1974 1.8L engine fast idle then stalls, Fuel injection issues |
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1974 1.8L engine fast idle then stalls, Fuel injection issues |
tshih914 |
Feb 19 2023, 11:45 PM
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#1
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Member Group: Members Posts: 79 Joined: 17-July 05 From: central NJ Member No.: 4,426 |
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?
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wonkipop |
Feb 25 2023, 08:56 PM
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#2
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Advanced Member Group: Members Posts: 4,658 Joined: 6-May 20 From: north antarctica Member No.: 24,231 Region Association: NineFourteenerVille |
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 |
Feb 26 2023, 07:57 AM
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#3
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Member Group: Members Posts: 79 Joined: 17-July 05 From: central NJ Member No.: 4,426 |
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. |
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