With 16 days and 2200km of sheer driving pleasure under my belt I've found something to whinge about but I'm not sure if this is a general issue or a fault with my car.

When using cruise control 101km/h in the 100 zome on the way to Bathurst I've found the cruise control to be perfect on the flat and surprisingly, even better on the down hill , it seems that on the uphill, the speed holds well until the crest and then seems to continue to accelerate well beyond the 101 and I had to intervene regularly when the speed hit 110.

Has anyone had a similar experience??

Rob

 

I have not had any touble with the cruise control. It has been holding the speed for me +/- 1km/h regardless of the slope of the road or speed.

 

No hassles here... works a treat. Love the kick in the pants when you bump it up 1 mph even in sixth gear.

 

Sorry but you are still on your own. Drove back from Stawell to Melbourne (200k) and it didn't vary by more than 1km in speed all the way.

 

I've seen this...

I've assumed the cruise control has a problem on steep down hills, I think it only controls the throttle not the brake, hence it is fine if the engine can control the speed, but on steep down hills it can't slow it enough.

I haven't really tested it closely, but I'll raise the issue at my 10,000K service on friday.

 

My cruise control works perfectly. I'd get this issue looked at asap.

 

Did 1000kms of driving over the weekend... I noticed something similar once or twice, although don't think it went more than about 4 or 5 above the cruise thing, but that may have been because I killed it before it went anymore. It only did it up hill, both times.

 

Sorry for butting in (I'm in the states), but I have noticed the same phenomenon. Whenever I let the speed drop significantly (more that 20-30km/hr), and press the "resume" button on the cruise control, it shoots past the mark I had set, and takes several (10-15) seconds to ease it's way back to the standard speed. Sometimes, it goes a significant way above the set mark (the first couple of times, I thought it was broken) before returning.

Set and forget, it's always been fine.

Sorry again for butting in, just wanted to assure you it's not just the Aussie cars with this phenomenon......

 

We've seen that problem in the U.S. See post https://www.rx8club.com/showthread.p...986#post109986

 

damn yanks, hijacking the thread. he's not talking about using resume, just constant cruising. I've seen neither problem with mine.

 

After 8,500k, I can report the 'surge' effect after hitting resume, overshooting the set speed by, say, 5-6km/h and then settling back but it is nothing more than I have experienced with other cruise controls.

Timbo

 

I've just completed a 4500 km round trip from Adelaide, to Sydney, up the coast to Byron / Federal via Dorrigo, and then back to Adelaide via Armidale and Hay. So you might be getting a few posts from me shortly.

Anyway, I tended not to use cruise control for a couple of reasons I will get to in other posts, but when my wife was driving she tended to use it a lot.

We did notice a problem with the speed overshooting by up to 15 kph. The control was set to 109 kph on the roads just west of Tenterfield in northern NSW, and only seemed to occurs after just cresting a rise.

 

Rob,

are you still getting this? I'm heading to Newcastle today [ i's 00:36:00 AM ] so I'll test it on the couple of perfect test spots for what you've seen as I suspect I'd had this a couple of times but both times I can recall I off'ed the CC to pull back in top of hill traffic - so stay tuned till tomorrow as I'll give it a good shot to either replicate or prove otherwise.

++dez;

 

Here's another yank's 2cents.

There's a long steep hill on my way home. The speed limit is 35mph and I usually have the cruise control on my AT set at 35 during the last stretch home (3 miles). Going up the hill, the car down shifts 4 or 5 times - each time it takes me about 2-4 mph faster than 35.

Going downhill, I sometimes drop it into a lower gear to keep from going faster than 40.

 

Hmm..

clearly it's repeatable then.

1st rule of problem solving is to make sure it's a reproduceable problem.

will post once I get back toay [ in around 10 hours ] if I can reproduce it.

++dez;

 

Dez

Its still irritating me although its the sort of irritation that is easily soothed by the leather, xenons, road holding and celebrity appeal of the 8 .... he he he

Of course when I gripe to the dealer service manager I may be less amiable!

