okay here's the deal:

I have an 88gxl s4......we put a 89 turbo 2 s5 engine & trans.(incl. s4 ecu, wiring harness, spark plugs etc.)

The car starts but sounds wierd like its not right... It's running really rich...and If you let go of the gas the engine dies...So it's not idling...

Can anyone help me and tell me what the problem can be?? So I can get it on the road asap. thanks.

 

vacuum leak? bad coil. check for spark.

 

Its not the sparks, cause the car's starting...which means there's sparks...it might be a vacuum leak..

 

just cause it starts doesnt mean you can't have bad spark going on...

 

well essentially you can run your car on 2 plugs, just cause it starts doesn't mean anything, i would check spark just to be sure, also check resistance from your coils.
dont just assume things are fine, eliminate every aspect, its called troubleshooting.

 

Could it be the S5 injectors with the S4 ECU? High and low impedence mix?

 

yes it could unless he has a resister. that is why he needs to check resistance.

 

Make sure you are using the correct boost sensor....the calibrations are vastly different between TII and NA.

 

im using the s4 injectors on the s5 engine because im using the s4 ecu and harness...im basically making the engine think it's and s4 but it's really an s5.

 

I'm doing same swap, but using s4 and s5 ecu (s4 for fuel s5 for everything else[from what mechanic said])
Hope mine works good.
Good luck.

 

So you wont use the last 1000 rpm?! From 7000 to 8000 I mean...S5 have lighter rotors and an intake that enables that.

 

That's only on the s5 n/a, not the TII. Besides, on a stock turbo there really isnt much point in going past 6500rpms. The turbo cant keep up and boost falls off.