No brake boost, low power, no brake indicator lights

As I was heading for Daytona on Saturday, my car suddenly lost power and brake boost.

I thought it was running on 4 cylinders, it was that bad. Stalling on re-start with very little power.

Short story: Car went home on a flat bed, I went on to Daytona. One less Mondial in the record attempt.

Back home now and the car starts and runs, although I can tell it is not running 100%, maybe 80-90%. Down on power and running just a bit rough.

None of the brake lights for the braking systems on the lower part of the panel are lighting up, nothing at start up, completely off at all times.

I drove the car yesterday and in addition to being down on power, I have no brake boost, and the resulting hard pedal that takes a lot of push to stop.

Seems like I may have lost a vacuum line to the booster? Plus some electrical problem that took out my indicator lights, which I must confess, have been off for a couple of weeks with no other problems.

I disassembled and cleaned all the connections at the brake master - no change.

Tachometer has been reading low for a while, so I disassembled it and cleaned the potentometer, this has fixed the problem in the past, but now it comes up to 1000 on start and stays there with a tiny bit of movement.

So...........

Need to check the electrical connections at the ABS unit?

Find out where the vacuum line for the brake booster runs to the plenum and check it out. Where is it?

Check and probably replace the crank sensor(s) for the tachometer and ECU?

Check fuse box connectors - all relays and fuses are new.

Timing belts seem to be OK.

I have good spark on both banks.

Anything else I should look at?

Alden

 

Check for vacuum leaks. Get some of those little rubber end plugs, then pull the hoses off the plenum one at a time, and install the plugs onto the plenum to make sure that hose is not leaking somewhere.

Check for system primary fuel pressure. Pull the air filter box off, turn the ignition key to run, then depress the air vane with your finger. There should be plenty of pressure there, and your fuel pump should be running. If pressure feels weak, check your accumulator. Pull off the return hose to the tank, and see if fuel leaks out of the accumulator. If so, replace it.

Check for misfires. There are exhaust test ports for each cylinder. The little pipes come out of the exhaust manifolds near the heads. Run the car for 2 minutes, then touch each of the pipes with your finger near the heads. They should all be too hot to hold your finger on. If you can hold your finger there without discomfort, that cylinder is not firing. The forward bank pipes are accessed under the interior access panel. This is a great way to find a clogged fuel injector.

 

Thanks for the response. I will check those additional items.

The big question I have is "is there a vacuum line running to the ABS system?"

I don't see one.

Found this quote on line:

"The [Teves Mk2] system uses an independent electrically-driven motor / pump unit to pro-
vide both boost pressure and brake application pressure."

Entire page here, this seems to be a gold mine of info on our early ABS system:
http://vw-passat-mk3-35i.blogspot.com/2013/07/volkswagen-passat-35i-mk3-abs-teves.html

Info and vidoes by Paul Nicholasen in this thread too:
http://www.ferrarichat.com/forum/348-355-sponsored-bradan/420424-ferrari-348-abs-system-videos-everything-you-never-wanted-know.html

So, I think I have my answer - no vaccum line to the system, it is electrically operated.

I have finally found more info on the "ECU Controlled Teves MK2 ABS system." Ferrari didn't feel it was important enough to put anything about it in my shop, owners, or parts manuals.
Alden

 

I have the non-ABS system, so no experience with it.


They do have a diagram of the system in the parts manual FWIW.

Ferrari Mondial 3.2 QV Mechanical Table 039 Brake Anti Skid System

 

Thanks!
Alden

 

Hi Alden,

I will look into this this evening. What I know is that there is an electrical vacuum pump so I don't ecpect a vacuum line from the motor. There are fuses installed on the ABS unit, have you checked these? There is no direct correlation between a bad ABS and a bad running motor but maybe but there could be an electrical issue.

 

Last night I checked, removed cleaned and put Deoxit on the connections, fuses and relays on the ABS ECU, all the connections at the master cylinder, removed the fuse box from the car and disassembled, checked the fuse box solder points on the back, cleaned the connectors on the fuse box and reinstalled the relays and fuses, cleaned and put Deoxit on all the fuses, relays and fuse box connections and put it all back together.

I did not put a meter on the relays, that might be the next step. All the relays and fuses in the box are new, but the ABS ECU units are original and hard to get, from what I hear.

No change. No indicator lights on the bottom of the panel. Did not take it for a drive, but pedal stil fees hard, and she started right up but seems to be running at 90% or so.

The fact that the 4 indicator lights, which are on a separate ground, at the bottom of the panel are all dark tells me something is amiss there. I fixed a ground issue in the upper part of the panel which solved a problem with the indicator lights getting squirely when the heeadlights were on. Grounding the lower panel made no differance, howerver.

I can hear the ABS motor running when I turn on the ignition key, so it is working OK.

Checked both coil wires front and back and back bank cylinder leads and they are all getting fire.

Today I am going to remove the acess panel for the front bank in the back seat and check each plug for fire.
Alden

 

I just noticed that they do not show any of the (proprietary?) relays as available that go with the ECU.

Are we SOL or has anyone found a source?

??
Alden

 

Not sure this will help, but see if any of the manuals found here have the diagrams: https://www.unevoiture.com/manuals/ferrari/mondial

 

Do you mean the bottom of the "Check Control" ? I had a problem with the lights on the bottom half of the Check Control going out. Sometimes they would pop back on whenever I would hit a bump. This was fixed by cleaning the connectors that go into the fuse box. You have to pull them off and clean both ends. Sometimes the the connector pins come loose, and need to be squeezed back together a little. You can tell the loose ones looking at the position of all the others.

