[Supras] Fuel pressure.

[Rich Peacock]

I don't know that there is a URL...  I was refering to rewiring the fuel 
pump with heavier gauge wire and a relay tripped off the ignition to let 
the pump draw full amperage and eliminate the 9v/12v switching circuit.  
Usually I see the topic of re-wiring come up when people are installing 
a Walbro...
-Rich

Jeff Mohler wrote:
> Where is a URL of the 12v mod?
>
> On 10/18/07, Rich Peacock <rdp at ix.netcom.com> wrote:
>   
>> There should be a check valve in the fuel pump to prevent back flow.
>> Fuel pressure should drop very slowly after the key is off, but loosing
>> all pressure overnight is totally normal.  Loosing pressure quickly
>> might indicate a leaking injector or bad fuel pump check valve.  If you
>> shut the motor off and it takes a bit to restart while still hot, that
>> could be some form of fuel vapor lock.
>>
>> Easy test would be to place a jumper (paper clip) between B+ and Fp
>> within the diag block.  This will send a 12v signal to the fuel pump
>> when you turn the ignition on pre-priming the fuel system.  If that
>> clears up your hard start problem, then you could check the voltage at
>> the fuel pump (the Supra uses a resistor/relay to step between 9v and
>> 12v to the fuel pump) or it might be time to replace the fuel pump.  If
>> the car is still hard to start, you might want to look for a weak
>> ignition.  Replacing the plugs and wires.
>>
>> Sean - once you do the 12v mod (putting 12v to the fuel pump via heavier
>> gauge wire and relay when IGN is on), many Supras fire right up when you
>> turn key.  Which actually might not be a bad idea for Vladimir's car
>> either...
>> -Rich
>>
>> Sean Cavanaugh wrote:
>>     
>>> far as I know, that's normal. after car is off, fuel flows backwards thru
>>> the pump into the tank. first few seconds of cranking reprimes the line with
>>> fuel and you're good to go. I have never heard of a MKIII with a stock pump
>>> that starts right up without a little lag.
>>>
>>> -Sean
>>>
>>> ----- Original Message -----
>>> From: "Vladimir Ponomarev" <vladiborev at yahoo.com>
>>> To: <supras at supras.com>
>>> Sent: Thursday, October 18, 2007 6:07 PM
>>> Subject: [Supras] Fuel pressure.
>>>
>>>
>>>       
>>>> Hi guys. I have noticed a fuel pressure drop after my 91T with 170 kmiles
>>>> sits overnight in the garage or even after few hours after stop. It takes
>>>> time to build fuel pressure again and to crank her. Question: what is the
>>>> most likely cause of the pressure drop? I have switched to AFPR, but it
>>>> didn't help. What is my next bet?
>>>> Thanks.
>>>>
>>>> Vlad.
>>>> _______________________________________________
>>>> Supras mailing list
>>>> Supras at supras.com
>>>> http://supras.com/mailman/listinfo/supras_supras.com
>>>>
>>>>
>>>>         
>>> _______________________________________________
>>> Supras mailing list
>>> Supras at supras.com
>>> http://supras.com/mailman/listinfo/supras_supras.com
>>>
>>>
>>>
>>>       
>>
>> _______________________________________________
>> Supras mailing list
>> Supras at supras.com
>> http://supras.com/mailman/listinfo/supras_supras.com
>>
>>     
>
>
>