Zen exhaust spitting lots of carbon powder at high revs after cold start!!

devrajman · 26th October 2009, 19:35

Sorry folks i delayed service of my zen. I will finally be going next week for service. Havent decided on which MASS.

Mostly Suraksha on Hosur road or RNS Yeshwantpur. Please let me know if you know some other MASS where your baby ZEN was handled impressively. This is my first service after i bought the car so you can understand the fear!!!

I have mentioned things TODO apart from 5000kms service which includes all fuild changed and overall inspection. Please let me know if some thing specific should be checked.

Things I noted down TODO:
1) Carb cleanup and overhaul (all jets checked & leaks checked, all vaccumm checked) and some perfect tuing from an exprienced hand (hopefully)
2) Air Filter changed/cleaned. How abt K&N stock replacement?
3) Brakes are sqeeking and not strong. Any BKM?
4) Engine oil change to Castrol Magnetec (should I do a mild engine flush?)
5) my cluch is very short, like the engage and disengage dipress is short. I tried to add some play by looseing it but engage and disengage depression needed is same. Not sure why. Cluch doesnt slip at any gear. Any reason?
6) Idling lil high and not smooth (may be due to 1 & 2)

Also recommened me any MASS in Blore who took care of your Carb Zen issues.

PS: I wanted to spend the day at service station for my curiosity as well as want things to be done perfectly. Do MASS allow customers to inspect the service?

Jaggu · 26th October 2009, 22:56

For 5) i think you need to tighten the nut and not loosen it. Suraksha near EC is a good one, thats what i have heard.

amalji · 27th October 2009, 02:32

I'm experiencing a similar problem on my Esteem MPFI.
Note: My car starts on Petrol, and switches to LPG on increasing the engine rpm beyond 1500.

On cold start, the car emits a lot of smoke. Within 2 to 3 seconds, everything is back to normal, and it even starts sprinkling water droplets. For the rest of the day, the same phenomenon is not repeated, even if I rev the car hard.

I called Autoteam, and they asked me to check oil and coolant level every day for a week. Both of them stayed intact even after 1500 kms. I'm not sure why the smoke is emitted only on cold starts. Any logical reason for this phenomenon ?

devrajman · 27th October 2009, 09:52

I think smoke at cold start is due to incomplete combustion.

Jaggu · 27th October 2009, 10:14

Might be due to a slight seepage of oil through the valve seats while being parked overnight.

How much has your car run amalji?

amalji · 27th October 2009, 21:22

Quote:

Originally Posted by Jaggu

Might be due to a slight seepage of oil through the valve seats while being parked overnight.

How much has your car run amalji?

Thank you, Jaggu. Your reasoning seems to make logic.
Should I worry about this slight leak as long as the smoke doesn't stay for long or the engine oil level starts to come down?
My car has run 85,000 kms.

The drive quality is smooth, and the car is well maintained after 77,000 kms. I'm not sure, what happened before that, because I bought it second hand. :(

Thank you, devrajman and Jaggu for responding.

Quote:

Originally Posted by devrajman

I think smoke at cold start is due to incomplete combustion.

I had done a timing adjustment, and somender's groove during my last service. Still, the problem persists. Again, water starts sprinkling from the exhaust after a few seconds, which some say is due to complete combustion. Isn't that info correct ?

Also, if it was incomplete combustion, why doesn't the same phenomenon stop in 4 to 5 seconds ? I'm just trying to find out the root cause. Sorry, if I'm asking too many questions.

Quote:

Originally Posted by Jaggu

Might be due to a slight seepage of oil through the valve seats while being parked overnight.

How much has your car run amalji?

It has run 85,000 kms. I bought it second hand at around 77,000 kms. Did 2 preventive maintenance services after the purchase. I'm not so confident about how the car was maintained by the previous owner.

Jaggu · 28th October 2009, 11:57

If there is no performance drop and oil consumption dont bother with it too much. Just keep a check on the exhaust, if its increasing then get it attended to. Also check/keep a watch if your coolant levels are intact and coolant holding the consistency/color.

amalji · 28th October 2009, 12:14

Quote:

Originally Posted by Jaggu

If there is no performance drop and oil consumption dont bother with it too much. Just keep a check on the exhaust, if its increasing then get it attended to. Also check/keep a watch if your coolant levels are intact and coolant holding the consistency/color.

Thank you, Jaggu.

For the moment, coolant levels are intact and the colour stays blue as always as well. I'll keep monitoring it for the moment. If something relevant happens, I'll update the forums. Thank you once again for your kind help.

rajeev k · 28th October 2009, 12:40

What I also suggest is a manual cylinder head decarb including valve lapping. This would also take care of replacement of the valve stem oil seals which would make your engine alive and kicking as earlier. Try to get original valve stem oil seals as cheap alternates would not seal properly.

