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Cruise Control Vacuum Pump


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Hello all, so I decided to look into why my dealer installed cruise control would never hold going up a hill. I set the cruise, and then when I approach a hill, it just slows down, like it was never applying more throttle. So I would then step on the gas, get over the hill, and all was good. I thought maybe the car doesn't have the power... But that doesn't make any sense, because it goes up the hill fine was I take over and apply more gas. Then I was thinking that maybe it had something to do with the fact that I have a turbo and that I create a positive pressure in the manifold while under boost. That's when I stumbled across this tidbit:

 

There were actually 3 different cruise control setups used by subaru.

 

1 was factory installed. It uses a electric Vac pump.

 

The other 2 are dealer installed, utilizing engine vaccum.

 

1 of the dealer installed systems utilized the steering wheel mounted controls.

 

The other dealer installed setup uses engine vacuum and a single control panel that mounts on the dash, right of column. Ever seen Cruise in a DL wagon? What he describes is this system. Dealer installed.

 

This of course proved my theory of producing positive pressure having an affect on the cruise control, since I have the last option, the one with the control panel mounted on the dash to the right on the steering column, not to mention the original invoice from when the car was sold requesting cruise control, and also the invoice after the cruise control was installed in my car from the dealer. Stupid dealer, install a manifold vacuum system on a boosted car. Where did they expect vacuum to come from while under boost ESPECIALLY at freeway speeds where you use cruise most of the time!? Seriously, what idiots, they didn't think that all the way through, especially when there is a factory solution to the turbo problem :rolleyes:

 

So my question is this, does anybody know the part number of the factory cruise control vacuum pump for my 1990 loyale turbo wagon? I can't find it anywhere. All I can find is the legacy part number. Can I use a pump from a legacy if I can't find one for the loyale? I know there will be some rewiring required along with finding a place to mount the leagacy unit if I go that route. I guess I should also ask if anyone has one they want to get rid of, if you have one, PM me, I am interested...

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Ok, so I called the Dealer and asked, and it's $420!!! Wow, no thank you. I did get a part number though, it's 87053GA000. So I think that I am going to try to get a legacy one to work, unless I can find a used turbo one...

Edited by eulogious
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I think I may have a legacy one that I absolutely don't need.

 

Sweet, I will keep that in mind. I think that I am going to wait a little while to see if I can find one for a loyale...

 

I am also waiting on my FSM's to arrive (thanks moosens!) so I can look at the wiring for it. The FSM should have the stock vacuum pump on it, so maybe I can compare wire colors/locations to the one that I have (non vacuum pump) to get an idea on where to start with adding a legacy vacuum pump into the system... I went to my local pick a part and took some pictures of a vacuum pump off of a legacy to try to get an idea of what I need to do. The wires don't match of course, but I think I have found the power and the ground, so I have half the wires found, I just need to figure out the air valve and release valve, and I think I will be able to hook it up. I guess I could always just try it one way, and then then other, but I still would like to find the loyale vac pump first.

 

The legacy vac pump should be the same as the loyale one, just different mounting hardware/wire colors, correct? It's not going to destroy what I have now is it? I mean it's got to produce more vacuum than my boosted manifold does :) I don't see how they could be all THAT different, considering the legacy was also around in 1990, I don't see them making a completely different setup for the two cars. Just modify one to fit in the other... But my thinking could be off on this.

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Why not install a vacuum reserve tank.

 

All you need is a small tank (similar to the one on the right hand strut tower for the HVAC controls)

 

Use one of these, http://cgi.ebay.com.au/ALUMINIUM-DRINK-BOTTLE-750ML-NEW_W0QQitemZ370285256314QQcmdZViewItemQQptZAU_Sport_Camping_Hiking_Hiking_Equipment?hash=item5636b89e7a#ht_4084wt_1084

Put a one way valve from the intake manifold, then a t piece, one going to the drink bottle, the other to the cruise control and it will enable you to climb most hills under cruise control

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Why not install a vacuum reserve tank.

