diff --git a/ImpesTPFAAD.hpp b/ImpesTPFAAD.hpp
index e304d53b0..bd877eff5 100644
--- a/ImpesTPFAAD.hpp
+++ b/ImpesTPFAAD.hpp
@@ -279,6 +279,11 @@ namespace Opm {
 
             const int nc = grid_.number_of_cells;
             M matr = cell_residual_.derivative()[0];
+
+#if HACK_INCOMPRESSIBLE_GRAVITY
+            matr.coeffRef(0, 0) *= 2;
+#endif
+
             V dp(nc);
             const V p0 = Eigen::Map<const V>(&state.pressure()[0], nc, 1);
             Opm::LinearSolverInterface::LinearSolverReport rep
diff --git a/test_impestpfa_ad.cpp b/test_impestpfa_ad.cpp
index 278da4378..2344dfc0a 100644
--- a/test_impestpfa_ad.cpp
+++ b/test_impestpfa_ad.cpp
@@ -99,7 +99,7 @@ int
 main(int argc, char* argv[])
 {
     const Opm::parameter::ParameterGroup param(argc, argv, false);
-    const Opm::GridManager               gm(3, 3);
+    const Opm::GridManager               gm(20, 1);
 
     const UnstructuredGrid*              g  = gm.c_grid();
     const int                            nc = g->number_of_cells;
@@ -125,7 +125,8 @@ main(int argc, char* argv[])
         THROW("Something went wrong with well init.");
     }
 
-    GeoProps geo(*g, props);
+    double grav[] = { 1.0, 0.0 };
+    GeoProps geo(*g, props, grav);
     Opm::LinearSolverFactory linsolver(param);
     PSolver  ps (*g, props, geo, *wells, linsolver);