mechgt5

Alright, so I just bought a 96 sc300 that's been sitting for a couple of years from a dealership for $600. Yes its auto, dirty, and it has 200k on it.

The problem is, I can't keep it running. Ive replaced fuel pump, did the fuel pump ecu mod, replaced ecu, new cap and rotor, and new wires.
I can soak the air filter in starting fluid and it will start and idle and even rev for about 20 seconds or so and then die. No RPM on tach, fuel gauge doesnt seem to work either. (it is low on gas though so idk) No codes in the ecu, but also no CEL (But i think the cel light is burned out)
obd2 is communicating though because I unplugged maf and it threw the associated code.
All fuses are fine, or new. It has about 3 gallons of fresh 93 in the tank also.

Im at a loss. It's like the injectors aren't firing, but every fuse is good.

Help?

RXRodger

iTrader: (2)

What about the ecu relay? And you say you replaced the ecu, it is a known good one right? You are going to have to check fuel pressure. When you say you have done the fuel pump ecu mod, what exactly did you do?

Turbostar

Unfortunately there is a laundry list of things to check.

Sounds like it is related to fuel, but also perhaps spark. You can check the coil if you have a multimeter (my 1993 manual says resistance should be between .2-.3 ohms).
Probably want to change the plugs as well.

As for fuel, can you pull a line and have someone crank it to make sure it is getting fuel? Also there are ways to electronically test the injectors with a multimeter.

Lastly, maybe clean the MAF, throttle body, and all that good stuff.

mechgt5

Replaced with a reman unit, all capacitors are good, i popped the cover and checked. Yes, relay is new.

Fuel pump ecu mod. Stripped the two wires and stuck them together.

I have pressure at the rail, brand new pump, and I can hear the fuel in the lines.

Also, its getting spark just fine, It was running and idling on starting fluid for about 20 seconds.

Turbostar

Sounds like you need to begin checking the injectors next. Thankfully you can do that with a multimeter.

Also, you mentioned it was low on gas in the original post. Perhaps old/bad fuel? Maybe add some more into the tank and see if that helps.

mechgt5

Not sure how to check injectors, and it was bone dry when I got the car, and I added about 3 gallons to it. It's def pumping from the pump.

mechgt5

Well, got it running.

Threw a new battery on it, and after about 5 minutes of starting and stalling, it runs and idles fine. No clue why the new battery helped, but it did the trick. These cars are finicky I can tell?

No tachometer though. All lights work, and no cel.

Turbostar

Glad to hear it is running well now!

Yeah the cluster lights going out is a very common issue with these cars. Look up Tanin Auto Electronics for restoration options.

mechgt5

Thanks, it's a little smoky, but hopefully thats just from it sitting since early 2019.
And the tach lights up fine, but the needle doesnt move at all, is that a common thing?
And the cel bulb is out, so thats been throwing me off the whole time.

So far, this $800 car has turned into about $1100, but hey the ac even works!

Turbostar

Man, its going to go up from there! Unfortunately these cars do not have the huge aftermarket of a Supra or something like that. For many parts on the car, once it is broke, its gone unless you can find a donor. No real reproduction stuff.

But, they are gorgeous cars when done right, as well as great drivers. Enjoy it!

Duck05

Welcome to the Club and your new addiction with this car!

In addition to the new battery, I highly recommend you replace the battery cables. The positive cable can be pricey so maybe a thorough cleaning is good but the ground cable is a cheap repair.

There are way too many electronic components in our cars and failures are routine (unfortunately). I just went through starting issues and on my now third ECU replacement along with fuel pump, fuel pressure regulator, water temp sensor, battery, and main relay until finally restoring normal status.

Welcome....

mechgt5

Thanks! And the battery cables are actually perfect. I checked all the grounds and power points while diagnosing the no start problem, no rust or corrosion anywhere on the car. And despite it sitting for three years, I took it on the road earlier and it drives great. Ice cold AC, just has a little bit of body damage and a rebuilt title for something.

I bought it to flip, but now I kinda like it too much lol