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Old 26th February 2010, 20:12   #31
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Default An update on the problem....

Hello everyone
I am sorry for the late update but I wanted to post a comprehensive report and thats why it took time.

After the engine overhauling was done, the gypsy was test driven for about 200 kms where the hesitation problem was again found. But the problem was lesser than before and the character was different. Earlier it was the engine sputtering and dying off and restarting after standing for sometime. This time around the character was something like the engine sputtering sporadically like it was not getting fuel supply or electricity supply intermittently and then again picking up when whatever was not reaching reached the engine.

On discussing the above with the mechanic, he initially identified either the distributor (delco in his words) Name:  distributor.jpg
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Size:  2.0 KB or the ignition coil assembly Name:  ignition coil.jpg
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Size:  12.4 KB to be the source of the problem and probably the ignition coil getting heated up and not supplying electricity properly. He initially tied a rag around the ignition coil and asked me to wet it with water (aka radiator for the coil) and see what happens when the problem recurred the next time.

I drove another 100kms and had to stop the gypsy a couple of times with the same problem. I did ike i was told... wet the rag over the coil and tried restarting. Sometimes the vehicle restarted with this maneoveur , sometimes it did not ---- conclusion : I was not sure if the problem was with the ignition coil . My solution : change the ignition coil and repeat the test drive.

i did another 100kms with the new ignition coil in place. THe problem recurred.

Everything was again checked at the workshop and this time the problem identified as "sticking needle valve" in the carburetor.
Carb Gypsy problem : ocassional Drop in engine power during highway driving-needle-valve.jpg
An equally ingenious sollution was also demonstrated by the mechanic. The solution was to slowy tap over the housing which stored the needle valve and manually drop it and get the carburetor back on track.

I was skeptical about this but had to believe his words when on doing the above manoeveur, the vehicle started on one crank.

Before changing anything else I told him that I would like to take a test drive of another 200 kms and then decide.

Over the next 200 kms, the problem recurred and was solved by tapping on the housing of the needle valve. This convinced me to change the needle valve assembly. so it was changed. (I was very lucky to get the SGP part costing 800/- right here in Nagpur) .

Carb Gypsy problem : ocassional Drop in engine power during highway driving-needle-valve-assy.jpg

The timing of the engine was reset and the mechanic said : Your problems are over balak !!! Enjoy your ride in peace.

I drove another 100kms - the problem did not resurface. But a friend of mine who regualarly drives my gypsy from day 1 said that the vehicle still didn't feel as smooth as before although the problem of hesitation was definitely gone.
I attributed this non smooth ride thing to the front prop shaft.

In the next 200kms the problem recurred. Since everything else was now rued out, the problem had to be in the fuel lines.
so this time around I tinkered with the fuel lines and removed the fuel filter and directly attached the main fuel tube (red) to the fuel pump inlet. With this the vehicle started and ran flawlessly for another 150 kms.

And then one fine day in the midst of a marriage party, the gypsy failed to start. It was towed back to the garage where the diagnosis was : the mechanical fuel pump was shot and had to be changed.
Carb Gypsy problem : ocassional Drop in engine power during highway driving-fuel-pump.jpg

A new fuel pump was immediately not available in nagpur and was costing a bomb (Rs 2400 as compared to Rs500 for gypsy 1L) and as the vehicle had to be started and not let standing it was decided that an electronic fuel pump be installed post haste (costing Rs 700).

While fitting the electronic pump my mech told that even this was not a good solution as electronic fuel pumps are known to fail and that we would have to think of something to make the fuel delivery system more reliable and fail safe.

a few things that he suggested were:
[1] having both the mechanical and the electronic pump at the same time and switching on the electronic pump when needed

[2] having 2 electronic fuel pumps with independent switches.

As of now, the electronic pump is placed somewhere near the tank -it is pumping fuel into the main fuel line (the red tube) which is entering the inlet of the now defunct mechanical pump and then the petrol is exiting the mechanical pump and entering the carb.

The vehicle is running like dream now. Whenever I put on the ignition switch, the fuel pump makes a strange noise ike rut-tut-tut-tut --- the vehicle starts in 1 crank. Fuel efficiency has dropped after conversion of mechanical pump to electronic pump. Earlier I used to get an average of 15kmpl while I am getting 9-10kmpl now. There is a rich smell of petrol whenever I switch off the engine


My question to everyone is :

What is your impression after going thorough my experience ?
How can I increase the efficiency of the vehicle more ?
Is the installation of the electronic proper ?
Is it a good idea to have both the mechanical pump and the electronic pump or 2 electronic pumps ?
Why has my fuel efficiency dropped and how can I go back to my previous fuel efficiency levels ?
Why is my pump making the strange sound everytime I switch it on ?

Anything else anyone would like to add from their experience.


regards,
Dr. Abheek Ghosh
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Old 26th February 2010, 20:17   #32
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wow thats a lot of info man..will be of great use i am sure
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Old 27th February 2010, 00:37   #33
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Originally Posted by KSM-Vtec View Post
wow thats a lot of info man..will be of great use i am sure
Thanks Kaushik.
I will be glad if anyone can help analyse the entire situation that happened to me and possible measures I could have taken to eliminate the trial and error process that led me to change a lot of parts ( which I am not sure if i really had to -- for eg the ignition coil ) .

