Thermoswitch and fuel tank questions

[go-for-it1]

Hi guys,

Whilst tracing a fuel starvation problem I found the Red thermoswitch in the cooling hose in front of the rocker box was broken in half. I know one switch feeds the intake manifold preheater and one the auto choke on a Pierburg carb but which one is which? I have a weber fitted and the auto choke is no longer needed and the engine runs ok once started so I'm assuming the red one is the autochoke, can any one confirm this as the Haynes book of lies is no use!!

Secondly, does a 1991 GT2 with the later fuel tank, (55Litre), have the gravity valve fitted to the fuel filler as indicated in the Haynes and if so, where is it located and what does it do as I cant seem to get enough fuel through to the fuel pump and wonder if this is worth checking.

Thanks in anticipation

Rob

[Nate]

i thought the gravity valve was just to stop fuel coming out the breather if you flip the car over?

open the inspection cover under the rear seat, open the tank and check for rust clogging the pickup. if there is, it points towards filler neck problems

[go-for-it1]

Fuel filler pipe changed, pick up pipe clear, tank magnetted, fuel pipework blown through from front to back and clear so I reckon the fuel pump is not creating enough suction to move the fuel from tank to front of the car. New fuel pump is the next option.

Anybody able to answer the Red thermoswitch question?

Rob

[Brunty]

The gravity valve should let air in to the tank as fuel is used so it prevents a vacuum. I've never heard of one going wrong though, I'd change the pump.

[fonzooorooo]

check fuel pressure at the pump, then again at the carb.
had a nightmare with mine, and found most of the fuel recirculating to the tank.
wrote it up on here in quite a bit of detail a couple of monthe ago.

[go-for-it1]

check fuel pressure at the pump, then again at the carb.
had a nightmare with mine, and found most of the fuel recirculating to the tank.
wrote it up on here in quite a bit of detail a couple of monthe ago.

How do you check the fuel pressure if you can't get it started or are you suggesting pressure when cranking? What should it be anyway?

[fonzooorooo]

4.5 - 5 PSI should be coming out of the pump.

summary of my nightmare and and the solving of it's here:

http://sciroccoregisterforum.co.uk/carf ... 257#p19257

it's a mechanical pump, so yes, output'd be the same when cranking or when running.