Fuel Pump Replacement

[LancerL]

Dear Members, as I feel my fuel pump has gone bad hence I need to crank few turns of engine to start after parking it few hours.

My engine is Mitsubishi Orient 4G12 and has mechanical pump.

Kindly advice me on following areas.

1. Possibility of repairing the current one.
   
2. Fixing a new mechanical pump or electric one which one is best.
   
3. Does electrical pump comes with a stop valve?
   
4. Rough cost for the project.
   

Thanks in advance.

[Sylvi]

LancerL,

It looks like you have have sorted out your problem to some extend with your careful examination of the carburetor that is very good.

Actually what that hole really does is to supply fuel to “secondary manual” pump based on Carburetor body to spray out fuel in to intake manifold for quick pickup when sudden paddling the accelerator.

According to the design of this, the secondary fuel line coming from fuel pump and return line going to tank both are inter connecting through the body of this. (I don’t know why the hell this Japanese has put this on such a way)

What happen is due to corrosion or some odd reason, this body of the “secondary manual” pump based on Carburetor has wear off and the pump is leaking fuel on to the line back to tank.(Please explain, as for your observation the carburetor “secondary manual” pump body is wasted, is it at the bottom of the pump body would-be, only there can be a leakage of gasoline this chambers can get empty.) So once the engine stops it sucks out entire thing including fuel on floating chamber.( Again the return of gasoline hole is at what point height of the carburetor)

Initially what I’ve done was to apply some glue and closed that hole on the floating chamber to stop leaking fuel through the pump.(I have a feeling this hole is not the cause to suck out gasoline of your carburetor)

I cleaned everything with kerosene and fixed properly.

I was half away successful, engine started without any issues and I’ve tuned it well.

But due to unavailability of the secondary pump on Carb, I cannot quickly pickup, ( I agree to this point because the engine get starved not enough fuel for the required power for quick acceleration) engine gets stall when I push the pedal fast. Other than that everything is alright. It just starts in one turn after keep stop for even two or more days.

Above is my opinion. Please do not misunderstand because I have not examined this faulty carburetor my self like to examine same please inform your car is situated where I will come and like to examine same. Because I too like to study the system.

Sylvi Wijesinghe.

[LancerL]

Sounds like an excellent piece of detective work there

Thanks Don..

[LancerL]

Happy to hear that you isolated the issue. And most importantly, I'm glad that you didn't go for the electric pump solution as the workaround.

Good luck on this LancerL, I'd love to see some photos of this!

Thanks Davy, Sure will take some Pics and share with you'll

[LancerL]

LancerL,

It looks like you have have sorted out your problem to some extend with your careful examination of the carburetor that is very good.

Actually what that hole really does is to supply fuel to “secondary manual” pump based on Carburetor body to spray out fuel in to intake manifold for quick pickup when sudden paddling the accelerator.

According to the design of this, the secondary fuel line coming from fuel pump and return line going to tank both are inter connecting through the body of this. (I don’t know why the hell this Japanese has put this on such a way)

What happen is due to corrosion or some odd reason, this body of the “secondary manual” pump based on Carburetor has wear off and the pump is leaking fuel on to the line back to tank.(Please explain, as for your observation the carburetor “secondary manual” pump body is wasted, is it at the bottom of the pump body would-be, only there can be a leakage of gasoline this chambers can get empty.) So once the engine stops it sucks out entire thing including fuel on floating chamber.( Again the return of gasoline hole is at what point height of the carburetor)

Initially what I’ve done was to apply some glue and closed that hole on the floating chamber to stop leaking fuel through the pump.(I have a feeling this hole is not the cause to suck out gasoline of your carburetor)

I cleaned everything with kerosene and fixed properly.

I was half away successful, engine started without any issues and I’ve tuned it well.

But due to unavailability of the secondary pump on Carb, I cannot quickly pickup, ( I agree to this point because the engine get starved not enough fuel for the required power for quick acceleration) engine gets stall when I push the pedal fast. Other than that everything is alright. It just starts in one turn after keep stop for even two or more days.

Above is my opinion. Please do not misunderstand because I have not examined this faulty carburetor my self like to examine same please inform your car is situated where I will come and like to examine same. Because I too like to study the system.

Sylvi Wijesinghe.

Dear Sylvi,

This “secondary manual” pump has fixed on to the body near bottom of the chamber.

Will drop you a P/M regarding your request.

Thanks,

LancerL

[Sylvi]

LancerL,

Please do Email me. [email protected] or [email protected]

Sylvi Wijesinghe.

