I am the original owner of my syclone, and for the last seven years it's been parked in the garage, had the engine remanufactured only 43,000 miles. Needless to say, during that seven years, other things have happened while it's been sitting, the one most critical one right now is the ABS system seems to malfunctioned. Good little Pitkin solenoid in that block, one seems to be stuck open, so I don't know if you can buy those individually, or the entire block has to be purchased. The brakes work absolutely fine, but clearly if it came to a point where the ABS had to pick up, it would not. Does anyone know where I can get the ABS system block under the hood, for this vehicle? I can't seem to find anything even closely resembling that online. Thanks, Mark
Looking for Syclone ABS
- Thread starter Markwood
- Start date
Bob, thanks, not sure how to do a PM on here. But, I am going to make sure I get a picture so we are talking about the same thing. It's not like it's a difficult, or hard to find item, it's just a difficult and hard to find item on the cyclone, and nobody can tell me if like an S10, or anything else is the same, because they don't have a listing for it, but I'm sure it's not unique to that truck, but obviously cyclone and typhoon in the same, so I'm sure it would work. But, let me get a picture together today, and I will send it, and tell me if we're talking about the same thing. Thanks so much for the offer Bob, I will probably take you up on it thanks
DaveP's Ghost
Well-known member
The Syclone and the 1992-only Typhoon use the same "Brake Pressure Modulator Valve". The 1993 Typhoon uses a different BPMV, and the 91-92 and the 93 are not interchangeable. The difference is that the 91-92 has four wheel speed sensors, including on the rear wheels. The 93-up system does not have rear speed sensors, it uses an input from the speedo sensor on the t-case for rear wheel speed. The programing and wiring connections are different for the 4-sensor and 3-sensor BPMVs. It is impossible to tell the two apart from observation, but if you plug them in, and access DTC's, it is possible to tell them apart by looking for wheel sensor codes for the rear wheels.
Other applications for the 91 Syclone BPMV will be 1991-1992 Olds Bravada, and of course the 1992 Typhoon. These are all "AWD" applications. It is possible to use a BPMV from a 1991-92 4-door (not 2-door) Blazer / Jimmy 4X4, and jumper one terminal in the 10-pin connector to ground to trick the BPMV into "AWD Mode" at all times. I did this in my AWD Blazer conversion, and it worked flawlessly for 10 years and 200k miles.
The BPMV is configured with 3 major components. The rear valve block contains the pump, valves and solenoids. The center white section is a connector block, and the front housing contains the electronics and processors. The rear valve blocks are usually where the issues are, especially if you have solenoid or reset switch codes. (Wheel sensor codes will NEVER be the BPMV, they are always the sensor or wiring. ) It is possible, and fairly straight forward to move your electronics section to a replacement valve block rear section. I've done it. You need a set of "security" torx sockets that have a hole in them to remove the screws.
I have several BPMV's here in my stash, two of which came off of functioning systems. Both are 1993, so you would have to do the transfer the electronics thing. You're welcome to any of them. I'll never use them.
TL/DR version: What is wrong with your current system? Can you pull codes? Does the BRAKE and ANTILOCK lights come on for bulb-test with key = ON? If any of these are NO, check the large red power wire at the BPMV for 12 volts at all times. If = no, look in front of the battery for corrosion issues on this wire. 9 of 10 times, fixing the connection at the battery fixes the ABS.
Good luck. If you need more, I'll try. Back in the day, I was one of the few peeps that had a good understanding of the SyTy ABS system. I haven't forgotten everything yet. Just ask.
Other applications for the 91 Syclone BPMV will be 1991-1992 Olds Bravada, and of course the 1992 Typhoon. These are all "AWD" applications. It is possible to use a BPMV from a 1991-92 4-door (not 2-door) Blazer / Jimmy 4X4, and jumper one terminal in the 10-pin connector to ground to trick the BPMV into "AWD Mode" at all times. I did this in my AWD Blazer conversion, and it worked flawlessly for 10 years and 200k miles.
The BPMV is configured with 3 major components. The rear valve block contains the pump, valves and solenoids. The center white section is a connector block, and the front housing contains the electronics and processors. The rear valve blocks are usually where the issues are, especially if you have solenoid or reset switch codes. (Wheel sensor codes will NEVER be the BPMV, they are always the sensor or wiring. ) It is possible, and fairly straight forward to move your electronics section to a replacement valve block rear section. I've done it. You need a set of "security" torx sockets that have a hole in them to remove the screws.
I have several BPMV's here in my stash, two of which came off of functioning systems. Both are 1993, so you would have to do the transfer the electronics thing. You're welcome to any of them. I'll never use them.
TL/DR version: What is wrong with your current system? Can you pull codes? Does the BRAKE and ANTILOCK lights come on for bulb-test with key = ON? If any of these are NO, check the large red power wire at the BPMV for 12 volts at all times. If = no, look in front of the battery for corrosion issues on this wire. 9 of 10 times, fixing the connection at the battery fixes the ABS.
Good luck. If you need more, I'll try. Back in the day, I was one of the few peeps that had a good understanding of the SyTy ABS system. I haven't forgotten everything yet. Just ask.
