Acceleration pumps suddenly stopped working
Acceleration pumps suddenly stopped working
I used to have a nice squirt in all inlets, but now completely dry. If I look closely at the edge of the diaphragm gaskets, I can se that they are wet. Do I have to remove the carburettors in order to find the issue? Or are there some other tips & tricks I can start with?
Re: Acceleration pumps suddenly stopped working
Can you give some more details? Engine type, what type of carbs (I am assuming you are talking two 'twin chokes' like C.32 PHH, C.35 PHH or C.42 DDHF)? Do I understand it happens on BOTH carbs at the same time? Is this happening after some time standing still?
If I get it, you look at the membranes from the outside, and the edges that protrude are wet? They shouldn't be.. look like they aren't closing off anymore, and that may mean the pressure from the pump action makes the fuel is pumped out trough the leaks due to not closing off, instead of going to the pump injectors (but I am only guessing from what you write).
It is possible that the membranes are 'dried out' (if the car has been standing still for a longer time). In that case, when soaked in fuel again, they may swell up and close off again.
But it sounds to me that the best course of action is to take them off, and open up at the bottom, maybe replace the membranes (but again, that is only guessing from what you write).
If you can provide more details about the circumstances, some more 'educated' advice may be possible :)
Marnix
If I get it, you look at the membranes from the outside, and the edges that protrude are wet? They shouldn't be.. look like they aren't closing off anymore, and that may mean the pressure from the pump action makes the fuel is pumped out trough the leaks due to not closing off, instead of going to the pump injectors (but I am only guessing from what you write).
It is possible that the membranes are 'dried out' (if the car has been standing still for a longer time). In that case, when soaked in fuel again, they may swell up and close off again.
But it sounds to me that the best course of action is to take them off, and open up at the bottom, maybe replace the membranes (but again, that is only guessing from what you write).
If you can provide more details about the circumstances, some more 'educated' advice may be possible :)
Marnix
Re: Acceleration pumps suddenly stopped working
Thank's for your reply. Excuse me for not giving more details.
It's 1.3 series 3, with Solex 35 PHH carburettors. Both acceleration pumps stopped working suddenly. From working fine, to not working at all. It has been standing still during the winter, but I have started it a few times. I have also cleaned the petrol tank, and inserted a new filter in it. I also have a filter to the pump inlet. Looks very clean. Petrol are running thrue the return hose, so I don't suspect the pump, or low pressure. Besides delayed acceleration, the engine is running well. Spark plug color OK.
As you write, I suspect pressure is building up inside the pump. I have removed the acceleration pump from one of the carbs. Some dirt in the bottom, but not much. It's hard to say how flexible the rubber membran should be. It flexes, and doesn't feel hard.
It's 1.3 series 3, with Solex 35 PHH carburettors. Both acceleration pumps stopped working suddenly. From working fine, to not working at all. It has been standing still during the winter, but I have started it a few times. I have also cleaned the petrol tank, and inserted a new filter in it. I also have a filter to the pump inlet. Looks very clean. Petrol are running thrue the return hose, so I don't suspect the pump, or low pressure. Besides delayed acceleration, the engine is running well. Spark plug color OK.
As you write, I suspect pressure is building up inside the pump. I have removed the acceleration pump from one of the carbs. Some dirt in the bottom, but not much. It's hard to say how flexible the rubber membran should be. It flexes, and doesn't feel hard.
Re: Acceleration pumps suddenly stopped working
I have now cleaned the carburettors, jets, ejectors and valves with an ultrasonic cleaner. I used Ticopur R33 as a solvent. All gaskets and the accellerator pump diaphragms replaced. Some dirt in the basin, but not much. The brass filter around the banjo bolt on carburettor 1, was pretty clogged with old remains of petrol resin. The smaller brass filter on carburettor 2 was clean.
The car runs much better now, but the accelerator pumps are still not working. The valve with the small metal ball looks very clean, and the ball rattles when shaken. I assume this is the outlet valve that should open, when you build pressure by activating the pump? The other shorter valve on top of the accelerator base should then be the inlet valve? I haven't found a way to inspects this valve, so I have order two new valves.
Observations:
1. Test drive was pretty ok. Parked the car, and the day after both floating chambers are empty. No petrol.
2. Turn the engine on the starter so the chambers get filled again. Push the accelerator, and the pressure comes up in the floating chamber.
3. Even if you change your petrol filters, petrol resin can bypass any standard filter, and clog up tiny passages inside the carburettors. It probably take many years but it will eventually happen.
I wonder about the two first observations:
1.
The petrol tank ventilation is working, so there's no vacum in the tank, and I have no petrol leaks from the carburettors or the tubes. What can be the reason for the floating chambers are drained for petrol during the night? Common problem with Solex PHH? I understand I'm not the only Fulvia owner having starting issues.
2.
I assumed that the purpose of the valves on top of the accelerator pump base was to let the chamber be filled, and prevent pressure to the floating chamber. That's basically why I ordered 2 new valves.
Please feel free to comment, if you have tips, or if my assumptions about the function of the valves are wrong.