How was the trip ???
- I'm interested to see how your reseach on the resume failure - reminds me of teh old toshiba T1200s !!!!

R

 

Toshies... yech... after my 8100 experience (5 times the same simple fault with the FL invertor had to be fixed in 3 years).. never again.

 

(Sheepish)

Well, I did a drive on the weekend that really exposed this problem, and realised that my normal drive -- Cbr/Syd & Syd Cbr (virtually all freeway) -- every week doesn't really expose this weakness. When using CC over more varied conditions, especially pressing Resume going uphill, boy does that baby overshoot.

I reckon that little controller found itself in an 8, and just can't help itself :D

 

well,

first days road testing to see if I can re-produce the "missile" cruise crontrol issue.. bzzztt.. I failed.. sorry..

I have to say I really did give it a good bash.. there as some pretty bloody good testing grounds for this sort of road test infact between Sydney and Newcastle [ where I was heading to and from yesterday ].

I did a range of tests..

1 - in 6th gear at 120km p/hr into down hill run and then back up a long winding curved hill

2 - in 5th gear into very big steep up hill section at 110km p/hr

3 - in 4th gear 500m before crest of rounding hill at 100km p/h

I did a range of other small tests but bloody cars kept getting in the way so I didn't include them.

But I could not repeat the "curise missile launch" effect, yet!

Rest assured I'm going to take the car out to the hills this weekend so I'll run another series of tests to see what I can get - I'm keen to experience this now.

Call me the cruious cat if you will.

sorry Rob, nothing conclusive yet * sigh *

but it has made me speed up my want to suck data from the car now, as I think the real acid test would be you driving into a steep hill in 6th gear, hit this curous cruise missile launch you're getting - catch the data on the old "palm pilot ECU OBD2 data sucker" gizmo - and see if we can play back to where the speed kicked in and perhaps write to Renesis / Mazda with out findings and see what comes of it.

Stay tuned!

++dez;

 

I have had these issues with cruise on several cars in the past, particularly when on overrun down a hill where speed climbs above the set-point, and then you start climbing a hill. The speed tends to drop way below (5-10 kph) the set point before the cruise susses things out, then accelerates to 5-10 kph over set point before figguring it out again...
I think this is fairly common and not particular to the 8...
Someone needs to figgure out a "preemptive" cruise system... one that can tell if you are about to climb a hill and react before dropping speed off.

 

Dez

Something to bear in mind is that the concensus seems to be that these 'launches' are observed often when pressing resume ...

Rob

 

this is way off the thread but has anyone else had their rear windows regularly "pop" open from the suicide door being closed, the main front door being closed normally, or even just driving along with the air con on?

it's driving me f*cking mad but randomly I get the little driver side read window pop open and I have to reach back and click it closed again, and now I have to make a note of checking the window is closed - and I reguarly find a reason to go get a hot choc and pass the car to check the frigging window is closed!

++dez;

 

Reminds me of my old Cooper S (sniff!)

No, have not had that problem, but do note the window has a double-click latch, so make sure you are getting the second engagement

 

ok,

I managed this week [ late post sorry ] to conclude the following:

"the issue with the crusise control is only on resume, it's easily repeatable, and should be watched closely if you're a few license points away from a permanently parked RX8!"

it's now a game I play, that is, enter a hill in low revs, high gear, resume CC, and watch the little blue bird attempt to fly!

every other possible combo I could dream up to put the CC through it's paces passed with flying colors, and as someone said here previously, that little "kick in the pants" every time you touch the "increase speed" button is just bliss!

I'm pretty ok with it all now, but if anyone is interested in the full boring details, in perhaps the interest of writing to Mazda / Renesis about it - PM me and I'll put you to sleep 100% gauranteed [ like I prolly did just now sorry ].

So there you have it Rob.

Real live demo's will be available on the next Wednesday Nightly Drive * grin *

++dez;

 

Dez,

Give us the boring details and I'll see if I can repeat it. If enough of us complain then maybe Mazda can rev the software in the ECU for us to fix the problem.

Cheers

sco