cruise control
 

on my recent trip to albuquerque nm i was kind of confused by my cc. i thought that it was supposed to hold the speed in a smooth flow? on my way back i had the cc set to 80 mph the whole way back and noticed that it pulse and glided. :thumbup: i didn't fill up again because i got home around twelve last night and was too tired to do anything. i will try to fill up again tonight to see what my outcome was.

oops i rambled. my question is: did the manufacturers add p&g to cc?? :D

We're about 2,000ft higher elevation than you are normally in El Paso, could it be that your cruise control was having trouble keeping speed? I run into that in Flagstaff, AZ and they are only about 1000-1500ft higher than the 5,500ft ABQ is at. You should see how my car runs at 10,000ft after driving to the top of Sandia... it's kinda sad.

Now that I think about it, I-25 doesn't have a whole lot of grades and such to cause a problem so who knows!

I had an intermittent issue like that with my 87 Integra cruise control- up and down by 1-2 mph. It annoyed me so I would turn it off and then reset it. Sometimes just reseting it would get it back to to keeping me at a steady speed.

lol! yea i didn't notice it untill i put my foot right next to it(i was wearing sandals) and i could feel the pedal slightly, very slightly move up and down. and i was on a flat part. on the obvious parts inclines/declines it did what it was supposed to do. this is kind of the way i counted it:
i would set the cc at 80 and it would accelerate to get acclimated i guess. then it would let up for about two seconds and get back on it for four then get off for two seconds and on again for four, and this was on the flat part of the road.

chevettes kinda does this, but really really bad, like id set it it would be slowly accelerating all by itself then it would fully let off the gas (manual tranny slows way fast) then gun it to get back to speed...

the speed wasn't affected at all it stayed at a constant 80 mph so long as i let the cc do its thing. i did notice the feeling on my foot as the pedal let off and on slightly, and the tone of the engine.

sounds kinda scary. lol! :eek:

Do you have an automatic or a 5 speed? In any case- about what is your rpm at 60?

I'm just curious- I looked at an auto 93 civic ex for sale 2 weeks ago (not running) and wondered how tall the trans was geared.

My Cressida did this because of a vacuum leak in the CC system.

it only does it if its cold, i bet grease in the cable prolly makes it hang up...

its a 5 speed EX, and if i remember correctly it was around ~2500-2750 im not too sure.

I have noticed the same thing in cars that I own now or have previously owned, I think it's just the nature of a C/C to do this you usually don't notice it until like you said you have your foot next to the pedal where you actually feel it. I think it just brings the car to the speed you have it set at and if you are going down a slight grade then it lets off just as you would if you were controlling the speed with the pedal youself. I don't think it is anything to worry about if it is keeping a constant speed.

well if you note on my gasslog, cruise control actually used up more fuel. i believe that this is because on up hills it would really try to maintain the 80 mph that i set, and would richen the hell out of it. instead when i was driving and i saw a decent slope coming i would speed up ~100 mph and just let it coast up to the top or leave it in gear coasting downhill.

I looked at your gas log. That is still pretty impressive numbers for 80-100 MPH driving. That is about the mileage I get on my 1997 Escort Wagon running a constant 80 MPH on the highway, the best I remember. I usually don't drive that fast anymore. When I was younger, when I hit the interstate I would set my cruise at 85-90, usually driving at night when I didn't have to contend with a lot of traffic. Off course gas was $0.50-$1.00 a gallon and I was driving cars that got 10-17 MPG. I guess old age is catching up with me.

lol wow i can barely remember when gas was $1.20 when i first started driving! :eek: i remember filling up my pontiac bonneville SSEi with a $20

C/C surges
 

I have taken a trip in the last week and used C/C a lot while on the trip. I checked the throddle position using my scan gauge. During acceration the throddle position would go up drastically. I checked it just make sure what I had previously told you was correct. Now I am even more sure that it is just the nature of the C/C and you have nothing to worry about. I also found out when using the A/C if you turned it off during down hill coasting in gear or in neutral MPG went way up, but you could use it during climbing hills without it having a terrible impact on mileage.

