[humyum]

Originally Posted by DeepChat

I got my car back from FASS 3 days back. I made them clean up the EGR (again) as well as the turbo hose. They took apart the intercooler too. I asked them to check and clean the accelerator sensor also. They assure me that there is no electrical issue (as there are no flashing lights in the dashboard), but I made them check this up anyway. However, I dont know if they actually cleaned this.

The issue is still there, but intermittent. I drove to Pondicherry and back (~850 kms) and didn't face the issue even once. In fact I got some fantastic mileage (~20 kmpl) even though a lot of the drive was at ~125 kmph.

However, the issue resurfaced when I went for a short drive within the city today. The acceleration was again slow in 2nd gear till about 2000 rpm and then picked up. Will drive some more over the next few days and provide an update on the performance.

You know I remembered this thread today morning, reason you know why ?

My building has a 90 bhp Quadrajet Manza. The guy in the car had some braking problems and he wanted me to check it out for him as he observed his car kept pulling slightly while braking. Never the less I ll get to my point his accelerator went 'EXACTLY' like how you guys mention, NUMB. It was totally how you guys are describing it, you stomp the accelerator and NOTHING. I instantly remembered this thread and shifted to neutral and jammed the accelerator and like I had expected, the car settled down at idle with the throttle full jammed to the floor.

Then I downshifted a gear and the revs came up and the throttle was still pressed down, suddenly she picked up power and behaved normally.

On probing with the building friend further he said He had a tough time on the Nasik ghats once when the car lost all power and refused to climb the slopes until he stopped the car ahead. Waited for sometime and restarted it back and it behaved normally.

Anyway, I have figured this is not an accelerator sensor problem but a MAF sensor problem.

Since my Swift Diesel does not have this problem, I cannot recreate it but I can help you folks fix it if anyone of you are willing to experiment with this in their car.

I observed through probing further that this problem is observed mostly in higher gears while accelerating, this happened to me too while I was going to shift from 4th to 5th and like the OP has stated this has happened to him at higher gears too.

When you are facing this exact problem, stop the car and disconnect the MAF sensor which is just a little downstream of the air filter, you can easily see it when you open the bonnet.

If the problem does it resurface, its a bad MAF sensor which needs replacement. If it happens right after this too, we'll have to look somewhere else, but I am positive its the MAF sensor.

PS: While you disconnect this sensor and run the car, an error code will be registered and you will need to your authorized service station to get this cleared. Hence the warning right at the start, do this only if you are willing to help yourself as well as others in finding a solution to this problem and are willing to go the whole 9 yards towards it.

You can make the service station guys carry out this experiment if you want.

[DeepChat]

Originally Posted by humyum

You know I remembered this thread today morning, reason you know why ?

My building has a 90 bhp Quadrajet Manza. The guy in the car had some braking problems and he wanted me to check it out for him as he observed his car kept pulling slightly while braking. Never the less I ll get to my point his accelerator went 'EXACTLY' like how you guys mention, NUMB. It was totally how you guys are describing it, you stomp the accelerator and NOTHING. I instantly remembered this thread and shifted to neutral and jammed the accelerator and like I had expected, the car settled down at idle with the throttle full jammed to the floor.

Then I downshifted a gear and the revs came up and the throttle was still pressed down, suddenly she picked up power and behaved normally.

On probing with the building friend further he said He had a tough time on the Nasik ghats once when the car lost all power and refused to climb the slopes until he stopped the car ahead. Waited for sometime and restarted it back and it behaved normally.

Anyway, I have figured this is not an accelerator sensor problem but a MAF sensor problem.

Since my Swift Diesel does not have this problem, I cannot recreate it but I can help you folks fix it if anyone of you are willing to experiment with this in their car.

I observed through probing further that this problem is observed mostly in higher gears while accelerating, this happened to me too while I was going to shift from 4th to 5th and like the OP has stated this has happened to him at higher gears too.

When you are facing this exact problem, stop the car and disconnect the MAF sensor which is just a little downstream of the air filter, you can easily see it when you open the bonnet.

If the problem does it resurface, its a bad MAF sensor which needs replacement. If it happens right after this too, we'll have to look somewhere else, but I am positive its the MAF sensor.

PS: While you disconnect this sensor and run the car, an error code will be registered and you will need to your authorized service station to get this cleared. Hence the warning right at the start, do this only if you are willing to help yourself as well as others in finding a solution to this problem and are willing to go the whole 9 yards towards it.

You can make the service station guys carry out this experiment if you want.

I have set up time with FASS to test the MAF and accelerator sensors. I'll update the thread with the results.

[lurker]

If it's a high mileage car, check your intercooler, it may be clogged, so get it cleaned. Also get EGR valve & catalytic converter cleaned and then check to confirm if there is indeed a sensor issue. Most of the cases I doubt the issue is really with the sensors.

[harryms]

MAF is easy to clean, see this video,

https://www.youtube.com/watch?v=g92GNcAPX-0

[DeepChat]

At the FASS. Just did the experiment that humyum had suggested. FASS said they cleaned the MAF and booster sensors. No change in pickup. I disconnected the MAF and drove again. My old car was back!! So i guess my MAF is kaput. They are now looking for a new sensor.

[scofield]

Please get all the hose pipe checked specially the inlet ones which takes the hot soot in the radiator and which also connects to the EGR
Any small leakage, will cause a big loss in power. Do you see more than normal black smoke ?

