P/S on Direct Scan is always on

[tb3]

I have recently installed direct scan in my 84 GN. I am still getting familiar with it. I have noticed that the P/S is always illuminated on the real time text screen. Per the manual that means the ECM is adjusting idle due to Power Steering input. Is this normal for this to always be on? I have never seen it go out. If its not normal...any suggestions on what the problem could be?
thanks in advance.

 

[JSAautomotive]

I have recently installed direct scan in my 84 GN. I am still getting familiar with it. I have noticed that the P/S is always illuminated on the real time text screen. Per the manual that means the ECM is adjusting idle due to Power Steering input. Is this normal for this to always be on? I have never seen it go out. If its not normal...any suggestions on what the problem could be?
thanks in advance.

The P/S on input should change states with the power steering being cycled. If it doesn't, you mighth have a bad power steering pressure switch input to the ECM.

 

[tb3]

hmmm.... I'm wondering if I even have a power steering pressure switch on my 84 GN. I can't find one physically, I wonder if the 84/85's came with one? I don't have a service manual for my 84. I have factory service manual for an 87, and I can't even find where it talks about a power steering pressure switch. I'm going to go over to gnttype.org and see if I can find the input for it into the ECM. Then I'll take a look at my 84 ECM connector and see if theres a wire there.

 

[JSAautomotive]

When we use the Snap-On scanner here at the shop, the LED's on the face are usually the ones that indicate P/S input high or low. If the car doesn't have a P/S pressure switch, the "state" of the LED stays the same.

 

[tb3]

I'm pretty confident at this point that the car didn't come with one. I'm going to post in the hot air section to see.

JSAautomotive... would you happen to know if this is affecting my ECM's ability to make the correct calculations for my car being its showing my P/S is on (requiring higher RPM I would imagine, to compensate for required power steering assist)?

 

[JSAautomotive]

I'm pretty confident at this point that the car didn't come with one. I'm going to post in the hot air section to see.

JSAautomotive... would you happen to know if this is affecting my ECM's ability to make the correct calculations for my car being its showing my P/S is on (requiring higher RPM I would imagine, to compensate for required power steering assist)?

Not unless it's giving you a problem under power steering load.

Usually if the car doesn't have a P/S input for load compensation, Buick programmers would look at something else like circuit 430 (RPM) or MAF/MAP to achieve the same response.

I rememeber once when me and Kenny Duttweiler where talking about chips and programming years ago.... one of the responses Buick engineers put into their logic for P/S input was to reduce ignition timing. When I used to smog the GN's years ago when we only had the 2 speed idle tests, the hydrocarbons would be too high. A yank on the power steering to lock the wheel against the steering lock would reduce the timing and hence make the car pass on hydrocarbons.

Little known Buick tricks of the trade.

-j

 

[tb3]

hmm... good info, thanks. I'm pretty confident that its not affecting anything when the power steering is under a load, so I'll just let it rest, and put up with the p/s being illuminated all the time.