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Old 28th February 2012, 22:42   #16
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Default re: Mysterious optra magnum engine problem - 12k km

I suppose I missed something, but is this a petrol or diesel?

When the car starts feeling heavy, can you please check and report the following:
  1. Can you shift easily into neutral and all other gears?
  2. Does the clutch feel normal?
  3. Does the car roll effortlessly in neutral even though the engine refuses to rev when you press the A-pedal?
  4. Is there any smoke from the tailpipe (esp. if this is the TCDi engine) when the engine begins to feel heavy and refuses to rev up?
  5. What is the max rev the engine would attain when the car is in neutral, at the time that the car feels heavy?
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Old 28th February 2012, 22:43   #17
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Default re: Mysterious optra magnum engine problem - 12k km

This does look like a TPS ( throttle position sensor) issue. I am not sure if your car is drive by wire or has an actual TPS on the TB. Maybe there are dead spots.

The TPS does not set a code most of the time.
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Old 28th February 2012, 22:47   #18
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Default re: Mysterious optra magnum engine problem - 12k km

Quote:
Originally Posted by BuRnT RuBbEr View Post
you should do that morning drive with the diagnostics connected and logging all the data. mayankk could lend his obd.

get the errors cleared in person as mayankk suggested.

alternatively, you could leave the car with service overnight and run the tests on the first morning drive there.

just thinking, could it be a handbrake problem? maybe you park overnight with the handbrakes active and in the morning, they remain stuck, heat up by the time you hit 8 kms and the problem starts?

what additive was added?
Again, the symptoms are highly intermittent with a steady pattern. I highly doubt the handbrake in this.

Quote:
Originally Posted by RevvMusic View Post
I too had faced a very similar problem in my Palio S10 last month. My Go-To Mechanic at the A.S.S analyzed it for an hour and found the culprit to be faulty wiring and loose connection in the cables that lead to the spark plugs.

One of the spark plug cables had somehow developed a loose connection and after the engine temperature increased to a certain value after driving for sometime, the current values in that wire started to fluctuate resulting in the car suddenly becoming heavy, followed by deceleration.

I'd suggest that you get the wiring of the spark plugs checked for optimum current and voltage levels and see if the problem gets rectified.
Thanks for the input. Common rail diesel engine here. No spark plugs in diesel engines. But there could be a similar problem in another signal carrying wire malfunctioning. But the symptoms again indicate something else. Cause the engine will only get hotter as the drive progresses, but in my case, the problem comes once in the morning, and never again the whole day!

Quote:
Originally Posted by mayankk View Post
Say, didnt I spot you in CP once?

anyway, this is with a petrol fiesta.

As for the TB, look for the hose coming out of the airbox, and where it connects to the engine block.
if located, open the clamp on the hose(easy job, not much to mess up there), if you see a butterfly valve, that is presumably it.

Or, head to the chanakya petrol pump, or pallika, and tell them to clean it.
Yes I think you did. Will let the service guys take another dig at the car in a few days. Too many strikes on today, including the A$$. Tomorrow's off too.

Quote:
Originally Posted by honeybee View Post
@ByDesign, it sure looks like a weird problem.

Have you tried taking the car on a different route? And if you are facing this problem every day without fail, why not take the workshop guys with you on the same route and show them the problem firsthand?

Also it might be a good idea to try a competent independent mechanic who can offer advice on what could be wrong.
Three answers coming right up sir!
  • Tomorrow we are going to try a different route. Results will be posted here later on in the day.
  • Have told the workshop guy to accompany us too. Day after we'll know if we can make this happen.
  • We will investigate the independent mechanic option after the A$$ has had their way. We are relatively new with this Optra (12k km only), so we don't want to go too far from the official guys.
Quote:
Originally Posted by CDM View Post
Did they also add any fuel additive?

A friend had a similar, though not identical, problem with his Scorpio when the service center guys added some fuel additive. In his case, his Scorpio would behave erratically and become sluggish suddenly. Draining the diesel tank solved the problem.

