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Old 12th April 2010, 12:06   #1
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CJ3B Fuel Delivery and over heating.

Need help from the Jeep Gurus.

My Cj3b 2.2 hurricane has done 1250 kms till date.
It had some initial teething issues with the gearbox, resolved to my satisfaction at Classic motors Noida.

The jeep was run in carefully, and then tested on various terrain along with NIOC. The jeep performed very well.

However come summers the jeep has been over heating and stalling almost on a regular basis. To the point where I would be in the middle of a rather dicey climb and the engine would quit on me. "N" number of cranking later,.. would have to use the starter motor to reverse out safely.

So there are two major problems.
1) Engine over-heating
2) Fuel delivery system faluire.

To addres probelm # 1 I am going to replace my radiator with a genuine 4 core copper radiator, as the existing one has been diagnosed with having a weak core, and probably is not doing its job well enough (the temp is always around 80-100 deg c). I am hopefull that this would take care of the over heating for the most part.

However there is no solution in sight for the fuel delivery system.
Thats as the original mechanical fuel pump gives up,..and the electrical pump is only good for a certain time after which it too packs up.

I have spoken with experts who say that since the 3B carburator does not have a return line, thus running it on electrical alone is not an option as it will not be able to regulate fuel flow and result in an over flooded carburator.

I have sent jeep back to classic to relocate the electric fuel pump further away form the engine bay (They had wrongly placed it right next to the header on the left frot fender).

But what I do about the mechanical fuel pump,.......no answer in sight
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Old 12th April 2010, 12:11   #2
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where have you located the electric fuel pump now? please go through Jaggus thread on his CJ3B where DB has given a comprehensive write up on installation of electric fuel pump in CJ3Bs

Spike
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Old 12th April 2010, 12:28   #3
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Hot Hurricane.

Hi Naveen,

Please post a pic of your Engine Bay.

Especially Radiator/Shield and Fan.

Check where you Ignition Coil is mounted, if it is on the engine block remove and fit it on the fire wall (inside the engine bay).

Regards,

Arka

PS - You can wrap a cotton socks filled with cotton waste on the Mechanical Fuel Pump and wet it before starting the engine, and keep it wet from time to time, I used to do this.
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Old 12th April 2010, 18:26   #4
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Wet cloth is the best know solution, otherwise check out DB's post here This has all the details you require, thanks to Mr DB

Get a good quality fuel pump from UCAL and see how it fairs.
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Old 12th April 2010, 20:36   #5
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hi naveen , saw your jeep at classic. i had a similiar trouble, it was sorted out by tuning the carb, changing to a new mechanical fuel pump and getting the timing issue sorted out , all done simultaneously a few months ago , since then no issue of over heating at all have troubled me.
saw jasvinder,s jeep too there.
how is your jeep doing otherwise?
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Old 19th April 2010, 03:43   #6
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A new copper core radiator has been put in, the electronic fuel pump has been repositioned away from the engine block, closer to the fuel tank, runningo the primary mechanical fuel pump though. Vehicle ran for 15 kms on mech. Pump alone, it then stalled and the had to put on the inline electrical pump and it ran ok for another 20 km before it packed off as well. The engine is running very hot. The temp needle was hovering around the 90-100 degree mark thru out. The moment the egine stalled whoosh the water bubbled out of the radiator. After cooling the mech pump down with a wet cloth and water, it started back up with the electroic and mech pump on (did not want take any further chances in a 4 lane highway) and safelt reached my destination.

There are two distictive problems a) why does the egine run so hot even after a new radiator (some incl @docfreak) have been pointing this towards timming and carburator tuning issues. Why should I still have tunning issues when I just paid 7.8 K at Mahindra authorised service center I don't know.

I am waiting on some direct expert intervention,..let's hope for the best.

Last resort,..is it possible to completly replace this carb and mechanical fuel pump assemby with a newer model carb with electronic (primary) fuel pump system. This would be the best compromise, as there is no better engine than this (2.2 hurricane) when it comes to SWB jeeps. Can this radical thought process be successfully put to practice. Has anyone done that !!
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Old 19th April 2010, 06:02   #7
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My 2 Cents on avoiding over flooding of carb, When using electronic fuel pump.

Connect the outlet of electronic pump to the inlet of the Mechanical pump (Which has excess fuel return feature). Connect the outlet of mechanical pump directly to the carb. This will regulate the excess fuel from entering the carb.
So even though your mechanical pump doesn't pump any fuel, It can at least be used to regulate the fuel.

I have done this in my gypsy, This even solves the noise issue that electronic pump's make (When in Low Rpm/Idling).

