Hello.

First time car owner here.

When I got the car three months ago, the short rubber hose at the fuel pump input was cracked. So I replaced the hose. Then a terrible fuel leak started from the fuel pump. After losing like 5 liters of fuel, I realized it and replaced the fuel pump immediately. The old fuel pump came with the car was Ruby brand. New one is Vika. I couldn't find an original part.

 

Several weeks ago, I decided to replace the engine oil. Old oil was 10W40. Previous owner claimed it was fresh. Reading the recommendations, because of engine's technology and age, 10W40 is too thin for this engine. Constantly losing some oil confirmed this. I also made a few thousand kilometers. At the beginning of the spring, I thought it was a good time to replace the oil.

 

I bought Castrol 20W50 LPG from a trusted vendor. They also had a free oil replacement service too. With a new oil filter, the engine oil had been replaced. After that day, a faint fuel smell appeared again. When I touched underside of the center ring of the fuel pump, I found the source of the leak. Again, fuel pump is leaking. Not like dripping before, just persistent dampness.

 

The fuel pump body is consisted of two main parts. Upper body and lower body and they are pressed together with a ring at the center. My theory is; this is a bad design to hold together pressurized parts with a gasket in the middle. If you apply some unbalanced force from top or bottom it will bend and/or loosen the pressed middle ring and cause a fuel leak.

 

I inspected similar era car's fuel pumps too. For example Lada Samara fuel pump has bolts securing main body parts together.

https://pasteboard.co/JWFQSzM.jpg

 

I think the guy who changed the oil filter had bumped the fuel pump while working to replace the oil filter and that was more than enough to cause a leak. He used a huge box end wrench to tighten the oil filter.

 

I never ran the car on fuel since I got it. I don't know current state of the original fuel system. The car is up and running but I know it's important to have a working fuel system as a backup and a healthy carburator. Considering the small LPG tank I have, it's a must have.

 

So what to do now?

 

My options are; (from cheapest to more expensive)

 

1- Remove fuel pump, and try to apply press on the retaining ring with a strong vise. $0 (Maybe new gaskets for fuel pump)

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2- Craft a framework with bolts and nuts to apply exterior vertical pressure to the pump body. $5

https://pasteboard.co/JWG5uwr.jpg

https://pasteboard.co/JWG6G8S.jpg

This will press the main body parts just inside ring. Not the ring itself.

 

3- Buy a new electrical fuel pump. Repair and preventative measure. $12

https://pasteboard.co/JWG8hSq.jpg

This is a universal pump. I did my research and found this;

https://www.briskoda.net/forums/topic/442681-how-install-mechanical-fuel-pump-to-the-felicia/

 

This owner here did it otherwise. Removed the dying universal fuel pump and installed a mechanical one.

The car is a Felicia with carburator. So it can be done.

Lowest pressure pump I could find is 3 bar, 90L/h universal fuel pump.

 

I can install this, and connect the electric input to LPG system so it won't turn on unless I switch to fuel. I don't know what will happen after such a modification.

 

4-Last solution; buy a new mechanical pump. $20-$30

I know the solid solution is buying a new mechanical pump but will it happen again? Spending $30 for the same part in three months plus, the expectation of a fuel pump leak and the dangers of such a failure is really annoying.

 

If you have read so far. Thanks! I've learned a lot from Briskoda and their veteran members.

 

Current situation:

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8 hours ago, R_Blue said:

Several weeks ago, I decided to replace the engine oil. Reading the recommendations, because of engine's technology and age, 10W40 is too thin for this engine. WRONG. Constantly losing some oil confirmed this. WRONG ASSUMPTION . I also made a few thousand kilometers. At the beginning of the spring, I thought it was a good time to replace the oil.

 

The fuel pump body is consisted of two main parts. Upper body and lower body and they are pressed together with a ring at the center. My theory is; this is a bad design to hold together pressurized parts with a gasket in the middle. WRONG. UNLESS YOU GOT A BAD ONE.

 

I think the guy who changed the oil filter had bumped the fuel pump while working to replace the oil filter and that was more than enough to cause a leak. WRONG ASSUMPTION. He used a huge box end wrench to tighten the oil filter.