CDM
Thanks for the valuable post. No fuel additive here. We might consider flushing the engine oil and try a fresh lot, without additive this time. That's definitely on the cards.

Quote:
Originally Posted by Blow Horn Ok View Post
Does the gears shift normal while the car is in problem? As you said the engine idles normally and there are no signs or wired noises, i doubt it to be transmission issue. Get it checked. When the car is is limp mode, does the engine rev normally (say 3-4k RPM)??
Engine revs, but very very sluggish. The tacho does not jump the way it usually does. Gear shift is fine, during the problem and otherwise as well. And engine revs to 4k rpm even during the problem, but just takes a lot of effort. Engine feels really when revving during the problem.

Quote:
Originally Posted by keyur View Post
The entire issue seems pretty weird, but there are a few things I would like to ask you :

1. Firstly, why would you do 60-70 in 2nd gear? See this post by me. At 2nd gear, 70 kmph means nearly 4000 rpm. You should not do that in 2nd gear. Check the chart - try shifting as per the chart and see if this happens.

2. 40kmph in 4th gear = 1000 rpm. That is definitely going to make the drive very laggy. At this speed, you will need to downshift to second to have any pickup. (see the chart in the post I mentioned again)

Optra has tall gear ratios, so you need to ensure that you drive in the correct gear. And then, till 2000 rpm you are going to be hitting the turbo lag region. From what I hear, you seem to be permanently in the lag region.

Still, the way you mention it, there seems to be something that is being miscalculated by the ECU or there could be a leak in EGR pipes or the air hose.

Try one simple thing. Switch of the vehicle, open the hood, disconnect the positive terminal of the battery and let it sit for about 15 mins. Then reconnect the battery and see what happens.
I don't drive that way usually Keyur! I might have forgotten to mention that I had read a post online, where someone had a similar problem with the Optra. They attributed it to a deposit in the cylinders. A good rough drive (nice high revs and super aggressive shifts) cleaned those cylinders right up! So basically, I was trying to drive with very high revs to see if the problem cleared up. So in other words, I was driving like this to see if it fixed the problem! Unfortunately it didn't. My driver usually drives the Optra, and always shifts according to the recommended guidelines!

We have been driving turbo diesels for some time in my family (Accent CRDi, Optra 2.0, and Palio MJD) and we are very familiar with turbo lag etc. No doubts there, this isn't just a driving and shifting issue. This is a problem that is inherent with the engine/transmission/whatever with the car.

Also, will disconnecting the positive terminal of the battery for 15 mins sort of reboot the ECU or something?

Last edited by ByDesign : 28th February 2012 at 22:49.
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Old 28th February 2012, 23:06   #19
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Default re: Mysterious optra magnum engine problem - 12k km

Quote:
Originally Posted by ByDesign View Post

We have been driving turbo diesels for some time in my family (Accent CRDi, Optra 2.0, and Palio MJD) and we are very familiar with turbo lag etc. No doubts there, this isn't just a driving and shifting issue. This is a problem that is inherent with the engine/transmission/whatever with the car.
Hey, no doubts on that - just put my thoughts there!

Quote:
Originally Posted by ByDesign View Post

Also, will disconnecting the positive terminal of the battery for 15 mins sort of reboot the ECU or something?
Yes. It resets the dynamic memory of the ECU. So whatever characteristics the ECU has 'learnt' are forgotten. I did this when I was trying to tune the RaceChip for my Magnum - it helped to forget the previous setting and helps to see the effect of the new settings faster.
The 15 mins is not required, but I suggested that so that the components like capacitors that may be holding some charge get discharged.
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Old 28th February 2012, 23:12   #20
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Default re: Mysterious optra magnum engine problem - 12k km

Ok, so it's a diesel.