 

All you need is a small tank (similar to the one on the right hand strut tower for the HVAC controls)

 

Use one of these, http://cgi.ebay.com.au/ALUMINIUM-DRINK-BOTTLE-750ML-NEW_W0QQitemZ370285256314QQcmdZViewItemQQptZAU_Sport_Camping_Hiking_Hiking_Equipment?hash=item5636b89e7a#ht_4084wt_1084

Put a one way valve from the intake manifold, then a t piece, one going to the drink bottle, the other to the cruise control and it will enable you to climb most hills under cruise control

 

I like your thinking! I think I may have found a vac pump, but still waiting to confirm it's the correct one that I need. I will keep that on the back burner. I will just go to my local pick a part and grab one of the vac tanks from there and use that if I go that route. I like that idea though, good thinkin' :)

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So I went to the JY and picked up a HVAC vacuum reserve tank and plumbed it into the cruise control, and my cruise now works WAY better :banana: I wouldn't say that it's 100% better, but about 90%. Going up long hills (1/2 mile fairly steep incline), the reserve isn't quite big enough to handle it. So instead of doing 70 all the way up the will, towards the end I might be doing 67 instead. Much better than the 50-55 I would have been doing before :) I have never been able to accelerate using the cruise either, and I can now accelerate going up small hills even! I was thinking about trying to plumb in another HVAC reserve tank, but I don't know if it's really worth it, but I might since the tank only cost me 3$ :grin:

 

I am still looking for the vac pump, that way I will never have an issue again... I have a lead on one, but nothing confirmed quite yet.

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I have also discovered the pinout for all the wires coming off of the cruise control computer, so I can now wire in either a legacy or the loyale one vac pump :grin: I am also going to try to wire in the steering wheel controls, since I now know what the wires are supposed to go to for the set-decel and resume-accel buttons. I also found out that the controls to power the cruise for the steering wheel controls are on the wiper controls, so I am going to be doing the intermittent wiper swap as well, since I am already there wiring in the cruise :grin: Kill two birds with one stone...

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So I got the entire cruise control system (vac pump, controls, computer, and wire bundle) from mdjdc :banana: This now should solve all of my problems. Since I already have the reserve vac tank installed, I am just going to plumb it into the setup with the vac pump, that way it will always have enough vacuum to be able to do the cruise correctly :grin: Thanks all for the help and the idea of the reserve tank, that was golden. I will post back when I get everything installed and functioning properly. Man I love these forums!! :grin:

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  • 2 months later...

Ok, I am now giving an update on this and reviving it since I have a new problem and didn't want to give all the background already given here... I unfortunately didn't get the vac pump that I wanted, but I did come across a unit locally :banana: Now it wasn't just a bolt in procedure to get it to work, since I found a factory installed system, and I have a dealer installed system. I had to take the unit apart and remove all the cruise stuff on the vac pump unit, and then once that was done I was left with a vac pump, vac tank, and a pressure sensor for the vac pump plumbed into the vac tank. I then connected that to a relay and set it up to turn on when the system turns on, and viola! My cruise control works as it should :banana: And it was easier to do than I thought it would be :grin: I will post pics once I get them onto my computer...

 

But now I have another problem... Since I got it all working, I want to add the cruise control buttons onto the steering wheel. so I got the controls, and I installed them onto my wheel, but when I went to plug them into my steering wheel, I realize that I only have one male connector (for the horn) when the other car the controls came off of had 3 male connectors (1 for the horn, 2 for the cruise controls). So my question is this, how can I get just the ring that has the 3 connectors on it so I can run the wires from the wheel to the steering column? I am guessing it is a ring but I really don't know... It could be connected to the steering wheel as well, which would mean I would have to replace the whole wheel, and that sucks :mad: I unfortunately do not have a steering wheel puller handy so I can't just take mine off and take a look, so any insight into this would be super helpful, or ideas to run the two wires from the wheel to the steering column. My FSM doesn't really show any helpful info either. From what I gather from my FSM is, it's part of the wheel, but I am hoping I am wrong and reading the FSM wrong. Thanks for the help, again!

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  • 1 month later...

Ok, giving a final update with pics finally :rolleyes: Lots of pics, you have been warned...