 

I never ran the car on fuel since I got it. I don't know current state of the original fuel system. This is the first correct assumption. This should be your first priority.

 

So what to do now?

 

My options are; (from cheapest to more expensive)

 

1, 2, 3 are WRONG

 

4-Last solution; buy a new mechanical pump. $20-$30

The original fuel pump for Favorit looks like this.

 

Or buy an original JIKOV pump.

 

Edited 10 April, 20215 yr by RicardoM

Thanks RicardoM

I've never saw that pump with reservoir before. Looks like it has a manual lever too. Pump body looks more solid with bolts, yet I have zero experience about reliability of both pumps. I'd like to take your opinion on that too.

 

Among non-reservoir models, I've never encountered Jikov brand. I will look for those two models in the upcoming days. I'll update any progression.

 

About oil; I've been told by a mechanic who has the same vehicle (93 favorit lx) as a daily driver, 10W40 was too thin. He told me that I would lose much oil with that viscosity. He told me, he was using 15W40 for winter and 20W50 for summer. Oil seller guy told me 20W50 is too thick for Škoda Favorit and urged me to buy 10W40 instead. I've browsed different sources on the net for answers but all I got was more confusion. Some users say, 20W50 is for trucks. Some say, it's the perfect oil for Favorit.

Solid info I could find was, what the original user manual said. It's 15W40.

I had to add 1 liter of 10W40 during past three months and 2000Km. It won't drop below -15ºC until next winter so I went for the 20W50. It's been 800Km with the 20W50 and oil level is still at the max.

I think an engine with good condition could do better with 10W40.

It's hard to find people skilled as you RicardoM. It's not a compliment. Reality. I've read a lot here on the past months before joining. I know what the "mechanics" did from my own car and from others'. You wouldn't believe If I told you.

 

 

My car has a Jikov mechanical pump. VIKA pumps use the same design but as usual the quality of the materials is lower. Chinese stuff motto is "make it look great using $hitty materials".

As for the engine oil, if all engine gaskets are good quality, not old and they are correctly torqued, then no oil should leak. One other thing. Favorit engine was designed for non-synthetic oils.

I couldn't find both the pumps you have mentioned. I've been told that, current situation affects spare part availability. My choice was another Vika or nothing. I've decided to give it a go to my project with a more simpler design. Just to try and see. I've used a metal cylinder that fits the bottom of the pump. This part is free. I've bought only two hose clamps.

 

 

 

 

I've installed on the car but the result was a complete failure. As soon I cranked the engine fuel started dripping. This time directly from the holes under the pump. So from what I've learned, if you let the mechanical pump run dry, (I did this like a month or longer) the pump diaphragm gets totally destroyed. So, time for a new pump.

 

Ennepetal/Germany item no: 070972000

One piece for both mounting a new pump, and sealing the pump mount. $1.75.

I've made small modifications to this part. You can see them all in the pictures. The installation was made over the original spacer with new gaskets.

 

 

 

 

 

 

 

It's working. But no road tests yet! I'll add pictures for fuel hose routes too.

Please, share your thoughts.

I almost forget the oem code:

15100-85501: Electric Fuel Pump

This one is a low pressure electrical fuel pump. I've learned that this one is a popular pump for various modifications.

3 hours ago, R_Blue said:

So from what I've learned

The other lesson you need to learn right now is that petrol will spontaneously ignite, so stop bodging the fuel system before it gets the chance.

3 hours ago, R_Blue said:

So from what I've learned, if you let the mechanical pump run dry, (I did this like a month or longer) the pump diaphragm gets totally destroyed.

I don't agree with this conclusion as a GENERAL rule. Since you found the mechanical pump to be faulty, open it. You'll find the problem in the photo below. You'll understand what is wrong.

1 hour ago, R_Blue said:

This one is a low pressure electrical fuel pump.

It is OK having low pressure otherwise high pressure would overcome the float needle valve and flood the engine. It has another advantage too. If the pump starts once the ignition key switch is set to on, the float chamber will be primed (filled with fuel) before cranking the engine. Usually the fuel evaporates from the float chamber if the car was not used for a while, especially on hot days. That leads to long cranking times from fuel starvation.

