Ask Xulfiqar - An Automotive Encyclopedia

[margallar]

sudden vacuum loss is a leak, usually a worn out PCV or some improper sealing gasket, In my experience I have also come across a warped intake manifold which I had to face, the head was also warped (odd yes I know) it was a G13 head.

can that warpage occur due to the absence of t-stat valve, the engine on the car @syncview is working on has had a ring and head job a few years back, maybe the mechanic who did it, didn't tighten the bolts evenly.

[Xulfiqar]

can that warpage occur due to the absence of t-stat valve, the engine on the car @syncview is working on has had a ring and head job a few years back, maybe the mechanic who did it, didn't tighten the bolts evenly.

more sounds like eneven tightening,

the manifold is tightened in a sequence - starting from center outwards and only torquing to the specified torque. Not gorilla handing it.

[margallar]

we (i mean osama) has a torque ratchet, we can remove the manifold and reinstall,i think we will need a gasket and some sort of sealant.

but what will be the effects of this vacuum leakage on the car's performance?

[umarkhan1]

If you start to see the engine is behaving out of normal, e.g. getting flatspots while accelerating, messed up fuel trims etc etc and your ignition system checks out OK you can then start the fuel pressure and volume check - 90% of the times it is found that the strainer in tank and the fine filter (if provided in the fuel line) requires replacement.

I also do one additional step because I have an infrared thermometer - aim it at the exhaust ports if you can and see if a certain cylinder is running colder than the others, that is a very good indicator of bad injector.

@xulfiqar
when i accelerate the car,there are slight flatspots aka phut phut sound from silencer but the problem vanishes if i drive the car or turn on the ac.what could be the reason??
car is cultus efi 110k kms driven and behavior is on both the fuels.

[Xulfiqar]

we (i mean osama) has a torque ratchet, we can remove the manifold and reinstall,i think we will need a gasket and some sort of sealant.

but what will be the effects of this vacuum leakage on the car's performance?

the carby works on vacuum signal and the airflow into its throats, if your engine is losing vacuum you are actually injecting air in the engine which is bypassing the carby.

you already know what the effect for that is

[margallar]

yup, lean running and dust getting sucked in , can that leak also cause the powervalve to kick in more often?

[Xulfiqar]

@Xulfiqar
when i accelerate the car,there are slight flatspots aka phut phut sound from silencer but the problem vanishes if i drive the car or turn on the ac.what could be the reason??
car is cultus efi 110k kms driven and behavior is on both the fuels.

could not understand.

are you experiencing the rev limiter? or do you hear a slight misfire from the exhaust at idle?

[umarkhan1]

could not understand.

are you experiencing the rev limiter? or do you hear a slight misfire from the exhaust at idle?

@Xulfiqar bhai
yp a slight misfire(from exhaust) but not at idle.it happens at about 1500-2000 rpm.and once it rev past 2k rpm its fine

[Kiki091]

@xulfiqar bhai, I recently changed the rear wheel bearings of my Mercedes w210 2001 e220 cdi, it was all good for a week but then it started as a slight "gummm" sound from the back and now its extremely loud at speeds of 100-120, I am guessing that it is the rear differential, could it be something else?? please help..

[margallar]

Zulfiqar bhai i want to rebuild my car's alternator. all the electricians here suggest replacing it, but there is no way to know whether a kabli one will be up to our standard, is it doable at home, i can ground the car for 2-3 days if it is possible to fix it at home.

i guess the mechanical parts should be easy but the regulator/ rectifier might be difficult

can it's output voltage be adjusted, like i want it to give 15v so that the calcium battery can be properly charged

[capsat]

@margallar rebuilding an alternator is very easy, specially if you are doing it yourself am sure it will be restored close to brand new one, when you disassemble the parts , everything will be available from the automotive electrical shops and you can choose the quality of items

[Kiki091]

@xulfiqar bhai, I recently changed the rear wheel bearings of my Mercedes w210 2001 e220 cdi, it was all good for a week but then it started as a slight "gummm" sound from the back and now its extremely loud at speeds of 100-120, I am guessing that it is the rear differential, could it be something else?? please help..

@capsat bhai any suggestions from your side about it.??

[margallar]

@margallar rebuilding an alternator is very easy, specially if you are doing it yourself am sure it will be restored close to brand new one, when you disassemble the parts , everything will be available from the automotive electrical shops and you can choose the quality of items

bro have you done it before? this will be a first for me, the rotating parts bla bla will probably be easy to understand, just the regulator worries me

[Xulfiqar]

@Xulfiqar bhai, I recently changed the rear wheel bearings of my Mercedes w210 2001 e220 cdi, it was all good for a week but then it started as a slight "gummm" sound from the back and now its extremely loud at speeds of 100-120, I am guessing that it is the rear differential, could it be something else?? please help..

get under the car with it supported and use a very good quality stethescope and try to listen to the hubs, if you feel them scratchy - you have found your problem. Changing the rear bearings on any W124 and W210 is a pain in the butt, they sometimes require 20 tons of force to move. What brand bearings and hubs did you use and how careful was the mechanic who was pushing the hubs back in - one slight movement can damage a perfectly good bearing.

