hatchsub Posted March 26, 2010 Share Posted March 26, 2010 I made mention of this in my other picture thread of the car but now im making a separate post to figure out what the hell is going on. The cruise i have is from an hitachi equipped EA81 (to work with my weber correctly). It worked great when i first installed it and would hold a highway speed no problem. Now when i turn it on on the highway at around 65 or 70 the light comes on but it will not set the speed or hold it or do anything really other than light up saying its on. Now here is the kicker. It will work at lower speeds around town...say 40 or so and maybe a hair more. All functions of it work at low speed but i cant get it to work at highway speeds like its supposed to. What should i be focusing on with these symptoms. Where is the cruise computer located and could it just crap the bed just like that? Quote Link to comment Share on other sites More sharing options...
eulogious Posted March 26, 2010 Share Posted March 26, 2010 I don't know anything about the ea81 cruise system I have an ea82, but I take it it's vac controlled? I had this same issueish with my cruise, but it's because I was losing vacuum, so therefore it couldn't hold the speed at freeway speeds, but around town it was fine. So you might want to check for vacuum leaks. If it's like mine, it's got an actuator by the pedal, if you have one of these, is it functioning properly? It could have an internal leak so the system can't hold pressure anymore. Same goes for the control unit for the vacuum system (not the cruise computer, this controls how much vacuum to apply to the pedal actuator itself). Mine is a separate unit, so if it develop an internal leak, it would cause the whole system to lose pressure as well. The computer failing just for high speeds, seems very unlikely. When these systems fail, usually they totally fail, or just a certain function, but since it works at low speeds, that would tell me that the computer is at least sending the signal to do something (this would be the function I was talking about, being able to send a signal), the system is just mechanically not able to do what the computer asked. Though anything is possible when dealing with older computers, they tended to do some funky stuff to make things "work", so the computer could be bad as well, but that would be the last thing I would check. So I would check for vacuum leaks/leaky, loose, broke hoses to startoff, then other suspect parts like the pedal actuator and the actual contol unit for the vac system, and then finally I would think about looking at the cruise computer. Again, assuming it's like mine and vacuum controlled... Hope this helps! Quote Link to comment Share on other sites More sharing options...
hatchsub Posted March 26, 2010 Author Share Posted March 26, 2010 I dont believe i have a pedal actuator. It is all cable operated with one main cable going into a box and the out to the carb and another cable that is hooked up to the main cable and goes up to the vacuum diaphragm. I tried swapping out diaphragms today with no change in the way it works. I dont believe i have a vacuum leak anywhere or at least one big enough to affect it that way. Quote Link to comment Share on other sites More sharing options...
eulogious Posted March 27, 2010 Share Posted March 27, 2010 I would still think that it has something to do with the vacuum or lack thereof. My car had almost the exact same symptoms, and since they are two different types of cruise systems, but they have the same problem, and the only common thing is that they both work off of vacuum, I would suspect the cruise vacuum system. I would try to test to see how much vacuum is in the system at freeway speeds. A little hard to do, but that's the only time you have a problem, so that's when you need to test it. That's where I would spend my time until I ruled out for sure that I have no vacuum leaks at all in the cruise system. Another option is to just get a dealer installed kit like mine and rig it into your car. The system is designed to be installed separately, so it will be easy to install if you can find one. Just a thought. Quote Link to comment Share on other sites More sharing options...
hatchsub Posted March 27, 2010 Author Share Posted March 27, 2010 Well im not sure what i did yesterday in the process of taking the cruise cables all apart...cleaning them and making sure everything moved smoothly it works again...but still not perfect. If i set it for 70 it falls back for a second and catches at 65 or so. I think it is vacuum related and that line going to the vacuum diaphragm is 28 years old and probably could stand a replacement. Quote Link to comment Share on other sites More sharing options...