Sorry for the late answer. A lot happened since my last post.

New fuel pump setup is working. It takes tremendous effort to tune the carburetor for both LPG and fuel. Just after the fuel pump installation, I've done a complete restoration to the carburetor according to guides found on internet. All for fuel only of course. The carburetor had sketchy modifications, neglected and dirty. After restoring it for fuel, it didn't go well for LPG. Auto-choke mechanism and LPG don't go well together. I'll explain this later on another topic.

 

I only used the fuel pump twice so far. The car is almost always on LPG. But I think when I need it, it will work. You should still consider this experimental.

 

 

It is OK having low pressure otherwise high pressure would overcome the float needle valve and flood the engine. It has another advantage too. If the pump starts once the ignition key switch is set to on, the float chamber will be primed (filled with fuel) before cranking the engine. Usually the fuel evaporates from the float chamber if the car was not used for a while, especially on hot days. That leads to long cranking times from fuel starvation.

 

This is the best advantage. When the car is on LPG, there is a fuel cut-off valve that redirects all fuel to the tank so carburetor goes completely dry. The LPG system has a switch inside the car. When you turn it at the fuel side, it opens the fuel cut-off valve. I attached fuel pump's cables to this valve. So before the ignition, I give the pump a good 30 seconds for filling the completely dry carburetor. After that, I pump the gas pedal a few times for priming the also-dry accelerator pump. Then, the engine successfully starts at one crank.

 

 

The other lesson you need to learn right now is that petrol will spontaneously ignite, so stop bodging the fuel system before it gets the chance.

 

My attempts was primarily on considering safety. When the car is on LPG, mechanical pump always circulates the fuel. There is no way to stop the mechanical pump. When you use the car on fuel, and if the fuel pump goes bad, the car will stop working and you know there is a problem. But, with LPG, all fuel may leak somewhere and you might notice it too late.

 

Fuel hoses:

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I cut open the faulty fuel pump as requested by RicardoM

Inside of a Vika fuel pump:

https://pasteboard.co/KbjS6Vo.jpg

https://pasteboard.co/KbjSKEz.jpg

https://pasteboard.co/KbjT11B.jpg

https://pasteboard.co/KbjTkUH.jpg

https://pasteboard.co/KbjTDbE.jpg

 

The only thing with this setup that bothers me is the affects of the fuel pump's placement to the pump itself. Mainly heat. This pump is for carburetor engine Suzuki Rascal. Pump placement on that vehicle is between the rear chassis frames, just behind the cab. A much cooler place than my setup. Does the heat kill this pump prematurely? Time will tell. So anyone who is considering to make such a modification should know that, this is an experimental setup. Do it at your own risk.

 

Further research revealed more pump models could be used for such a project.

These are low pressure diesel pumps used for small forklifts or other small machinery. It generally goes by the code HEP02A. The picture below shows alternate/interchangeable pumps or codes.

 

This particular model may be easier to install and looks more sturdy. You may locate it elsewhere so it may work cooler than my setup. I have only heard people with old cars that use mechanical pumps use this as a general purpose electrical pump but this needs solid confirmation.

 

On 15/07/2021 at 21:46, R_Blue said:

Does the heat kill this pump prematurely

dont bother the placment is fine is max gets to 60-70c

On that note I actually like your approach you seem pretty mechanically minded and thats good you will not have an issue keeping you fav up and running

14 hours ago, Thefeliciahacker said:

dont bother the placment is fine is max gets to 60-70c

Thanks. That's relieving.

14 hours ago, Thefeliciahacker said:

On that note I actually like your approach you seem pretty mechanically minded and thats good you will not have an issue keeping you fav up and running

Also relieving. But I learned a lot from here. You are one of the members here highlighted in my mind. Thanks for sharing info and making the world a more livable place.

7 hours ago, R_Blue said:

You are one of the members here highlighted in my mind

Well a lot of members here are very knowledgeable and personally I'm commited to sharing my knowledge. Whats the point of not sharing what you know. Someday we will all end underground and what's good if you take your knowlegde with ya.

