| Maruti Swift Diesel - Mysterious starting problem due to carbon brushes (starter)
MYSTERIOUS STARTING PROBLEM DZIRE ZDI 2008
Please excuse for a long write up. Could not find a similar thread with same problem and solution.
The starting problem in my 2008 year Swift Dzire ZDI occurred for first time on 29 December 2015. The car had clocked around 83.000 kms by then. It took six months of investigation and troubleshooting to fix this. Finally on June 23 2016 the problem was resolved and I was relieved and happy.
Following is my experience over the six month period.
This car is primarily used by my wife for her office commute. Right from day one I have always filled full tank. If I travel out of town, I make sure that the car has enough fuel and my wife need not visit a pump. For once the car was low on fuel, and was filed up somewhere in Delhi by my wife. We live in Gurgaon and I always fill at a pump near our house. On my return I was informed that the car needs to be cranked longer than usual to start up. First question if there are any warning light on which was answered in negative.
I thought this to be adulterated fuel problem and should go once the fuel is consumed. I checked for common tell-tale signs such as black/white smoke on revving, abnormal sound, power loss. There was no abnormal smoke, no loss of power or any unusual sound. This made me wonder if fuel is the root cause. I even checked the exhaust smell. It was normal diesel exhaust smell, no odour of kerosene or something else. The next day I got the diesel filter replaced hoping this should solve the problem. No change. Problem persisted. The average fuel consumption was also same as what normally get in my city drives. Car would behave as normal after starting up.
We would not switch off at signals or if had to wait for few minutes as cranking had become longer. I noticed that morning start or when the engine is not very hot, the car would start easily. When hot, it would take longer time or sometimes not start. Would wait for 5-10 minutes and try again.
Before this problem occurred the car would need cranking for about 1-2 seconds to fire up. After this problem, it would need continuous cranking of 5 -7 seconds or more to fire up. We kept using the car and after about 2 week when the fuel was low I filled her up, tank full, at the same pump where I always filled in the past eagerly expecting the problem to go away. I drove for 20 kms. To make sure the old fuel is burnt and we have clean fuel in the system. Tried again …. No change. Problem remains.
When this problem started I spoke with my brother who lives in Patna and has an automobile workshop for his advice. His suggestion was to get the starter motor carbon brushes replaced.
The car is a daily drive home to office and back. Hence it would start at home in the morning and at evening in the office as engine would be cold. We kept on using the car and sometime in March went to an authorised Maruti workshop. They are one of the largest dealers of NCR. Met the service Manager and demonstrated the problem. He suggested to com e on a weekday as they are busy on weekends. Went to him on Monday. His diagnosis was Common Rail sensor.
The car was handed over to their ace mechanic. The mechanic swapped parts from their own Dzire ZDI demo car. They changed the complete Common Rail with sensors and replaced one glow plug. Prior to this they used their scanning tool and checked for error codes No errors were displayed. Also checked the immobilizer and key settings using the scan tool. I had brought both keys of my car here. Both keys with remote were used to trouble shoot
They disconnected the fuel tank fuel pump and used their own test fuel pump .It’s a rig with small tank pipes and electrical connectors. Started the car and the behaviour remained same. No changes. They also checked the cranking RPM which was around 300and normal. (Don’t remember the exact value) The battery was also swapped from their own car. My battery was about 1 year old when the problem started.
I spent my whole afternoon here hoping to nail the problem but could not. They said to leave the car to further investigate. Did not leave it with them. Bill for this exercise was Rs. 2400/-. I mentioned to them if the starter motor could be an issue. Everyone said the engine is turning at the correct speed when cranked. The starter is doing its job.
After using the car for few weeks I went to an expert in Delhi. Here they again did a scan. No error code. Was told that sometimes error codes don’t show up hence they changed the cam position sensor and crank sensor. Checked the main fuel pump relay and all electrical connections. Here too I asked if the starter motor is fine. Everyone said no problem with it. I was then told to take the car to a fuel pump repair shop. They are located in Zamrudpur and specialize in repairing high pressure fuel injection pump.
Here we replaced the main high pressure fuel pump with a reconditioned pump. Changed the 2 sensors on the common rail. Spent about 3 hours. The problem remains. Both workshops did not bill me anything saying we cannot charge as we did not solve the problem.
Kept on using the car and even went to Shimla and came back. The car performed flawlessly apart from the starting problem. Got overall fuel average of 21 km/l. By now the car had clocked 88000 kms. The only thing which was not checked or serviced was the starter motor as advised by my brother. On a Saturday morning I took the car to my neighbourhood mechanic. Told him to replace the carbon brushes of the motor. The electrician checked the starter motor by cranking. He said no problem in your starter. I insisted on him servicing the starter motor and replacing the carbon brushes.
The starter motor is placed behind the engine towards the fire wall lower down. It is fastened by 2 allen bolts. While trying to loosen the bolt the allen key sheared the groves of bolt head and this bolt could not be loosened anymore. This bolt is inside the gear box bell housing and cannot be reached until the gear box is removed. Disheartened, came back home. Spoke with my brother and he said to remove the gearbox and get the starter carbon brushes replaced. Since the gear box was to be removed I also planned for new clutch plate pressure plate and release bearings as the car had clocked 89000 kms on original clutch
The gear box was removed from the engine and the damaged bolt could be accessed easily. The bolt was loosened and the starter motor came out. The electrician serviced the starter and replaced the carbon brush plate. New clutch fitted. The engine fired up in one go with less than 2 seconds of cranking. Switched off and started 5 times. Every time the car started normally. I could not believe this. Used the car for few days and never did face the dreaded starting problem. Even when the engine was hot. Finally I was convinced that the problem has been resolved. SUCCESS AT LAST
It was the carbon brushes that was causing the problem. On closer inspection the carbon brushes had some life left but the pigtail wire connecting the brushes had become loose at the point where it meets the brush. The carbon had changed its colour too indicating overheating. Some flaking and erosion on the carbon brush surface was also present. Again a sign of over heating
The question as to why doesn’t the car start when it’s cranking at the desired speed?
Most Swift diesel owners must have experienced that they need to change the battery even when it keeps on cranking and starter runs at normal speed. The car does not start because there is voltage drop at the ECM /ECU. At this low voltage, say 8 volts the ECU does not work or gives signal and hence the engine fails to start. This probably is a design fault with the Swift ECU as it stops working if the voltage falls below a certain threshold value. I don’t know what this value is but it is quite high as the starter motor still cranks at its normal speed. As told to me by my brother a battery which fails to start a swift diesel easily starts his Toyota Quails. Even Ford Figo works fine with battery rejected by Swift Diesels.
In my car we had a good battery but the starter was drawing lot of current and this resulted in voltage drop at the ECU hence the starting problem. Not sure if Maruti has modified the ECU to work on a lower voltage. It also seems the authorised Maruti dealers are not aware of this problem.
Last edited by Aditya : 15th October 2016 at 08:26.
Reason: Spacing rectified
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14th October 2016, 17:35
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Thanks
