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Old 9th January 2008, 17:01   #1
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Default Zen - Engine Switching off on long drives

Hi All

I have a Carb Zen which has a rare problem. The Engine is switching off during long drives.

This I noticed when I was driving on a highway with a speed of 80-90kms consistently. First 30-35kms there was no problem & suddenly the engine switched off. I kept the accelarator pressed to see whether it will start again & after 10-15secs engine started with jerks.

Then again it stopped after 10kms & the frequency kept increasing. After some time it started repeating every 3-4kms.

It was very annoying & was very dangerous because couple of times the car stopped in the middle of the road(this was during climb) & took 10-15 secs to start and move again.

Surprisingly I dont find this issue when driving in stop-go or city traffic.

I got the car checked for spark plugs which they told was Ok, Alternator was fine. fuel flow is OK.
garage guy told that they will check the fuel pump for any problems.


I dont know what is the actual problem.

Guys suggest on how to solve this issue.
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Old 10th January 2008, 11:35   #2
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Some questions.
What model the car is ? How many Kms It has run ?
Have you done Carburettor overhauling(when was it done last) ?
I think here clogged carburettor is the culprit.
Also check out for faulty spark plug wires, n Airfilter.
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Old 10th January 2008, 12:21   #3
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Hi Tiger,
Sounds like
1. Clogged or dirty fuel filter
2. Improperly functioning fuel pump

also, like sushrutha said, checkout the plug wires & air filter

depending on how many KM's your car has clocked, go with replacing the fuel filter

ALSO, does a carb zen have a PVC valve?

Keep us posted
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Old 10th January 2008, 16:29   #4
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Thanks for the suggestions,

It is a 97 model & run 75000 kms.
I got the carburetor cleaned with 3M choke & carb cleaner, & airfilter was cleaned some 500kms back.

I will get the fuel filter, fuel pump, plug wires checked this saturday.
I dont know about PVC valve, will check.
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Old 10th January 2008, 17:13   #5
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Check your vaccum hose, it could be cracked, that could be the culprit. Replace all the hoses that lead in & out of the carb.
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Old 10th January 2008, 18:05   #6
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check electricals mainly the coils..i have observed when they get hot after long run the resistance increases and this happens ..the current stops flowing.
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Old 10th January 2008, 18:35   #7
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Default wire harness chafing, short circuiting.

Quote:
Originally Posted by Tiger View Post
Hi All

I have a Carb Zen which has a rare problem. The Engine is switching off during long drives.
Carefully inspect all wires and especially wire harnesses under the bonnet for chafing. Movement of wires and their harnesses due to road vibration often leads to insulation quickly wearing off wires (chafing) and then they short circuit. This sounds more like an electrical problem to me than a fuel or vacuum hose problem. Check your battery leads, too.
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Old 10th January 2008, 21:08   #8
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Checked temperature? I know of one case where the engine used to switch off coz the temperature gauge was not working, resulting in the cooling system not functioning properly.
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Old 10th January 2008, 21:29   #9
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QUOTE]Check your vaccum hose, it could be cracked, that could be the culprit. Replace all the hoses that lead in & out of the carb.[[/quote]

The crack in pipes can cause the problem...
A kind of same problem occured to our car(800 carb) once. It used to stop with a jerk as if there is no petrol. The problem was with petrol inflow pipe and some other pipe cracked(radiator or oil) not sure which one, they created this problem. They informed us that the other liquid is getting mixed up with petrol and causing the problem. They changed the both pipes and that problem did not repeate again. May this info help you

Let us know what caused the problem.

Last edited by ravi_28_8 : 10th January 2008 at 21:31.
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Old 10th January 2008, 21:57   #10
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After u check all that is mentioned above and your problem does not get sorted also check the keyhole where u insert the key to start the car.
Had the same switching off problem in my 800 and took me a month to diagonise it to the keyhole.It was heating up and stopping the flow of current.
Initially started with misfires and then reached to a stage of total shutdown like u.
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Old 11th January 2008, 10:28   #11
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Exactly samething had happend to My sister's M800 a couple of years back. It was happening only after running 50-60 kmts. This issue was getting worst after travelling 20- 30 kmts more.Faulty fuel pump was the culprit. This issue has never resurfaced since i changed the fuel pump.
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