Jaggu · 28th October 2009, 13:14

What rajeev has mentioned can also be done, but if you are doing this its better to do a good overhaul while opening up so that you dont land up opening once more for some other thing.

amalji · 28th October 2009, 17:10

Quote:

Originally Posted by rajeev k

What I also suggest is a manual cylinder head decarb including valve lapping. This would also take care of replacement of the valve stem oil seals which would make your engine alive and kicking as earlier. Try to get original valve stem oil seals as cheap alternates would not seal properly.

1) Rajeev, I had opened my head recently to do the grooving ( Somender ), and had to replace the gaskets because of that. Will this work mean that I'll have to replace the gaskets again ?

2) Do you have an idea regarding the cost in doing an engine head decarb and valve lapping? And could you give me any relevant URls which explains what exactly valve lapping is and how it helps the engine perform better ?

Quote:

Originally Posted by Jaggu

What rajeev has mentioned can also be done, but if you are doing this its better to do a good overhaul while opening up so that you dont land up opening once more for some other thing.

Jaggu, I apologize for my ignorance. could you please mention the specific jobs done as part of the engine overhaul. Any URLs which explain that would be great.

Regards,
Amal

Jaggu · 29th October 2009, 12:15

It depends on the state of engine. If its minor issues one can just live with a head deacarb, which you would have already done when you did the groov'ing. Second is to check on valves and redo the valve seating if worn or if there is too much carbon deposit.

Now comes the block where one needs to see if piston, rings are in good shape. Compression check will give you an idea. If minor drop ring change will help. If its major then you need to think about new cylinder piston kit or a sleeve job.

Then comes the lower end where, crank, connecting rods and bearings will have to be checked and corrected.

All this adds upto cost, so unless there is serious issue, just let it be.

amalji · 29th October 2009, 21:17

Quote:

Originally Posted by Jaggu

It depends on the state of engine. If its minor issues one can just live with a head deacarb, which you would have already done when you did the groov'ing. Second is to check on valves and redo the valve seating if worn or if there is too much carbon deposit.

Now comes the block where one needs to see if piston, rings are in good shape. Compression check will give you an idea. If minor drop ring change will help. If its major then you need to think about new cylinder piston kit or a sleeve job.

Then comes the lower end where, crank, connecting rods and bearings will have to be checked and corrected.

All this adds upto cost, so unless there is serious issue, just let it be.

thank you for your detailed explanations.

for the moment, i'll just let the car run without further work. in case the performance drops, i'll go for an engine overhaul.

sumeethaldankar · 21st November 2009, 21:12

Hi devrajman,
would like to know the update on your carbon issue.Did you get the car serviced by now?Hopefully your problem has been solved.

devrajman · 23rd November 2009, 10:42

@sumeethaldankar
Sorry, I had posted details in different post. Yes, its resolved. No issues currently. However now only thing is carbon thrown out of exhaust at very high revs is still there. This will remain as lots of carbon has settled inside exhaust over 9 years.

I will do couple of Italian Tuneups with a month gap. Hope some carbon inside engine and in exhausts clears.

You can read more details in "Zen and the art of maintenance" Thread.

26th October 2009, 19:35	#16
devrajman BHPian Join Date: Mar 2009 Location: Bangalore Posts: 505 Thanked: 118 Times View My Garage	Zen Service planned for next week. Sorry folks i delayed service of my zen. I will finally be going next week for service. Havent decided on which MASS. Mostly Suraksha on Hosur road or RNS Yeshwantpur. Please let me know if you know some other MASS where your baby ZEN was handled impressively. This is my first service after i bought the car so you can understand the fear!!! I have mentioned things TODO apart from 5000kms service which includes all fuild changed and overall inspection. Please let me know if some thing specific should be checked. Things I noted down TODO: 1) Carb cleanup and overhaul (all jets checked & leaks checked, all vaccumm checked) and some perfect tuing from an exprienced hand (hopefully) 2) Air Filter changed/cleaned. How abt K&N stock replacement? 3) Brakes are sqeeking and not strong. Any BKM? 4) Engine oil change to Castrol Magnetec (should I do a mild engine flush?) 5) my cluch is very short, like the engage and disengage dipress is short. I tried to add some play by looseing it but engage and disengage depression needed is same. Not sure why. Cluch doesnt slip at any gear. Any reason? 6) Idling lil high and not smooth (may be due to 1 & 2) Also recommened me any MASS in Blore who took care of your Carb Zen issues. PS: I wanted to spend the day at service station for my curiosity as well as want things to be done perfectly. Do MASS allow customers to inspect the service? Last edited by devrajman : 26th October 2009 at 19:36.
	() Thanks

