Quick Cruise Question

[NitroRoo]

Sorry I know this topic has been beaten to death. I just replaced my vacuum lines.

When does the solenoid open and close on the vacuum pump? When I check the vacuum by squeezing the throttle bladder, it's still leaking although not as quickly. I'm assuming the valve on the pump is open... how/when does it close?
Also, when should there be voltage to the pump? Only when cruise is set at the vehicle is moving over 28mph? Or should there be power to the pump as long as the cruise switch is on?

Thanks!

 

[NitroRoo]

Ok... so I've verified that I do not have any vacuum leaks, and the pump does run when I try to set the cruise. The cruise does not set though... and I believe it is because the solenoid on the pump isn't closing... either that or my vacuum hose to pump connection is leaking (I had to put hose clamps on the T connector to get a perfect vacuum).
Does anyone have experience repairing/replacing the solenoid?

 

[jcs2179]

I'm going exactly through everything on my cruise to get it going again (fuse #18, black Seemens relay, dash-switch (lights up ok), brake switch (ok ), CC switch (ok), hoses (new), t-valve (?), actuator (holds vacuum), CC pump (works), spiral cassette and 'set' button (continuity test shows okay) and ECU :banghead: .....it turns out it will most likely be the effing ECU not sending the right signal to the pump to activate. Will see, but I'll update tomorrow...

good luck

 

[NitroRoo]

Thanks.... I guess mine COULD be the ECU not keeping the pump on.. but once the pump draws vacuum it should at least hold there. Doesnt seem to be able to draw vacuum. Either the pump isn't strong enough or there's a leak somewhere (in the pump its self). I guess the ECU could also be telling the solenoid to stay open for some reason. All the fuses and relays I've gotten to check out ok, ECU/relays click when cruise is turned on.. just no cruise. I'm leaving for a 2500 mile trip on friday and was really hoping the vacuum lines would fix it. :banghead:

 

[jcs2179]

well, if you get to the bottom of YOUR problem, please come back and post the resutls....good luck!

 

[MNSUROVER]

When I was chasing down cruise issues on my D1 after a wheeling trip, it ended up being the check valves in the pump were leaking due to mud entering through the vent. It is easy to check if they are sealing- Pull the pump out and use a hose to try and blow into and then pull vacuum on each nipple of the pump. The one to the diaphragm up on the throttle should only let air flow in when you blow and the other should only let air flow out when you pull a vacuum. On mine the vent side was allowing air to flow both ways due to the valve being stuck. To clean mine out I simple hooked a nine volt battery to the pump to make it run and stuck both hoses on the suction side in a glass of water. After a moment it pumped up and blew some crap out the other side. After that both valves would seal. Not sure that this is the recommended method but it seemed to work.

You would have to check the manual or pull the cover off the unit to see which terminals to hook the battery to; it was a while ago when I did mine. I know I didn't use jumpers, I just stuck the 9 volt across the terminals and it worked...