I did a 2.0 conversion on my sidekick and I'm having fuel trouble. running stock fuel pump. and running too rich . Any ideas? Thanks

how hard was the conversion to do? did you have to fab up motor mounts or did it go into the 1.6 ones. sorry its off topic but im going to do a 2.0 conversion in my 98 when the 1.6 blows

Maybe you'd like to share some more details ?

Should we assume you're running the original ECU, injectors, etc., etc., is there a check light, is it OBDI, OBDII, does it have an O2 sensor?

I did a 2.0 conversion on my sidekick and I'm having fuel trouble. running stock fuel pump. and running too rich . Any ideas? Thanks

Are you running the return fuel line? 

Like the others I would like to hear more about your installation.  We installed one in Dron637's race car but with just basic motor function wiring it was easy to do.  We are running a racing pump (way over kill), but have the return line plumbed back to fuel cell.

Ok, so I am running a fuel return line. I'm runnning a trail tough wiring  harness with the 2.0 ecu. That draws power through four wires that tie into the 1.6 harness. Stock 2.0 injectors etc, everything is 2.0 motor wise I am running the stock sidekick tank and pump. Off topic I did build the motor mounts myself, used the transmission to locate the motor.

Sounds similar to the race rig.

Are you using the MAF from a 2.0 or the one from your Sidekick?  You must use both the 2.0 air flow sensor, and the 2.0 maniflold air pressure sensor for the the 2.0 (I would also use a 2.0 IAT) sensor. 
Grounds are EXTREMELY important.  Lack of or poor grounding can send you chasing the wrong issues (BEEN THERE, STILL CHASING SOME).  TT should have the grounds covered in there wiring harness, so just be sure they are all tight.

I've used all 2.0 stuff  iat, maf, grounds are all tight and clean, even added an extra ground from the motor to the car, jluck had made the giant battery cables as well, all plugs are very dark brown indicating rich. I've replaced plugs, fuel filter, cleaned everything and I'm not dumb, just stumped.

The other thing I've looked into is that the fuel pressure regulator could be bad. I've looked into it from my chilton manual says that if I turn the key on with the fuel return disconnected I should not get fuel through the regulator. However everyone I've talked to says that its normal and the chilton is wrong which I don't doubt but . Even if its bad wouldn't that make it run lean if its stuck open?? I've also checked the fuel return line and its not plugged. I can blow through it. Not easily but I can. The only other thing I can think of is that its not sufficient enough to move the proper volume of fuel.

What does the 02 sensor read via your ODBC II reader?

I would give Trail Tough a call, if they put together the harness they should be able to help you troubleshoot the wiring.

What does the 02 sensor read via your ODBC II reader?

I would give Trail Tough a call, if they put together the harness they should be able to help you troubleshoot the wiring.

 I didn't say anything about wiring.  Wiring is fine I just can't find why it running rich.

If it is running rich it is because the computer system thinks that it is running lean so it is putting more gas into it to compensate.  That happens because the 02 sensor is either giving the wrong reading because it is bad or because you have extra resistance somewhere in the line that is leading to the computer receiving the wrong information.

Do you think it is running rich because you can smell un-burnt fuel or does the 02 sensor tell you that it is running rich?

Another possible reason for it to run rich is a defective ECT sensor or wiring, or a missing thermostat, and since this is an engine swap - incorrect cooling system plumbing - if the ECT reports the engine as below operating temperature, whether that be erroneous or not, the ECU will stay in open loop and ignore the O2 sensor.

The J20 has a somewhat unusual cooling system - the ECT is a dual element sensor (one for the ECU one for the gauge) located on the water outlet elbow at the back of the cylinder head, and from there the flow splits three ways, one through the heater core, the second through the throttle body, and the third goes to the radiator top hose, down through the radiator, back to the engine, and through the thermostat to the water pump, before re-entering the block.

Thanks for the info. Is there a way to test the sensor? The plugs are very dark and I can smell the unburnt fuel.

The other issue I'm having is that when it does warm up it will stall at stop lights I can start it right back up. But when I come to a stop it will choke out and die almost like its flooded.

You can check it with an ohmmeter - should be between say 300~3000 ohms, going lower as the temperature rises.

I think it's also a good idea to get a fuel pressure gauge on there - and as other people have said, I think there should be fuel flowing in the return before the engine starts.