355 Brake Pump not working with engine running...any ideas?

Strange. I guess you have the Teves braking system? What year? Motronic 2.7/ 5.2?

The pump relay coil is powered by the "ACCY" contact of the ignition lock (i.e. position "I"). When you put the key to ON (RUN).. i.e. position "II", the commutator on the ignition lock still keeps power going to the relay coil (via the ACCY wiring). The commutator is a conductive segment which can contact more than two terminals at the same time.

Are you getting brake pressure prior to engine start with the key in ON (position "II")? i.e. if you keep pumping the brake, does the pump restart because you are using up the pressure? If not, maybe you have an ignition key problem.

When you go to crank the engine, the pump relay is de-energised (to allow max battery power to go to the starter). The pump relay is de-energised by another relay during cranking (i.e. the Auxilliary ABS Relay).

If you are getting brake pressure with the key in ON/RUN prior to start, but not after, maybe the auxilliary relay is sticking in the start (cranking) position. Seems odd though. Does pump operation always resume when you turn off the engine and go back to the ACCY (position I)?

Do you know where the relays are for the ABS system (in the frunk)?

Note that the pump relay coil still needs an earth (from the system pressure switch). Low pressure = earth. I suppose you could have a dodgy pressure switch which doesn't like the car vibrating.

Experts?

5.2. Teves wiring diagram here if you need it:

https://www.dropbox.com/t/crD3mqxoWebTjCnv

Link expires in 6 days

 

Here's the 2.7 diagram

https://www.dropbox.com/t/8W8Vq3YIofHZrnf9

The behaviour seems too consistent. It may not be the relay problem I described. Anyway, I believe the auxilliary relay is the one next to the 3 amp fuse. Orange or yellow.

 

Image Unavailable, Please Login

I don't mean the relays and fuses on the left hand side of the car under the square cover, I mean the ones under the "carpet" on the right hand side (near the right hand frunk latch).

 

I see you have a RHD 2.7 with a TODA spec engine....

By the way, has the car recently had any work done on the brakes. I believe if the test fuse has been inserted into the test slot, you get strange things happening.

The fuse slot should be empty. That's the one next to the "diodes box". The diodes box looks like a relay, but usually has a white circular sticker on it.

Seen at 2 minutes into the video:

 

Here's a case of someone leaving the fuse in the test slot:

https://www.ferrarichat.com/forum/threads/348tb-abs-problem-abs-on-ever-in-cockpit.177495/#post-137289402

 

Oh, so there was one there. I wonder how it got there. Do you know how long it has been there? I'm not sure if there are any long term effects of the fuse being there.

Perhaps a worn commutator. Let's hope it's not like this:

https://www.ferrarichat.com/forum/posts/146236744/

Note that ignition lock failures have caused brake problems previously:

https://www.ferrarichat.com/forum/threads/bizzar-problem-abs-and-break-light-on-then-key-would-not-release-from-ignition.647155/#post-148071785


Moving onto your relays and fuses... .I see that your fuses seem to be all jumbled up:
The test holder should be 5 or 10 amps (but not installed unless testing)
The fuse next to the orange relay should have a 3 amp fuse (I guess 5 would be ok for now)
The other relays should have 30 amp fuses next to them.

Anyway, an easiest first step might be to change that orange relay. At least we can take it out of the equation. By the way, WD40 is really not the best for electrical contacts as it attracts dirt. Use some no residue electrical spray and if you are really serious, some DeoxIT.
I believe the part number for the orange relay is 131940. The parts manual calls it a "systems release relay". The parts diagram show it in a different physical location to yours, but don't panic (yet). I'm sure I've seen the same colour order on other 355's (to yours). It probably depends on what day of the week it was (which fuse socket goes where). Maybe when we start running out of ideas, we could check that the relays are in the right slots by using wiring colours.

 

P.S. I didn't realise the relay holders were coloured. I assume if the colours match the relays, you should be good to go.

By the way, I made a few small edits to my last message. You may want to read it again

 

Are you familiar with the test procedure using the fuse? Instead of chasing our tails, I suppose we could let the car tell us what is wrong with the system.

 

Image Unavailable, Please Login

"MARCIA" = position I (in Ferrari-speak)

Image Unavailable, Please Login

I have a Bosch brake system without this test function. I have no idea how difficult it is to interpret the flashing lights on the Teves system.

 

You can do a simple test: while the engine is running and you have no function of the ABS pump, pull the orange relay out and note whether it clicks at the point of disconnection; then push it back in and again note whether it clicks. In normal operation, this relay should not click when pulled out or pushed in.

Further test: Remove the orange relay and bridge the sockets of the relay pins 30 and 87a. This is what the orange relay provides all the time except when cranking when the relay will disconnect 30 and 87a. With the bridge plugged in (instead of the relay), the only difference will be that there will be no switch-off of the ABS pump and the ABS computer during cranking.

If the ABS pump works well with the bridge, the problem is either a fault in the orange relay or with something that prevents the orange relay from switching off once it was switched on during cranking. Do you have an additional aftermarket starter relay or any other aftermarket electrical installation?

 

Of all the problems I see with the Teves system, there are two common themes:

1. Component failure of the pump, accumulator, pressure switches.
2. System wiring done by bad mechanics.

If you don't have a lot of history with this car (how did that fuse get in there?), you should check the wiring on the system. A bit of a pain in the butt, but make sure the wirings are correct. That corner of the car is subject to a lot of abuse by stereo installations.

 

Pressure switches are AC Delco part #25530882. I'd find one and hang on to it, I bought one from Rock Auto for $75 new but it seems they are getting MUCH harder to find.

 

Miro's relay jumper sounds like a good idea for the orange relay. I didn't realise the Hella relays were so expensive:

Ricambi USA
https://www.ricambiamerica.com/car-diagrams/ferrari/v6-v8/348-group/348-1989-1992/brake-system-with-antiskid/131940-relay.html

Eurospares UK
https://www.eurospares.co.uk/search?partNumber=131940