Disregard last suggestion the information is incorrect!! Don't cut and run any jumper wire , it is wrong and will not work. hanky

 

Repeating ----disregard last suggestion !! Do not cut ACT wire. The info I have is incorrect and it will not work! You were right in suspecting an open to the sig ret wire. ,,,,,hanky

 

well unfortunately - I've been driving around unable to locate the issue for the check engine light. No worries Hank - I didn't cut any wiring.

I think it's the VAT sensor - after doing some reading. Remember I replaced the ACT sensor with no change in results.

However - check this out

This is the OEM negative battery cable for a 90 BII. It has 2 pigtails (red) and (black) that connect to a sensor. The actual THICK negative battery cable goes into the large part of the unit and then down to what seems to be a sensor of some sort in the oil pan - or something. The blue tape is from me - to what I presume is the negative wire since the sensor plug cannot be reversed...you basically take the raw wire of the negative cable and literally bolt it into the large black piece of the unit seen in the pic with the 2 pig tail wires coming off it.

The question is - on the female end of the sensor (the part that plugs into the part with the blue tape) - there is a black/green stripe wire and a black/white stripe wire. Which is ground? The male end of the sensor has 2 black wires coming from it.

The previous owners had a ****ty splice from the negative battery cable that had one smaller wire coming off it..going into the 2 wires for the sensor. I found the random 3rd battery cable hanging down by the damn axle the other day - WTF. It was grounded to the frame, but just swinging in the damn breeze. I unhooked it from the ground point it shared with the "new" cable put in by the previous owner and now the truck starts with a loud buzz or humm as if the starter is frozen, then it slowly starts up.
There is a smaller negative wire grounded to the frame tied into the LARGE negative battery cable. It is still connected to the frame. Bt connected to nothing else since I removed the random battery cable.


smaller wire coming off the negative battery cable

goes here

old crappy splice - see...one wire...with 2 on the other side.

that's the negative battery cable. It was hanging down swingin in the breeze - with the only ground connection being that smaller wire. The replacement cable someone else did shared the same ground - hope that makes sense. I think the sensor in the oil pan requires 13v and it was getting it by piggy backing off the ground connection on the frame shared by the replacement cable used by the previous owners.

 

well I got everything connected and the truck started up as normal. Still have the check engine light code 54 - but when I start it, it doesn't buzz or hum (as if the starter motor freezes) and then crank slowly before firing.

Apparently the sensor or whatever that is in the pic above with all the oil - apparently that wire requires 13v and gets it from the negative battery cable as it is a direct connection with a ground in the middle. The negative battery cable IS the same wire that goes into that sensor in the oily pic above.