
             // the EOS has three intersections with the pressure,
             // i.e. the molar volume of gas is the largest one and the
             // molar volume of liquid is the smallest one
+#warning HACK, should investigate why
             if (isGasPhase)
-                Vm = Z[2]*RT/p;
+                //  Vm = Z[2]*RT/p;
+                Vm = max(1e-7, Z[2]*RT/p);
             else
-                Vm = Z[0]*RT/p;
+                //  Vm = Z[2]*RT/p;
+                Vm = max(1e-7, Z[0]*RT/p);
         }
         else if (numSol == 1) {
             // the EOS only has one intersection with the pressure,
@@ -203,27 +206,28 @@ public:
             Evaluation VmCubic = Z[0]*RT/p;
             Vm = VmCubic;
 
+#warning, should investigate why here
             // find the extrema (if they are present)
-            Evaluation Vmin, Vmax, pmin, pmax;
-            if (findExtrema_(Vmin, Vmax,
-                             pmin, pmax,
-                             a, b, T))
-            {
-                if (isGasPhase)
-                    Vm = std::max(Vmax, VmCubic);
-                else {
-                    if (Vmin > 0)
-                        Vm = std::min(Vmin, VmCubic);
-                    else
-                        Vm = VmCubic;
-                }
-            }
-            else {
-                // the EOS does not exhibit any physically meaningful
-                // extrema, and the fluid is critical...
-                Vm = VmCubic;
-                handleCriticalFluid_(Vm, fs, params, phaseIdx, isGasPhase);
-            }
+            // Evaluation Vmin, Vmax, pmin, pmax;
+            // if (findExtrema_(Vmin, Vmax,
+            //                  pmin, pmax,
+            //                  a, b, T))
+            // {
+            //     if (isGasPhase)
+            //         Vm = std::max(Vmax, VmCubic);
+            //     else {
+            //         if (Vmin > 0)
+            //             Vm = std::min(Vmin, VmCubic);
+            //         else
+            //             Vm = VmCubic;
+            //     }
+            // }
+            // else {
+            //     // the EOS does not exhibit any physically meaningful
+            //     // extrema, and the fluid is critical...
+            //     Vm = VmCubic;
+            //     handleCriticalFluid_(Vm, fs, params, phaseIdx, isGasPhase);
+            // }
         }
 
         Valgrind::CheckDefined(Vm);
diff --git a/opm/material/eos/PengRobinsonMixture.hpp b/opm/material/eos/PengRobinsonMixture.hpp
index ce987177f..d93453999 100644
--- a/opm/material/eos/PengRobinsonMixture.hpp
+++ b/opm/material/eos/PengRobinsonMixture.hpp
@@ -87,12 +87,28 @@ public:
       * R. Reid, et al.: The Properties of Gases and Liquids,
       * 4th edition, McGraw-Hill, 1987, pp. 42-44, 143-145
       */
+#warning should check why this function is changed
     template <class FluidState, class Params, class LhsEval = typename FluidState::Scalar>
-    static LhsEval computeFugacityCoefficient(const FluidState& fs,
-                                              const Params& params,
+    static LhsEval computeFugacityCoefficient(const FluidState& fs2,
+                                              const Params& params2,
                                               unsigned phaseIdx,
                                               unsigned compIdx)
     {
+#warning also a HACK, should investigate why
+        auto fs = fs2;
+        double sumx = 0.0;
+        for (int i = 0; i < FluidState::numComponents; ++i)
+            sumx += Opm::scalarValue(fs.moleFraction(phaseIdx, i));
+        if (sumx < 0.95)  {
+            double alpha = 0.95/sumx;
+            std::cerr << "normalize: " << sumx
+                      << " alpha: " << alpha << "\n";
+            for (int i = 0; i < FluidState::numComponents; ++i)
+                fs.setMoleFraction(phaseIdx, i, alpha*fs.moleFraction(phaseIdx, i));
+        }
+
+        auto params = params2;
+        params.updatePhase(fs, phaseIdx);
         // note that we normalize the component mole fractions, so
         // that their sum is 100%. This increases numerical stability
         // considerably if the fluid state is not physical.
diff --git a/tests/test_chiflash.cpp b/tests/test_chiflash.cpp
index 4d7823727..f81f2e0a3 100644
--- a/tests/test_chiflash.cpp
+++ b/tests/test_chiflash.cpp
@@ -78,7 +78,18 @@ void testChiFlash()
     fs.setDensity(FluidSystem::gasPhaseIdx, FluidSystem::density(fs, paramCache, FluidSystem::gasPhaseIdx));
 
     ComponentVector zInit(0.); // TODO; zInit needs to be normalized.
-    const double flash_tolerance = 1.e-8;
+    {
+        Scalar sumMoles = 0.0;
+        for (unsigned phaseIdx = 0; phaseIdx < FluidSystem::numPhases; ++phaseIdx) {
+            for (unsigned compIdx = 0; compIdx < numComponents; ++compIdx) {
+                Scalar tmp = Opm::getValue(fs.molarity(phaseIdx, compIdx) * fs.saturation(phaseIdx));
+                zInit[compIdx] += Opm::max(tmp, 1e-8);
+                sumMoles += tmp;
+            }
+        }
+        zInit /= sumMoles;
+    }
+    const double flash_tolerance = -1.; // just to test the setup in co2-compositional
     const int flash_verbosity = 1;
     const std::string flash_twophase_method = "ssi";