Does it sound like I've toasted my double relay?

[al_kaholik]

I was doing some messing with the wiring around the double relay attempting to fit my megasquirt and got recovered later that evening by my breakdown company after returning it to "stock"...

Went to try to start it today, as they thought it was flooded so I left it a few days. The pump comes on when cranking, the engine catches then dies as soon as its off the starter. I can rev the engine while just off the starter, but it dies almost instantly.

So is it likely to be the double relay? Or should I be looking else where?

I've just bought a good second hand at a very reasonable £5 delivered, so even if not I have a known working spare. Its a BMW one, slightly different, what would be described as a Federal one rather than a CA, but all I need to do is relocate the ground (85) to the other side - I have some 2.5mm terminals from my fan box installation which are just the job for this :)


Thanks as usual

Al

[Amskeptic]

I was doing some messing with the wiring around the double relay attempting to fit my megasquirt and got recovered later that evening by my breakdown company after returning it to "stock"...

Went to try to start it today, as they thought it was flooded so I left it a few days. The pump comes on when cranking, the engine catches then dies as soon as its off the starter. I can rev the engine while just off the starter, but it dies almost instantly.

So is it likely to be the double relay? Or should I be looking else where?

I've just bought a good second hand at a very reasonable £5 delivered, so even if not I have a known working spare. Its a BMW one, slightly different, what would be described as a Federal one rather than a CA, but all I need to do is relocate the ground (85) to the other side - I have some 2.5mm terminals from my fan box installation which are just the job for this :)


Thanks as usual

Al

Let's not throw parts. Your pump is running during cranking because the starter terminal #50 is energizing the double relay coil to command the pump. That means the double relay is working. Go to my Double Relay Article AT ONCE, and read it thoroughly and see if you can figure out why the pump is losing juice after you release the key. I won't say to check the AFM connection #36 and #39 or anything like that.
Colin

http://itinerant-air-cooled.com/viewtop ... =50&t=5459

[vwlover77]

Am I mistaken, or is this exactly the behavior exhibited when the wiring harness is not plugged into the AFM? I think it is....

[Amskeptic]

Am I mistaken, or is this exactly the behavior exhibited when the wiring harness is not plugged into the AFM? I think it is....

You're that "A" student who always had his hand waving in the air while the teacher tortured the slacker, arncha?
Colin

[al_kaholik]

I'll give it a look over, its possible its come loose - I know the connector wasn't as tight as I would have liked last time I had it off...

[Amskeptic]

I'll give it a look over, its possible its come loose - I know the connector wasn't as tight as I would have liked last time I had it off...

Check especially the little fingers in the mpc sockets to the AFM and the double relay. Sometimes the terminal ends go loose and get shoved back as you plug them in.
Colin

[Lanval]

Or sometimes the previous owner of the wiring cuts one of the wires, shortening it, so that it won't even fit into the little socket ~ eh Colin?

L

[Amskeptic]

Or sometimes the previous owner of the wiring cuts one of the wires, shortening it, so that it won't even fit into the little socket ~ eh Colin?

L

Eh yeah actually . . . after the other checks.

[al_kaholik]

Okay, I've been out and removed/reconnceted all the connectors in the engine bay and the wiring splice I did.

Double relay is good, I can hear it positively clicking on the key, sounds nice and strong. A spare in the box for £5 won't hurt :)

First couple of times the engine will catch then die off the key, after that, it'll only fire with the pedal down, then dies too - guessing the fuel is pooling?

I notice that the rotor cap is quite badly tracked, points look alright. Will go get another cap tomorrow and try - Beru ones are what I can get and quality is ok, nothing more...

I'll have a look at setting the valves too at the weekend, but i can't imagine that they are far out if at all. Oil pressure is fine.

Perhaps the CSV is the culprit from my reading?... Or the TPS?

[Amskeptic]

Double relay is good, I can hear it positively clicking on the key, sounds nice and strong. A spare in the box for £5 won't hurt :)

First couple of times the engine will catch then die off the key, after that, it'll only fire with the pedal down, then dies too - guessing the fuel is pooling?

Perhaps the CSV is the culprit from my reading?... Or the TPS?

No, do not speculate further into the weeds without first answering our prior question.

The click when you turn on the ignition is merely the double relay energizing the ECU and AAR heater. You have yet to answer our question:

Does the fuel pump remain energized when you release the key at "catch".
The best way to test it, is to remove the black cap on the AFM, turn on the ignition only, get back there and move the wiper as though the engine had started. Any distance will do. You need to hear the double relay click and the fuel circulate in the fuel rail. If you do NOT get this click and subsequent pump running, you need to first bridge the 36 and 39 terminals of the AFM plug with a little jumper wire.
Let us know if the pump runs with the ignition on.
Colin

[al_kaholik]

Right,

I have in front of me the AFM, with black cap off. I've moved the wiper board slightly as it looks tracked, as per the great diagrams :)

And with the ignition on, the pump can be heard working - little more tricky for the double relay as its in the back of the car. Presumably if the FP is getting power it means that the double relay must be too :)

Where do we go from here?

Thanks,

Al

[Amskeptic]

Right,

I have in front of me the AFM, with black cap off. I've moved the wiper board slightly as it looks tracked, as per the great diagrams :)

And with the ignition on, the pump can be heard working - little more tricky for the double relay as its in the back of the car. Presumably if the FP is getting power it means that the double relay must be too :)

Where do we go from here?

Thanks,

Al

Do you have an assistant with basic human language comprehension skills and fundamental motor coordination?
Colin

[Amskeptic]

Right,

I have in front of me the AFM, with black cap off. I've moved the wiper board slightly as it looks tracked, as per the great diagrams :)

And with the ignition on, the pump can be heard working - little more tricky for the double relay as its in the back of the car. Presumably if the FP is getting power it means that the double relay must be too :)

Where do we go from here?

Thanks,

Al

I have to keep a focus here, there is possibly extraneous info here, to wit:
you moved the wiper board as it looked tracked. What do you mean? You loosened the board and shifted it? If so, nice, but you still have to answer the question:
Did the pump TURN on when you moved the WIPER? Or was the pump running because you turned the ignition on?
Colin

[al_kaholik]

The board was moved as per the AFM tuning guide, screws loosened, shift board over a bit then tightened down. Seemed sensible to do it while it was open and on the table.

The pump ran because the ignition was in the run position and the wiper deflected by hand.

Assistants are hard to come by when work schedules conflict. I'll try to get one tomorrow and give it another crack.

[al_kaholik]

Did the pump TURN on when you moved the WIPER? Or was the pump running because you turned the ignition on?
Colin

Ok, just to make this all 100% clear as after I looked at it I don't know whether it was.

The pump does not run with the ignition in the first position, but does when cranking.

The test carried out to move the wiper, with the ignition on resulted in the pump turning only when the fuel pump contacts in the AFM were touching.

I will check today with a helper if the double relay clicks when the wiper is moved.