Ask Xulfiqar - An Automotive Encyclopedia

[margallar]

if you are getting spark, then it seems like this is a fuel problem.

there is a valve that opens petrol flow to carburetor, it has two connectors, ek bhi utar jaey toh petrol off. check it now

[ali15144]

if you are getting spark, then it seems like this is a fuel problem.

there is a valve that opens petrol flow to carburetor, it has two connectors, ek bhi utar jaey toh petrol off. check it now

Valve is open...cng kit already bypassed

[ali15144]

if you are getting spark, then it seems like this is a fuel problem.

there is a valve that opens petrol flow to carburetor, it has two connectors, ek bhi utar jaey toh petrol off. check it now

It just started for a moment and then the rpm fell and its off again

[margallar]

hmm, i think that the ignition coil might be dying, first of all check all plug wires. where do you live

[zainiqbal1990]

probably your air intake is blocked with tape

No. Got no blockage.

[zainiqbal1990]

@xulfiqar

Car vibrates when releasing clutch and getting in motion. I asked a mechanic for the solution he said cuts lag tai hai i guess clutch plates par. Is this some sort of jugar?

[DUDE007]

It just started for a moment and then the rpm fell and its off again

Had same issue a while ago. The slow jet or idle jet was the culprit. Also see if the dash pot diaphragm on your carb works by holding the rpm after pumping the gas pedal.

[syncview]

It just started for a moment and then the rpm fell and its off again

Does your car have a central locking system installed?

[Xulfiqar]

@Xulfiqar

Hey friend. Since the first day i bought this car the petrol mileage is a joke. 2 kilometers per liter. Mileage on CNG is pretty good. When i rub my finger inside exhaust tip it's clean. Just dust. But when i drive on petrol and do that my finger turns black. After few days of driving on CNG the inner exhaust tip gets clean again. Just dust then.

overhaul the carburettor and test it correctly. For mileage that bad, it must be smoking like a bad diesel engine or you would see fuel drip from the exhaust. Is the powervalve piston vacuum line connected on carby and the secondary diaphragm working in it?

[DUDE007]

Is the following brake bed in procedure ok?

1) drive to 60kph and brake with moderate pressure to 10kph for 3 to 4 times.
2) drive to 80kph and brake with harder pressure(not enough to trigger ABS) to 10kph for 2 times.
3) let brakes cool to 60 degrees C or below and then park otherwise no complete stops using brakes.

Is it normal to see smoke coming this way? And the burning rubber smell?

Bump @xulfiqar

[Xulfiqar]

yes you will smell the brake roast - that is what we want to do to "burnish" the brakes - you can now use the brakes correctly as they will work nicely for a long time.

[DUDE007]

Is it ok if the bed in process is delayed say a week. i couldn't find any empty roads and this process looks weird to someone looking from the outside.

[Xulfiqar]

its best to do it with fresh pads.

make sure that you actually clean off the brake discs of any greasy fingerprints or oil smears before you bolt the wheel to the car, oiled up brakes are the worst to bed in.

[umarkhan1]

@xulfiqar @syncview
cultus efi 111k kms driven.engine valve stem seals are showing signs of weakness.
symptoms=blue puff at morning start and blue puff when revved a little high after 5-10 minutes of idle.
is it wise to replace the seals now??

[margallar]

talking of valve seals, i think cng messes them up, Zulfiqar bhai, is it lean running that causes this?

i read in datasheets of the special "cng" oils of two brands , that those oils clean deposits off of valves

[ahmed2396]

talking of valve seals, i think cng messes them up, Zulfiqar bhai, is it lean running that causes this?

i read in datasheets of the special "cng" oils of two brands , that those oils clean deposits off of valves

I doubt cng or petrol do any harm to valves, but operating temperature oil changes on time with good oil air filters and pcv valve are key to long life engine. I guess cultus G10 engine has better design then F8B? , have seen some of mehrans having valve job at 180k and some at 50k. Its all about how you maintain your ride.

[Xulfiqar]

It also highly depends on the valve job itself, if the mechanic is slapping it together sloppily with extra tight clearances and then is also only making a valve seat width of 0.5mm - the valve will overheat as it cannot shed its heat fast enough into the valve seat and eventually into the head, it then proceeds to cook the valve seals.

Add a bad quality oil and the rubber cooks into a hard rock.

Also take into consideration - hammering in on valve seals by inexperienced mechanics.

[margallar]

but i really think they tune cars too lean on cng, the egt is very different on petrol and cng (though i am using my senses, rather than a thermometer, but the cng exhaust seems really hot, petrol is bearable, cng is just short of scalding hot)

[Xulfiqar]

but i really think they tune cars too lean on cng, the egt is very different on petrol and cng (though i am using my senses, rather than a thermometer, but the cng exhaust seems really hot, petrol is bearable, cng is just short of scalding hot)

yes CNG does burn hotter partly due to the POS CNG systems in Pakistan which are best meant for standalone fixed load generators. This creates additional load on the valve train.

[syncview]

@Xulfiqar @syncview
cultus efi 111k kms driven.engine valve stem seals are showing signs of weakness.
symptoms=blue puff at morning start and blue puff when revved a little high after 5-10 minutes of idle.
is it wise to replace the seals now??

blue smoke at startup and then none after a few minutes / engine warm is bad valve seals