Dayle97SE

iTrader: (7)

I need help trying to identify a part in the engine bay of my '86 max, I don't really even know what it is called or its function. When you are looking down at the engine bay it is directly behind/next to the passanger side headlight. It looks like some sort of air pump?...with a little vacuum hose coming out the back of it. This part also makes noise and vibrates while the car is running or the with the key just turned to the "on" position, and it sounds like the kind of air pump you would use in an aquarium. I have the FSM, but is has no picture or even mention of this part. My car seems to be running fine but i've never heard this thing make this constant noise before. I'm also having problems with my cruise control engaging correclty, there is somewhat of a delayed reaction with it(you set it, take your foot off the pedal then car slows 5-6 mph before "kicking in" and is very jerky), not sure if there is any connection. Sorry for the long post, and I realize a picture would help, I'll try to post one if I can, -Dayle

turboast4

My cruise control does that too, although it doesn't really "jerk" when it starts to accelerate but there is a noticable surge. I think it's normal though. I'd guess that the computer is slowly openning the TB til it gets to the proper speed. It is pretty annoying, as when I accelerate when passing without taking the cruise off it'll slow down that extra few miles per hour when I let up the gas to slow down after I'm done passing. Sometimes the car or truck I just passed decides to pass me again since I slowed down. Also, keep in mind that the cruise won't engage beyond about 78mph. I don't know what happens if you try to, I've never done it, but if you try to engage it below 35mph nothing happens.

blackmaxima88

that little air pump looking thing with the vacuum line going to it is the cruise control servo. I bet there's a cable running from it to the throttle cable too, right?

perhaps that's malfunctioning and that's why the cruise doesn't work right.

Dan

max95q

iTrader: (10)

Its all done by vaccuum from the engine you could have a vaccuum leak somewhere. Not saying that is the cause, just an FYI.

blackmaxima88

the cruise never worked in my 88 se. the one green light on the dashboard came on when I pressed the main switch, but I could never get it to set and turn on the other green light. maybe it's a common problem?

Niku-Sama

iTrader: (1)

my cruse works fine. theres 2 (i think 2) things with werid wire screens on top....i have no idea what they are other than some peice of the vaccum system but i bet the hose came off that...

i had the teeniest hose come off there and it was loud, i could hear it from inside my car.

if you turn the car on is it quiet and than the noise start a little after you start it?

Dayle97SE

iTrader: (7)

well my mystery part is solved and so is my cruise control problem. It turns out the part is part of the cruise control - thanks to blackmaxima88! Here is a link to a pic of this cruise control motor/servo:

http://a8.cpimg.com/image/5A/C0/4274...-02000180-.jpg

I figured out that there was nothing wrong with this part, but I traced the problem to a vacuum leak - thanks max88q. Here is another link with a pic:

http://a0.cpimg.com/image/5C/C0/4274...-02000180-.jpg

Against the firewall, under the wiper motor there is a round box type thing with various little vacuum hoses comimg out of it, apparently it is also part of the cruise system. One of the hoses on mine had a nice size crack in it, making the whole system act up. In my case I could even hear the air leak, it was pretty loud. Anyway thanks to all who replied, and those with cruise control problems, these are some more items to check if you haven't already.

cardana24

iTrader: (81)

I see in your first post you said that the car ran fine, but I am just wondering how it ran at idle....was it irratic at all? I am having a problem and I swear its a vacuum leak but I cannot find it....I will have to look at the box you are talking about under the wiper motor.

Dayle97SE

iTrader: (7)

well a couple of years ago i was having trouble with the idle, and i had to replace alot of parts and i'm not sure which one was actually the culprit, I replaced the air regulator, fuel pressure regulator, and some misc. vacuum hoses going to and from the intake manifold. Then over this past summer I did a major tune up - plugs, distributor cap, rotor, plug wires, air & fluel filter, and cleaned TB and I also removed and cleaned the idle-up solenoid. After all that my idle really smoothed out and pickup and driveability really improved. Then these past couple of weeks I had been noticing problems with my cruise and that loud vacuum leak that I could hear, but my idle and driveability was not affected at all, and is unchanged even now that I have fixed the cruise cont. vacuum hoses.

cardana24

iTrader: (81)

I have done everything you have listed other than the fuel pressure regulator within the last 6months....but still when I crank the car somes times it shoots up to 1500 then back down to ~200 RPM then it does this several times then catches its self around 1300 (when cold)....but even when it does catch the car idles like it is missing, but when you drive it, everything is fine....smooth acceleration etc. I will probably check out the FSM and see what the factory setting are for the TPS then put the volt meter on it. Congratulations on getting your problem fixed...hopefully I can find my problem soon.