Hi all,

cruise control did not hold the speed, so i changed the vacuum lines. Since then the cruise control keeps accelerating about every 5 to 10 seconds. The rpm barely moves but it is noticeable, the L/100km on the ultragauge confirms this.

i removed the cruise control pump and checked the lines again, they are looking good.

then i thought i might be able to check something with the nanocom.
so i connected the nanocom, started the engine, enabled the cc button and opened the ‘hella cc’ option on the nanocom.
went to ‘inputs’ and saw the following while standing still with gearbox in neutral and handbrake on;


The up and down sequence of the roadspeed shown in the video is almost the same sequence my cruise control is accelerating.

what are your thoughts?

 

Weak pump, I have had them before. Leaking valves or bad pump. Easiest to just get a replacement.

 

All D2's have a surge to them. Make sure the cable to the Throttle Body doesn't have a lot of slack. 2-3mm will make it work much much smoother.

 

What Best4x4 said... Mine was doing the same thing--took almost all of the slack out of the cables and it's much better. Actual speed doesn't change much at all now and while the engine does still surge it's not nearly as much or as often. Seems to do best going uphill, oddly enough, when it has to keep some extra power on. Holding a speed at cruise on level road is where it "hunts" the most.

 

Thanks, i’ll reduce the slack in the CC cable. I know there is more slack in the CC cable while pulling it until i feel resitance. Certainly compared to the throttle cable.

 

Hey Extinct, what is your sense of the failure rate for the DII cruise control pump? New ones are very expensive, but there's no point in buying a salvage replacement if the failure rate is high.

Plus, could it also be the actuator, which is a separate component? Or do you recommend replacing both? And, same question about the failure rate for the actuators.

I took a 320-mile roundtrip last Friday to Durham. The cruise control worked on the way to Durham, but felt weak. It didn't work on the return trip later that day. I'd try to set the speed and the speedometer would drifter lower and lower. Thanks.

 

Given that there are rubber parts in both pieces (hoses in the pump; the flexible chamber on the actuator) I would imagine that failures are inevitable in time as the rubber hardens and cracks.

 

so instead of the rave 4.0-4.5 mm do 2-3mm?

 

Yes make the gap smaller