On 15/07/2021 at 21:46, R_Blue said:

I cut open the faulty fuel pump as requested by RicardoM

Typical chinese parts. It only looks good on the outside. The quality of the metal and especially everything rubber is horrible.

Long term review & update.

 

Last fuel pump mod resulted inconsistent work, or at least made me thought so.

It was cutting fuel supply like the tank was empty.

 

Sometimes stopped working too. I thought it was overheated and damaged.

Like I had mentioned before, another alternate was a HEP02A.

 

I tried another installation with a HEP02A.

I made this bridge and HEP02A was on here. Fuel line was connected to it.

 

Result was same. Inconsistent work. Sometimes pumped, sometimes not. This was fuel pump mod V.2. Very short lived.

 

Here is V.3.

 

I think this is the best place. Pump will stay cool.

Another important detail is; fuel pumps' suction capacity is very limited. You better keep it close to the fuel tank.

 

Success? NO!

Inconsistent work again.

But this time I detected a pattern. Fuel supply stops when tank level reaches the same level.

I didn't know there was a rubber hose inside of the fuel tank.

After 30 years of fuel contact made the middle rubber part decay. I replaced it and now everything works perfect. 

 

I want to add some personal observations and notes for the future mod attempts by fellow Škodians.

 

Both fuel pumps I've used here are sometimes referred as "low pressure universal fuel pump". That means car enthusiasts around  the world found them useful for general use.

 

First one is from Bedford Rascal: With OEM code 15100-85501.

Advantages:

- Noise and vibration level is average.

- It has its own vibration stabilizers.

- Suction ability is better than HEP02A but I didn't measure exact height.

Disadvantages:

- It has to be placed straight up. Its not so ordinary shape could give you some trouble when installing in custom projects.

- Fuel input and output parts are made from plastic. You have to be very very careful with your assembly. Input and output fuel hoses must NOT put any mechanical stress on the pump.

Check 15:10

 

 

It has some kind of contact breaker mechanism inside:

I've also saw one in a Japanese source with electronic circuit inside.

 

Second pump is a HEP02A

Advantages:

- Very sturdy. All metal body.

- Easy to mount. Orientation doesn't matter.

- You can use it for diesel projects. Originally it's a diesel pump.

- Inline free flow compatible. (Not tested myself. I read it from some other place) They use it in large excavators as priming pump for the main pump. If you are familiar with old diesel machinery you know its purpose.

 

Disadvantages:

- It's an excavator fuel pump! Very loud. I can hear it from back of the car even the engine is running. It's makes you feel like you are driving a Citroën 2CV Sahara.

At least, when it gets warm, it gets quiet and bearable.

- You have to take vibration stabilizers into account and design the mounting accordingly or you will feel it working on your bottom.

- Suction capacity is low. I measured 40cm height maximum.

 

I don't know which one is more durable in everyday use. I used my HEP02A last winter as a starting helper in cold winter days. It worked every time even in sub -15ºC conditions.

Edited 25 May, 20224 yr by R_Blue

Well as long as you did not run out of fuel every pump is fine I really liked the second pump the black one. 

I think without the perished hose it would be perfect 

5 hours ago, Thefeliciahacker said:

I think without the perished hose it would be perfect

I was like this >  When I discovered the root cause.

 

I hope this topic serves well for anyone who needs this kind of modification. I couldn't find detailed info about these two particular fuel pump models. So I had to try them myself.

 

If anyone digs this in the future and has some questions in their mind, just ask. If I'm still alive, even if I don't have this car or any car at all. I will still try to answer.

Edited 30 May, 20224 yr by R_Blue

Before buying an "universal" fuel pump, you have to check the specifications: max. fuel flow and output pressure.

For carburetor Felicia, too high output pressure will overcome the float needle valve and flood the engine.

16 minutes ago, RicardoM said:

Before buying an "universal" fuel pump, you have to check the specifications: max. fuel flow and output pressure.

For carburetor Felicia, too high output pressure will overcome the float needle valve and flood the engine.

Exactly.

15100-85501 and HEP02A output pressure below 1BAR. Before buying, I made sure that, they won't overflow the carb.

Pressure info is easy to find but other details like noise & vibration level are harder to find.