I just got my EVO 8 back together today after it had been sitting for about 1 month. As soon as I started the car it started to overheat. I cleaned out the radiator and it got better but its still running hotter then normal. I just replaced the thermostat 2 months ago. Also it has a bad idle at times like theres a bad boost leak or something but when I get on it a bit it goes away, and then I am spewing black stuff out the muffler and theres way more smoke (black) then there should be when I boost at above like 8 PSI. I checked all my intercooler pipes and stuff and they are good. Any ideas on these problems. I just put in a 10.5 hotside and a new O2 housing and headers and got a new reflash.

 

black smoke= rich mixture, as far as the overheat, where is the gauge? above 1/2? may have a bad misfire also... need more info! cannot compute........

 

Yeah its running richer then when the ECU was stock and I have 700cc inj. a walbro BR stage 1 and 2 but I finally got it reflashed by dynoflash and its running way rich. and the temp gauge sits right at half or slighty above, my water temp is reading almost 210.

 

Chris, Any codes?? I would check the emmisions equipment, is it MAP or MAF, is FPR hooked to Vac, ohm and voltage the injectors and check for vac leaks.

210 seems a little high but its not going to damage anything at that level.