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Aftermarket Rostra Cruise Control Problem

Thread starter #1
My problem:
I have installed the "Rostra" aftermarket cruise control in both my street rod that I built and my motorcycle.
Either unit works perfectly in the street rod. But when installed on my motorcycle here is what happens:
It randomly works when I first fire it up. Usually (not always) it works fine until I come to a stop. Then (most of the time) it wont lock up again... until I (1)come to complete stop again and (2) turn the motor off and back on. Then it will(usually) lock up (as many times as I like) until I come to a stop again. Anything other than doing the two steps outlined above wont reset it.
The only difference between the street rod and the motor cycle is... the street rod has a 4L60-e transmission and I use the VSS signal for speed input. The motor cycle has no VSS unit so I mounted 2 magnets on the rear wheel along with Rostra's coil pick up. And of course, I select the proper pin switch positions for that configuration. Again, when it works, it works great.
I have gone over the harness too many times to count and anyway I don't see how it could be a wiring problem since it does work some of the time. It can't be the unit itself since both work fine in the street rod.
For some reason the engine has to be turned off/on while the rear wheel is stationary to get a good reset. That's what has me stumped.
(Rostra customer service wont talk to me when they find out the unit is installed in a motorcycle).
 

crutschow

Well-Known Member
Most Helpful Member
#2
Perhaps the cycle is putting out some electrical noise that is causing the unit to latch up.
Shutting the engine off would disconnect the power and allow it to reset.
You might try adding a capacitor (say 100μF) directly across the power and ground connections or use a commercial vehicle radio power filter.
 
Thread starter #3
crutschow,
Thanks for chiming in. I will certainly try what you suggest. But it still leaves some things to ponder...
I currently have the cruise control on/off switch wired directly to the positive post of the battery.
So when I turn off/on the ignition swt, power is still always being applied to the CC. The only other variable is the brake circuit but that shouldn't be any part of the 'mystery' since when I cycle the ignition swt, power to the brake swt is lost/gained but the CC should not even see that since the brake circuit isn't be energized at the time of the 'reset'.
Again, when I lose the ability to engage the CC, cycling the ignition swt while running down the road will never reset the CC. It must be the combination of cycling the ignition swt while at a dead stop. Hmmm, that just gave me an idea. Next test I think I will put a temp off/on switch on one of the speed sensor coil wires, then when I 'lose' the CC I could open that switch, cycle the ignition swt while running down the road and see what happens.
 
Thread starter #4
crutschow,
I am definitely out of my comfort zone when the discussion goes to things like capacitors and 'electrical noise' but I clicked on your link and read many reviews of the various filters and found this...

"I started using my radar/laser detector on my motorcycle recently. It was unusable due to false laser alerts every time I twisted the throttle to accelerate. To keep my heart healthy I decided to install this AX-ANR1000. To my pleasant surprise it worked!"

so maybe... just maybe...
 
Thread starter #5
crutschow,
You ARE the man! Could'nta/would'nta fixed it without you. Thank you so much!
I purchased and installed that cheap (7 bucks) noise filter (the AX-ANR1000) and just got back from an exhaustive test ride. Could not make it fail! I had almost no faith that this thing would fix it given the odd method I had to use to reset it. I kinda panicked the first time I applied power, then turned it off. The lamp indicating the unit has power just stayed on! I stood there staring at it wondering what in the heck I did wrong, when it faded out. AhHa! I know enough to understand the capacitor(s) inside that little box was providing power for a bit.
At some level I am curious as to exactly how this filter fixed it, but right now I am just so darn glad its fixed I don't really care!

But one last thing, recently you posted:
"Perhaps the cycle is putting out some electrical noise that is causing the unit to latch up.
Shutting the engine off would disconnect the power and allow it to reset."

One of the things I did during testing was to wire the CC off/on switch directly to the battery. So when I cycled the ignition switch (while stopped), the CC always had power.
 
#6
I had the same problem and tried the above with a similar audio noise filter but to no avail.

Currently, the cruise control will either surge say 20km/h or more so you have to disengage it via the brake, and/or it will just not engage again. When opening the cruise control controller box, the magnet connected to the servo is disconnected from the magnet controlling the throttle cable. In the reset position, they both touch and the throttle cable has the throttle plate in a closed position. Sometimes, when turning the car back on, the servo will reset and it will start working again, but this resetting is intermittent, it doesn't occur every time you turn the car on and off after the cruise control stops working.

