1974 1.8L engine fast idle then stalls, Fuel injection issues Options

[tshih914]

My 1.8L 914-4 with stock Bosch L?-Jetronic FI after being stored several years started to develop a hard to start problem. When finally started would stall when I give the gas pedal any input to raise the revs. I suspect there was some kind of intake air leak and while fiddling around had a backfire which blew the AF meter which I had Pelicanparts repaired. After replacing the fuel lines with the stainless ones from Tangerine Racing and flushing out the fuel system with Techron the engine started to run normally for a short time. Now the engine can be started and fast idles at 3000 rpm but again any input to rev up the engine results in stalling. The idle adjustment screw at the base of the throttle housing is fully closed. Any suggestions on how to fix?

[Van B]

Definitely sounds like the AFM is doing stuff… but also, you can’t have that idle screw all the way down. You won’t idle like that. Put it two turns out and leave it there till you’re ready to set it up correctly.

Ref the video I made for you, remove the vac hose on the decel valve that runs from the side of the valve to the manifold. Block off the manifold and the port on the decel valve. Leave everything else connected for the moment.

Give it a start and lets see how it behaves.

Also, please post up your door placard so, we can confirm your mfg date.

[tshih914]

Definitely sounds like the AFM is doing stuff… but also, you can’t have that idle screw all the way down. You won’t idle like that. Put it two turns out and leave it there till you’re ready to set it up correctly.

Ref the video I made for you, remove the vac hose on the decel valve that runs from the side of the valve to the manifold. Block off the manifold and the port on the decel valve. Leave everything else connected for the moment.

Give it a start and lets see how it behaves.

Also, please post up your door placard so, we can confirm your mfg date.

Did as instructed I opened the idle adjustment screw 2 turns and after cranking a bit the engine started with a rough idle then stayed around 2000-2500 rpm. Again when gassed the rpm drops to almost stall but when I release the throttle it would idle back up to 2500 rpm. After 2 stabs of the throttle it finally stalled. I 've included the photos of the blocked off manifold T and side of Dcel valve along with the door label showing a Jan.1974 build date.

[tshih914]

Definitely sounds like the AFM is doing stuff… but also, you can’t have that idle screw all the way down. You won’t idle like that. Put it two turns out and leave it there till you’re ready to set it up correctly.

Ref the video I made for you, remove the vac hose on the decel valve that runs from the side of the valve to the manifold. Block off the manifold and the port on the decel valve. Leave everything else connected for the moment.

Give it a start and lets see how it behaves.

Also, please post up your door placard so, we can confirm your mfg date.

Did as instructed I opened the idle adjustment screw 2 turns and after cranking a bit the engine started with a rough idle then stayed around 2000-2500 rpm. Again when gassed the rpm drops to almost stall but when I release the throttle it would idle back up to 2500 rpm. After 2 stabs of the throttle it finally stalled. I 've included the photos of the blocked off manifold T and side of Dcel valve along with the door label showing a Jan.1974 build date. The "idle" speed does not seem to be changed by turning the screw