GT40 Engine Questions

MrMcD wrote: First, pressure does not evaporate when the key is shut off.  There is a spec, it will say something like pressure should hold for five minutes and slowly decline over the next 30 minutes.  If you are losing pressure instantly you have a large leak.  Either the pressure regulator is stuck open or your injectors are not closing.  Black smoke on a restart points to injectors. Mark

If you have a mechanics stethoscope I would listen to the injectors while the engine is running.  Each injector should be making a very specific snap snap sound as the injector opens and closes while running.  If one is quiet, and your engine still runs strong, one is not closing.  Could be more than one.   Another way to test the pressure regulator is to block off the return line.  Your pressure should go much higher and stay there because it has no place to go.   Be careful how you block it off because the system may see 80 PSI or more blocked and you could create a high pressure gasoline spray gun doing this if your block off blows out.

I ran the pumps with the key on and the ground wire at the test connector.   Ran them several times, sometimes fuel pressure would hold.  Never got to test full throttle fuel pressure, engine got hot at dock.  Engine runs strong but I think it has more in it.  

Final update on this engine.  When replacing the impeller I decided to replace the thermostat too, only there wasn't a thermostat there.  The PO or the POO evidently had cooling problems and instead of replacing the impeller the just removed the thermostat.  With the new thermostat and impeller the engine stays rock solid at 160 degrees on the gauge.  

Soak those old bolts in a 50/50 mix of ATF and acetone.  Pour some on and let it soak in, overnight or longer if you have time.  Re apply a couple times if possible.  ATF = automatic transmission fluid.

Last time out, Tue 3 Nov, 65 degrees air temp, the problem is gone.  It may have something to do with the engine running hot, or the intake air temp sensor.

You can clean up those risers and manifolds pretty quick if you get a rubbermade type of container large enough to hold one. Being careful you can soak them in muratic acid- it will clean the insides of that crud. Keep an eye on them as you do it you don't want them in any longer than necessary. 

Exhaust manifold is almost completely closed at water outlet.  Hose is collapsed into manifold.

Only broke 2, both on the driver side.  Installed with stainless bolts and lots of anti-seize.