i think it would be advisable to first look into what Aaron suggested and have a look at the p/s cpu

 

any progress w/ those power steering cpu pictures?

 

Well as for the pump working, it sounds smooth as silk and if it works at all it seems the mechanicals would be fine, but there is always that chance.

Air in the system, i would be surprised if there was not any when i got it, but i have bled it over and over. Seems like it would be gone by now. I filled it up when i got it and it went down a little at first but the fluid has not dropped since. Now i am not saying there could not be air, very likely there could be, but would air really cause it to only work in some places? but yet not everytime?

I actually would not mind a manual rack and be done with it, the problem is the $$$ and trouble of doing that.

So what would you recomend? Really, i am totally lost and looking for advise. Oh, and i am not trying to spam this thread, i just know that since my thread is so long only a few people read it.

Already swaped the CPU from my parts car over and though it seems to work a little better at first, i swaped them back and it worked the same.

I can snap a picture of mine if that is what you are asking.

And thanks everyone for the help. Sorry for the hijack.

 

I've got the same thing in my '88 TII. theres a clunking noise coming from up front when i turn my wheels at all in any direction or when im starting out in the low RPMs. any ideas??

 

i'll replace the cpu today and post back

 

Well I guess since this is bumped anyways i might a well update mine.

So i have now been driving it a few times and got it running (until i got a flat tire that is). In this time the power sterring has been working more and more.

I have tried both of the computers i have but that never changes anything.

The one thing i HAVE found consistant with it is that if it is not working, say when pulling out of the driveway, if i let the clutch out just a little to where it tries to pull the car forward, 90% of the time the power steering will kick in. Not sure if it is the clutch or the RPM that are doing it though.

But since it has and will work anywhere along the turning radious, just when it feels like it, not when i do, i know that the rack will work all the way around (it is not leaking or using any fluid BTW).

I also know that the pump is good, (when at idle and i get it to kick it you can hear the rpm's drop some).

And i would think between 2 computers 1 of them would at least act differnt then the other, but they both act exactly the same.

So at this point i have power steering that works about 75% of the time, and pretty much at random. I am 95% sure the rack and pump are fine and it is some kind of computer problem.

Any more ideas as to what it could be and why it is getting better to more i drive it?

 

Used power steering CPUs from junk yards are a crap shoot. When I was rebuilding them, about 50% of them from the junk yards and part sellers were bad.

Try opening it up and resoldering where the plug pins meet the board. you will need to remove the old solder first, and then flow new solder in.

And remember you need to stick to the same type. There are the speed sensing and engine sensing power steering CPUs. S4 models only used the speed sensing units. Mixing units (for example using a engine sensing unit in a speed sensing system) will end up with the power steering not working correctly when it should, and constant boost at lower RPM's.

So make sure that is you have any S4 or a S5 turbo you are using a FBXX power steering computer, but if you have a 89-91 non turbo that you are using a FCXX unit.

 

Good info.

My S4 vert kind of does the opposite. My p/s steering is full power even though i am over 40 mph, it doesnt tighten up. So i would have to turn off the car and coast a little then turn the key back on and kind of jump start it, then it would be ok.

Does this sound like the p/s CPU? maybe i'll just pull it and check the joints.

 

Yep... the power steering CPU has some bad joints.

Many of the 88 models didn't have the beeper to tell you when something failed like the 86 and 87's did

 

Do they all go bad in the same way?

My car is an 87 NA and the parts car is an 86 NA. Those should be compatable right?

Does my problem sound like a CPU problem, with it now getting better as i drive it more?

Too bad i can't solder worth a darn, know of anyone that still works on them or where i can get a working one for cheap?

So if it is my CPU i should have some beeping?