If she's running 90%, I would look at the spark plugs, and the fuel injectors. Clean the spark plugs with a propane torch, check the gap, apply a little anti-seize, use a torque wrench to install.

Injectors are a little more work. Pry them out, remove the o rings, then soak them in carb cleaner overnight. The injectors have a little filter screen inside that can get clogged if you let the car sit, and the fuel dries out. You may have to poke something in there to break it up. Just be careful not to damage it. Test the injector spray before installation, with an air compressor and hose filled with fluid.

I'm thinking your low power problem may have been a bad coil. I had a coil go out, and it was intermittent. Sometimes it would go into "4 cylinder mode" with no warning. Sometimes it worked just fine.

 

The 4 indicator lights don't have a common ground but a common plus! The same plus is feeding the ABS protection relais so your ABS and lights problems have probably the same cause. The same plus is feeding the tachometric relay which can be the cause of the tacho problems. It is also used in the ignition system so probably also causing problems there.

I suspect a problem in the key operated contact switch. You can check this by measuring the voltage at the 3A fuse of the ABS. There should be 12V when the key is switched in the first position.
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OK, I found the problem that was causing the car to run at low power: One spark plug extension that was clearly bad and one that had some cracks in it and was probably failing intermittently. Both on the front bank.

Car starts and runs great now! 100%!

I checked for power at the 3 amp fuse at the ABS unit and I have 12.5 volts with the key in the "run" position.

I didn't have the opportunity to run the car on the road tonight, so I don't know if the brake boost/ABS is working again.

But, the lower 5 lights on the panel are still dark.
Alden

 

As I said, I removed all the relays, fuses and connectors, removed the relay box from the car, disassembled it and checked all the solder joints, connectors. Cleaned all the connectors in the box and the white multi pin plugs with electrical contact cleaner then applied Deoxit to all the connections. The circuit board looks remarkably good considering the reputation for failures here.

Put it all back together and put it back in the car.

Both the coils showed strong current to the distributors, but I could have a bad one that is going out when the car is run for a while or it could be one of the ignition modules on top of the coils going south. But she seems to be running normally for now.

Yes, bottom 5 indicator lights are still out: Brake warning, parking brake indicator, seat belt (which has never lit up) ABS, and slow down lights. They went dark a few weeks ago with no immediate problems.

But, per the post above, I do have power the the 3 am fuse at the ABS ECU so I must have at least some power coming from the ignition switch. Also, I can hear the ABS pump running when I turn the key to the run position without starting.

Alden

 

Good! The lights are dark because there should be 12 V on the common pin. This is directly fed from the ignition switch. One connector is in between (the one in the dashboard). The ABS problem is another one to resolve later.

 

Great news!

When I checked the front bank, I found one plug extender that was clearly bad and one that had a few cracks that may have been shorting intermittently. I replaced both extenders and took her for a long run today and ..............

She starts and runs 100%+ now and I have brake boost and the ABS system has power and seems to be cycling up normally, though the indicator light is dark.

I did re-solder two shady looking connections in the fuse box yesterday and I think one of them was the problem with the ABS.

The tach is still reading low, I will re-calibrate that, and I still have 5 dark indicator panel indicators, but sounds like that may be a simple fix since they all share one positive power source.

I am elated to say the least.
Alden

 

Good news! You'll need an alternative for the fusebox though

 

Salesman.

True enough, but I was really surprised when I dismantled it at the remarkable shape it was in.

But.......I will be getting one of Guido's "Russian tank worthy" fuse boxes as soon as I get over the expense of my "Mondial Euro Tour" and Ron's "B" pillars. lol!

Now, someone find me a way to get 12V+ to the lower indicator panel!
Alden

 

I take it you are ok for the full wiring diagrams as i have a copy of the factory book, if u need any info

 

Yes, I have a full set, but thanks for the offer!
Alden

 

Alden, if there is 12.5 V at the ABS fuse ("to the 31") then there is voltage at the connector. In that case the problem is probably a bad connection between the connectors itself (red arrow).
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That connector is difficult to access without tearing the dash apart, so I was hoping I could find the problem closer to the panel or provide another power source like I did with a ground source for the upper panel.

I see that power supply circuit has a diode, allowing current to only flow in, not out. Might have to start removing the dash unless there is another way in.

I could also put a diode on the alternate power supply, if anyone knows the spec for this.

Pics of the connector behind the panel would help too, just so I know where I have to go.
Alden

 

The diode is only for one lamp. If the diode is defect, the other three should still work. Don't test the diode with AC voltage/current but use your multimeter (diode test setting).

 

Looks like the diode is on the brake warning light only?
Alden

 

No, it's for the alternator light. If the voltage from the alternator is lower than the battery the light will be on. So if the motor is not running this light is on. The diode is to prevent current flowing through the ignition switch to the battery in case the alternator voltage is higher than the battery and the connection between the alternator and the battery is loose. This prevents smoking/red glowing wires...

 

I have power and full/normal function in the battery indicator light.

It is not one of the bottom 5 in my ABS car, they are: Brake warning, parking brake indicator, seat belt (which has never lit up) ABS, and one slow down light since I only have one cat.