I recently got a '88 GXL and have been getting it running, well it starts up and runs fine .. until it warms up completely. Then it will start but won't rev over 1500rpm and will just surge from 1200-1500 when you give it any gas at all. It also blows black smoke out the first time you give it gas. It will idle fine unless you pull the gas pedal up and then it will idle down until it tries to die. If you let it sit for a few hours and cool down it'll start and run normally again until it gets completely up to temp. Any help is appreciated as I really want to drive this car but it's not cooperating.

 

black is usually very rich condition. Its possible a coolant temp sensor has given out.

 

Unplug the TPS and have a go at it.

 

checking the plugs wouldnt hurt either.

does the car have a fuel shut off switch?

 

I tried a new TPS and it didn't change anything, the plugs are dark as it is obviously running extremely rich, the question is why is it running too rich? I also noticed that there are new injector connectors spliced into the harness by the previous owner so I don't know if it's running stock injectors or not.

The car doesn't have an aftermarket fuel shutoff but I don't know about stock, since it's spouting black smoke I'm looking towards too much fuel not too little.

I'm guessing there are two different temp senders, one for the gauge and one for the computer because the gauge reads just fine. I'll look around and see what I can find in terms of another temp sender and how to test it. Keep the ideas coming, this is great!

 

The water thermo sensor used by the ECU is on the back of the water pump Housing. Two wires, green colored jack.

Did you ever just UNPLUG the TPS and then try to drive the car? The RX is driveable without a TPS connected up. TPS do not deliver fuel.

 

The car is completely undriveable when it's doing this, you can't make it go faster than about three mph. I didn't get a chance to work on it today like I planned, I ended up swapping fuel pumps in an FD instead.

I haven't unplugged the TPS and tried it like that, I'll do that tomorrow.