Hi folks,

It'* time for getting the '91 Bonnie ready for our summer travel plans.

This is a follow-up to a post from a couple of years ago:

http://www.bonnevilleclub.com/forum/...937&highlight=

I just pulled codes again and the cam sensor circuit (41) is still bad; the O2 sensor is now open (13), which should explain the serious plunge in fuel economy we saw a few months back; the "power steering sensor switch" code (46) is still set; and we've added a code 48, which is supposed to be "Misfire Diagnosis."

Code 46: Can anybody please tell me where I will find this power steering pressure sensor switch on the Bonneville, and what condition will cause this code to set? An hour with Google barely dredged up a couple of descriptions of where it ought to be. I can see the high pressure line coming out the back of the power steering pump, but I haven't traced it all the way to the steering gear, yet, to see if the switch is hanging off of it somewhere. (It'* raining today! )

Code 48: What'* this and do I need to worry about it?

We'll be tackling the O2 and cam position sensors, along with a few minor body and suspension issues. It'* a shame the rust is so bad, the car'* holding up very well otherwise.

Thanks,

Mike D.

Sounds like your getting what we call multiple ghost codes.
Start by unhooking the battery, then put the ECU connectors on and off a few times to establish contact. Then re-check for codes.
Could also be a bad computer.

Hi SSE,

Actually, the only one that might be a phantom is the 48 code... I hope!

The O2 sensor was bad. Will soon be replaced.

Power steering pressure switch is also shot (fallen apart in pieces). We'll be replacing it if we can get the remnant out of the steering gear housing.

Given the above, I have no reason to doubt there'* a problem with the cam position sensor, which is what we're tackling right now...

These problems have accumulated over the last year and a half, at least, as the car slowly rusts apart. <sigh> When the three sensors are taken care of and the battery hooked back up, we'll see if I still get any codes...

O2 Sensor question: The Chilton book talks at length about needing a special solvent to soak the sensor threads with before you can remove it, and a specific high temperature anti-sieze compound that is also electrically conductive... This is new stuff to me. Will these be easy to get from the auto parts store?

Progress is good. Being done will be better!

Mike D.

I have not been able to find a HowTo for replacing this power steering pressure switch...

What should I expect as far as steering fluid seeping or pouring out the hole when I pull the old piece out and put in the new? Does replacing this switch require draining the fluid first?

Is there a problem if a few bubbles of air get in, like with brake lines?

There'* an O-ring seal, so I assume I don't need any kind of sealant on the threads, and the oil inside should keep it from seizing, right?

Moving along well on our several repairs. The 4 nearby auto parts stores, between them, have had everything we've needed in stock so far.

Thanks in advance!

Mike D.

PB Blaster= best solvent, I don't know if it will harm the new sensor though. It is pretty common, the Wal Marts here carry it.

It wouldn't hurt anything to change the PS fluid and use all new fluid. In fact if it has been in there a while, it would be a good idea to plan on changing it.

The last O2 sensor I bought included anti-seize. That has been a few years, not sure if they still include it. A good parts store will have some for you if it isn't included with the sensor, just check it before you leave the store.

Don't sweat it Mike. Unscrew the old PS switch and thread the new one in. It will seep a little but the power steering circuit is self-bleeding. Runing the rack a couple of times by turning the steering wheel from lock to lock will clear any air bubbles that might get in while changing the sensor. No sealant required, the O-ring is the seal on the sensor.

Like bastard just posted, if you want to change the PS fluid, now is as good a time as any. If you look at the lines between the PS pump and the rack, you'll notice that one has crimped hoses (like the AC lines), the other is just plain rubber, with a hose clamp on the the end that plugs into the pump. That simple hose is the low pressure side of the rack feeding fluid back to the PS pump resevoir to be recycled. If you want to dump the old fluid to refill with fresh, seperate that line at the pump and let it drain into a cup (it'* about a pint of fluid in the PS pump). Reconnect the line to the pump and refill the pump at the cap with the dipstick built into it.

Oh, don't turn the steering wheel lock to lock over and over again...it will not damage the pump or rack, but it will flat-spot the tires. Do it once or twice, move the car a little and do it again.

Hey CLM and Bastard,

Thank you very much, that'* just the info I needed.

Okay, we'll look at changing the fluid.

PB Blaster: worth it'* weight in fine Kentucky whiskey.

If we're tempted to lock-to-lock the wheels too much, we'll lift the front end with the jack.

This O2 sensor has a smear of anti-seize already on the threads. I guess it'll do!

Once these sensors are done I'll put in the SeaFoam Trans Tune and drive it a few miles to get some gas. That'll give us a starting point to measure the fuel economy (hopefully improved!) and let the cleaner do its job.

Then we flush the trans... and see if the slipping in the low end of 1st gear gets any better!

Thanks you guys.

Mike D.

Wow! Making progress here!

First off, the SeaFoam Trans Tune worked very well to eliminate the slipping in the bottom of 1st gear from a standing start, as I report in this thread:

http://www.bonnevilleclub.com/forum/...077360#1077360

Installed the new power steering pressure switch and O2 sensor, and did the cheater installation of the cam position sensor interrupter magnet with JB Weld. So, for the first time in probably 3 years, we don't show a Service Engine Soon light!!!

We made a run up the expressway with my son in chase mode, and he was able to see that the left rear wheel is the one that'* causing vibration above 65, so now we'll be diagnosing that problem. (Probably just needs new tires on the rear!)

So far, the repairs have been going really well. It'* nice when you can significantly improve things and enjoy the savings of doing it yourself!

Thanks for all the help, folks!

Mike D.

Outstanding Mike, you'll have it all sortted pretty quick.

Sounds like youre doing well!

On that wheel vibration, I've seen issues with grime caking on the inside of the rim and causing it to go out of balance at higher speeds so I would consider just removing the rim and inspecting it for debris and check the tire for bulges or bald spots.

Also, inspect the bearing while the car is in the air. Try to push the wheel back and forth and if there is any slop then the bearing is bad. If there is any creaking or squeaking then the bearing is bad.

Odds are, your tire is probably bad but might as well check other possibilities while is in the air