[admmys]

Hello All,

I have been a voracious reader of the posts on the forum from various other BHPians but have never posted stuff myself. However, i'm faced with a peculiar issue with my vehicle and wanted some opinion on what could be wrong with my vehicle

This vehicle - Toyota Innova 2.5 VX has been a great daily driver, still is a great one with its driving feel and has been driven mostly within the family (not drivers) and taken very good care of with ASC services except for some body work that was done at FNG. Its in pristine condition mechanically other than the issue below.

We have the vehicle driven for over 3.1L KMs without any major issue (had regular replacements and wear and tear along with replacements of steering mount, AC Compressor and Driver Airbag sensor that was malfunctioning).

I replaced the brake pads, timing belt at 3L KMs along with the regular service of changing the filters (Air and Diesel). However off late i'm noticing for the last 5-6K KMs, there has been

1. Lot of black smoke like unburnt fuel that you see from your rear view mirror (soot like and not white/ grey)

2. Drop in mileage (8-9 KMPL vs 13 that i used to get earlier)

I have raised this concern with the ASC and they say its normal for an old car which i dont agree.

Some of things that i have done so far:
1. get the injectors cleaned
2. Filters cleaned again (yes the new ones too)
3. engine decarbonization
4. used purge as well from liqui moly (which kind of made the drive smoother)

Here are my observations:

1. The smoke appears in the rear view mirror when i accelarate and cross 2000 RPM. (not a very scientific way but just my observations on my way to office)

2. The smoke doesnt appear when the vehicle is in the nuetral or if the clutch is fully engaged.

This leads me to think this has something to do with my clutch plate? maybe its jumping and worn out? The ASC says that should not be the case. The gear shifts are smooth however i'm not convinced from their answers.

Has anyone experienced similar problems and do you know what the solution could be? I'm planning to keep the vehicle as long as I can (until Diesel is banned) and will continue to use it for 20KMs trips every day across the city.

thanks in advance

[NomadSK]

Black smoke from the old diesel engine mostly points to rich mix fuel input in the combustion chamber during hard acceleration. So basically more fuel is getting injected in the engine as compared to the fuel/air mixture. Hence partial combustion and low mileage.

- Get your injectors checked,
- since you have replaced the air filter that’s fine
- clean the EGR valve
- clean the MAF sensor
- Check the function of catalytic converter

Ask your mechanic to plug in OBD scanner, mostly the faults would get reflected in that.

[jeeva]

Originally Posted by admmys

I replaced the brake pads, timing belt at 3L KMs along with the regular service of changing the filters (Air and Diesel). However off late i'm noticing for the last 5-6K KMs, there has been

1. Lot of black smoke like unburnt fuel that you see from your rear view mirror (soot like and not white/ grey)

2. Drop in mileage (8-9 KMPL vs 13 that i used to get earlier)

Since you've already checked and cleaned most of the components, and the smoke started appearing immediately after the timing belt change, it could indicate an incorrect timing. Additionally, you might want to inspect the air intake system, including the intercooler and turbo.

[Jeroen]

It is definitely nothing to do with your clutch.

Somehow the air fuel ratio is incorrect, leading to a rich mixture and not burning fully. Hence the black smoke.

Apart from what you had done already, I would check the EGR valve and the air mass meter too.

How did they clean the injectors? I am not a great fan of injector cleaning. I would pull the injector and check them them for correct working on a test rig. Only way to make sure they are working properly.

As Jeeva pointed out, what about the timing belt? Did these problems start directly after the replacement of the belt? Usually, when a belt is placed incorrectly there are some ticking noises to be heard as well.

But that would be a last resort. I would check EGR valve for dirt build up and proper working , clean the MAF (make sure they use the correct cleaning agent and not just brake cleaner), test the injectors and take it from there.

Good luck

Jeroen

[sagarpadaki]

I agree with Jeroen. Bad timing can cause black smoke. If timing is fine, get the EGR system removed and cleaned.

Here is a video. It is in Tamil. But you can get a gist of what is the issue

https://www.youtube.com/watch?v=dlh0gr2YfZo&t=268s

[Kosfactor]

Get the easier things out of the way first. Signs of a turbo hose leak to me, but could be something else too.

- Check if some genius has packed the air intake with cotton waste while washing.
- Check for hoses that connect air filter \ intake side to turbo, the entire circuit, these may have been disturbed while servicing the other items.

[R-Six]

Since you already clarified that the smoke is only during hard acceleration, it is typically a sign of an imbalanced air-to-fuel ratio. There’s either too much fuel or too little air in the engine and the smoke that you are seeing is the carbons from unburned diesel in the combustion chamber.

