Long time lurker of your forum. The forum has given me some help in the past so I figure I would share something. I doubt I'm the only one whos had a rich condition that seemed unsolvable... So here's the ride. 1986 4runner that I picked up from a police auction for $250. The auctions are sight unseen minus some basic pictures so the prices are cheap since you can't inspect the vehicle prior to sale. It had some front end damage and looking at the description, it was impounded from a dui so I figured that must mean it was running when parked and I was right... sort of. It fired right up after tow truck pulled it off the impound lot and I drove it home. It had many typical issues of having never been taken care of such as rust, no rear brakes, that sort of thing but I'm going to focus on the engine running condition. Driving it home, it smoked...ALOT.. Like a powerjoke trying to roll coal. Left soot everywhere and would blubber at idle.
1st thing to do was basic tune up, new plugs, cap, rotor and wires went in, old ones were so fouled there was almost no gap. Checked timing, spot on but jumpy .. figured timing chain was shot. Adjusted valves. Ran much better but still smoked.
Idle was all over the place so I figured idle valve was messed up so I taped off the inlet hole in the throttle body and re-adjusted to idle. Ran a little better, idle stayed still but still smoked.
Checked for vacuum leaks. Here's a fun one.. At some point, someone made a deliberate hole in pcv hose.. I'm guessing to lean it out. Replaced pcv hose, smoked worse, idle dropped, code 5 every once in a while until I gassed it to burp it out.
Code 5 says 02 so I checked o2 sensor. .9 volts steady at idle, small change at 2000ish rpm. No change with pulling of vacuum lines. Figured lazy 02 so I replaced with a new denso. Same voltage reading.
So what else controls fuel and stuff? Tps seemed like a good place to start. Couldn't get it into specs so I pulled it off to inspect. Was sticky and wouldn't "return to zero." Ordered a cheap aftermarket replacement from oreilly. Dead on arrival, did same thing as the old one. Ordered an oem replacement. Installed, set per instructions, checked timing. Runs a little better. Shifts where it should now. Still smoking.
Hmm..maybe the egr is acting up. May as well delete. Sawzalled the ends of egr off and filled with weld as block off plates. No change.
Checked cold start injector by removing and bending back to watch if it sprayed. No problems.
Mayble cat is plugged, removed it and it was, well maybe a little. Replaced with a cheap bosal. Still smokes, but now it burns the eyes instead of just being smoky.
I've made afms add more fuel before by adjusting, maybe I could lean it out too. Adjusted afm, no change. Tested afm, had some dead spots so I replaced with a reman. Drives better, still smokes.
Maybe fuel pressure regulator is acting up? Nope. 30psi with vacuum, 38 without.
Ect messed up? Well its old and ect is cheap. Replaced. No change.
Compression so low it cant combust correctly? Nope. Pleasant surprise, 180 on all 4.
Skipped a tooth on timing chain? Nope, a little off, but fine.
Something grounding injectors? My power probe has an injector pulse test mode and they were pulsing not solid. Cut apart engine wiring harness just to double check everything...All good.
Could it be a bad ground? Nope, all grounds were intact and I daisy chained another ground to be safe that goes battery-passenger fender-intake (at existing ground location)-bolt on head-firewall-igniter body-driver fender. No change, but hey, we're grounded.
Weak coil? Nope, ohmed out fine and swapped with another from a runner to double check.
Distributor pickup coil ohmed out fine, air gap was good.
Checked injectors. One had different resistance. Got a set from lce and installed. Its gotta be the injectors at this point.. So pull the plugs to clean the carbon prior to what I'm just positive will fix it. WOOHO no more smoke, idles great. Go to pull it out of driveway for test drive and it just backfires HARD. Ended up blowing the lid off of reman afm. Smell fuel, was running nice because I messed up an injector o-ring on install and it finally leaned out (by dumping fuel on the engine instead of in it.) Reinstall new o-rings on injectors. Now its missing pretty bad.. Every other time I've changed something major, I pull the plugs to clean the carbon off em and this last time the cheapy wires had enough. Replaced wires. Runs better, still smokes.
Maybe ecu is toast? Pulled it off and looked inside. Smelled fine, no corrosion, all the resistors looked ok, no burns. Probly fine.
Decided maybe timing chain was stretched enough to cause issues. I knew the timing chain guides were toast but I really didn't want to deal with locking up the motor to tighten since this is an automatic. I bit the bullet and replaced the timing chain without pulling head or pan since I'm lazy. Got everything back together and still didn't want to mess with pulling starter to lock engine for crank bolt tightening so I tried something else.. I put a 2x6 from the crank pulley to my floor jack. I jacked it up till wheels were starting to unload from the ground. Torqued it to spec just fine. EASY PEASY. Runs a little better but still wayyy rich. Drives ok and no oil leaks but this thing is just spitting fuel.
At this point I've replaced and checked all I can think of and most of the forums with similar symptoms are left unanswered or end with a motor swap. I will not be defeated by this thing. So I do what I should have done in the 1st place. Ordered an FSM. Then I get to thinking, I've replaced everything I can think of besides the ecu...What the heck, may as well try one. Lucked out and found one on ebay advertised 86 4runner automatic. Plugged it in. Runs great.
