Better Beaters - Building Cars and Daily Drivers

 Getting the '96 Mustang ready for possible sale.

The Mustang has been sitting on jack stands for a couple of days.

Or at least for next year's registration.

As I said earlier, the CEL lit up on the dash. However, the car seemed to run as good as it ever has. I continued to drive it until I swapped places with the '06 to put a new set of tires on it. The CEL went out on it's own before I made the switch.

When it came out of the garage, the CEL promptly lit up again. I used a code reader again, I have to figure this out, registration is due soon. That means a smog test this year prior to renewal.

I put a code reader on it and came up with the codes PO136 and PO141. I looked in my Haynes manual and the codes were identified as oxygen sensor codes. It indicated a problem with the sensor heating circuit. This engine uses four O2 sensors, two upstream and two downstream. Which translates to ahead of, and behind the catalytic converter. 

The manual didn't offer much of a description so I googled; "1996 Mustang 4.6 engine, what does a code of PO136 mean?" I found a lot of info. It indicated that it could be the wiring harness, a leak in the exhaust system, or a bad sensor. There were several videos about the repair/replacement process. I googled the same question about the PO141 code and the answer was similar. 

My car has over 215,000 miles and I'd bet that the sensors were bad. My Brother had a '80 BMW 320i that started going through O2 sensors every 50,000 miles, so I guess that I've been lucky. 

I went to  my local O'Reilly's and found that they wanted almost 60.00 per sensor. 

Then I looked on RockAuto. I believe in supporting my local businesses, but I already spent 200 bucks  buying a battery at my local Indie auto parts store in June. I gotta find ways to save some money. 

You can see the special socket on the right.

Rock Auto had the sensors for about 24.00 a piece, so I thought it best to replace all four if I'm going to be under the car. I also decided to spring for the special socket. This is where Rock Auto got an extra bite out of me; extra shipping, since the items originate from different locations. That's something that you have to watch if you are buying several different items at one time. However the RA price was so much lower that it was still a good deal. 

Today I switched out the Riviera and the '96 Mustang so that it would be ready to receive the sensors when they arrived.

First I have to deal with the sensors, then I'll get the oil changed, and have the smog check done.

While I was at O'Reilly's the young counter guy expressed some interest in my car after a bit of conversation I told him that I was thinking of selling the car.

Last weekend I brought my Mustang to a Cars and Coffee event in San Jose. Just before I was planning to leave I went and placed the for sale sign on the dashboard. I returned to the car and saw an older guy  photographing the for sale sign. I engaged him in a conversation and learned that his Son in law was looking for a car. His Daughter in Law was with him, so she got to see the condition and we discussed the car.

I would prefer that I replace the sensors, change the oil, and perform the smog check before I put the car up for sale. The expenses would be approx 130.00 for the sensors, fifty bucks for the oil change, another 50 bucks for the smog test, and 160 dollars for the '25 registration fees. 

I have priced the car at 3,000 dollars which I feel is a fair price even after I spend this money on the car. Even if I don't end up selling the car, I still need to do this stuff anyway. 

I watched a few videos on YouTube, which gave me an idea on what to expect. Except that one the videos showed a car that had changed the stock exhaust manifolds for headers and a front sensor bypass. Also the car in the video was a coupe, while my convertible has a large cross brace that ties the front cross member to the rocker panel area. This brace makes access pretty tight around the passenger side upstream sensor.

You can see the front end of the brace.

I initially thought that I would remove the brace to gain more access, it is held on with quite a few bolts, mostly 13mm. However at the rocker area there was a big plate under a plastic cover with a 10mm bolt as well as three 13mm. bolts. I tried to loosen the 10mm bolt, but it was very tight, and while it moved a bit, I was afraid that it might snap off. I don't like to break bolts and decided to try to remove the sensors with the brace still in place. 

The only location with really restricted access is for the passenger side upstream sensor. This is where the starter motor is located. I easily removed and replaced the driver side upstream sensor since I could insert my hand into the space.

Below the green connector and above the cross member you can see
the bung where I unscrewed the sensor.

Removing the sensor was pretty easy as I have a few large 7/8 combination wrenches that could reach the sensor. I can insert the sensor in the hole easily, using the wires to position it. The problem is to start the sensor threads into the bung. Like a spark plug, you want to make sure that it is properly threaded by using your fingers. I tried turning it by twisting the wire harness attached to the sensor, but that didn't work as it's not stiff enough. The problem is to hold it in place, and turn it by hand. Unfortunately, I can only get the index and middle finger of my right hand into the space. 

Peek a Boo, I see you! 
I just can't reach you.

Can I refer to a shop manual for handy tips to make the job easier? Maybe not this one.

These Haynes manuals are pretty useless.

The Haynes manual doesn't offer any help. It illustrates O2 sensor removal with a photo of a guy unscrewing it from a detached exhaust pipe! No problems with access there!

I decided that an enclosed box wrench would be best to tighten the sensor. However the connector won't quite fit through the 7/8 opening.

I carefully cut off the top portion of the retaining clip with a hack saw. Now the connector fits through the opening. It should still snap together, but I can wrap the connector with duct tape just to be sure.

If you are going to replace the sensors, it would be easy to cut off the connector of the old sensor and use the enclosed end of the wrench to loosen and remove it. So now I've figured out how to snug it down, but I haven't figured how to start threading it in the manifold. 

I have often used a section of fuel line to help start threading in a spark plug. I adapted this idea to the sensor. I slit the tubing, positioned it, and taped it on. This worked well for raising the sensor into position, though it was hard to determine if the sensor was seated squarely in the manifold. Even though the fuel line is not very thick, it was too tight to be able to manipulate the position of the sensor. I must not have gotten the sensor positioned correctly, because even after several hours of attempts I was still unsuccessful. 

I had spent an entire afternoon under the car and had only replaced one sensor. needless to say I was pretty frustrated. 

I need more room to turn the fuel line/sensor unit, or to get three of my fingers into the space. It looks as though I may have to remove the starter. 

Returning to the Haynes manual, it says simply to remove the wires, and remove three mounting bolts. If it was only that easy!

I found a very good video online that dealt with replacing the starter on a convertible model like mine. There is a top bolt which is hidden in view from the bottom. There is also an issue with limited room behind the starter and cross member. If a long extension is used on the socket, once the bolt is loosened, it will jam the ratchet against the cross member. The video guy recommends using three short extensions instead of a single long unit, so you can shorten the extension as the bolt is backed out. 

There is one small ray of hope. There is a heat shield that covers the wires connected to the end of the starter. By removing that, I might gain enough additional space to get an extra finger in, or allow me to manipulate the fuel line and properly position the sensor.

I haven't tried that yet.

So that's where it stands. The car will remain on the jack stands until I can get back to it. I am fortunate to have it in my garage, instead of in the driveway. I'm also fortunate that I don't need the car for transportation, so it can sit for a while. 

Taking a break has a lot of benefits. It reduces frustration, it allows me to put the situation into perspective, and lastly and maybe most importantly, allows the old body to recuperate from the aches and pains of crawling around under the car! 

More to follow in a future post. The job has to be completed, so I will be back under the car again, soon.