diff --git a/include/cantera/oneD/IonFlow.h b/include/cantera/oneD/IonFlow.h
index 5ce7019e02..6143c2ceee 100644
--- a/include/cantera/oneD/IonFlow.h
+++ b/include/cantera/oneD/IonFlow.h
@@ -79,6 +79,10 @@ class IonFlow : public FreeFlame
                               vector_fp& mobi_e_fixed);
 
 protected:
+    /*!
+     * This function overloads the original function. The residual function
+     * of Poisson's equation is added.
+     */
     virtual void evalResidual(double* x, double* rsd, int* diag,
                               double rdt, size_t jmin, size_t jmax);
     virtual void updateTransport(double* x, size_t j0, size_t j1);
diff --git a/include/cantera/oneD/StFlow.h b/include/cantera/oneD/StFlow.h
index 9f31c9c238..9b39a07683 100644
--- a/include/cantera/oneD/StFlow.h
+++ b/include/cantera/oneD/StFlow.h
@@ -242,9 +242,13 @@ class StFlow : public Domain1D
         m_kin->getNetProductionRates(&m_wdot(0,j));
     }
 
-    virtual void updateProperties(size_t jg, double* x, double* rsd, int* diag,
-                                  double rdt, size_t jmin, size_t jmax);
+    //! Update the properties (thermo, transport, and diffusion flux).
+    //! This function is called in eval after the points which need
+    //! to be updated are defined.
+    virtual void updateProperties(size_t jg, double* x, size_t jmin, size_t jmax);
 
+    //! Evaluate the residual function. This function is called in eval
+    //! after updateProperties is called.
     virtual void evalResidual(double* x, double* rsd, int* diag,
                               double rdt, size_t jmin, size_t jmax);
 
diff --git a/interfaces/cython/cantera/onedim.py b/interfaces/cython/cantera/onedim.py
index 2b4bc7028f..e40c786a95 100644
--- a/interfaces/cython/cantera/onedim.py
+++ b/interfaces/cython/cantera/onedim.py
@@ -547,10 +547,10 @@ def write_csv(self, filename, species='X', quiet=True):
         csvfile = open(filename, 'w')
         writer = _csv.writer(csvfile)
         writer.writerow(['z (m)', 'u (m/s)', 'V (1/s)', 'T (K)',
-                         'phi (V)', 'E (V/m)', 'rho (kmol/m3)'] + self.gas.species_names)
+                         'phi (V)', 'E (V/m)', 'rho (kg/m3)'] + self.gas.species_names)
         for n in range(self.flame.n_points):
             self.set_gas_state(n)
-            writer.writerow([z[n], u[n], V[n], T[n], phi[n], E[n], self.gas.density_mole] +
+            writer.writerow([z[n], u[n], V[n], T[n], phi[n], E[n], self.gas.density] +
                             list(getattr(self.gas, species)))
         csvfile.close()
         if not quiet:
diff --git a/src/oneD/StFlow.cpp b/src/oneD/StFlow.cpp
index e5d8962195..2b08d09632 100644
--- a/src/oneD/StFlow.cpp
+++ b/src/oneD/StFlow.cpp
@@ -240,12 +240,11 @@ void StFlow::eval(size_t jg, doublereal* xg,
         jmax = std::min(jpt+1,m_points-1);
     }
 
-    updateProperties(jg, x, rsd, diag, rdt, jmin, jmax);
+    updateProperties(jg, x, jmin, jmax);
     evalResidual(x, rsd, diag, rdt, jmin, jmax);
 }
 
-void StFlow::updateProperties(size_t jg, double* x, double* rsd, int* diag,
-                              double rdt, size_t jmin, size_t jmax)
+void StFlow::updateProperties(size_t jg, double* x, size_t jmin, size_t jmax)
 {
     // properties are computed for grid points from j0 to j1
     size_t j0 = std::max<size_t>(jmin, 1) - 1;