A quick thought: First off, please check the diesel tank filter (the fine wire mesh through which diesel is sucked up from the tank bottom). Might have lint stuck on it. Produces somewhat similar symptoms on smooth roads - don't ask me why!
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Old 28th February 2012, 23:12   #21
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Default re: Mysterious optra magnum engine problem - 12k km

Quote:
Originally Posted by RevvMusic View Post
I too had faced a very similar problem in my Palio S10 last month. My Go-To Mechanic at the A.S.S analyzed it for an hour and found the culprit to be faulty wiring and loose connection in the cables that lead to the spark plugs.

One of the spark plug cables had somehow developed a loose connection and after the engine temperature increased to a certain value after driving for sometime, the current values in that wire started to fluctuate resulting in the car suddenly becoming heavy, followed by deceleration.

I'd suggest that you get the wiring of the spark plugs checked for optimum current and voltage levels and see if the problem gets rectified.
2 litre CRDi Diesel = no spark plugs

Quote:
Originally Posted by mayankk View Post
Say, didnt I spot you in CP once?

anyway, this is with a petrol fiesta.

As for the TB, look for the hose coming out of the airbox, and where it connects to the engine block.
if located, open the clamp on the hose(easy job, not much to mess up there), if you see a butterfly valve, that is presumably it.

Or, head to the chanakya petrol pump, or pallika, and tell them to clean it.
Do Diesel Engines have throttle body? I don't think so, kindly check.

Try the solution SS-Traveller has provided.

Can be due to any of the following:

1. Dirty diesel choking filter
2. Water entry in diesel tank (filter may not have water separator / water is not drained from filter)
3. Injector clogging (highly unlikely, but as the injector holes are in the order of microns, so even minute dust will choke the holes).
4. Check Air filter for choking.
5. The air mass sensor may be malfunctioning, giving wrong reading to the ECU, which may inject wrong qty of fuel.
6. Faulty sensors (cam position / crank angle) may cause injectors to inject diesel at wrong time (timing issue).

Check and rule out all the points with your A** before going to a third party mechanic.

Last edited by autocrat : 28th February 2012 at 23:23. Reason: Missed a few points
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Old 29th February 2012, 02:36   #22
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Default re: Mysterious optra magnum engine problem - 12k km

As ssingri and SS-Traveller suggested, The first thing I'd try would be to try and disconnect the engine from the wheels - read, press the clutch; and then put it in neutral - to see what symptoms it exhibits. Whether the lack of RPM and heavy feeling is still there. This should guide you to whether the problem is in the rolling of the car or with the power being produced and reaching the wheels.

If the engine revs freely, you would look at the brakes and the like. If the engine does not rev freely, you'd look at the Fuel line, ECU, currents etc etc. This should help in the diagnosis by the A$$.

All that said, the practical solution to such things, is what you are already doing. Have a mechanic with you when the problem occurs, and this is simple for you, as the problem has a consistent way of showing up. Diagnosis is hugely better if a competent mechanic witnesses the issue.

Would suggest you to keep to the GM Authorized staff, keeping warranty issues in mind.

GM may also be maintaining some kind of a central database of problems in their cars. Just in case the local chaps are not able to help, one could try to get in touch with the GM's technical staff, who should be able to guide the local guys about the issue. Often, the local guys would be reluctant in getting in touch with the company, as it may make them seem incompetent. Encouraging them to, or getting in touch directly, may be of a lot of use.

Since the issue has only come up after a similar period of usage, one is inclined to think on the lines of something heating up (possibly electricals) or something to do with the fuel line.

BTW, have very often taken the car to 70-80kmph in second without any issue whatsoever. A simple guideline is to use the car between about 1300-4000RPM. Or to keep it simpler (turbolag complaints, less competent driver etc.) from about 1600-1700 to 3600-3800.

Disconnecting the battery to reset the ECU, as Keyur suggested, should also be worthwhile. But better to do this after the mechanic has witnessed the symptoms.