Also make sure you replace the axle nuts, dont reuse them.

Still easier than the W123 and W126 etc rear bearings where you have to become the green hulk to set the clearances

p.s. for noise - also check the driveshaft center bearing.

[Xulfiqar]

bro have you done it before? this will be a first for me, the rotating parts bla bla will probably be easy to understand, just the regulator worries me

capsat is right, its not very hard to rebuild, the parts are also available - you cannot change the charging voltage because your regulator is internal, you can try to put something in the sense line circuit that can drop a volt, but some alternators have it internally bridged. So it becomes useless.

[Kiki091]

get under the car with it supported and use a very good quality stethescope and try to listen to the hubs, if you feel them scratchy - you have found your problem. Changing the rear bearings on any W124 and W210 is a pain in the butt, they sometimes require 20 tons of force to move. What brand bearings and hubs did you use and how careful was the mechanic who was pushing the hubs back in - one slight movement can damage a perfectly good bearing.

Also make sure you replace the axle nuts, dont reuse them.

Still easier than the W123 and W126 etc rear bearings where you have to become the green hulk to set the clearances

p.s. for noise - also check the driveshaft center bearing.

So if its scratchy then its the differential???
The bearings were febi, and they worked fine for about 2 weeks..

[Kiki091]

get under the car with it supported and use a very good quality stethescope and try to listen to the hubs, if you feel them scratchy - you have found your problem. Changing the rear bearings on any W124 and W210 is a pain in the butt, they sometimes require 20 tons of force to move. What brand bearings and hubs did you use and how careful was the mechanic who was pushing the hubs back in - one slight movement can damage a perfectly good bearing.

Also make sure you replace the axle nuts, dont reuse them.

Still easier than the W123 and W126 etc rear bearings where you have to become the green hulk to set the clearances

p.s. for noise - also check the driveshaft center bearing.

And what are the signs of a bad differential??

[margallar]

capsat is right, its not very hard to rebuild, the parts are also available - you cannot change the charging voltage because your regulator is internal, you can try to put something in the sense line circuit that can drop a volt, but some alternators have it internally bridged. So it becomes useless.

okay then,i will do it :), i just saw a couple of rebuild projects on google, i just wonder why electrician hazraat insist on replacing it

today my brother showed the car to some desi mechanic, he confirmed that it was bad and then insisted on replacing it with the alternator from carry dabba, his logic was that your wiring is old and needs a bigger gen.

[Kiki091]

@xulfiqar bhai, here's the thing, I jacked up the car and tried to move the wheels by hand, now the right wheel moved with ease making a slight hissing sound, where as the left wheel was hard to move, it required a HUGE amount of force as compared to the right wheel..what does this tell me??

[Xulfiqar]

So if its scratchy then its the differential???
The bearings were febi, and they worked fine for about 2 weeks..

FEBI usually repack unbranded bearings and are straight up scrap, I never use dodgy bearings, always insist on name brand quality bearings like ***, SKF, Timken, National, NTN, Koyo etc and always make sure the press is 100% square on the hub carrier, it is a huge problem as the carrier is very awkward shaped, a technique I use is 3 or 4 very strong bolts to level the carrier when the bearing is pressed in - This makes sure you dont tear up the thin metal brake shield.

@Xulfiqar bhai, here's the thing, I jacked up the car and tried to move the wheels by hand, now the right wheel moved with ease making a slight hissing sound, where as the left wheel was hard to move, it required a HUGE amount of force as compared to the right wheel..what does this tell me??

If the wheel is hard to move, firstly undo the caliper punch pins and release the brake pads if the hub is still hard to rotate and you are sure the transmission is in neutral and the whole rear of the car is jacked up - then adjust the parking brake correctly, You should clean the mechanism thoroughly (the activation mechanism has a very bad failure mode - they fail when engaged because the design has a wallet and an expanding wedge that pushes the shoes out. If the wallet is rusty the wedge siezes and then you are in for a lot of fun.

I have also seen many mechanics damage the brake shoes as they try to wrestle the disc off without releasing the parking brake adjusters - they are little star wheel adjusters that need to be rotated so they are fully closed off, they can be reached from a bolt hole in the disc/hub at about 1 and 11 o clock positions depending on which side of the car you are.

The process is quite simple but it pays to make sure that you read the service manual and actually implement the entire process.