1980 308 THAT STALLS AT IDLE

Hi,
I have a 308 that just started stalling at idle . the fuel pump relay clicks and seems to shut off the fuel pump when the rpm drops to about 1500 rpm. the car runs fine above that rpm. when it is first started I notice the relay clicks on and off untill the rpm is above 1500
I switched the relay with a known good relay same problem.
Anyone ahve any tips.

 

There are two relays involved in running your fuel pump. If you have already tried a replacement for relay H -- Relay for fuel pump (Bosch ...113), also try a replacement for relay P - Relay for start injector (Bosch ...101).

 

Thanks,
i wll look into that but I can put my hand on the relay that is clicking when the car stalls.(fuel pump relay). but what i don't understand is how the circuit is affercted by lowering the rpm.

 

When I raise the RPMs my windows go up faster...

 

At lower engine RPM, the voltage output from the alternator will be lower (i.e., at higher RPM, and higher voltage, sometimes a flaky connection or a "weak" relay mechanism will start to work). You may have some other problem, but trying different relays in both positions is the easiest first thing to try IMO.

 

Yea that sounds good I am hoping that it is that simple
I will try that first thing when I get home.

 

Ichecked all the fuses and relays, checked all reounds with a ohm meter all good
found that the guy I bought the car from put a aftermarket air intake tube that did not fit good and caused a leak. when I replaced it with to oem part It fixed the problem.
Thanks for the help.

 

You don't need the cold start relay to maintain idle speed, it's function is only to slightly richen a very cold engine for a few seconds, but you do need the fuel pump relay. As the fuel pump relay circuit sounds to be working properly, the in car electrics are not the problem area. (hopefully you already have Birdman fuseblocks-a possible problem)

There is a switch in the air supply connected to a disk which detects air flow. (It's just behind/below the fuel distributor. That switch will turn off the fuel pump when air flow ceases. If maladjusted, it will turn off the relay, hence turning off fuel, when engine speed drops near idle.

To know for sure, disconnect the blue connector which goes to the air flow switch and immediately try to start the car. Disconnecting that blue connector will cause the fuel pump relay stay on as long as the ignition switch is on.

If a warm engine is now able to run at normal idle speed as before the problem arose, you have a joyous 'eureka moment'. Time to adjust the air flow disk switch.

I've not personally done that adjustment so will leave others to explain the DIY of a very delicate procedure.

And if your idle problems persist with the blue connector disconnected, good luck in further troubleshooting.

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