@ByDesign mate, Please don't refer to me as some Optra Guru. I am very very far from being even remotely considered one. Am just someone who has a lot of appreciation for the design of this car and someone who really enjoys it.
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Old 29th February 2012, 07:14   #23
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Quote:
Originally Posted by autocrat



Do Diesel Engines have throttle body? I don't think so, kindly check.
.
There isn't?
Oh, never realized.
Then probably check the equivalent of it. I'm sure there's something that regulates the air flow.
But any which way, seems to be a long weekend ahead for bydesign.
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Old 29th February 2012, 15:00   #24
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Default re: Mysterious optra magnum engine problem - 12k km

Quote:
Originally Posted by SS-Traveller View Post
Ok, so it's a diesel.

A quick thought: First off, please check the diesel tank filter (the fine wire mesh through which diesel is sucked up from the tank bottom). Might have lint stuck on it. Produces somewhat similar symptoms on smooth roads - don't ask me why!
Mr. SS-Traveller, so sorry I didn't notice your post earlier during my multi-quote reply. I'm noting all these inputs down. I have been in touch with the service center. We will be coordinating another attempt at fixing this soon enough. It's just that I work a rather time consuming job every day till late, and there's very little I can follow up on during the week. +1 thanks for your input sir.

Also, for your earlier post, I will have to check those inputs exactly when the problem is occurring. As far as I remember, the clutch felt perfectly normal when the problem was underway. Also, the engine revved upto about 3k rpm when the problem was happening, but with great restraint. Felt horrible to rev that hard.

Quote:
Originally Posted by autocrat View Post
2 litre CRDi Diesel = no spark plugs



Do Diesel Engines have throttle body? I don't think so, kindly check.

Try the solution SS-Traveller has provided.

Can be due to any of the following:

1. Dirty diesel choking filter
2. Water entry in diesel tank (filter may not have water separator / water is not drained from filter)
3. Injector clogging (highly unlikely, but as the injector holes are in the order of microns, so even minute dust will choke the holes).
4. Check Air filter for choking.
5. The air mass sensor may be malfunctioning, giving wrong reading to the ECU, which may inject wrong qty of fuel.
6. Faulty sensors (cam position / crank angle) may cause injectors to inject diesel at wrong time (timing issue).

Check and rule out all the points with your A** before going to a third party mechanic.
1. Will follow up on this
2. Might need to drain diesel tank while checking fuel filter too
3. You're right. Highly improbable, also based on the fact that the car's 12k kms old too.
4. Air filter was cleaned and replaced pretty recently.
5 and 6. Faulty sensors will generate an error code, which did not show up during the scan.

Quote:
Originally Posted by Poitive View Post
All that said, the practical solution to such things, is what you are already doing. Have a mechanic with you when the problem occurs, and this is simple for you, as the problem has a consistent way of showing up. Diagnosis is hugely better if a competent mechanic witnesses the issue.

Would suggest you to keep to the GM Authorized staff, keeping warranty issues in mind.

GM may also be maintaining some kind of a central database of problems in their cars. Just in case the local chaps are not able to help, one could try to get in touch with the GM's technical staff, who should be able to guide the local guys about the issue. Often, the local guys would be reluctant in getting in touch with the company, as it may make them seem incompetent. Encouraging them to, or getting in touch directly, may be of a lot of use.

Since the issue has only come up after a similar period of usage, one is inclined to think on the lines of something heating up (possibly electricals) or something to do with the fuel line.

BTW, have very often taken the car to 70-80kmph in second without any issue whatsoever. A simple guideline is to use the car between about 1300-4000RPM. Or to keep it simpler (turbolag complaints, less competent driver etc.) from about 1600-1700 to 3600-3800.

Disconnecting the battery to reset the ECU, as Keyur suggested, should also be worthwhile. But better to do this after the mechanic has witnessed the symptoms.

