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.

Not specifically. Wouldn't a regular tyre pump work? Yes, it blocks the fuel once it doesn't have power. I think the problem lies within the carb bc it isn't a problem when the choke flap is closed. I don't have the original manual, but so far, I've only really needed torque settings. The fuel filter is on the right, see-through case (it's new). I do take care of the car. I have put in new oil, coolant, and air filter. I do know the importance of maintenance, and I want to keep the car in good condition. Will change the gearbox oil soon as well. The car itself drives really well. I haven't tested other models, but mine is very good. The brakes feel good, and the gear changes are nice.

Yes, after unscrewing, i pulled it out and checked the tiny holes (there were 2), both were clean. There also seems to be a really small hole at the bottom, but i dont know if it leads anywhere. I dont know where the two holes lead to on the carb, but I didnt check them bc they are deeper inside and hard to access it seems.

I dont know if it is running rich anymore, i dont see why it shouldnt. As for running lean i cant confirm, although it does seem like it, bc when the choke flap is closed, it chokes the egnine of air and that fixes the problem. (But it could also pull in fuel differently). I think that the choke works well, although the system is complex, it does what its supposed to. I can close the chocke flap (square one on top of the carb) by just holding it down with my fingers, which makes the idle good. I think it pulls fuel differently then, bc the car wont shut off when the idle cutoff valve wire is pulled. I could try to hold it open but the choke "turns off" anyways whem the engine is warm. I havent yet checked the valve clearences bc i dont have the tool, but i could figure smth out on the weekend. I use the Haynes manual as a guide with the bigger jobs and torque settings but all the parts should be good., exept for the leads as they were made by a chinese company. I could check the coil on the weekend, any suggestions how? When purchasing the car it had almost an empty tank so fuel is new. I only put in 98, dont know if its E5 or E10, but should be one of them. That was before changing the headgasket, havent checked it now but its a mixture of oil and coolant. The wire got disconnected accidentally when removing the filter but when testing, it was on.

Thank you for clarifying, but both of the holes were clean.

The choke is automatic and according to the Pierburg manual, it is supposed to be 2000 +-200, (mine is a clone: Jikov 28-30). I can adjust it tho. I also adjust the screw when the engine is warm, the temp gauge is in the middle. The air intake has a flap inside that should open at 70 or smth degrees and let in colder air. When it's closed, it can only pull warm air from on top of the exhaust manifold (a pipe goes there). It's warm to the touch, including the air filter housing.

Interesting, I have to somehow test it then. On the weekend when I have time, tho. Any suggestions on how to do it?

I know that's why I'm asking for help. I do believe that there is a leak. The idle shouldn't be that bad even if it was running lean, I think. I haven't tested the pollution after the rebuild, but the exhaust smells very strongly of gasoline. For the previous reply.

The setup part I'm trying to figure out. The choke works as expected: when cold starting, revs go to 2k and then fall to about 1500, where they will stay at till the engine is warm, then drop to about 800. When adjusting the CO screw, turning out makes it idle better but not that much anymore, when its almost fully in the revs drop a bit and the car struggles to keep the revs. Really starts moving up and down (+-100). (Also happens when the screw is turned out more) Only at idle. I try to adjust the idle according to the mixture. Also read from a forum that running lean may help with the icing but haven't seen any proof of that yet. Starts up well, takes less than a second. Idle is very good as long as the choke flap is closed.

I purchased the car a few months back (driving back home, it averaged around 7.5 L/100km), and it was already smoking then. After checking the vehicle at a technical inspection place, it ran way too rich. (too much unburnt fuel exited the exhaust). It also started icing (I believe). The throttle becomes unresponsive, the car starts jerking and eventually dies. After a few minutes of standing, it's fine again. So I took the carb apart completely and put in new gaskets. The idling problem was occurring then as well but mostly when the CO screw was turned out only about 2 turns and the car wouldn't turn off when the idle cutoff valve wire was pulled. The base gasket was in bad condition, but I couldn't find a new one, so I used Victor Reinz gasket maker (which @RicardoM recommended in another forum thread). After fixing the gasket, the engine would shut off when disconnecting the wire. Not the same case when turning in the CO screw (it should cut off fuel). It only died when the idle screw was set so low that it just didn't have enough rpm. Also changed the head gasket (quite new looking) and manifold gasket (pretty rough). Before changing the head gasket, some white residue would collect underneath the oil cap after driving (occasionally) but disappeared after standing still for a night. Oil seemed fine. Dont know what was done previously with the car. Only has 100k km. I haven't driven it much, only a few hundred km, since I want to fix it. Pictures are taken without the air filter on. I also changed the distributor cap, spark plugs and wires and the belt.

Here is a video: https://youtube.com/shorts/wV0-MSAXp7M?feature=share. It isn't heard in the video, but it sorta coughs at idle, stutters a bit.