Ok so i got my truck running okay. I have a few things which kind of trouble me.

#1. The COR Relay still needs to be corrected as I have to jump the green / yellow wire to a ground for the fuel pump to come on the second ign click. with the key. Also the pump is constantly on. Should pressurize and turn off so it doesn't burn it's self out. <Using stock 3.0 COR>

#2. o2 sensors are not hooked up at all, and the ECU isn't throwing any codes... The Check engine light turns on and then goes off. Once started. I hookup my obd2 reader and get no codes back. Kind of interesting. You would think the ECU would fire off codes right off the bat.

 

1) i have a 92, and didn't mess with the fuel pump wiring at all.

2) you don't happen to have the obd2 power wire running to the check engine light do you?
Are you not running the o2's, just to test you obd2 port?

 

really, and you used the stock 3.0 COR... man your good, i can't get it working correctly how it should....

i posted my wiring on this thread. ham was trying to help me out....

https://www.yotatech.com/forums/f160...44/index3.html


no. LOL! the obd2 has a constant hot, both grounds are ground, and the sil is connected to plug D on my ecu harness at the sil connection. I had the sil connection crossed with the speed sensor and the obd2 reader kept giving me a p1600. Then i corrected that issue, and everything is code free. But i'm sure the ecu would trigger a check engine light as the o2's are not even present. Meaning i don't have them yet. Still sitting at the store to be bought. =)

 

BTW I ran to autozone and found a aftermarket 3.4 COR Relay. The part number for autozone is 19997. Now i just have to figure out how to wire it in. I think i have it wired in correctly but i could be wrong. Can't find any 3.4 COR Write ups...

 

yeah i didnt mess with it, at all. Unfortunately all my wiring diagrams are 100miles away right now.

 

i ran the 3.0 COR. i can't remember exactly how, but it sounds like you aren't going that way now. i had to drive mine a couple of times without the o2 sensors while i was getting my exhaust dealt with. it took a few miles of driving before the ecu threw the codes.

 

This is good to know about the codes. Any how i got the 3.4 Relay working just fine. I will post a link a sticky to it for people wanting to go that route. I documented it pretty well, and using the autozone relay for 5 bucks you can't go wrong. In total you use three wires. The grounds that the 3.0 uses you can tuck away.

 

https://www.yotatech.com/forums/f160...-howto-213623/

fixed the COR issue. fuel pump turns on and off like it should.
woot! friday i'll be heading down to the mufflershop. oh btw i noticed the old o2 sensor is a four wire. Is it compatible with the 3.4? If this works, i can just make a o2 simulator for the rear.

 

i looked at you cor post, and i must have wired in the green/yellow, to the cor.

 

yes... it was like 5 something in the morning when i did this. Give me a break... =) LOL! Thanks and it's been fixed.

 

Okay now i'm making progress. I got the engine to pop off the o2 sensors. This is good because i know the obd2 system is working spot on. Now my other question is shouldn't the VSS Speed Sensor pop off a code as well if it's not hooked up at all? I still need to crawl under the truck and wire that in. heading to the muffler shop today, to fix my exhaust. More stuff to come...

 

don't you have a mechanical speedo? did you hook up the wire from the comb. meter to the ecu? if you're speedo isn't electric, then that wire is the only one you need, and the ones that go to the tranny are scrap now.

 

no mine is electronic. I have one wire hooked up to the ECU. I think it's connected to the D connector. But I have not cut and spliced into the connectors on the transmission yet. So as far as reading speed, or backup lights. It's not hooked up at the source. But i would figure i'd get some kind of VSS code as it's not hooked up at the sensor level of things.