@ByDesign mate, Please don't refer to me as some Optra Guru. I am very very far from being even remotely considered one. Am just someone who has a lot of appreciation for the design of this car and someone who really enjoys it.
Points noted. Also, have indicated to the A$$ to send a service guy for a ride along in the morning when this problem happens. I will look for a GM email address. I have already saved FIAT numbers through T-BHP for reference, but is there a place I can get a worthy email address for GM? Other than their general contact email address.

Quote:
Originally Posted by mayankk View Post
There isn't?
Oh, never realized.
Then probably check the equivalent of it. I'm sure there's something that regulates the air flow.
But any which way, seems to be a long weekend ahead for bydesign.
Long weekend indeed. Considering i'm packed with work during the week as it is. Oh well, such is life.
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Old 29th February 2012, 17:57   #25
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Default re: Mysterious optra magnum engine problem - 12k km

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Originally Posted by ByDesign View Post
I have already saved FIAT numbers through T-BHP for reference, but is there a place I can get a worthy email address for GM? Other than their general contact email address.
Also on T-Bhp

http://www.team-bhp.com/forum/techni...ml#post2480393 (Too many problems with my new Chevrolet Optra Magnum)

http://www.team-bhp.com/forum/techni...ml#post2695974 (Too many problems with my new Chevrolet Optra Magnum)

This would be a starting point. You may get more relevant contacts from there. If you do, please share with the forum.

BTW, Karl Slym is no longer the MD of GM.
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Old 1st March 2012, 11:44   #26
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Default re: Mysterious optra magnum engine problem - 12k km

Will take the car to Pallika today to get the fuel filter cleaned. Can anyone tell me about a reputed mechanic in pallika? Or should I just go to any of them.
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Old 1st March 2012, 13:10   #27
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Default re: Mysterious optra magnum engine problem - 12k km

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Can anyone tell me about a reputed mechanic in pallika? Or should I just go to any of them.
Not in Palika, but you can try this one (Friendly Neighborhood Garage (FNG) - Imtiaz & Ayub (New Delhi)).
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Old 1st March 2012, 13:15   #28
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Default re: Mysterious optra magnum engine problem - 12k km

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Will take the car to Pallika today to get the fuel filter cleaned. Can anyone tell me about a reputed mechanic in pallika? Or should I just go to any of them.
If you plan to clean the airfilter, you can do it yourself. Takes about 15 mins and is very very easy.

Just have a clean damp cloth handy (big enough to cover the air filter box)

Open the hood. To the left hand side, you will see the housing for the air filter (big black box) with 4 nuts/bolts.
Loosen all the 4 nuts and the cover will open up easily. Just remove the filter from the box (you just need to pick it up).

Cover the intake with the damp cloth and close the box (no need to tighten the nuts). This is to prevent any insects / debris from going in.

Now, take the filter to a tyre repair shop and get it blown with compressed air. If it has not been replaced at 10000 km, go ahead and replace it. Costs just 500Rs and is worth it.

Just to get an idea about the amount and type of debris, bang the filter on a soft flat surface (like the seat of a bike) - dirty side down and see the kind of stuff that falls out!


Someone had mentioned water entering the pump / fuel lines etc. I doubt that as it would have caused a more repeatable issue, at all times. Still, check the user manual of the Optra - it has an option to get the water out, and also to bleed the fuel pump if required.
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Old 1st March 2012, 13:44   #29
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Default re: Mysterious optra magnum engine problem - 12k km

Quote:
Originally Posted by ByDesign View Post
Will take the car to Pallika today to get the fuel filter cleaned.
Quote:
Originally Posted by keyur View Post
If you plan to clean the airfilter, you can do it yourself. Takes about 15 mins and is very very easy.
Guess it is the Fuel Filter and not the Air Filter that he is talking about.
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Old 1st March 2012, 14:07   #30
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Default re: Mysterious optra magnum engine problem - 12k km

Quote:
Originally Posted by ByDesign View Post
.... but in my case, the problem comes once in the morning, and never again the whole day!
.....
Makes me strongly suspect the fuel pump.

Sorry if I missed it, but have checked it? If not, please do.
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