Will also appreciate if anyone can help me out with the answers to my question at the end of the narration.

regards,
Abheek
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Old 27th February 2010, 11:00   #34
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Quote:
Originally Posted by abheekg View Post
Hello everyone


My question to everyone is :

What is your impression after going thorough my experience ?
How can I increase the efficiency of the vehicle more ?
Is the installation of the electronic proper ?
Is it a good idea to have both the mechanical pump and the electronic pump or 2 electronic pumps ?
Why has my fuel efficiency dropped and how can I go back to my previous fuel efficiency levels ?
Why is my pump making the strange sound everytime I switch it on ?

Anything else anyone would like to add from their experience.


regards,
Dr. Abheek Ghosh
Hi Abheek,

Man you have really done some exercise on your gypsy I am no expert but i have been through a similar kind of situation so here's my 2 cents

How can I increase the efficiency of the vehicle more ?
- Since your engine has just been rebuilt, give it sometime i am sure the efficiency and average problem should be sorted out. If your re-built engine was giving you 15 kmpl that would have been my concern may be it was running very lean. Since you have mentioned that you smell petrol smell now i am assuming its running a little rich right now .. may be a little tweaking in the carb can get you to 12- 13 kmpl .

Is the installation of the electronic proper ?
Is it a good idea to have both the mechanical pump and the electronic pump or 2 electronic pumps ?

- I have been running only an electronic fuel pump and no mechanical pump for the last 3 years, no issues what so ever. However to be on a safer side you can have the following setup : Electronic fuel pump > Mechanical fuel pump > Carb, with a switch for electronic fuel pump whenever you feel the lag you can switch it on. On a personal note i have observed mechanical fuel pumps going kaput on long distances , rallying and off-roading.

Why has my fuel efficiency dropped and how can I go back to my previous fuel efficiency levels ?
- As mentioned earlier, seems engine is running a little rich ... get it more towards the leaner side, that should take care.

Why is my pump making the strange sound everytime I switch it on ?
- Its a very common mistake our mechanics make, Make sure line out from petrol tank and electronic fuel pump are atthe same level with not much elevation, also the closer it is to the tank, it will be easier to pump the petrol. That sound is nothing but when the pump runs without the petrol that what that sound is all about, once it starts to get the petrol that sound will go away.. correct me if im wrong. If you get that sound continuously then its a faulty fuel pump.

Hope this helps.

Regards,

Fahad

Last edited by Jeepfreak : 27th February 2010 at 11:04.
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Old 27th February 2010, 12:06   #35
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Abheek,

Arka had suggested in his initial response to check for fuel delivery system (it was very comprehensive check involving, petrol delivery pipe, pump, carburator, etc..). Now that engine and carburator is clean after overhaul and even distributor done you wouldn't have any problems in future.

Coming to fuel line , fuel pump and fuel rich smell, I would suggest change the fuel line completely and change the fuel pump to gypsy genuine part. Fuel clog is still seems to be problem in the line. when the pressure builds up in fuel line , it can ooze out from ends.
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Old 27th February 2010, 18:25   #36
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I will second what Dwarak suggested, chuck out all the old parts and go with OE parts and you will be just fine, and these things once set right, rarely goes kaput.
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Old 27th February 2010, 23:15   #37
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And make sure you add back a new MGP (PUROLATOR) fuel filter. That was prolly the root cause of your problem in the first place.
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Old 28th February 2010, 00:51   #38
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I doubt the addition of fuel pumps cured the patient. If this was your problem then the problem would be a design problem and there would be a great multiple of reports from people who had the same problem along with an inquiry from the Army, the largest user of these vehicles. No such problem has been reported in great numbers. I think you are going to experience this problem again.
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Old 28th February 2010, 01:29   #39
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Quote:
Originally Posted by satan View Post
And make sure you add back a new MGP (PUROLATOR) fuel filter. That was prolly the root cause of your problem in the first place.
The manual has to say this about the fuel filter :

Attachment 296624

But why do you say that the fuel filter was the root cause of my my problem ?

regards,
Dr. Abheek Ghosh
Attached Thumbnails
Carb Gypsy problem : ocassional Drop in engine power during highway driving-fuel-filter.jpg  

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Old 28th February 2010, 02:24   #40
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Quote:
Originally Posted by DirtyDan View Post
I doubt the addition of fuel pumps cured the patient. If this was your problem then the problem would be a design problem and there would be a great multiple of reports from people who had the same problem along with an inquiry from the Army, the largest user of these vehicles. No such problem has been reported in great numbers. I think you are going to experience this problem again.
EVen I doubt the same and this doubt made me search the online resources all over again.

I have found that this problem has indeed been reported by a lot of people in the US where the gypsy has been sold by the name of suzuki samurai and it came with the same 1.3L carburetor engine as my vehicle till 1989.