The car runs much better now, but the accelerator pumps are still not working. The valve with the small metal ball looks very clean, and the ball rattles when shaken. I assume this is the outlet valve that should open, when you build pressure by activating the pump? The other shorter valve on top of the accelerator base should then be the inlet valve? I haven't found a way to inspects this valve, so I have order two new valves.
Observations:
1. Test drive was pretty ok. Parked the car, and the day after both floating chambers are empty. No petrol.
2. Turn the engine on the starter so the chambers get filled again. Push the accelerator, and the pressure comes up in the floating chamber.
3. Even if you change your petrol filters, petrol resin can bypass any standard filter, and clog up tiny passages inside the carburettors. It probably take many years but it will eventually happen.
I wonder about the two first observations:
1.
The petrol tank ventilation is working, so there's no vacum in the tank, and I have no petrol leaks from the carburettors or the tubes. What can be the reason for the floating chambers are drained for petrol during the night? Common problem with Solex PHH? I understand I'm not the only Fulvia owner having starting issues.
2.
I assumed that the purpose of the valves on top of the accelerator pump base was to let the chamber be filled, and prevent pressure to the floating chamber. That's basically why I ordered 2 new valves.
Please feel free to comment, if you have tips, or if my assumptions about the function of the valves are wrong.
Re: Acceleration pumps suddenly stopped working
Remotely diagnosing is obviously rather hard. I can only guess at possible causes. It seems we are talking several problems now.
The valves:
- the brass valve at in the pump body is the input valve, correct. In my experience, they are almost never faulty. I can only imagine in extreme circumstances them being blocked or stuck by hardened petrol or so after a very long time standing still. Seems unlikely to be any reason for the troubles.
- the valves with the ball + weight are the output valves indeed. In contrast, they are almost never very good. The seat in the body where the ball rests is almost always not good, making that the valves leak. Sometimes not enough to stop the acceleration from working. Sometimes so bad that it doesn't work anymore.
The emptying of the carbs:
There is no way that the petrol can get out through the top. The float valves are sitting above the fuel level. It can only get out somewhere below the float fuel level. It could be anywhere, but the most likely is through the seals from the acceleration pump. It doesn't need to be a gigantic leak. With like one drop of fuel seeping through every minute, you probably empty the bowls after a night standing still. The most common reason for the leak at the pump is that the screw seats where the small screws fix the pumps are worn out (or rather: worn-in), making the screw go deeper and not tightening the pump against the seal anymore. The screw then hits the bottom of the threat in the body, feeling like it is set alright, but actually not pressing the pump with the seal to the body enough. The screw length is quite critical. When I assemble the pump, I individually test each screw tightening against the body WITHOUT the seal first. Each screw should fix the pump hard against the body. I frequently have to make the screws a bit (like 1mm) shorter to make them short enough to fix the pump. This is a rather common problem.
I am surprised at your observation that there is nothing coming out from the acceleration pump injectors (on BOTH carbs at the same time?). I once made the stupid mistake forgetting to put the small springs in the pumps, making them unserviceable. The car was nearly impossible to drive, acceleration from standstill required to first rev up to 5000 RPM and the let the clutch slip slowly. To see if the injectors don't give nothing: run the engine, to fill the bowls. Stop it. Remove the air filter so that you have a clear view inside the barrels from the input side. Shine with a small light into each barrel, and the move the throttle by hand from closed to fully open in one go. You should be able to see a squirt coming out of the injector at the far end.
The valves:
- the brass valve at in the pump body is the input valve, correct. In my experience, they are almost never faulty. I can only imagine in extreme circumstances them being blocked or stuck by hardened petrol or so after a very long time standing still. Seems unlikely to be any reason for the troubles.
- the valves with the ball + weight are the output valves indeed. In contrast, they are almost never very good. The seat in the body where the ball rests is almost always not good, making that the valves leak. Sometimes not enough to stop the acceleration from working. Sometimes so bad that it doesn't work anymore.
The emptying of the carbs:
There is no way that the petrol can get out through the top. The float valves are sitting above the fuel level. It can only get out somewhere below the float fuel level. It could be anywhere, but the most likely is through the seals from the acceleration pump. It doesn't need to be a gigantic leak. With like one drop of fuel seeping through every minute, you probably empty the bowls after a night standing still. The most common reason for the leak at the pump is that the screw seats where the small screws fix the pumps are worn out (or rather: worn-in), making the screw go deeper and not tightening the pump against the seal anymore. The screw then hits the bottom of the threat in the body, feeling like it is set alright, but actually not pressing the pump with the seal to the body enough. The screw length is quite critical. When I assemble the pump, I individually test each screw tightening against the body WITHOUT the seal first. Each screw should fix the pump hard against the body. I frequently have to make the screws a bit (like 1mm) shorter to make them short enough to fix the pump. This is a rather common problem.
I am surprised at your observation that there is nothing coming out from the acceleration pump injectors (on BOTH carbs at the same time?). I once made the stupid mistake forgetting to put the small springs in the pumps, making them unserviceable. The car was nearly impossible to drive, acceleration from standstill required to first rev up to 5000 RPM and the let the clutch slip slowly. To see if the injectors don't give nothing: run the engine, to fill the bowls. Stop it. Remove the air filter so that you have a clear view inside the barrels from the input side. Shine with a small light into each barrel, and the move the throttle by hand from closed to fully open in one go. You should be able to see a squirt coming out of the injector at the far end.
