Ok so I bought a '97 SC300 from a buddy for 1000 dollars with a blown head gasket. Took the whole motor apart and had the head cleaned resurfaced and checked for cracks and warping. Head came back clean so I replaced the head gasket and put it all back together. Some of the vacuum lines have yet to be plugged in due to me not marking a few of them. There is also one plug that I cannot find where it goes (pic attached). The car turns over and it sounds like it wants to start but it won't. A friend of mine who owns a shop and does a lot of supras told me that just a few lines being unplugged would just cause a rough idle. He has no idea what the plug goes to though. Any ideas? Its a grey two wire plug that looks like it comes from under the Y pipe. Any help on getting it running? Thanks in advance!

 

Moved to maintenance. Plug everything (the ones you know go where) in, including the vacuum lines just to be safe and try to start it. Is that orange connector connected to the right in the photo?

 

Yeah everything that I know where it goes is plugged in. And yes the orange connector is plugged into the first fuel injector. The color for those is orange, grey, orange, grey, orange, grey correct?

 

there is normally a vsv for the egr in that area that is on a bracket that goes between the stud you can see there next to the valve cover with nothing on it, and there is a bolt on the plenum underneath the front that the other half of the bracket bolts down on. there is a vsv on the bracket that has a plug. the vsv also has 2 vacuum lines on it that come off metal hard lines.

its pretty difficult to route the hoses on this motor without knowing where they go or where they came from.
the one I am talking about is the "vacuum switching valve" and it is between the throttle body and the egr towards the bottom of the diagram.
you wont see the vac lines going there but if you follow the metal hardlines under the Y part of the intake you will see they do go where the diagram shows.


IF its a california model, there will also be a blue vsv (directly under the above vsv in the picture) for the fuel pressure regulator in that area, in line with the fuel pressure regulator vacuum hose, and a blue plug on the harness. this is only on cali models or if you are 96+ all sc300 got it. if you do not have a blue plug hanging out there on the harness then ignore that part on the diagram that says cali only that is what I am talking about, the vsv is sort of a dotted line to show its not on all models.

I would start by reconnecting all the vac hoses properly. your friend is right it will not want to run well or sometimes wont even start without it being back together.
yes the injector plugs alternate brown and silver, do not mix them up and hopefully that isn't an injector plug.

next time takes lots of pictures when dismantling it helps prevent this type of situation. I know where all the stuff goes but its still hard to explain it over the internet.

 

I just want to know where you find 97+ SC's in any shape for $1k, let alone just a HG issue... Good find man.

Any more pictures of the car?

 

Make sure your two engine harness ground (located on the intake manifold side) are properly bolted... car won't start if one of those is not bolted well to the ground.

 

This^^ .

And also it sounds like the distributor was not installed properly.. timing might be off.