Definitely renew the main relay.

 

Hi Grant if by mistake I switches the two relay, will it break then or cause other damage?

 

JP,

Dont tempt fate.

The Main is 100% a 5 pin, and that 5th pin is the one that supplies power TO the Pump relay, so DEAD car if the Pump Relay, in the Main Socket has NO 5th terminal.

Not sure what Auto Parts people you have up there, but I would take each relay to them, place them on the counter, and request "one of each the same please".

Relays have changed a LOT in recent years, with weird pin layouts etc etc. We are Old School, standard Auto Relays.

 

Does the fuel pump relay has only 4 pins then?
I will check with our auto supplier this morning.
thanks.

 

Yes.

The Main has 5 pins, of which the 5th (centre) is the 2nd #87.

Used for years on all makes and models of cars, not unique in any way.

 

Some of the relays have an internal diode. Most all relays have the internal diagram stamped or printed on the side of the case; look for the little diode symbol. The 'main' relay has the diode as I recall

A bit more explanation on Grant's remarks

Jaguar (and others) used a lot of "dual 87" relays. The terminal designations are 30-85-86-87-87. Your main and fuel pump relays should be of this type

Also very common throughout the industry are the standard switch-over relays...which have terminal designations of 30-85-86-87-87A

The two types operate differently; if you unknowingly use the wrong type you be scratching your head for a long time !

Cheers
DD

 

Hi Grant, how different is the fuel pump relay? has it only 4 pins?

 

According to my diagrams it should be a 5-pin, dual-87, no diode

Cheers
DD

 

This is the front of the motor. Three relays.

This is on fire wall three relays

 

This is the front of the motor. Three relays.

This is on fire wall three relays

I check the power going front the relay to the injecter only some injecter are getting power about 4 of them the other have no Juice going. I check the harnais and only two connectors have power.

The harnais has only two prongs with power from the red relay.

 

I finally made some Progress!
I found out that the main relay is at the front of the motor the one on the right. It was not the right one. I switches it with a relay with two #87 and now the power goes to all 12 injectors.
I also change the relay beside it with a 5 prongs and now the the fuel pump kick in for 2 seconds.
So power to the injectors and power to the injectors.
I hear the injectors clicking when I rotate the throttle cam.
the only problem now is that the starter will not Turner. I check the starter relay and there is no power going to it. Is there a fuse between the ignition switch and the starter relay?

I change it as i had a spare one. There is power on the Brown wire but it does not transfer to the starter wire.

 

No fuse that I am aware of.

Is the Gear lever in P or N, that will isolate that relay if it is NOT properly sitting in either of those positions.

Doug is the S3 Guru, as I have never had one. All my V12 were the XJS beasts, wiring and relays were located in different places.

 

Has the starter ever worked? If not the relay itself might be bad, like the others were.

 

Hi Grant
the starter worked well all along except yesterday. there is a relay beside the starter relay on the left, I Wonder if this relay activate the starter relay when the ignition is on?

 

JP.

Dont know.

The White?Yellow wire on the starter relay is the wire from the key switch that supplies the power to that relay when on the Start Position. Check it for power when in the Start position.

If there is power, check the Solid Brown wire, that is Battery Hot (Live all the time)..
After that, is the earth circuit, which is via the neutral start switch on the gear lever.

 

Things can get a little tricky here. Not all cars have exactly the same circuits, depending on year and market.

In your case I'd say white/black wire should be the ground/earth with the transmission in P or N. However, this ground does not come directly from the neutral safety switch. It comes (most likely) from the feedback inhibit relay.

The feedback inhibit relay is powered by the main relay and triggered by the neutral safety switch.

This is where diodes come in.

If your car is wired the way I think it is the main relay should have a diode. Does It? And does your replacement relay match what came out of the car? If your main relay has a diode you'll see the symbol on the side of the case:




Cheers
DD

 

Don’t know if this helps but I think this matched up to what I saw in my 87 Canadian market v12. It came from an SIII guide.

 

Hi Doug,
I grounded the WB wire on the starter relay and the engine now cranks. So there is a problem with the ground wire going to neutral switch. is the neutral switch on the transmision itself or inside the shifter console?
Now here s where I am:
The engine cranks
I can hear the injectors cliking when ignition is on and I rotate the TPS disc.
I have 12 volts going to the coils when ignition is on.
The fuek pump pumps 36 lbs to the injector.
When I crank the engine, There is is gas going to the spark plug.
But the engine does not start nor does it giggles.
This is what is missing:
When I crank the engine, there is no spark/ark coming out of the coil lead (when I hold a screwdriver 1/4 from the body). Couple of days ago I did have ark)
There is also no spark coming out of the spark plug wires which yells me there is no spark going to the cpark plugs.

Any idea what I should be looking at now?
Is there a relay that activate the coil to spark?
Power Amp?

 

Console.

Is your car equipped with the feedback inhibit relay? it'll have white, black, black/green, and white/black wires

Did you check the relay compatibility?

Since the no-crank problem occurred only (and immediately) after replacing the 'main' relay, and the main relay being part of the cranking circuit, I would check there first before digging into the console.

Cheers
DD

 

I replace the two coils with brand new ones. Still no spark coming out of the HT coil into the distributor cap.
Can a faulty amplifier prevent spark to go to the distributot? if not what is the role exactly of the amplifier?
Is there something else that can prevent the power to go from the coil to the distributor? ECU signale? That is the last issue I am dealing with. Everything else is working. I feel that I am so close to have the motor running....
I checked again the continuity between the amplifier lead to ECU pin #18 and it is good.
I checked the continuity between the starter relay (white and red wire) going to ECU pin# 24 and it is ok.
Doy ou believe that my problem may be the amplifier or the distributor pick not working? I read on your comment on how to test the pick up (2.2 to 4.8k Ohm.
I will also test the amplifier as per your instructions as well.
Let s hopes It is one of the two. I epent too many hours trying to figure out this power issue...