O2 sensor install troubleshoot (4)questions

Lucys500dollar87z24i · Dec 25th, 2004, 06:24 PM

Hi all!

Been trying to get my 87 4cyl z24i hardbody through inspection again. it has 176000 mi. A sudden idle problem became an emmisions problem here in the Garden State. A friend took the truck and gave it to a "crack" mechanic for 2 months. Excuses and lies from these boneheads got old and I got the truck back with no change, except for new vacuume lines. The idle was still high and they kept my haynes manual (POS anyway)

I studied the forum, and library resources and started troubleshooting myself. I learned that the O2 sensor could be an issue and searched for it. The sensor connector had melted against the exhaust (manifold?). I cut off the melted plastic/resin, wacked it with a hammer (great fun!!!) and inspected the (spade?) connection. I wanted to see if there was anything special about the connection that needed to be encased in plastic. Didn't see anything unusual. The idle dropped when the sensor was disconnected so I replaced the sensor with the new one. FYI, a socket was attached to the old sensor. I didn't expect this and couldn't get the two pieces apart. I assume it was the original sensor. I paid a guy at pep boys to heat it up and remove it from the old sensor.

I had to extend the wire from the new sensor to meet the thicker wire from the wiring harness. I crimped and used the shrink tube, and then made the final connection to the ECU side wire. Again, crimp and shrink. Should be fine right?

I took the ECU out from under the seat (and may not ever put it back) and ran through all diagnostic modes. The results in oxygen sensor mode I shows there is a problem with the sensor or the circuit. There is just a green light on all the time. I redid 2 crimps and reran the test.

I see 4 possible/probable failure points - the 3 wire crimps and the connection into the ECU. I redid 2 crimps. same result.

I have a wiring diagram and am struggling to locate the correct wire on one of the 3 connectors attached to the ECU. The wiring diagram indicates it is wire 111/blue and green that connects the O2 sensor with the ECU. Should I spend the time and effort to trace this connection? (Q1)

There is another connector attached to the wiring harness that is black with a flat purple cover. There are little circles on the purple piece. many wires, some in sleeves are attached to this connector. It is really stuffed full and tight. I noticed that I can see the silver of one wire that is clearly not completly connected. I tried pushing it in. The good news is that it hasn't completely come out. Should I pursue this as a possible problem? or just leave it be? (Q2)

Should I remove the crimps and pay someone to solder the connections to the O2 sensor? (Q3) Is there a special wire type I should have used for the extension? (Q4)

is there anything else I may have overlooked? (Q5)

All feedback appreciated and Happy Xmas to all!

**88pathoffroad** · Dec 27th, 2004, 12:13 AM

There's another connector under the hood for the O2 sensor...

Lucys500dollar87z24i · Dec 27th, 2004, 02:10 AM

Quote:

Originally Posted by 88pathoffroad

There's another connector under the hood for the O2 sensor...

Thanks for your reply. Please add some detail for me as I am new to this! Note: the O2 sensor only had one lead to connect. What is your thought about the other connector?

Also, I discovered that the engine side wire is aluminum, encased in all sorts of sheathing (similar to coax, only smaller) so it can't be soldered. I used some type of grey goo made to enhance the connection of alum to alum and alum to copper. I recrimped 2 of the 3 connections and now have some green light activity on the ECU. One blink - 4 short of the necessary 5, but one more than I had yesterday. I will re-crimp the other one tomorrow .

I know it's cheezy, but I can offer a six pack to the the person who provides the final solution to this problem.... :-)

Thanks!

bestblinds · Dec 28th, 2004, 04:47 PM

Quote:

Originally Posted by 88pathoffroad

There's another connector under the hood for the O2 sensor...

may I interupt and ask for a solution to my problem.1989 6 cyl. 5 sp/4wd made on 3/89. listing for replacement 02 sensor is bosch 15207. It has 3 wires on each end. OEM has 3 wires at 02 sensor and a fourth wire factory spliced into black wire at connector. This is a white wire from a single wire plug right next to the 02 connector.This spliced in wire goes to the black 02 harness connection and becomes a fatter black wire untill it gets close to the sensor at exhaust and then thins. Should I splice this white wire into the bosch 15207 3 wire harness? This bosch sensor comes in a bosch box but is really made by NTK(NGK) I was hesitant to splice because I didn't see the bosch wires fatten in the harness. Thank you for your help.