Engine swap

[irod1990]

I have a 1994 300zx that was non turbo. I swapped in a VG30DETT engine with the ECU a couple of years ago. I had the custom piping made to connect the intercooler (the piping wasn't done too good as far as welding), changed the fuel pump, and installed the blow up valves. It doesn't run smooth and seems to misfire. Ive had trouble with it overheating several times. The first time was a broken water hose in the back of the engine that was then fixed, and now it's overheated again twice in the past couple of weeks. Both time have been in hot days driving a long distance, and when it overheats it leaks water from the back of the engine again. I can drive it short distances without it overheating. I haven't found the leak so Im not sure whats wrong. If someone can help me with the overheating problem and the misfiring

[solaire]

Misfires on these cars are common so it could be something like an injector or PTU wiring but the fact that it overheated means it could have blown a head gasket. There's a lot of small hoses on the back of the engine so it could be anything. May need to pull the battery to make room and get back there to check.

[t.mcginley.jr]

Overheating can be caused from: bad thermostat, bad water pump, bad head gaskets, leaking radiator, bad fan clutch, or just not enough cooling (like if you installed an electric fan and it wasn't strong enough), or air in the cooling system.

Misfiring could be anything, what spark plugs are you using? how old are they? and how old are your injectors?

Also, how come you made custom intake piping? Do you have a front mount intercooler or something?

[nissanfreak12]

Blow up valves? That could be your problem.

[nissanfreak12]

When you did the swap, did you get the ECU tuned for the swap? Have you checked the ECU for codes? Have you tested te injectors? They should read 10-14 ohms. No more, no less. Are you sur you have the wiring correctly on the injectors and coil packs? 5 & 6 are very easy to mix up on the coil packs.

The water coming from the back of the engine could be a number of things, heater core hoses, the many hoses that connect to the plenum, the turbo cooling lines, freeze plugs, and as stated headgasket. MOre than likely a hose, head gaskets normally leak in the in the engine. Did you flush the system before installing the engine?