hakanson@orstcs.UUCP (07/22/84)
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It sounds like what is sometimes called the "sensitivity" needs to be
adjusted. This is the adjustment which tells the cruise control how
much throttle to give when the speed falls, etc. In general, you want
as much sensitivity as you can stand, in order to keep the speed relatively
constant. The setting is dependent on the relative power of your car,
which might explain the remark about gearing being different, which could
cause a "standard factory setting" to be wrong. Another possibility
is that the speed sensor is weak or bad -- my brother has an aftermarket
cruise control which uses magnets stuck and taped to the driveshaft to
sense the speed. One of these came off and resulted in behavior similar
to that which you describe.
Some cruise controls have a total of three adjustments which can be made:
the sensitivity; the low speed adjustment (controls how fast the car must
be going before it will take hold, and also affects the top speed range
it can give); and, the centering adjustment (usually the last to adjust,
since on the one I installed the other adjustments throw centering off),
which when adjusted properly keeps your car from slowing down or speeding
up immediately after the cruise-control is engaged.
In short, yes, something is wrong, you are not crazy, and you should have
the dealer adjust the thing properly.... Good luck.
Marion Hakanson CSnet: hakanson@oregon-state
UUCP : {hp-pcd,tektronix}!orstcs!hakansonwookie@alice.UUCP (07/25/84)
The gearing story is a bunch of #%$&'%$.. There is no reason you cannot install a cruise control with a manual transmission. In fact the cruise control will (should) attempt to maintain the set speed reguardless of the gear you are in. The only limitation involved there is engine RPM. Surging is simply oscillation in the system and is not normal to its operation but does occur in some systems. Typically I have found the surging is due to the linkage from the cruise control servo unit to the accelerator linkage being bound up or stiff. Sometimes simply changing the size of the accelerator return spring has helped rid the system of oscillation. In factory original systems where the cars speed is sensed off the speedometer sometimes the speedometer cable oscillates a bit and throws the system out of whack. Anyway I am betting on the stiff linkage from the servo route so have them check into it and don't believe that garbage about gearing.....the man who told you that obviously doesn't know his ........ from a ........ or is trying to snow you under! Keith Bauer White Tiger Racing
rib@edsel.UUCP (RI Block) (07/26/84)
You should be able to get a lot of info on this problem; almost all Accords and Camries have cruise control either as standard or "semi-required" option. I have a 1984 Camry with a 5-speed and CC. It works like a charm under most but not quite all driving situtations. I have never had a problem with "hunting" (I think that's the correct servo lingo for your problem). A freind of mine has a Accord. I noticed no problems during a RT to Whippany, which is about an hour's drive over varied terrain.
mikey@trsvax.UUCP (07/26/84)
#R:decwrl:-273800:trsvax:55200092:000:905 trsvax!mikey Jul 26 09:03:00 1984 You didn't state what kind of cruise control it is. Most aftermarket units sense the speed and use engine vacuum to pull the throttle and thus maintain speed. If you have a vacuum leak, it could cause the range of the unit to vary, giving the symptoms you described. Most factory units are simpler and a vacuum leak is even more noticeable. The aftermarket units with a solid state control box will usually not be as bad on a vacuum leak. They usually have an internal ajustment for "Lock Range" of the speed. The sears unit I put in my Sport Fury a few years back could be adjusted to hold the speed to within 1 mph or let it vary up to 5 or more mph. Most places that install these types will usually set them for a fairly wide range, as this gives better fuel economy, but too wide can give the results you are getting. I'd say have the thing checked and/or adjusted. mikey at trsvax
bossert@ssc-vax.UUCP (John Bossert) (07/26/84)
I mailed a similar letter to the original poster; maybe this is info for the whole group: Cruise control basically consists of a magnet attached to the driveshaft, usually behind the transmission, and a fixed sensor attached to the underbody of the car. As the driveshaft rotates, it stimulates the sensor, causing it to send pulses to the electronics box on the engine, which controls the engine speed. I had a similar problem with my 320i. The problem, it turns out, is that the sensor is not close enough to the magnet. It misses pulses, and the engine surges. The solution to the problem is to perform some creative bending on the brace holding the sensor to the bottom of the car. There should be no more than the thickness of a few pieces of paper between the two components when they are in line. The only concern is that they do not rub when the driveshaft (and magnet) rotates. Cruise control works fine on a manual transmission car, so long as you don't try to cruise at 10 mph while in 5th gear :-) John Bossert Boeing Computer Services Seattle, WA uw-beaver!ssc-vax!bossert -- John Bossert Boeing Computer Services Seattle, WA uw-beaver!ssc-vax!bossert