26th October 2009, 22:56	#17
Jaggu Team-BHP Support Join Date: May 2004 Location: Bangalore Posts: 20,215 Thanked: 15,907 Times	For 5) i think you need to tighten the nut and not loosen it. Suraksha near EC is a good one, thats what i have heard.
	() Thanks

27th October 2009, 02:32	#18
amalji Senior - BHPian Join Date: Sep 2009 Location: Bengaluru Posts: 1,641 Thanked: 3,177 Times	I'm experiencing a similar problem on my Esteem MPFI. Note: My car starts on Petrol, and switches to LPG on increasing the engine rpm beyond 1500. On cold start, the car emits a lot of smoke. Within 2 to 3 seconds, everything is back to normal, and it even starts sprinkling water droplets. For the rest of the day, the same phenomenon is not repeated, even if I rev the car hard. I called Autoteam, and they asked me to check oil and coolant level every day for a week. Both of them stayed intact even after 1500 kms. I'm not sure why the smoke is emitted only on cold starts. Any logical reason for this phenomenon ?
	() Thanks

27th October 2009, 09:52	#19
devrajman BHPian Join Date: Mar 2009 Location: Bangalore Posts: 505 Thanked: 118 Times View My Garage	I think smoke at cold start is due to incomplete combustion.
	() Thanks

27th October 2009, 10:14	#20
Jaggu Team-BHP Support Join Date: May 2004 Location: Bangalore Posts: 20,215 Thanked: 15,907 Times	Might be due to a slight seepage of oil through the valve seats while being parked overnight. How much has your car run amalji?
	() Thanks

28th October 2009, 11:57	#22
Jaggu Team-BHP Support Join Date: May 2004 Location: Bangalore Posts: 20,215 Thanked: 15,907 Times	If there is no performance drop and oil consumption dont bother with it too much. Just keep a check on the exhaust, if its increasing then get it attended to. Also check/keep a watch if your coolant levels are intact and coolant holding the consistency/color.
	() Thanks

28th October 2009, 12:40	#24
rajeev k Senior - BHPian Join Date: Jul 2009 Location: Emerging Metro Posts: 3,352 Thanked: 1,947 Times	What I also suggest is a manual cylinder head decarb including valve lapping. This would also take care of replacement of the valve stem oil seals which would make your engine alive and kicking as earlier. Try to get original valve stem oil seals as cheap alternates would not seal properly.
	() Thanks

28th October 2009, 13:14	#25
Jaggu Team-BHP Support Join Date: May 2004 Location: Bangalore Posts: 20,215 Thanked: 15,907 Times	What rajeev has mentioned can also be done, but if you are doing this its better to do a good overhaul while opening up so that you dont land up opening once more for some other thing.
	() Thanks

29th October 2009, 12:15	#27
Jaggu Team-BHP Support Join Date: May 2004 Location: Bangalore Posts: 20,215 Thanked: 15,907 Times	It depends on the state of engine. If its minor issues one can just live with a head deacarb, which you would have already done when you did the groov'ing. Second is to check on valves and redo the valve seating if worn or if there is too much carbon deposit. Now comes the block where one needs to see if piston, rings are in good shape. Compression check will give you an idea. If minor drop ring change will help. If its major then you need to think about new cylinder piston kit or a sleeve job. Then comes the lower end where, crank, connecting rods and bearings will have to be checked and corrected. All this adds upto cost, so unless there is serious issue, just let it be.
	() Thanks

21st November 2009, 21:12	#29
sumeethaldankar Senior - BHPian Join Date: May 2007 Location: Mumbai Posts: 3,937 Thanked: 3,318 Times View My Garage	Hi devrajman, would like to know the update on your carbon issue.Did you get the car serviced by now?Hopefully your problem has been solved.
	() Thanks

23rd November 2009, 10:42	#30
devrajman BHPian Join Date: Mar 2009 Location: Bangalore Posts: 505 Thanked: 118 Times View My Garage	@sumeethaldankar Sorry, I had posted details in different post. Yes, its resolved. No issues currently. However now only thing is carbon thrown out of exhaust at very high revs is still there. This will remain as lots of carbon has settled inside exhaust over 9 years. I will do couple of Italian Tuneups with a month gap. Hope some carbon inside engine and in exhausts clears. You can read more details in "Zen and the art of maintenance" Thread.
	() Thanks