[T3] Fuel Pump Relay - 69 Fastback

[Tim Schiller]

I will follow the ground and check the fuse

I did hook a reliable 12V to the red wire going to pump. Pump buzzes loud and clear. 

I had purchased 2 relays and swapped just in case one was bad, but same results 

Sent from my iPhone

> On Jul 9, 2021, at 10:35 AM, Jim Adney <jadney at vwtype3.org> wrote:
> 
> Tim,
> 
> 86 should get 12 V from the main relay as long as the key is ON.
> 
> 85 gets grounded by the ECU for ~1 seconds unless the engine is turning 
> over. If the engine is turning over (or running) the ECU keeps this terminal 
> grounded.
> 
> 85 & 86 are the connections to the relay coil, so the relay should close and 
> send 12 V to terminal 87 for ~1 second after the key is turned ON or as long 
> as the engine is turning over or running.
> 
> Check the fuel pump fuse carefully. Sometimes the fusable link can break 
> but still look good.
> 
> 87 is the power source for the fuel pump. It should have 12 V on it as long as 
> there is 12 V from 85 to 86. Follow that red wire to the firewall and find a 
> brown wire that comes along with the red wire from the pump. The brown 
> wire is the fuel pump ground.
> 
> It can be helpful to get someone to listen down by the RF tire, to see if they 
> hear the fuel pump buzz. It should always buzz for that first ~1 second.
> 
> On 68-70 cars that brown wire goes to ground via a rather torturous route. I 
> make a very simple $10 kit to greatly improve the reliability of that ground, 
> but I need your VIN to get you the right kit.
> 
> If you're not getting full voltage from the pump relay, try a small jumper wire 
> from a reliable 12 V source to the red wire to the pump.
> 
> There are lots of possibilities for why your car won't start. Check to see if the 
> pump is running. If it's not, continue checking out its power source, both 12 V 
> and ground. If those are okay, the problem could still be in the pump. I 
> rebuild them, but that starts to cost real money.
> 
> Stick with this and keep us in the loop. We all want to see you get this 
> running nicely.
> 
> Jim
> 
>> On 8 Jul 2021 at 22:07, Tim Schiller wrote:
>> 
>> Car had been running well until it would not start. It initially started but sputtered, then nothing. I did not try to start again for about 4 month´s. I tried again, it started, I washed, waxed and went to fill up before a show. After waiting 3 1/2 hours for a tow at the gas station, it hasn´t started since. I tell this story only for background leading up to my question.
>> 
>> Tested Fuel Pump Relay and no power to the 87 pin for the 1-1 1/2 seconds when key is turned. The 86 pin has 12V when key turned and 12V to power relay under back seat.
>> 
>> I tested fuel pump directly and it appears to work fine when it has 12V
>> 
>> Replaced Furl Pump Relay and I get power to the 87 pin for the 1 - 1 1/2 seconds. Car still doesn´t start. Check voltage to 87 pin again and I´m only getting about 5V for the 1-1 1/2 seconds. Should I be getting 12V? If I should have 12V, suggestions on why I not and what I should check next?
>> 
>> Any help is appreciated 
>> 
>> Tim
>> 
>> Sent from my iPhone
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> 
> 
> -- 
> *******************************
> Jim Adney, jadney at vwtype3.org
> Madison, Wisconsin, USA
> *******************************
> 
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