(10-02-2021, 11:46 AM)k1n3k Wrote: hey guys, new to the forum, but not suzuki's. I'm currently working on the third tracker in my fleet, and boy is it messed up. 

there are multiple problems compounded on each other from what I can tell, mostly previous owner not knowing what was allowed and what was not...

So what I have is a 1993 FED 16v 4 door manual trans sidekick. I believe the engine harness has been swapped and the engine has been swapped, all from different sources. The Diagnostics plug by the battery has 4 pins, i believe the 16v 4 doors came from factory with a 6 pin IIRC. It runs like crap. Limp mode, rough idle when cold and sitting at 3000 RPM, surging idle when warm between 1500 and 2500 RPM. when I picked it up, there was a 1994 FED manual 16v ECU in it, throwing a code 23 for the missing IAT. no problem, I had the old ECU and it was correct for the vehicle. Tossed it in. Code 53. removed and cleaned all of the grounds in the engine bay. code 53.  Took apart the ECU and it had a leaky capacitor and some PCB damage, I repaired the corroded traces and replaced the capacitors (I have electronics experience and have done similar work on many things with great results).

After repair, with the jumper in it started (still ran like crap) and had code 12 and would sit there until you touched the throttle then it would throw code 53.  disconnect the EGRT and threw a 10k resistor in the plug, reset codes by pulling dome light fuse. No change. Disconnected the resistor, reset again. Code 12 until throttle was touched, code 53. Ordered a rebuilt ECU from cardone as this one was pretty hammered with corrosion. Installed new ECU, EGRT connected, code 53 on key on. Disconnected EGRT, install resistor, reset codes, code 53 on key on. Pull resistor, nothing connected to EGRT, Code 53. Test continuity of wire, pass. Check for short to ground, none. Find somewhat sketchy splice for O2 sensor, disconnect. No o2, no EGRT, test fire and get a code 12 even after test drive. Clearly something is messed up here. Still runs like crap.

I talked to previous owner, he fiddled with everything on the throttle body as well. IAC seems to not be able to control idle. reset the bleed screw as per the instructions on this site, just backed off the throttle plate stop to allow it to fully close to troubleshoot the other issues first. Now the idle is down to 1500 and is no longer surging. Better, but not there yet. 

So this is where I'm at. Are there any differences between the wiring harnesses that can cause these issues? There is a deteriorated tag under the windsheild wiper motor on the harness that has some numbers, they are y0fe2-3660-70???? and 2f 37224. I hate to throw money at this vehicle as the engine does smoke a bit and the compression is a tad low. Is this thing a lost cause to get it running decently? I have a VW diesel that I could swap in, but thats sort of a last ditch effort to keep the vehicle from being parted out. Its a decently straight, rust free body and a good interior. 

There is also a thermal switch on the intake that is not connected to anything nor is there a plug to connect to it.  (no photos , to me , hard to guess this) (YES AC engine overheat switch ) yes. NO AC means useless switch.

Any help is appreciated, I'm not sure where I should be concentrating my efforts at the moment.