I have come across a technical service bulletin from suzuki which reads as follows :

Carbureted Samurais are known to exhibit a “hesitation,” “bogging down,” or “flat spot” during acceleration. The problem may be exhibited in any or all gears. In my Samurai, the problem appeared as a distinct lack of power at some points in the acceleration curve. If you’ve got a carbureted Samurai (using the factory Hitachi carburetor) this fix is definitely worth a try. It improved the Samurai’s performance significantly.

And the fix according to the service bulletin is as follows :

Hesitation.doc

The fix involves fixing a vent tube nozzle to the vent opening of the secondary throttle plate of the factory fitted hitachi carburetor.


The factory fitted hitachi carb on 1.3L samurais in US market

Name:  hit carb.jpg
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The service buletin mentions that the stock carburetor has a flat-spot around 3000rpm. This is caused by the drop in vacuum in the manifold through the vent hole in the secondary throttle plate, causing the secondary to not open properly.

diagram of the hitachi carb showing the vent opening in green

Name:  samurai_carb_diagram.GIF
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The simple addition of an inexpensive carburetor vent tube will cure this problem.

Aftermarket vent tube
Name:  venttube.JPG
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This OEM part is available from several of the Suzuki aftermarket companies in the US.

This however does not seem to be the solution in my case. As we in India have the Aisin carburettor factory fitted on our 1.3L gypsies. And these Aisin carburetors already have the vent tube nozzle factory fitted to the vent opening.

Aisin carburetor on Indian 1.3L carb gypsies from the manual showing the vent tube nozzle factory fitted

Carb Gypsy problem : ocassional Drop in engine power during highway driving-carb-top.jpg
Carb Gypsy problem : ocassional Drop in engine power during highway driving-carb-vent-tube-nozzle.jpg

Does the carburetor on your 1.3L carb gypsy look like this (This is different from the 1.3L esteem carburetor
Carb Gypsy problem : ocassional Drop in engine power during highway driving-carb2.jpg


I hope the above rambling makes any sense

So if this is not the solution, then what are we dealing with here guys ?

Awaiting your inputs.
In the meanwhile the Explorer-I goes for another 400km test drive tomorrow.

regards,
Dr. A Ghosh

Sorry about the back to back posts but I saw DD's post only after I replied to satan's post

Last edited by abheekg : 28th February 2010 at 02:40.
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Old 28th February 2010, 10:14   #41
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Hi,
Flat spot is not the problem you are facing.

Can very well be the mechanical fuel pump. Remember the first lot of Maruti vans with Ucal fuel pumps. This was an intermittent problem showing up ONLY when the pump was hot. Something to do with valves sticking open, rather than vapour lock. Difficult to diagnose. Only way to be sure, I feel, would be to fabricate a T, and connect a pressure gauge semi-permanently, and drive. When it stops, check pressure, and if defective, use the electronic pump.

Installation, though only for diagnostic purposes, has to be of good quality. You don't want pipes coming off, fuel spraying all over, and starting a fire.

The electronic pump works best under flooded inlet conditions. Pump making constant noise means pump is starving. If pipelines/ filters are choked, that might be your problem.

If outlet pressure is sufficient on electronic pump alone, don't run the fuel through both pumps.

Regards
Sutripta
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Old 28th February 2010, 11:04   #42
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Quote:
Originally Posted by Sutripta View Post
Hi,

The electronic pump works best under flooded inlet conditions. Pump making constant noise means pump is starving. If pipelines/ filters are choked, that might be your problem.

If outlet pressure is sufficient on electronic pump alone, don't run the fuel through both pumps.

Regards
Sutripta
I am sorry I could not understand this part. How to ensure I have a flooded inlet ? How do I ensure that the pump is not starving ? Do you recommend a complete changing of the fuel lines ?
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Old 28th February 2010, 14:58   #43
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It would help me greatly if someone can tell me how to mount my current fuel pump properly for optimal performance.
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Old 28th February 2010, 20:03   #44
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Hi,
Without getting into details of whys and whereofs, the piping should be fuel tank - filter - electronic pump - carburettor. With the filter and pump placed close to the tank (ie rear of vehicle) at around the same level as tank. Below fuel level gives better performance. Above fuel level gives safety:- a leak will not drain out the tank by gravity. Your call.

If your tank and fuel line have not rusted, internally or externally, there is no real need to change these. Just clean these out.

Regards
Sutripta
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Old 28th February 2010, 21:15   #45
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Quote:
Originally Posted by Sutripta View Post
Hi,
Without getting into details of whys and whereofs, the piping should be fuel tank - filter - electronic pump - carburettor. With the filter and pump placed close to the tank (ie rear of vehicle) at around the same level as tank. Below fuel level gives better performance. Above fuel level gives safety:- a leak will not drain out the tank by gravity. Your call.

If your tank and fuel line have not rusted, internally or externally, there is no real need to change these. Just clean these out.

Regards
Sutripta
at present my setup is tank - electronic pump - filter - carb . will discuss with my mech and sort these minor issues out asap.
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