rjtrials

Hey everybody!

i recently bought an 89 toy pickup that had a 95 engine dropped into it. i was under the impression that one or two sensor changes were needed for it to run smoothly. this was not the case. basically it runs rich at all times. somehow there is way too much fuel being dumped into the system.
The first issue was to replace the cold start time switch which had been broken when the new engine was put it. this fixed the start issue, but not the richness.
i put in:
plugs and wires
fixed the ECM vacuum hose bull crap that whoever did the swap left me
02 sensor
fuel pressure regulator
The ECU has faults still for coolant temp, tpms sensor, air mass meter, air temp sensor and knock sensor.

my thoughts are that its probably a ground or wiring issue to throw all those codes at once...
so, i am looking for a good Toy obd1 mechanic to help me sort out my issues.

Thanks for any help!
RJ

RJR

First, if you haven't already, pull the EFI fuse for 30 seconds to clear out all of the codes, to make sure you're not reading codes from a long time ago. Then run the engine until it gets warm and see what shows up. If you still have all of those codes, I would wonder about imcompatibility between the wiring harness and the new engine/ECU.

Also, what do you mean by "fixed the ECM vacuum hose bull that whoever did the swap left me"? If you just randomly pulled out vacuum hoses and capped the ports, the ECU is not going to be happy, and your engine will not run well. Toyota designed all those vacuum lines, sensors, and controls as a system, and when all together and healthy, it works quite well. Mess with it at your own risk.

rjtrials

i would guess that a full third of the hoses were either running to the wrong sensor or capped unnecessarily. There is an excellent post on this forum that helped my sort it out.
The only ports i blocked off were the AC idle up. on my engine, each of these has and extra, smaller port that comes off, and i couldnt find any info on what those do. the engine idles better with them routes to each other rather than capped off.

RJR

It sounds like you indeed have a grounding issue or a harness incompatibility issue. I would take the sensors one at a time and trace them out and make sure they are going to the proper pin on the ECU. Use an ohm-meter to check for continuity and isolation from ground. Leave the knock sensor til last, not because it's unimportant, but because it's a bear to get to, and maybe in fixing the others you'll wind up correcting that one as well.

Also, somewhere on this forum is an excellent post describing all of the grounds and their locations. I wish I'd bookmarked it, but all I can do is suggest searching. Usually Google finds stuff better on this forum than the internal search engine.