FUEL PUMP RESISTOR

[superwedge]

car will not rev,only very slowly,if you press fast engine cuts out or comes back down to tickover, its says in the steves h book thar it might be the fuel pump resistor, where is on these cars, if needs replaceing where to get one,all help needed please,

[Wedg1e]

Throw it away, most V8s don't have one.

[ralph350i]

Hi Dave
Am pretty sure its located by the fuel pump behind the driver side rear wheel mate, cheers, Ralph

[Danny Hoffman]

I had this intermittently when I first got my 350i, it turned out that the ECU multiplug wasn't plugged in properly

[superwedge]

so do these cars have one or not?

[Jack Valiant]

Not aware of any fuel pump resistors on the V8. The pump is down by th driverside rear wheel arch the only electronic component you will find down there is a suppressor.

Start with the easy stuff.... check fuel pressure idealy should be around 32-35 psi at the fuel rail.

Check for air leaks on the induction side

Check the dizzy vacuum pipe if it has a leak valve take it out of circuit and check again

Electrical connections especailly if you have been rooting about on the top of the engine, well known culprit is the Throttle pot plastic connector as it gets a lot of heat from the engine

As mentioned check the ECU connector and resistor pack connections

Finally have careful look at the opration of the advance and retard bob wieghts in the dizzy

Hope that helps lt us know if you find the culprit as it helps others

Cheers

Chris

[honestjohntoo]

superwedge said:

car will not rev,only very slowly,if you press fast engine cuts out or comes back down to tickover

I think you need to go back to the Plenum Air Leak suggestions and discussion of your "Misfire" thread - 7 May - as I have not read any subsequent confirmation that you performed all the suggested tests - and found no cause!

superwedge said:

its says in the steves h book thar it might be the fuel pump resistor, where is on these cars, if needs replaceing where to get one,all help needed please,

For information the fuel pump resistor was fitted to reduce pump noise on the SD1 Efi system, but don't know if it was fitted to the Basic TVR?

The reduced voltage at the pump (about 9 volts) does not adversely affect the maximum pressure required in the fuel rail.



and to help you identify it, it looks something like this:

[adam quantrill]

>> does not adversely affect the maximum pressure required in the fuel rail

Agreed with standard BHP but when you start pulling more fuel through in the larger engines it starts to have an effect with WOT and max revs. Apart from the noise issue the resistor prolongs pump life.

Yes I think the 350i has a fuel pump resistor - but given it's a 12 ohm jobbie I reckon it would fail outright if it went.

You can get more life out of a failing pump by shoring the resistor out. Also a tuning tip is - if you are suffering from low fuel pressure at the top end, short out the resistor on demand, for example with a relay triggered from the throttle pot voltage (you'll need a little amplifier to help achieve this). Let's face it when the wedge is on full chat you'll never hear the pump anyway!