Since you have already checked the regular suspsects (Injectors, Air Filter etc), here are some other areas to investigate:

• It could be a bad MAF Sensor. If MAF sensor is gone, replace.
• Also, if you haven't aready, get the EGR value checked. A clogged EGR valve can cause drop in the fuel efficiency (which you already mentioned) and black smoke
• Did you check your turbocharger?
• Also, as others mentioned, do look at the engine timing. Even if the engine timing is off, it can alter the fuel injection leading to incomplete combustion and black smoke

Hope you are able to nail down the faulty part and get it sorted soon.

Drive Safe,
R-Six

[anjan_c2007]

What about its engine oil consumption? Do you have to top up the engine oil after a long distance drive? There could be issues with the piston rings, though the very well built Toyota engines last 600 K kms or more. In case piston rings are worn out the Innova would not be as peppy as it was earlier.

Clutch plate wear manifests with much higher rpms of the RPM X 1000 gauge with less corresponding RPM's of a car's wheels. The abnormal engine sound resulting from more push required on the gas pedal, to move ahead can be diagnosed by any seasoned driver.

[svsantosh]

Sniff, Sniff! (Missing my diesel days!!)

1) Change all 4 injectors, they are past their prime.
2) Change fuel filter, air filter.
3) Remove and inspect and clear MAP, MAF. Mostly the MAP is covered in soot, post a pic here. Inspect Camshaft censor while at it, clean all sensors with isopropyl, google for it.
4) Remove intercooler and tie one end with a plastic cover and many rubber bands, and make it erect and fill diesel from top, soak for 1-2 hours, drain, fill with petrol, sock, drain, wash with tap pressure water, dry and refit.
5) Remove Inlet manifold - inspect & decarbon it and spray the inlet with abundant WD40 or brake cleaner and de-gunk the valves.
6) Remove cat-con - wash from the 'wrong' way, exit side, with tonne of water. Do it until water comes out nearly clean. While at it, clean the entire exhaust.
7) Remove EGR, blank... err, clean it and refit.
8) Please flush the engine with a proper engine flush and then drive it with a cheap oil again for 5-10 kms, and then again fill it with a good grade oil. 3Lacs is enough to have a ton of debris inside the mating surfaces and can stress the combustion cycle.

Do all these and then share the results.

If you want to learn more about Diesels and Black smoke related... you can refer some of my DIYs. Note - Better not to do anything which can make your car illegal, just know which component does what and service it or replace it.

EGR Blank/Related
https://www.team-bhp.com/forum/diy-d...-blanking.html (DIY : Chevrolet Sail UVA 1.3 TDCI - EGR blanking)

PCV/Inlet Manifold link
https://www.team-bhp.com/forum/diy-d...ntilation.html (DIY - PCV Delete (Positive Crankcase Ventilation))

DeCat
https://www.team-bhp.com/forum/diy-d...testing-2.html (DIY: My experiments with DeCat, EGRs and PUC testing)

MAP Sensor cleaning
https://www.team-bhp.com/forum/long-...ml#post4858872 (Living with a (abandoned by maker) Chevrolet Sail in India | EDIT: Sold at 182,500 km & 7 years)

Intercooler Cleaning
https://www.team-bhp.com/forum/long-...ml#post4860387 (Living with a (abandoned by maker) Chevrolet Sail in India | EDIT: Sold at 182,500 km & 7 years)

Inlet Manifold
https://www.team-bhp.com/forum/long-...ml#post4871439 (Living with a (abandoned by maker) Chevrolet Sail in India | EDIT: Sold at 182,500 km & 7 years)

Injectors
https://www.team-bhp.com/forum/long-...ml#post5037297 (Living with a (abandoned by maker) Chevrolet Sail in India | EDIT: Sold at 182,500 km & 7 years)

[cooldip]

I have 1KD Fortuner with 169K on the Odo. Since the engine is very similar to the 2KD I'll share an experience.

I had very black smoke from the tailpipe on cold start. The problem had started after cleaning the injectors.

TASS wasn't able to diagnose the problem. All other parameters like EGR, filters, sensors and intercooler are always in ship shape.

I finally traced the problem down to injector seats. The injector seats are known to wear out and your's is well past its serviceable age. My TASS had taken the injectors out but never replaced the seats. As per the service manual the seats have to be replaced anytime the injectors are removed. Engine oil was entering the combustion chamber because of a pinched injector seat.