Re: Acceleration pumps suddenly stopped working
PS: I am very wary of replacement input valves for the pump. The ball in the original Solex is stainless steel. When cleaning some of the valves in ultrasonic, one or two came out with the ball black - some kind of aggressive action on the the material. The cleaning solution I use for brass jets etc is can be somewhat aggressive alright against some weak materials like soft iron and aluminum when used rather concentrated and higher temperature, but not against brass and stainless. So which couldn't have happened if the ball was stainless. I never had an original Solex input valve that was, after cleaning thoroughly in ultra sonic, was faulty...
Re: Acceleration pumps suddenly stopped working
Thank you very much for your valuable input.
Whith the top cover removed, and the floating chamber filled to normal position. Pressing the accelerator creates pressure in the floating chamber. It bubbles but it doesn't look like air is coming into the floating chamber, so I assume that the pump chamber is filled with petrol. I thought that the valve should prevent the petrol taking the "wrong direction" when the chamber was set under pressure?
Before I got the issues with the accelerator pumps, I checked the function as you describe, and there was a nice spray from each tube. No dripping. The strange thing is that both pumps stopped working at the same time. During the winter I cleaned the petrol tank, changed filters and filled it up with alkylate 95 octane petrol. Will change to E95 98 octane, when the tank is empty. I have also added the apropriate mix of Liquy Moly valve cleaner. There was no corrosion in the tank, but a thin hard layer of petrol resin.
When I had finished the cleaning I found a small brass fragment in the basin. It's cylindric, approximatly 1 mm in diameter and 2 mm length. See picture attached. Do you have any idea of what this could be?
Whith the top cover removed, and the floating chamber filled to normal position. Pressing the accelerator creates pressure in the floating chamber. It bubbles but it doesn't look like air is coming into the floating chamber, so I assume that the pump chamber is filled with petrol. I thought that the valve should prevent the petrol taking the "wrong direction" when the chamber was set under pressure?
Before I got the issues with the accelerator pumps, I checked the function as you describe, and there was a nice spray from each tube. No dripping. The strange thing is that both pumps stopped working at the same time. During the winter I cleaned the petrol tank, changed filters and filled it up with alkylate 95 octane petrol. Will change to E95 98 octane, when the tank is empty. I have also added the apropriate mix of Liquy Moly valve cleaner. There was no corrosion in the tank, but a thin hard layer of petrol resin.
When I had finished the cleaning I found a small brass fragment in the basin. It's cylindric, approximatly 1 mm in diameter and 2 mm length. See picture attached. Do you have any idea of what this could be?
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Re: Acceleration pumps suddenly stopped working
These are the valves I have replaced. As you also may see, I found out where the small cylindric brass piece come from. The hole in the accellerator housing, on the left one.
I have also attached a picture of the accellerator pump injector. It doesn't look like the ones on various drawings I have seen.
Now there are no bubbles in the floating chamber when I activate the pump. But pressure is building up so much that both carburettors are leaking petrol from the accelerator pump housing. I still don't have a squirt from the tubes. I'm out of ideas now.
I have also attached a picture of the accellerator pump injector. It doesn't look like the ones on various drawings I have seen.
Now there are no bubbles in the floating chamber when I activate the pump. But pressure is building up so much that both carburettors are leaking petrol from the accelerator pump housing. I still don't have a squirt from the tubes. I'm out of ideas now.
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Re: Acceleration pumps suddenly stopped working
That's indeed a plug from the acceleration pump base. It is quite common that plugs come out in the ultrasonic, you got to watch for it.
There are two things I suggest:
1. Make sure the bottom is not leaking. See method I described. In worn pump fittings, the screws are slightly too long to make the seal fit tight.
2. You could try to check the injectors with a fine wire. The size of the injectors is '40' meaning a hole of 0.4mm diameter. So a wire which is close to but less than 0.4mm diameter. Push the wire in the injector FROM the bottom (don't try it from above, it will most likely not work due to the way the hole is manufactured (too complicated to explain). So from the bottom means from inside the barrel. DO NOT push the injectors out, they are press fitted.
There are two things I suggest:
1. Make sure the bottom is not leaking. See method I described. In worn pump fittings, the screws are slightly too long to make the seal fit tight.
2. You could try to check the injectors with a fine wire. The size of the injectors is '40' meaning a hole of 0.4mm diameter. So a wire which is close to but less than 0.4mm diameter. Push the wire in the injector FROM the bottom (don't try it from above, it will most likely not work due to the way the hole is manufactured (too complicated to explain). So from the bottom means from inside the barrel. DO NOT push the injectors out, they are press fitted.
Re: Acceleration pumps suddenly stopped working
To answer your remark about the injector not looking as you imagine. It looks EXACTLY as it should be. What you see is the chamber where the injector sits at the bottom of. With the brass blanking screw on top. The injector itself is at the bottom of the chamber, press fitted in a through hole towards the barrel.