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?

[wonkipop]

i just watched your video @Van B .
your decel is rigged right or at least same as diagrams and how it is normally done.

i'm looking at his and it looks the same.
from what i can see of it.
but it would be nice to see a close in photo just to be sure.

[tshih914]

I have every vacuum hose hooked up the same as the diagram that wonkipop posted. My photo show the 2 plugged ports to the side of decel valve and the t leading to the boot (I will be ordering a new one from AutoAtlanta as the one currently in the car is an old used one from eBay that I got when the AFM explosion triggered the search for cause of stalling after starting). I have also removed the hose connecting the two ports
as instructed for this test. The idle adjustment screw at the base of the throttle valve was adjusted 2 turns from fully closed. I did mention that while the engine was idling at 2500-3000rpm I did try to cover the air filter box's snorkel with my hand and the engine did not stall indicating that there must be a vacuum leak. When I get the new boot installed I will hunt for the source of air leak with the Smoke in a can used to test fire alarm smoke detectors.
I just reattached the hose and started the engine after many cranks to get it idling at 2800 rpm before repeating test3 and 5 (wonkipop's earlier posts). When hose to side port of decel valve was pinched closed RPM dropped by 400-500 rpm. When AAV hose was pinched rpm dropped by 800-1000rpm. The smoke in a can wasn't useful in finding the source of air leaking pass the AFM pathway.

[Van B]

I have every vacuum hose hooked up the same as the diagram that wonkipop posted. My photo show the 2 plugged ports to the side of decel valve and the t leading to the boot (I will be ordering a new one from AutoAtlanta as the one currently in the car is an old used one from eBay that I got when the AFM explosion triggered the search for cause of stalling after starting). I have also removed the hose connecting the two ports
as instructed for this test. The idle adjustment screw at the base of the throttle valve was adjusted 2 turns from fully closed. I did mention that while the engine was idling at 2500-3000rpm I did try to cover the air filter box's snorkel with my hand and the engine did not stall indicating that there must be a vacuum leak. When I get the new boot installed I will hunt for the source of air leak with the Smoke in a can used to test fire alarm smoke detectors.
I just reattached the hose and started the engine after many cranks to get it idling at 2800 rpm before repeating test3 and 5 (wonkipop's earlier posts). When hose to side port of decel valve was pinched closed RPM dropped by 400-500 rpm. When AAV hose was pinched rpm dropped by 800-1000rpm. The smoke in a can wasn't useful in finding the source of air leaking pass the AFM pathway.

The AAV is designed to increase idle by that amount until the engine reaches operating temperature. So, nothing revealing there just yet. I think the aspect that should be focused on right now is the non-response to throttle input.

I’ll tell you that in getting my L-Jet sorted, I replaced every old hose on that entire topside. My car was very original but what had been replaced wasn’t exactly the right size most times. Belmetric has almost all the correct hoses at a good price and wonki has provided you with his artisan diagram that I just love!

We also need to consider your fuel injectors are full of garbage and not spraying correctly or at all. Have you looked at plugs?

[wonkipop]

I have every vacuum hose hooked up the same as the diagram that wonkipop posted. My photo show the 2 plugged ports to the side of decel valve and the t leading to the boot (I will be ordering a new one from AutoAtlanta as the one currently in the car is an old used one from eBay that I got when the AFM explosion triggered the search for cause of stalling after starting). I have also removed the hose connecting the two ports
as instructed for this test. The idle adjustment screw at the base of the throttle valve was adjusted 2 turns from fully closed. I did mention that while the engine was idling at 2500-3000rpm I did try to cover the air filter box's snorkel with my hand and the engine did not stall indicating that there must be a vacuum leak. When I get the new boot installed I will hunt for the source of air leak with the Smoke in a can used to test fire alarm smoke detectors.
I just reattached the hose and started the engine after many cranks to get it idling at 2800 rpm before repeating test3 and 5 (wonkipop's earlier posts). When hose to side port of decel valve was pinched closed RPM dropped by 400-500 rpm. When AAV hose was pinched rpm dropped by 800-1000rpm. The smoke in a can wasn't useful in finding the source of air leaking pass the AFM pathway.

The AAV is designed to increase idle by that amount until the engine reaches operating temperature. So, nothing revealing there just yet. I think the aspect that should be focused on right now is the non-response to throttle input.

I’ll tell you that in getting my L-Jet sorted, I replaced every old hose on that entire topside. My car was very original but what had been replaced wasn’t exactly the right size most times. Belmetric has almost all the correct hoses at a good price and wonki has provided you with his artisan diagram that I just love!

We also need to consider your fuel injectors are full of garbage and not spraying correctly or at all. Have you looked at plugs?

bit by bit we are heading towards the Van B/wonki situation.

you ended up doing everything and checking everything on the EFI system as you went.
i did all of mine before we even attempted a start. the whole lot. after a 16 year sleep.
but i had mike looking over my shoulder. do this. etc. now do that. and on.
injectors, injector seals, hoses, distributor operation, ......on and on.

anyway, it should be solvable. trial and error. tick off the bits one by one.