[LancerL]

Dear Members,

As I posted on my previous post, I removed the Carb again and cleaned all Glue I applied last time, it was not easy to remove those hence it fixed hardly to the body.

After getting troubled nearly one hour I was able to clear all the glue out of hole without damaging to Carb body.

Then I fixed pump to Carb body and connected both lines together with a small tube to avoid leaking fuel to outside (seen on picture).

Also I connected that secondary line coming from main fuel pump directly to the return line to tank with a metal tube (Earlier it was through pump body which caused leaking).

Fixed everything together and mount Carb to intake manifold.

Start engine and let it to run few minutes and examined for leakages.

Given couple of quick throttles and observed that the pump is working well and injecting extra fuel to intake on demand.

It was around 6.30 and some of late taken pictures are in low light and my apology for that.

Fixed everything back including air filter and let engine to run nearly 5min and start tuning it.

This time I got better air/fuel mixer and it tuned well and start dropping water from silencer!!!!!

Driven couple of trail runs and acceleration and pickup was excellent and didn’t experience that engine stall issue on quick acceleration.

It was pleasure to me that I could this entire job my self without going to a single garage.

Of cause the time taken from the day beginning to the completion date was a long period with all the trails and errors, but it has given me a very good experience and self satisfaction where you cannot value on money.

I tried many times to upload image to forum and coulden't do it, please find below URL for project pictures.

http://imageshack.us/g/1/9876665/

Thanks for all the support guidance given by everyone to get this project success!!!!!!

[LancerL]

Dear Members,

As I posted on my previous post, I removed the Carb again and cleaned all Glue I applied last time, it was not easy to remove those hence it fixed hardly to the body.

After getting troubled nearly one hour I was able to clear all the glue out of hole without damaging to Carb body.

Then I fixed pump to Carb body and connected both lines together with a small tube to avoid leaking fuel to outside (seen on picture).

Also I connected that secondary line coming from main fuel pump directly to the return line to tank with a metal tube (Earlier it was through pump body which caused leaking).

Fixed everything together and mount Carb to intake manifold.

Start engine and let it to run few minutes and examined for leakages.

Given couple of quick throttles and observed that the pump is working well and injecting extra fuel to intake on demand.

It was around 6.30 and some of late taken pictures are in low light and my apology for that.

Fixed everything back including air filter and let engine to run nearly 5min and start tuning it.

This time I got better air/fuel mixer and it tuned well and start dropping water from silencer!!!!!

Driven couple of trail runs and acceleration and pickup was excellent and didn’t experience that engine stall issue on quick acceleration.

It was pleasure to me that I could this entire job my self without going to a single garage.

Of cause the time taken from the day beginning to the completion date was a long period with all the trails and errors, but it has given me a very good experience and self satisfaction where you cannot value on money.

I tried many times to upload image to forum and coulden't do it, please find below URL for project pictures.

http://imageshack.us/g/1/9876665/

Thanks for all the support guidance given by everyone to get this project success!!!!!!

If anyone can guide me how to upload pictures to forum or suggest me a better file sharing site I'm ready to share…

[carboy2011]

From experience I feel that if the carb is really messed up then you might need to get a recon one as i had the same issue and no one could sort it hence had to buy another one,most mechanics promise the sun and moon and after spending a few 1000's of Rs the problem is was still there

Right, so your problem is not in the fuel pump, it's in your carburetor. And as The Don said, you're trying to treat the symptoms rather than the actual issue here. My advice would be for you to first get a good mechanic to overhaul your carburetor. There should be something very trivial wrong with your carburetor and a competent mechanic should be able to figure it out.

The workshop manual below will have everything you need to know about your specific type of carburetor (there were 4 types). Print the manual and take it with you to the workshop and carefully identify what's wrong. I have helped diagnose many carburetor issues this way.

4G Series Fuel System - Carburetor - Workshop Manual

If you're thinking of converting the fuel pump to electric because of this issue, you might want to think again.

Hope this helps. Good luck!

[The Don]

From experience I feel that if the carb is really messed up then you might need to get a recon one as i had the same issue and no one could sort it hence had to buy another one,most mechanics promise the sun and moon and after spending a few 1000's of Rs the problem is was still there

I think Lancer L is doing this as a diy project now and learning as he goes along. He probably knows more about this particular carb now than most mechanics!

[LancerL]

I think Lancer L is doing this as a diy project now and learning as he goes along. He probably knows more about this particular carb now than most mechanics!

Thanks Don..

Edited November 19, 2012 by LancerL