Just another one... "pumping" cruise control - ZR-1 Net Registry Forums

Matt B · 04-25-2021

While I took her for another spin today I discovered another unexpected behavior. When using cruise control I recognized a "pulsating" motion of the car. First I thought it may be because of very low RPM and rather low speed. Later on the Autobahn I realized that even the gas pedal slightly but very noticeably moves in and out about 2 times a second. This motion is very constant and seems to happen at all (engine) speeds.

Can it be a result of my recent speedo adjustment via module by Ecklers? To offset my 335/35 rear tires I accelerated the signal by 2%. Speedo is back to GPS correct reading now.
Or would you rather suspect a vacuum issues? Or something else?

04-25-2021	#1
Matt B Join Date: Jan 2021 Location: Beautiful Bavaria Posts: 523	Just another one... pulsating cruise control While I took her for another spin today I discovered another unexpected behavior. When using cruise control I recognized a "pulsating" motion of the car. First I thought it may be because of very low RPM and rather low speed. Later on the Autobahn I realized that even the gas pedal slightly but very noticeably moves in and out about 2 times a second. This motion is very constant and seems to happen at all (engine) speeds. Can it be a result of my recent speedo adjustment via module by Ecklers? To offset my 335/35 rear tires I accelerated the signal by 2%. Speedo is back to GPS correct reading now. Or would you rather suspect a vacuum issues? Or something else? __________________ ZR-1 #638/1991 Last edited by Matt B; 04-26-2021 at 11:08 AM.