Hope this will be helpfull.

Krishna Thanthri

Last edited by krishnathanthri : 19th April 2010 at 06:08.
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Old 19th April 2010, 10:09   #8
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Dear Torque Active - please configure your vehicle's fuel system as I have detailed in Jaggu's CJ3B thread, then, your vehicle will work properly. It is also necessary to ensure that all engine tuning parameters are as per specification.

If in doubt, please ask.

Best regards,

Behram Dhabhar
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Old 19th April 2010, 11:29   #9
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Which is the best bet (make/vehicle model) for electronic fuel pump for CJ3B? Mine conked out after the kachra fiasco and now running only with mech pump
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Old 19th April 2010, 12:19   #10
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Mr.Behram Dhabhar,
Many thanks for your comments posted above.
I have read your Phase-I write up on the adaptation of the electronic fuel pump over and over again to understand it in totality.

My jeep does not have a return fuel line as suggeted by you,.. and it is certainly beyond my scope to explain or give directions for the fitment to the Mahindra A.S.S Classic Motors. I am still a Newbie when it comes to the CJ3B.

I have asked Jasvinder (diesel_maniac) to read the passage and understand your points before taking it either back to Classic Motors or a more competant service center, probably somewhere where they are a little more passionate about such jeeps.

However with regards to engine over-heating and the brand new radiator boiling over, I am still at a loss of words.
Can a over-flow reservoir be fitted in the CJ3B ?

The timing seems spot on, as the vehicle pulls cleanly in every gear and does not sputter or mis fire. In fact my last OTR it went thru every single obstacle without a whimper. The only time I had felt loss of power was climbing a winding inclinded road on 2nd gear high (2wd mode), I had to shift to 1 high (2wd) to climb, which felt rather strange. This was when the weather was still pleasent and there was no overheating issue expireinced.

Why would the jeep constantly now show 90-100 deg C, (even after a new radiator is installed) when the vehicle is seemingly in a good state of tune.

The vehicle was sent for routine service, and engine tune-up to Classic Motors after completion of 1000 kms. All of the orginal problems remain,...any more ideas, as Classic Motors have given up saying this is the best they can do.

Last edited by Torque-ative : 19th April 2010 at 12:27. Reason: added info.
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Old 19th April 2010, 12:24   #11
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How is the engine tolerance set at overhaul? If its tight give it some more time to free up. Also what grade engine oil are you using? For delhi heat, i suggest you go to 50w oil for summers.
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Old 19th April 2010, 14:23   #12
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@Jaggu, this is a resleaved engine. Has been run in for 500 kms on tarmac in 2 wd mode.

Taken off-road after this and used on and off road for another 500 kms without any over-heating issues till summers came in.

If the tolerances were set low (Meaning running too tight), would'nt this issue have crept in earlier on into the running in process.

I know it is scorching hot outside these days, and it certainly has a part to play in this bizzare equation. Still need to find that particular variable causing the bulk of the porblems.

I am going to get some jeepers / and their mechs to look at the timing and carb tuning again. I dont want to slam Classic motors any more than I already have,...but I paid them Rs.7800/- for the same thing (Engine tune-up and timing/valve adjustment, fix the over heating problem along with complete service and replacement of old parts etc.)

Last edited by Torque-ative : 19th April 2010 at 14:31.
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Old 19th April 2010, 14:47   #13
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Dear Torque Active - engine tuning parameters must be set to specification and confirmed by instrumentation measurement. Vehicle "pulling cleanly in every gear" means nothing. The valve clearance for inlet valve is 0.4 mm and for exhaust valve is 0.45 mm, both in cold condition (engine not run for minimum 6 hrs, maximum 30 hrs).The static ignition timing is 5 degrees BTDC. These are the 3 basic parameters, which you must confirm as being in order. Please check for main jet size. It must be 140. Please check for venturi size. It must be 25. Please check radiator cap for proper functioning of pressure and vacuum valves. Replace if required. Please refer to Tejas's CL340 classic threads for details.

If all as above is in order, engine will work properly.

Best regards,

Behram Dhabhar
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Old 19th April 2010, 14:54   #14
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DB/Spike: What's the correct spec of oil for CJ3B?

Also as per spec put by Spike intake is .45mm and exhaust .40mm, so which one is the right spec?
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Old 20th April 2010, 08:52   #15
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Dear Jaggu - the workshop manual specifies SAE30 engine oil for temperature above 0 degrees C. However, getting mono grade oil will be difficult now, so SAE20W40 should suffice. Intake and exhaust valve clearances with cold engine are correct as mentioned.

Best regards,

Behram Dhabhar
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