My suggestions

• Plz get a set of new injectors (or Denso refurbished injectors) - this is expensive
• Plz ensure that the TASS replaces all service parts as per the service manual
• Replace the vacuum filter (small white filter near the EGR)

[Akash5653]

Originally Posted by admmys

I'm faced with a peculiar issue with my vehicle and wanted some opinion on what could be wrong with my vehicle

Hello, it could also be a turbo issue other than what the other members have mentioned, get your turbo checked before proceeding any further.

[MT_Hyderabad]

I feel your catalytic convertor is filled with soot which came from engine decarbonising and purge treatment.

I will first do an Italian tune up on an open highway and then see if the smoke is still present or not.

https://www.team-bhp.com/forum/techn...ally-work.html (Italian tune-up: Does it really work?)

If the problem persists, I will doubt fuel quality first before initiating any labor intensive procedure what the other members are suggesting.

[puneetakhouri]

I have had a similar issue with my Tata IndiGo eCS BS4 diesel. In my case it would throw huge black smoke that was visible in the mirror at around 1500rpm and above. And the culprit was the turbo and I was advised to change it. Since yours happens above 2000 RPM so turbo can be a cause. Keep an eye on your engine oil levels and see if there's a drop. Alternatively, if they open one side of the intercooler and see oil dripping then that will answer your question.

[admmys]

Hello All,

Thank you for all the valuable inputs. I was travelling for a few weeks and could not get back faster.

I paid a visit to the TASS and my mechanic who takes care of the car for years told me not to leave it in the showroom as the TASS is not really interested in getting to the root of the problem and will start opening up the entire piece by piece and get me a huge bill. He told me a bill of 2.8 Lakhs was provided to another 2005 innova user with similar issue and and he resonated the steps that were mentioned by svsantosh here as his suspected issues.

I then decided to turn to my FNG who maintains our 2003 Fiat Palio 1.2 NV.

I had the turbo checked and MAF sensor tested and they were all fine with soot however around them and was cleaned. There was no issue or error code that popped up either on the screen.

Hoses all appeared fine as well and no oil leaks either.

Based on svsantosh's comprehensive checklist, here are my inline comments:


1) Change all 4 injectors, they are past their prime. - They were inspected and i got the history from my dad who said they were changed at 2.1 Lakhs KMS when I was outside the country for a couple years and injectors were good to go.

2) Change fuel filter, air filter. - these were done at 3.03 Lakh KMS.

3) Remove and inspect and clear MAP, MAF. Mostly the MAP is covered in soot, post a pic here. Inspect Camshaft censor while at it, clean all sensors with isopropyl, google for it. - MAP and MAF had soot and were cleaned as well. My mechanic forgot to take pics before cleaning.

4) Remove intercooler and tie one end with a plastic cover and many rubber bands, and make it erect and fill diesel from top, soak for 1-2 hours, drain, fill with petrol, sock, drain, wash with tap pressure water, dry and refit. - He performed this action as well.

5) Remove Inlet manifold - inspect & decarbon it and spray the inlet with abundant WD40 or brake cleaner and de-gunk the valves. - This is where the culprit was actually. There was a lot of gunk that was choking the inlet. Have some videos that i will upload later.

6) Remove cat-con - wash from the 'wrong' way, exit side, with ton of water. Do it until water comes out nearly clean. While at it, clean the entire exhaust. - This step was skipped for now. Will be done along with step 8 in next month or so.

7) Remove EGR, blank... err, clean it and refit. - EGR was dirty as hell and was cleaned and fit again.

8) Please flush the engine with a proper engine flush and then drive it with a cheap oil again for 5-10 kms, and then again fill it with a good grade oil. 3Lacs is enough to have a ton of debris inside the mating surfaces and can stress the combustion cycle. - We didn't do this step yet as we wanted to see if the above addressed the issue to a certain extent first and it has reduced the smoke issue significantly. We will be planning to a complete engine flush next month. There was a ton of debris here that was cleaned up but a complete flush is to be done.

One of the points that my FNG mechanic mentioned was the ASS generally dont a complete flush and he recommended that whenever there is change in timing belt, as a thumb rule, tires, brakepads, discs, injector clean, EGR check and complete engine flush/ decarbonization should be done to increase the longetivity.

He mentioned he as a taxi driver whose 2009 Innova has run beyond 10L Kms and still going strong and he does the above activities with the FNG every 1L KMS no matter what.

Thank you all for the help and i will post a few videos of the gunk on youtube and share the link later this week.

[svsantosh]

Originally Posted by admmys

Based on svsantosh's comprehensive checklist, here are my inline comments:

So finally is your problem resolved?