355 Teves ABS help

I must be missing something here. Do you agree with the following:

The black relay is the most aft relay in all photos of LHD cars. Green is the third.

The black relay is the pump relay.

The wiring diagrams show the pump relay as having 4 pins.

The black relay is part number 198050 according to all sources.

Maranello, Eurospares, the WSM, the paper parts manual all show the P/N 198050 relay as being in the 3rd position, not the aft position.

 

Your photo, as well as other photos that I have, show the relay arrangement as: Diode Box -- Orange -- Green -- Black. So, yes, the Green is third if the Diode Box is counted as the first.

The Black relay (last in the row stated above) is the Pump Relay. It has 4 pins (85, 86, 30, 87), two diodes and it is for 40A. The original is made by Ate. Its part number is 158090 for 355 and 131939 for 348. They are basically same (interchangeable) except that the 348's one has a mounting tab.

The 348 part diagrams show the arrangement of the Diode Box and the 3 relays in the same order as written above (like on the pictures) but the 355 diagrams, for some reason, show the 3 relays in a different order. Possibly an error in drafting the 355 diagrams or, perhaps, instead of the intended arrangement shown on the part diagrams, the arrangement as in the 348 was adopted for the production.

 

I think we can assume that all 355's with Teves have the black pump relay in the far aft position. I wonder if @Ricambi America, Maranello UK, Eurospares UK, etc, is aware of this?

 

Ricambi, Maranello UK, Eurospares UK and others just follow the part diagrams produced by Ferrari so it is Ferrari to be questioned. Otherwise, the part numbers and pictures of the relays shown at the online parts diagrams are correct. It is only that the 355 part diagrams, as well as the drawings in the WSM, should not be followed as to which relay goes where in the case of the 2.7 355s (do 5.2 355s have ABS relays lined up as shown on the parts diagrams/drawings ?). Now I see on the new John's pictures that the relay sockets have the same colours as the relays which is a good guide.

 

Your relays are, obviously, in their correct positions and, I believe, they are all good. You have yet to inform us on the following:

1. Did you perform a test by pulling the orange relay out and pushing it back in while the key is in the ignition "on" position (or while the engine is running) ?
2. Has a starter relay been added to your car ?
3. New question: do you have daylight running lights that are switched "on" automatically with the ignition "on" (but switched "off" during cranking of the engine) ?

 

Ian,

Regarding the relay "R" ("P" on the 5.2), I noticed that the legend states "circuits energised by ignition key (RUN)". Perhaps you should add "de-energised during START". This relay, and any automatic daylight running lights relay, may cause malfunction of the orange ABS relay if a cube type starter relay is added.

 

Not sure. It's hard to tell a 5.2 Teves from a 2.7 Teves from photos. My car has Bosch (no external relays)

Which diagram is this in? I can't find the legend.

 

I saw it on your diagrams "Fig3_1994_2.7_Injection_System_Ignition" (Ver 14) and "Fig11a_1997_5.2_Injection_System_Ignition V.17" (these are the versions I currently have, you are probably at higher versions by now). I did not check whether it is repeated on any other diagrams.

 

I am amazed this thread is still going ...

 

It is probably because we have not solved the John's problem yet. Give us a bit more time.

 

Isn't there anyone in Oregon that can sort this out for John? Local eye on the problem goes a long way.

 

Ah, I see what you mean. Funnily I have a marker next to the relay suggesting there should be an accompanying note about cranking.

 

I guess you could do a resistance check between the steering column ignition connector and a good ground. The normal resistance of the starter solenoid is around 0.0 to 0.1 ohms. An aftermarket starter relay is probably much higher. Just look for the white plug at the base of the steering column with the thick ignition wires on it and disconnect it. The white wires are the start wires. Do a resistance check on the car side of the plug (not the ignition key side).

USA connector shown:

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On the standard setup, the seat belt buzzer module and the orange relay coil in the start circuit would modify the resistance slightly, but by very little. If in doubt, you could remove the orange relay and disconnect the seat belt buzzer. Maybe Miro has a simpler suggestion?

The buzzing sound may simply be the Teves pump. Pulling the orange relay removes key power from the pump relay coil. Make sure it's the orange relay clicking, not the black or green relay. I guess you could pull the green and black relay beforehand.

 

John,

Test #1: With the ignition "off", press the brake pedal about 20 times. Switch the ignition "on" and listen to the buzzing sound you heard earlier. The sound should stop after some 40 seconds (let us know how long) and this would mean that the ABS pump, the ABS Black relay and the pressure switch are all good.

Test #2: Ignition "off", gear in neutral (or better disconnect the battery). Remove the Orange ABS relay and the "R" (or "P" if your car is 5.2) relay on the footwell panel. Insert a length of wire having a male spade terminal into the relay socket marked on the picture below. Measure the resistance between this relay socket and the ground and let us know the reading.

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Do you think relay R is causing this? i.e. the coil is the wrong resistance, allowing too much current to reach the orange relay, but not enough to turn the starter?

Maybe the wrong part number fitted? Relay R should be a Bosch 0 332 019 103.

Coil resistance should be 85 ohms, according to the spec sheets.

 

The R relay cannot cause any problem when there is no starter relay (the left drawing below) but, with a standard cube starter relay installed (the right drawing), the current flow through the coil of the R relay will maintain ~4 volts on the start line which will most likely cause the Orange relay not to switch "off" after the key has been released from START which, in turn, will keep the ABS system inactive. We had a discussion on this in one of the earlier threads. As shown on the drawing below, with the starter relay installed, the 3 relays form a voltage divider in the ratio 85 ohm (R relay coil) and 42.5 ohm (starter and orange relay coils in parallel) resulting in ~4 volts on the start line. As we also established in the earlier thread, 4 volts is enough to prevent the Orange relay from releasing after the engine cranking.
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In the original configuration (left drawing), the near to zero ohms starter solenoid will maintain practically zero volts on the start line all the time except during engine cranking when there will be ~ 12 V on this line. So (with the ignition "on"), when there are zero volts on the start line, relay R will be "on" (its contacts are "on") and the Orange relay will be "off" (its contacts are "on") ; when there are 12 volts on the start line (cranking), relay R will be "off" (its contacts are "off") and the Orange relay will be "on" (its contacts are "off").

 

Thanks for the detailed explanation/diagram, Miro.

I guess the easiest way to see if this is the issue on John’s car would be to pull relay R (or P on the 5.2) and see if the ABS works. The items associated with relay R shouldn’t stop the car running but I wouldn't go too far on a test drive because relay R powers the wipers, brake lights, reverse lights and turn lights (and the HVAC panel on the 5.2 car)

 

Or just jumper the orange relay (sockets 87a & 30) . I assume a good battery will be able to start the car and run the ABS pump at the same time.

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ohms or milliohms?