midtownmobile

I just bought a 1988 DOHC Si with a 1992 PGMFi intake and it idles up and down like in a cycle. I cleaned the idle control solenoid and that didnt fix it. My next move is to put a vacuum pump on the EGR and check the OHMs for resistance then clean that. Its also running rich and i've checked and rechecked all the vacuum lines. The up and down high idle seems to be a vacuum leak (the usual suspect) but it could be a number of things. Being that the car is as old as it is its probably an OBD1 system. How do i check for error codes and where is the port(s)

teenlude09

no port if theres an error code start the car look on the floor on the passenger side there should be a little flap pull it back and thats the ecu if theres a code itll flash a certain amount of times count the number and look up the code.

midtownmobile

Fixed the code it gave me an injector DTC. But the idle still revs up and down in a cycle. I removed and thoroughly cleaned the idle air control module, the fast idle valve and the bypass control valve. They were a little sooty from running in limp mode (rich v lean) and rerouted all the vaccuum lines according to CHILTONS and still have this idle surging problem.

teenlude09

did you check the eacv? thats the most common problem with 3rd gens. hell thats the problem im having with mine at the moment although mines a bit different