Wow, Dave, you really know your stuff, thank you so much for that information. That makes it so much easier. I figured it shared a system with something else on the market.
Will I have to program anything if it comes from anything else? Much thanks, Mark
I'm sorry, I forgot to answer what's wrong with my current on. Well, not really sure, but if you look at the front of the module block, there's like two screw in ceiling light type things, one of them is completely out, so I'm assuming the sensors picking it up as a malfunction because it's stuck open, the brakes work fine, but it's enough to throw the code, and that's Illinois that's in there you can see it's like all corroded, but that little tab is sticking out. So, I assume everything's probably corroded in there, because it has been sitting for 7 years, and I'm not sure if that's a replaceable part or not.
DaveP's Ghost
Well-known member
The "ceiling light things" are accumulators. They have a pin in the middle, sticking out of a rubber grommet. Is this what you mean? If one of the pins has extended, this is not really a problem. I've never heard an explanation for the pins changing state, or affecting anything, but it doesn't seem to affect anything at all. Try pushing it back in. I think it will.
Here's what I would do:
Turn the key to RUN. Do the BRAKE and ANTILOCK lights both come on for 2 seconds and go out? If = NO, something is wrong. Begin with the battery connection wiring. If = YES:
Jumper A and H (top row far right is A, bottom row second from left is H) in the ALDL. Turn key to RUN. The ANTILOCK light will flash the codes. The "normal" all-is-well code is 14. (If you see code 12, you have a 4X4 or 2WD BPMV). (If you see Code 15, your foot is on the brake pedal).
If there are other codes, write them down. Then clear them. Remove jumper. Turn key to RUN. Jumper A and H for two seconds, remove for one second, jumper for two seconds, remove for one second, repeat. When ANTILOCK and BRAKE lights come on, then go off the code-clear was successful. Learning to clear the codes is fussy. Turn key OFF, wait about 10 seconds, then turn key ON and try again. You'll eventually get it.
Recheck for any codes. If there are still codes, it is a current code. Usually a wheel sensor code, and will be the sensor or wiring. Wheel sensor resistance is 1,000-2,000 Ohms. IIRC, typically 1,700-ish.
When you're code-free (only 14 remains), go for a drive. At 8 MPH-ish you should hear a "grrrr" of the motor doing its self-test. Another test I sometimes try: After first start, ride the brake pedal a little, and accelerate gently to 15+ MPH. The ANTILOCK light should come on at 15 MPH. Stay above 15 MPH and release the brake pedal. ANTILOCK light should go out. (If you ever find Code 86, it is from this happening too many times. 86 will always clear if the brake pedal switch is adjusted correctly).
There's some ideas.
Here's what I would do:
Turn the key to RUN. Do the BRAKE and ANTILOCK lights both come on for 2 seconds and go out? If = NO, something is wrong. Begin with the battery connection wiring. If = YES:
Jumper A and H (top row far right is A, bottom row second from left is H) in the ALDL. Turn key to RUN. The ANTILOCK light will flash the codes. The "normal" all-is-well code is 14. (If you see code 12, you have a 4X4 or 2WD BPMV). (If you see Code 15, your foot is on the brake pedal).
If there are other codes, write them down. Then clear them. Remove jumper. Turn key to RUN. Jumper A and H for two seconds, remove for one second, jumper for two seconds, remove for one second, repeat. When ANTILOCK and BRAKE lights come on, then go off the code-clear was successful. Learning to clear the codes is fussy. Turn key OFF, wait about 10 seconds, then turn key ON and try again. You'll eventually get it.
Recheck for any codes. If there are still codes, it is a current code. Usually a wheel sensor code, and will be the sensor or wiring. Wheel sensor resistance is 1,000-2,000 Ohms. IIRC, typically 1,700-ish.
When you're code-free (only 14 remains), go for a drive. At 8 MPH-ish you should hear a "grrrr" of the motor doing its self-test. Another test I sometimes try: After first start, ride the brake pedal a little, and accelerate gently to 15+ MPH. The ANTILOCK light should come on at 15 MPH. Stay above 15 MPH and release the brake pedal. ANTILOCK light should go out. (If you ever find Code 86, it is from this happening too many times. 86 will always clear if the brake pedal switch is adjusted correctly).
There's some ideas.
There may be a way to flash these, but it is specialized equipment, dealer-only shit, that they probably can't find anymore because they haven't used it for 20 years, and some tech took it home... The best way to deal with a replacement module is to either transfer your electronics module, or power it up and watch for certain codes. And the easiest is to obtain a 91-92 4-sensor module, and jumper pin D in the 10-pin connector to ground, which puts the module in 4WD mode at all times, so it will behave very similarly to the AWD program.
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I am do sorry, that pin thing was a typo...auto correct thing. You gave excellent advice. My issue is the solenoid thing in the front of the valve. It appears to be stuck open because you can see the pin pushed out. So I assume its bypassing and why my light is on....looks really corroded, so I assume it's bad and why I have issues. Thank you....
DaveP's Ghost
Well-known member
If the ANTILOCK light is on, there are codes. But the "pin" thing has nothing to do with any codes.
Jumper A and H and turn the key on. What are the codes?
Jumper A and H and turn the key on. What are the codes?