[Poptart]

Originally Posted by theWeezL

An internal combustion engine needs 3 things to run: fuel, spark, and compression. The easiest one on to check on a Supra is spark. Pull a spark plug out, using an insulated or non metal tool hold the threaded part of the plug against ground somewhere. Have someone crank the engine, if you got nice blue spark your electricals are fine.

Fuel and compression are little hard to check. you need to see if you have adequate fuel pressure at the injectors but you need a fuel pressure gauge to do it properly. I dont know for sure on the Supra 'cause I havent had to get in there and check myself, but usually there is a fuel pressure relief valve somewhere on the the fuel rail. It looks like a tire valve basically. if you press the valve you should get a squirt of fuel. if there is no valve on the Supra, you might just be able to squeeze the soft supply line going to the fuel rail and see if if it feels like there is pressure there. Otherwise your going to have to buy or borrow a fuel pressure gauge.

Compression is relatively easy to check, it just requires the proper tool. any auto parts store should have one. You simply place the testers hose in place of each spark plug and crank the engine over. Read your higest compression and watch for leakdown, then move on to the next plug.

So in short, test for spark, test for fuel pressure, test for compression...whichever one is your issue will require further diagnostics, but at least you will have a place to start.

Thanks for you response WeezL, I will let you know on further information =)