I don't know about newer vehicles, but I have adjusted the cruise on my 1981 Buick Regal to make it smoother. I also remember dad doing the same adjustment on the cruise on our old 1980 Pontiac Bonneville Safari wagon when I was a kid. I've never had to adjust the cruise on my 86 Chevrolet C-10 or my 98 GMC Sierra so I don't know how, or even if the newer cruise controls are adjustable. I'm thinking they have to be adjustable somehow.

I haven't ever heard of any adjustment on C/C. There may be one??? How did you adjust it on the Regal?

Where the vacuum line goes into the cruise unit was a brass fitting. Turning that fitting right or left adjusted the unit. I think it just regulated the amount of vacuum available to the unit, but by adjusting it you can make the unit run smoother. I had another cruise control in my 74 chevy C-10 (aftermarket) that had adjustable resistors that were turned to adjust how sensitive the unit was.

yup thats hoiw the CC is on my chevette, thjeres a sensitivety pot and an acuracy pot.

modern ones i dont belive there are adjustable ones since thier run off the speed sensor

LOL, Speed Sensor, What's that??? On the 80 Pontiac Wagon and on the 81 Buick Regal the speedometer cable runs through the cruise control unit!

I'm not sure what the speed sensor is, but on the newer cars the speedometer works electronically. If your battery is low of charge then your speedometer doesn't work correctly. I am guessing that it is an electronic sensor that feeds the information to the ECU.

A quick googling for VSS info returns pretty much what you'd expect:
https://autorepair.about.com/library/faqs/bl600g.htm
https://z.about.com/d/autorepair/1/0/T/3/79086182.gif

Ummm, thanks for the really good answers, but I was joking when I asked what a VSS is. Anyway, the late 70's/early 80's GM V6 & V8 cruise controls operated with the speedo cable running through the cruise control unit. There's a great pic of the cruise unit on TheHolyCow's 1980 Buick LeSabre here: https://picasaweb.google.com/ronanian...37319228846530 (Hope you don't mind me linking to your pic)Its the same cruise unit that is in my Buick. You can see the speedo cable going in and out on the right, and you can see that brass bushing with the hex sides on the top vacuum line, right where it enters the cruise unit. Turning that bushing right and left adjusted the sensitivity of the unit.

-Jay

Heheh. I knew you were joking, but then I wasn't sure if Ford Man was or not.

I certainly don't mind the link.

In fact, the reason I had that there was because I wondered what that thing was. I assumed the cruise would be near the carburetor, not on the wheelwell. Thanks! :D

I have almost acheived guru status with early 80's GM setups. I can even tell you just by looking at the unit that you only have a set button on the end of your turn signal to set the cruise. It looks like you do not have a resume feature on your car, but you do have a light on your dash that comes on when the cruise control is on. I grew up with my dad working on our 1980 Pontiac Bonneville wagon, I even learned to drive on that car. When my grandmother died I was set to inherit her 1984 Buick Skyhawk (The Buick version of the Chevy Cavalier at the time). It was a nice garage kept car, but I have long legs. My sister was complaining that this 1981 Regal she had bought a few months earlier was using too much gas so when I got the title to grandma's car it was only in my hands for a few seconds before I traded it with my sister. THe 81 Regal with the 3.8 V6 is a real bastard unit. It was the first year of computer control. GM tried this thing with a computer controlled carb, but it didn't work well, and its a pain to find someone who knows how to work on it now. I think they only made that setup for about a year and a half before they said screw it, we're putting fuel injection in them. Now when the car needs service I whip out my 1981 Buick service manuals and start reading. I don't need to read as much anymore as I've made almost every adjustment that can be made on the car in the 18 years I've owned it.