Trying to keep my FB 85 GSL as close to stock as possible *and* fully functional, so I'm trying to get my cruise control functioning again...

It looks like I may have a squirrely actuator pump, so I'd like to replace it; but it looks like the nut on the end of the actuator cable is going to be a pain to remove. The actuator lever seems like it's buried in as hard-to-reach a spot as possible.

Before I start removing things that may not have to be removed (like the carb), can anyone suggest the best/easiest way to unhook the cc actuator cable with a minimum of fuss? I.e., I'd rather not have to take off the carburetor if I don't have to.

Thx!

 

its been a while, but i think you pop the little clip off, pull, and the nut part of the cable will come out enough to slide out of the bracket, then its fairly easy to pop the cable end out of the throttle arm.

 

Yeah, it's the cable end that was giving me trouble (i.e., the little cylindrical nut on the very end); I'll dig into it some more this weekend.

But you don't remember having to take apart the carb for access?

 

no you don't, the cable will slide out

 

FB 85 GSL 12A; totally stock.

I've now checked out everything for the cruise control according to the FSM, and it *still* doesn't function...

1) I've used the Mazda ACC checker tool to check all sensor and switching inputs, and all check out OK according to the manual (Speed sensor shows good, combo switch shows good, clutch & brake switches show good). The actuator also functions, and I've set the cable so that when using the ACC tool, RPMs go to 2500 when activated during idle (mid-range according to FSM).

2) I replaced the computer with an ostensibly working unit from an 84 GSL 12A (part serial numbers were identical).

3) When I'm at speed, with the CC power switch on, and push the SET button on the combination switch...nothing happens. Literally nothing.

I'm really at a loss at this point.

Any suggestions?

 

Manual or automatic transmission?

 

Sorry, manual...

 

I admit the cruise control system isn't something I know much about, but just looking through the FSM I just had a couple ideas;

I know you said that you have checked everything, but I just wanted to double check - did you test the Cruise Control Unit actuator solenoid?

Also did you check the vacuum hose for leaks?

 

I checked the solenoid by having the ACC unit connected, idling the engine, then pushing the rocker test switch on the ACC unit. With the cable connected to the throttle, I played with the adjusting nut on the threaded portion of the cable to the point where RPM would increase from <1000 while idling to ~2500 when the rocker switch was activated.

I also confirmed the solenoid operation by disconnecting the cylindrical nut at the end of the cable from the throttle, and just observing whether the actuator actually was pulling the cable when I pressed the rocker switch. In this situation, there was about a half inch of pull on the cable when the solenoid was activated. No idea if that's an appropriate amount.

I did *not* check the vacuum hose for leaks...what's the best way to perform such a test...?

 

Did you check the CC computer under the bins behind the seats?

 

Unfortunately there's no direct method for testing the CC computer; the FSM says that if CC is not working, and all the other tests fail ("no abnormal condition when an ACC checker is used to check items 1 to 10"), and I quote: "try replacing the cruise control unit."

I've done that once now, replacing the original CPU when *that* wasn't working, with another--which *also* hasn't solved the problem...

I guess it's *possible* I've gotten a couple bad CPUs, so I can try swapping another one in...

 

So, I went ahead and changed out the vacuum line with another line from another actuator.

No joy, still no worky...

Damned frustrating...

 

Probably not the problem but you are traveling faster than 25 mph (40 kph) when you try setting it.

(just reaching right now, lol)

 

I had same problem. The speed sensor is built into back of the speedo. Changed speedo and fixed the problem.

 

Hmm...how tough is it to replace the speedo...? My console and dash are in pretty good shape, and I'd hate to crack open the instruments and risk screwing up something else.

Can the speed sensor be replaced without removing the speedo?

 

It is pretty easy, but will require patience. The main plugs will require some finesse to nut break the white retainer tab in the center. But once you get it out of the car it is pretty straight forward. I am pretty sure the speed sensor is built in so you will have to swap the whole speedo assembly. Sorry.

 

Ugh.

Don't really want to change the speedo/odo at this point just to get the CC functioning...especially since it's not clear that it will fix the problem (as the ACC checker shows the speed sensor functioning).

The engine's got 114k on it, so if I can't get the CC functioning with any other fix attempts, I'll add it to the list of things to address when the engine needs to be rebuilt.

I'll try a couple more computers, a couple more actuators...if it still doesn't work I'll live with no CC--although it will bug me incessantly

Then, in 2017 I'll drop in a 16X and stop worrying about it.

 

I would try the ACC checker one more time to double check. With everything checking out okay, including the actuator, I don't understand why its not working. I would hope that something got missed with the checker the first time around.

Either way, let us know what you find. I am curious what you find.

 

Yeah, tried it again, straight down the checklist, all M/T tests with the ACC checker were Pass....

I'll see if I can dig up a couple more CC CPUs, maybe another actuator or two, and go from there.

Very strange...wish there was a way to run a diagnostic on the CPUs....

 

Isn't the definition of insanity trying the same thing over and over and expecting different results? I'd try the speedo just to validate it's not the issue. You can always put the original one back in.

 

Reasonable point, but at this point the only element of the system that hasn't been tested (because it can't be, short of it being shown to work in a vehicle) is the CPU.

The speed sensor actually passed according to the FSM tests (which doesn't mean it's working right, just that it passed), so there's still a chance (albeit increasingly unlikely) that the CPU(s) have been bad.

So given the potential risks associated with mucking with the gauge cluster (mainly breaking something through clumsiness...), the lower-risk approach is to check another CPU or two, get satisfied that it's a vanishingly small probability that *all* the CPUs I've tried were bad, then check the speedo by swapping out the gauge cluster.

That said, I'll probably go to a picknpull this week to practice pulling a speedo...

:-P

 

The 130mph speedos are different than the 85mph speeds. My '82 had the 85 in it and I swapped it out for the 130. Dimensions are the same but there is a bit on the bottom which I am guessing is part of the CC buffer signal which you have to swap over.

I reflowed the solder joints in the CC module, installed the other speedometer, and disassembled the stalk switch and cleaned the contacts and got mine to work.

Contacts are starting to get a little crappy again. If you're following the FSM it really should narrow it down to the Speedo or the Module itself.

 

I'm guessing that the green piece is the speed sensor element, from the 130mph speedo?

So, it looks like it's removeable/swappable with other gauge clusters?

Also: can the stalk switch be removed/disassembled/cleaned without removing the entire combo switch?

 

bump?

 

Swapped in a different gauge cluster and the dam CC started working--perfectly!

My old cluster had quite a bit of rust and dirt, now I want to see if I can still use my old speedo in the alternate, cleaner cluster, and maybe still get a working CC...

I just don't want to have to mess with a different odo...