eulogious Posted March 27, 2010 Share Posted March 27, 2010 Well, I am glad you made some progress! My system has a hard line that runs across the top of the engine compartment that then connects to a "soft" line, if you have something like that, check it, there could be a crack in the hard line that you can't really see. I would just replace all the vacuum hoses with new just to be on the safe side, that stuff is cheap enough that it really can't hurt. Sounds like you are at least are on the right path! Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted March 27, 2010 Share Posted March 27, 2010 (edited) Do you have a check valve in the vacuum supply line to the actuator? The more you open the throttle, the less vacuum there is to work with - there is a point at which the actuator simply doesn't have enough pressure differential to hold a given speed - and it can't accelerate to change speed for a hill, etc. I would think it would need a vacuum supply and a check valve to insure it works at freeway speeds for a decent interval even at close to WOT..... I would guess these are probably built into it. The check valve may not be seating properly. Try adding a second check valve in the line going to the actuator. Also - something I noticed at the yard yesterday - on gen 1 Legacy's they went back to the second cable on the throttle w/vacuum actuator in the engine bay. I wonder if one of those would work..... GD Edited March 27, 2010 by GeneralDisorder Quote Link to comment Share on other sites More sharing options...
hatchsub Posted March 28, 2010 Author Share Posted March 28, 2010 Im not sure to be honest GD. I did have to cut some of the rubber line to fit it into my setup. I dont think there was a check valve in what i took out. There is a hose connection in the middle of the line that could be the check valve you speak of however. Im going to start simple and replace the rubber line and see where i stand after that. If it fixes it great...if not ill keep working my way up until it works to my standards lol. Quote Link to comment Share on other sites More sharing options...
hatchsub Posted October 15, 2010 Author Share Posted October 15, 2010 Figured id bring this back from the dead and let everyone know what the cause turned out to be. I found a massive vacuum leak (engine ran great for the size leak it had). It was on one of the vacuum fittings on the intake right next to where the cruise was picking up vacuum from so thats why i had no cruise. Fixed the leak and i have cruise again. Quote Link to comment Share on other sites More sharing options...
Gloyale Posted October 15, 2010 Share Posted October 15, 2010 Well im not sure what i did yesterday in the process of taking the cruise cables all apart...cleaning them and making sure everything moved smoothly it works again...but still not perfect. If i set it for 70 it falls back for a second and catches at 65 or so. I think it is vacuum related and that line going to the vacuum diaphragm is 28 years old and probably could stand a replacement. The old Cruise systems won't work over 70. I've read it in owners manuals. And sincve it's basing that speed on a simple 4 pulse/ rev reed switch I imagine it could be off a few MPH. My OE ea81 crusie never worked (probably after the digi-dash removal, they never hooked it back up. So I Installed a Legacy vac pump, cruise computer, and an EA82 pedal box w/diaphrahm. It's wired in to the factory EA81 controls to look stock. Works up to 85 now. (as if my EA81 w/3at 4WD would go that fast) Quote Link to comment Share on other sites More sharing options...
hatchsub Posted October 15, 2010 Author Share Posted October 15, 2010 The old Cruise systems won't work over 70. I've read it in owners manuals. And sincve it's basing that speed on a simple 4 pulse/ rev reed switch I imagine it could be off a few MPH. My OE ea81 crusie never worked (probably after the digi-dash removal, they never hooked it back up. So I Installed a Legacy vac pump, cruise computer, and an EA82 pedal box w/diaphrahm. It's wired in to the factory EA81 controls to look stock. Works up to 85 now. (as if my EA81 w/3at 4WD would go that fast) Mine does. Cruises at 75 no problem. Not sure why it wouldnt work over 70 Quote Link to comment Share on other sites More sharing options...
Gloyale Posted October 16, 2010 Share Posted October 16, 2010 Mine does. Cruises at 75 no problem. Not sure why it wouldnt work over 70 Are you sure your Speedo is correct? I know my 84 the speedo is almost 8mph under actual speed by the time It reads 70. The reed switch and the CPU interpretting it will be more acurate than the needle sweep. There could be alot of variation. I am sure though that at least forEA82, in year 85 (the Manual I read it from) says that cruise is limited to 70 or maybe 75? but I definately remember it was annoying in that car(GL-10 turbo) Quote Link to comment Share on other sites More sharing options...
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