Cruise control brain fix
#16
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Rennlist Member
Rennlist Member
I fixed mine last night. First I tried resoldering the connector as one person suggested, no help. then I started in on the whole board, but decided I'd like to narrow it down a little, so I just did the components that get hot. I could see discoloration on the component side of the board around the components that generate a lot of heat, and so I remembered where they were, flipped the board and resoldered those. Worked like a charm! I ended up doing the two guys with the heat sinks (op amps?) and a couple of big diodes, maybe a few other things that had browned the circuit board a bit.
Before I decided to do the stuff that gets hot, I resoldered all the connections about 1 cm from the end near the big connector connections (does that make sense?) so one of the two procedures fixed it. My guess is resoldering the high heat components is the ticket.
I was going to jack up the back of the car (for testing it in my driveway) and do other groups of components if I didn't get it working after the second try. Thankfully that wasn't neccisary.
Anyway if you want to try fixing your CC brain, you might try the big connector pins and the high heat stuff first, before doing all the damn things.
-Joel.
Before I decided to do the stuff that gets hot, I resoldered all the connections about 1 cm from the end near the big connector connections (does that make sense?) so one of the two procedures fixed it. My guess is resoldering the high heat components is the ticket.
I was going to jack up the back of the car (for testing it in my driveway) and do other groups of components if I didn't get it working after the second try. Thankfully that wasn't neccisary.
Anyway if you want to try fixing your CC brain, you might try the big connector pins and the high heat stuff first, before doing all the damn things.
-Joel.
#17
ahhh... aren't thru-hole parts great! i'd challenge you guys to try this technique on the cruise controller in any new car. those 0603 (6x3mm surface mount) resistors are kinda hard to solder with a pencil iron!
i saw someone mention erratic cruise control operation after installing a throttle cam. this is expectable... you have a certain amount of gain in the feedback path (controller) and you have just upped the gain of your "plant" (added gain to the throttle input => road speed transfer function) therefore changing the dynamics of the system and potentially driving it into unstable oscillation.
Ben, fighting off nightmares of laplace transforms...
i saw someone mention erratic cruise control operation after installing a throttle cam. this is expectable... you have a certain amount of gain in the feedback path (controller) and you have just upped the gain of your "plant" (added gain to the throttle input => road speed transfer function) therefore changing the dynamics of the system and potentially driving it into unstable oscillation.
Ben, fighting off nightmares of laplace transforms...