RalfRannet

I finally got a new fuel pump, but that didn’t fix the issue. So, I checked the fuel level sensor (which I had replaced) in the tank and noticed that the filter could block the pipe at times. After securing the filter with a clamp, the gas pedal worked consistently during testing. Now, I just need to fix the leak in the base gasket, and it should run perfectly. I also don’t think carb icing was ever the problem.

Sorry for the long silence, the car is really eating away at my patience and it doesn't seem to be a simple issue. The throttle cable doesn't get stuck. But a new problem has surfaced, possibly the same as suspected "freezing". For weeks now, the car hasn't idled. It just dies. It started happening after I added some fuel additive that should increase the fuel freezing temperature, but it shouldn't be a problem because I also have tried running the engine from a gas canister with good fuel. After adding different silicones, gaskets, etc, to the carb main gasket (between the manifold and carb), it still doesn't work. I even ordered a new flange and added reinzol silicon gasket, which now sometimes lets the car idle at 500 rpm. I still suspect that it's an air leak bc when spraying carb cleaner, the revs increase, also I can't see that much fuel being pulled into the barrel. Still happening after the choke flap has opened. But driving in warmer weather, the accelerator pedal stopped working again for a few seconds, then started, stopped and so on. I have cleaned the different holes again, but I can't figure out the cause. My theory is that it doesn't get enough fuel at times. But could a mechanical fuel pump fail like that or does the float get stuck at a similar time every time?

Air intake temp flap that I now removed and blocked off the cold air pipe completely. It doesn't get too warm inside the carb, never will. The mixture is set so that it idles smoothly and runs well. I understand. On the carb, the choke flap sits on top and when it's closed, it pulls more fuel through a different place, bc the idle cut-off valve doesn't kill the idle anymore. That in theory should allow the engine to stay running even if the main fuel "pipe" freezes. I may be wrong but it can't be too rich, bc when the screw is turned in more, the idle gets rough and the car dies. The CO measurements came back as 0.2... and the allowed was 3.5 so if anything it's running a bit lean.

I changed the thermostat very recently actually because it was stuck open, when driving the engine temp went down to 0. Now it gets up to temp fine and mostly stays below the middle line. How interesting! I'm not running on LPG, but does your carb happen to have the heating element on the back side of it? On this website it correlates to number 37, it sits just below the idle cut-off valve (8).

Yes I know, I think that temp. also plays a role (it just hasn't happened in warmer weather for me). Anyways how could one fix that then? I've heard that closing the choke plate could help (making the choke manual).

I think the leaks are fixed by now. Turning in the CO screw now kills the car and the revs drop as they should. The idle is smooth, no movement in the rev gauge. Hiss sound is constant and spraying carb cleaner doesn't increase the revs as it previously did. If you have any ideas on how to prevent the carb from icing, it would be very great. It does get only warm air now, the pipe going to the air filter was really warn, not hot (it doesn't burn my hand) and the air filter housing was also warm and it still froze. (-6°C when testing).

Okay, so it came out that when the flap opens, it almost closes the warm air intake, so I removed it (the flap). I also blocked the cold air intake so the only air coming in could be warm. It got better, car started stalling at the similar time but throttle worked a lot longer. It seemed like the ice could melt a bit when at lower rpms and that kept it going at least 25 min. It sometimes cut out but started working again. The car did stall like 60% of the time when pressing the clutch in but that seemed enough for it to stay running just a few sec after that.

The whole air intake system was warm, even the round air filter cover that sits directly on top of the carb. I have started the car outside and inside the garage. I tried blocking the first pipe with an old shirt but the shirt was dry and I've also tried to redirect the first pipe to end near the exhaust manifold as well, neither of which worked. The engine is very warm and melts the ice in a few minutes once it forms. The ice forms in about 15 min of driving, the revs can be kept below 3k, doesn't matter. First, the idle drops, when pressing the clutch in or just taking it out of gear and the engine stalls. For a bit, the revs can be held higher by pressing the accelerator but eventually, the accelerator stops working. Press it as much as you want, nothing happens, then it dies and I have to wait a few minutes before the pedal works again and the engine doesn't stall. Right before it dies fully, the pedal usually cuts in for a few seconds but then stops responding till the ice is melted. The car works well, the idle is good, doesn't move up and down and the acceleration is fine.

I see, I was a bit confused as well. The airbox doesn't have any hoses going to it anywhere except one from the rocker cover, near the oil fill port.

The flap can't be controlled manually. It should be directly on the flap I think, it's inside the pipe and isn't connected to anything outside. And the heat got discontinued in 2013 and I haven't found a place that sells it.

My car has a round airfiler. The pipe from the airbox splits into 2. The flap is inside the first pipe and cant be accessed like that. The second pipe just goes to the heat shield, where its connected to a hole that gets warm air from around the exhaust manofold. When blocking the first pipe, the whole air intake system got warm to the touch and the car still died.

The diaphgram (inside the accelerator pump) should be controlled by pressing the accelerator and doesnt have any hoses going to it. I dont think felicias have it. The airbox doesnt seem to have sensors anywhere. I belive there is only 1 temp. sensor in the thermostat and another on the radiator.

The air intake has a flap inside it which opens at a certain degree, even if that pipe is blocked off with other things and the car pulls warm air from on top of the exhaust manifold, it still freezes. It happens when temp. is below 3°C.

Okay, i corrected the valve clearences and readjusted the carb. It idles well now and also passed emissions with 0.2.. % CO. The big problem now is the carb icing.

@nta16 Thank you for all the info. I suppose I should check the gaps and timing and so on, I just need the tools now (and the owners/workshop manual if anyone has a link or smth). Will tell you when I get the issue sorted.