Via dip switches on the cruise control, it is currently set to '5 or 6 cylinder' when my car is a 4 cylinder. I'm going to change that and see if it changes anything. It's worth saying that when the cruise control is actually working, it works well, this is why I never changed this setting previously.

Also I don't understand / don't know what to set:

Pulses Per Mile - 2000, 4000, 5000, 8000.
Control Switch - Open Circuit Control Switch, Closed Circuit Control Switch.

Does anyone know what they mean / how I determine what is the correct setting for my car?
 

debe

Active Member
#8
Open circuit control switch is most probably what you have, when pressed closes the circuit. The other closed circuit control switch, opens circuit when pressed. All depends on the control supplied.
 
#9
Thanks for your responses.

The Cruise Control Module receives constant power +12V and accessory power +12V. I've hooked up the filter to the constant power +12V, but could the module be receiving interference from the accessory power +12V circuit?
 

shortbus=

Well-Known Member
#10
The constant 12V is for the memory built in the unit. The 12V accessory power is for when it is actually in use. Most thing made for a vehicle environment are made to take anything a normal vehicle could through at it. But things like aftermarket solid core spark plug wires can sometimes create problems.
 
#11
The constant 12V is for the memory built in the unit. The 12V accessory power is for when it is actually in use. Most thing made for a vehicle environment are made to take anything a normal vehicle could through at it. But things like aftermarket solid core spark plug wires can sometimes create problems.
That's what I would've thought as well. So do you think it's advisable to have the filter connected to the +12V ACC instead of constant?
 
#13
So after reading online and looking at Rostra manuals, one manual mentioned that the blue wire which connects to the tachometer is not used on a manual car, if you have a clutch switch installed on the clutch pedal. I wasn't the original installer of this aftermarket system on my car, but when previously testing, I worked out that there appeared to be a switch installed on the clutch pedal. The Rostra manual mentioned that if a clutch switch is installed, the blue wire should be grounded to prevent "trashy" signals being received. Testing the voltage of the blue wire with a micrometer displayed variable voltages going down (sort of between 6v going down to 3v). This would explain why the cruise control stopped sometimes but not others. I grounded the blue wire to a constant 12v grounding. Test drove it again and it's all working...for now. I'll have to see how it goes on my next long drive.

In the process of trying to fix this, I lubricated the shaft that carries the electromagnet with WD-40. It appears that this also lubricated the drive shaft out of the electric engine connecting to a rubber belt, which connects to the gear pulley which moves the electromagnet. This has caused the belt to slip! I degreased it but it still slipped. I shoved a piece of dishwashing sponge in their to try and guide it and stop it from slipping off the engine shaft. I moved the gear and belt backwards and forwards a number of times and it appeared to stay. A pretty dodgy fix to getting the belt to stay on I suppose but I couldn't think of any other way of keeping it on there.
 
Thread starter #14
Confused,
For the first time on a long time I checked this thread. I see you are having (sorta-kinda) the same problem I am. I would like to chat. Ping me if you read this.
 
#15
It turned out to be the blue wire causing the intermittent problem. Once I grounded it that stopped it. But during the troubleshooting my lubricating of the mechanical components inside the Rostra box has resulted in the drive belt always slipping off. So without knowing a way to fix the drive belt, I've resolved to eventually buy another identical Rostra box and mate up with the (now) correct wiring.
 

crutschow

Well-Known Member
Most Helpful Member
#16
At some level I am curious as to exactly how this filter fixed it
The electrical devices in your vehicle can generate various voltage deviations (spikes or electrical "noise") on the DC voltage from the battery.
This can get in the electronics of some devices and cause erratic operation.
The filter uses capacitors (and sometimes inductors) to suppress these deviations, giving a smoother DC voltage and preventing a problem in the device.

This also indicates that the device did not have sufficient internal filtering to operate in the electrical noisy environment of a typical vehicle. That's probably not unusual in aftermarket devices that are designed to be built as cheaply as possible.
One of the things I did during testing was to wire the CC off/on switch directly to the battery. So when I cycled the ignition switch (while stopped), the CC always had power.
That likely also helped to reduce the electrical noise.
 

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