 

So I got the ring connector I was talking about earlier, it happen to come with a new switch assembly that I found that had intermittent wipers on them, so I pulled the wheel, installed the new turn signal/headlight switch unit, found out how the dealer system tells the cruise what to do, wired in my new buttons, and BAM! I got intermittent wipers AND cruise controls on my steering wheel all with one stone :banana:

 

Here's a the pinout for the dealer cruise control unit:

 

Dealer%20Cruise%20Control%20Pinout.JPG

 

Here's a couple photos of my modified vacuum pump assembly:

 

IMG_0616.JPG

 

IMG_0615.JPG

 

Here's what the original looked like from a factory installed cruise system:

 

IMG_0621.JPG

 

Now, the dealer unit is a real simple unit and it was easy to figure out how it worked. Basically there is a small control unit for the cruise that is located where the power mirror control is normally located:

 

IMG_0635.JPG

 

Here it is out of the car:

 

IMG_0629.JPG

 

IMG_0632.JPG

 

All this unit has is four wires going into it. One main power, and 3 others that turn it on/resume/accel, set/decel, and turn it off. All the switch does is apply a positive voltage to the correct wire to get it to do that function. Meaning that if I want to turn on the unit, all I have to do is apply 12v+ to the on/resume/accel wire, and it will turn on/resume/ or accel. Easy enough. Subaru also made it easy for me with the factory cruise buttons, they are wired with power (12v+) already! All I had to do was take the wires for the steering wheel buttons and splice them into the wire coming from the existing switch and bingo! Now my steering wheel controls work for the cruise :banana:

 

Here is the connector I spliced into (I haven't spliced it at this point):

 

IMG_0628.JPG

 

IMG_0630.JPG

 

And here it is installed in my car :banana:

 

IMG_0633.JPG

 

IMG_0634.JPG

 

Here's where I moved stuff around in the engine compartment and where I spliced into the cruise harness in the engine bay to install my relay:

 

IMG_0637.JPG

 

IMG_0646.JPG

 

IMG_0639.JPG

 

Here's a pic of the dealer vacuum valve that is powered by engine vacuum:

 

IMG_0642.JPG

 

Here's a shot of the vac pump unit installed, the red wire is the power to the motor of the vac pump, it buried but you get the idea, it's locate in the stock location:

 

IMG_0645.JPG

 

Sorry some of the photos aren't so good, they were taken with an iPhone :rolleyes:

Edited by eulogious
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So to sum up everything...

 

I started out with having cruise control that "worked" but wouldn't hold speed up a hill, wouldn't accelerate, etc because I have a turbo motor and when I hit boost the engine no longer produces vacuum, therefore causing the vacuum operate cruise control not to work. So first I had to come up with a vacuum pump to put the cruise control on it's own vacuum subsystem. I then modified a factory vacuum pump by removing all the controls from the pump, just leaving a pressure switch, reserve tank, and pump. I then proceeded to wire in a relay to kick on to turn on the vacuum pump when the cruise was turned on. Then I had to add in the cruise control steering wheel controls. That was easy. Just splice away and you are good to go!

 

So all said and done I am very happy with this setup. I have solved all my problems with the cruise and it's WAY better than it was when I first got it. I hope that this helps someone else out. If you have any questions about it, feel free to ask!

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great write up. but glad I have factory cruise!

 

Ya I basically have "factory" cruise now! At least most of the "factory" parts :lol:

 

The original owner spent $550 to have the dealer install the cruise control back in 1990 when they bought it new, I have the original invoice :grin: For that much money, especially back then, I have no idea how it was acceptable to have your $550 cruise control system NOT function properly :eek: If I spent that much money to have cruise, you damn well better bet it will work the way EVERY other cruise system works, or I will raise hell. But not the PO, they just didn't care or something. Seriously lame :-\ It cost me about $40, a little bit of R&D, and time to fix the system. I just don't get some people :rolleyes:

 

You should copy and paste all of this into an entry for the USRM.

If not just ask and I'll do it :D

But I'd rather you get the chance to do it yourself and edit out any extra unnecessary stuff and complete some of your thoughts better.

 

Twitch

 

I should do that. I will look into what it takes to get an article submitted and what not. Then I can take better pics as well :rolleyes: Thanks for the suggestion!

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