ABS Pressure Swith Where is it?

[superdave]

I have a 1990 carbed turbo with ABS. I've heard a lot of talk about ABS lights on etc. I know it can amount to the accumulator but does any know where the pressure switch is located?
Is there a cross reference part number like the accumulator which is a Jaguar XJ40 part?
I know I should get the car into a dealer to check the codes out. I was wondering whether it was possible for anyone to come up with somthing similar to freescan that would work on your ABS?

Any help will be appreciate.

[dictys]

Dave,

try this link...

http://members.aol.com/carpix256/pages/abs.html

this seems to be a program to that gives all the ABS trouble codes etc. I think it is about 18 quid. I not sure if its exactly what you are looking for but may do the trick.

Rgds
Dictys

[superdave]

dictys said:

Dave, try this link... http://members.aol.com/carpix256/pages/abs.html this seems to be a program to that gives all the ABS trouble codes etc. I think it is about 18 quid. I not sure if its exactly what you are looking for but may do the trick. Rgds Dictys

Thanks for that,
Ima not sure whether it's the right thing though but it's a starter for ten.
This only gives fault codes which you can get for free on http://home.att.net/~aldridgec/TGP/brakes/powermaster.htm I think.
It's the interface lead and software to connect to a pc or laptop. They do however have a link to another site, so well done and many thanks.

Cheers,


Dave Walters
ps. Have you picked up you new car yet? if so then send me an e-mail off line to [e-mail]

[Mark91SE]

Pressure Switch is attached to and below/behind the electric pump next to the accumulator ball. It has a wired connector to it.

There was a change specified by Lotus to a lower pressure switch #B082J6137S. The older one has a black connector receptacle built into the pressure switch, the new lower pressure one has a grey receptacle. Some say they get a slightly better feel... some experience no difference. Either way, if it stops working, you're likely to get a nice tablespoon full of brake fluid seeping from out of the reserviour cover down below it. Clean it up fast or it will eat away any paint there.

Here are some comments to test to see if it's within specs;

1. Pump Switch Test (older one): With ignition on... press pedal 6 times and the pump motor should run for around 4 seconds, then shut off... pretty consistently every time. I would guess the newer grey one would respond sooner, with 1 or 2 fewer presses, but still should be consistant.

2. Accumulator/system leak test: With ignition on... get it pumped up (item 1), then let it sit there for a bit (a few minutes should suffice)... the pump should not come on until you press the pedal 5-6 times again.

2. With ignition off... press pedal 30-40 times... turn ignition on...
pump should run for runs for around 30+ seconds.

I have dissabled my ABS by replacing the connections to the 3 solenoids in the Master Cyl by disconnecting the connectors to them and replacing those connections with 10k resistors, to fake out the computer into not lighting the ABS lamp.

I've driven it this way for several months now and prefer the better (non-hard-pedal) feel.

- Mark91SE

[superdave]

Mark,
thanks for that I'll go and try it out.
I think that I've already have done some of these tests. The promlem is that my ABS lights up when I switch the ignition on. When I start it up, it goes out after a few seconds. I never lights up when the car is stationary. I could leave the car standing for an hour and it still won;t light. As soon as I drive it a few hundred yards, the light comes on and stays on.
I was sort of thinking that it could be one of the wheel sensors maybe?

cheers,


Dave Walters

Mark91SE said:

Pressure Switch is attached to and below/behind the electric pump next to the accumulator ball. It has a wired connector to it. There was a change specified by Lotus to a lower pressure switch #B082J6137S. The older one has a black connector receptacle built into the pressure switch, the new lower pressure one has a grey receptacle. Some say they get a slightly better feel... some experience no difference. Either way, if it stops working, you're likely to get a nice tablespoon full of brake fluid seeping from out of the reserviour cover down below it. Clean it up fast or it will eat away any paint there. Here are some comments to test to see if it's within specs; 1. Pump Switch Test (older one): With ignition on... press pedal 6 times and the pump motor should run for around 4 seconds, then shut off... pretty consistently every time. I would guess the newer grey one would respond sooner, with 1 or 2 fewer presses, but still should be consistant. 2. Accumulator/system leak test: With ignition on... get it pumped up (item 1), then let it sit there for a bit (a few minutes should suffice)... the pump should not come on until you press the pedal 5-6 times again. 2. With ignition off... press pedal 30-40 times... turn ignition on... pump should run for runs for around 30+ seconds. I have dissabled my ABS by replacing the connections to the 3 solenoids in the Master Cyl by disconnecting the connectors to them and replacing those connections with 10k resistors, to fake out the computer into not lighting the ABS lamp. I've driven it this way for several months now and prefer the better (non-hard-pedal) feel. - Mark91SE

[superdave]

I can report back with my test results.

Test 1. The pump operates when I press on the pedal three and is always constant. The pump activates a similar amount of time you state.
Test 2. After test one I left it for about 3-5 minutes, no pump operation. I only had to press the pedal three times again and the pump operated.
Test 3. Ignition off, pressed the pedal 40 times, switched the ignition back on and it took about 33-35 second for the pump to stop making that awful noise.

So what's the verdict doc? Will she live?

Cheers,


Dave Walters
ps. Is there any more tests that I can do or can someone tell me what's wrong from the test results so far.

[Mark91SE]

So are you actually getting an ABS light?!

Did you check what color connector receptacle was on the pressure switch? The 3 pumps (instead of 6 or so) would probably signify you have the newer greay receptacle (lower pressure) switch. If not, I suppose it could be out of spec and not putting enough pressure in, but I don't know how the computer would sense this in order to turn the lamp on, as I believe it would get its sensing from that pressure switch.

Other than that... if you get an ABS light, it could be possible one of the connectors for the solenoids is faulty or something... or more so, that one of the fuses is blown to them. There are two ABS Solenoid fuses which feed 3 solenoids (1 rear and 2 front). And, although brakes will function okay with either/both of those two fuses bad or removed, the pedal won't be as hard (a good thing), but you 'will' get an ABS light on the dash!

Hope that helps. Sounds like your accumulator is holding fine.

- Mark91SE

[superdave]

Thanks for your reply. Silly question, where are the ABS sensor fuses located?

Cheers,


Dave Walters
(with fingers and everything else crossed)

[superdave]

Does any have a service or workshop manual that will help me locate where these fuses are for the ABS solenoids?

Cheers,


Dave Walters