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?

[nihil44]

I have been pursuing running issues and vac leaks for the past 8 months. I have used smoke machine, compressed air (as recommended by factory - Bowlsby website for this) and vacuum from a vacuum pump and a vacuum cleaner

Smoke machine:- I made one from PVC plumbing fixtures as in a few YouTube websites. Worked ok but the smoke went everywhere, it lingered in the engine compartment and it was not easy to see just where the smoke was coming from. Also, I had the machine going for too long, it overheated and melted some of the PVC - result one buggered smoke machine

Vacuum pump hand held: - intake chamber volume too large for pump and unable to pull a vacuum

Vacuum cleaner:- very simple construction. 6omm OD pvc plumbing pipe with end cap glued to pipe. Hole in end cap of a size to accommodate a grommet and the vacuum cleaner nozzle










I used kid's bubble mix liquid diluted with a little water into a squirt bottle, applied and waited for the bubbles to appear

Compressed air:- same construction as above except in place of the grommet on the end cap I used a schrader valve to connect to the compressed air via an adjustqable regulator





Some of the results:-

Small crack in the neck of the oil filler tower. George Hussey says in listing for this item used, that they always break. I had to get underneath with a mirror to find that one



Both inlet manifold gaskets had cracks in them. One obviously had a washer embedded in it which caused the crack





I bought a set of Victor Reinz gaskets which are phenolic resin with a thin gasket material applied to both sides. I fitted them and just to be sure I re tested them for vac leaks and sure enough, one side leaked. So I put a thin universal gasket on both sides of the gasket but the overall thickness was too much and I couldn't do up the nuts on to the studs. I ended up compromising by putting the thin gasket on just one side and this is working

Victor Reinz standard gasket. Note how thin the gasket facing material is