[DeepChat]

FASS guys did not replace the MAF sensor as they are not sure it is the culprit, or whether it is a loose connection. They even had a conference call with the Fiat engineers to discuss this. They have asked me to use the vehicle for another 2-3 days, and check if the problem persists. Unfortunately it does :( I will go back to FASS over the weekend to have the sensor replaced.

Originally Posted by scofield

Please get all the hose pipe checked specially the inlet ones which takes the hot soot in the radiator and which also connects to the EGR
Any small leakage, will cause a big loss in power. Do you see more than normal black smoke ?

No black smoke being emitted.

Yesterday morning the dashboard showed an error in the air flow and thats what convinced FASS to accept the MAF sensor theory.

[harryms]

Good Luck Buddy, hope the MAF sensor replacement will resolve your issue.

[humyum]

Originally Posted by DeepChat

At the FASS. Just did the experiment that humyum had suggested. FASS said they cleaned the MAF and booster sensors. No change in pickup. I disconnected the MAF and drove again. My old car was back!! So i guess my MAF is kaput. They are now looking for a new sensor.

MAF sensor it is. My assumption was right Get it replaced and you ll not face this problem anymore.

Originally Posted by scofield

Please get all the hose pipe checked specially the inlet ones which takes the hot soot in the radiator and which also connects to the EGR
Any small leakage, will cause a big loss in power. Do you see more than normal black smoke ?

All this will cause a constant loss of power, not an intermediate one.

Originally Posted by DeepChat

FASS guys did not replace the MAF sensor as they are not sure it is the culprit, or whether it is a loose connection. They even had a conference call with the Fiat engineers to discuss this. They have asked me to use the vehicle for another 2-3 days, and check if the problem persists. Unfortunately it does :( I will go back to FASS over the weekend to have the sensor replaced.


No black smoke being emitted.

Yesterday morning the dashboard showed an error in the air flow and thats what convinced FASS to accept the MAF sensor theory.

I don't get it, how can the MASS not suspect this and me having driven someone's car with this problem just once know that its the MAF sensor ? I mean, they must seen this atleast 20 to 50 times till now this problem since lot of people are complaining about this on teambhp, So I am sure there must be many out of team bhp too.

Anyway, I guess everyone out here facing this problem has finally seen some light, thanks to deepchat going along with my experiment.

[DeepChat]

My MAF was replaced a couple of days back. The car is accelerating better than when it was new! Effortless! The only worrying thing is that I did notice a loss in power for a few minutes once in the 50 kms I have driven after the change. Will keep testing and update this thread.
Thanks humyum for pointing me in the right direction. I have asked Fiat service center guys to add this to their knowledge base. They told me that I am the first to change this sensor in the 3 years that they have been working there.

[DeepChat]

The initial euphoria died quickly as the car quickly went back to its old ways. In fact overall engine power seemed to have reduced substantially and I was getting increasingly frustrated. In the meantime, a number of minor issues cropped up and it was really joyless driving. I came to know that Vecto Motors is my best bet to get this sorted out. Apparently they are the best I can hope to find in Bangalore for Fiat. They are an official Fiat service center. So visited them last week. They have identified the cause as either a faulty egr valve, or an issue with the fuel pump. I also got a complete servicing done. The last one was 9k kms back, and I am inclined to take the 15k service interval with more than a pinch of salt. Vecto did the servicing, and have disconnected the egr valve. They gave the car back to me to drive it for a couple if days and check if I still notice the power loss issue. If I don't, then the egr valve will be replaced as part of the extended warranty. I have been driving it for almost 2 days now and the issue has not surfaced even once. I will be giving the car back for the egr valve replacement tomorrow. Fingers crossed that this finally solves the problem.

[arun_josie]

I think I am facing a similar issue as well, it is intermittent though,
Once in a while, I feel a loss of power in my Linea MJD, while this happens, it feels as if someone is pulling from behind.
- mostly it happens above 2000RPM.
- i have noticed this on inclines especially when on second gear
- and happens during my first drive of the day, but not always.
I regain the power within 2-3 seconds and a feel a thrust from behind when this happens. What could be the reason for this issue?

ODO is @ 25300 Kms.

Originally Posted by DeepChat

I will be giving the car back for the egr valve replacement tomorrow. Fingers crossed that this finally solves the problem.

Did the EGR valve replacement help to resolve this issue?

[DeepChat]

Yes. The EGR valve replacement has solved the issue. My problem was sustained low acceleration unless I restarted the engine. Apparently the EGR valve was not closing completely.

[Sandm4n]

Originally Posted by autocrat

However with my car, the car just does not move in second gear, even if there is a mild gradient. I push the car to about 2000 rpm in first gear, upshift, and slowly depress the accelerator and the car just does not gain speed. On a moderate incline, it slowed down to the point of stalling and I had to downshift to keep from stalling. Is there a cure for this? the car is otherwise fine - and third gear is fantastic.

Request your help - to understand whats wrong and whats the corrective measure.

A component in the air filter assembly might not be working properly. I have had the same problem with Swift Dzire.
You can disassemble the assembly by yourself, but you wouldn't find out what component is causing it unless you replace it by another, obviously.

Hope this fixes it.

[funkykar]

^Are you referring to the MAF sensor here? If one suspects it, get it cleaned at FASS once then try swapping it.