[CRDIsamir]

I would like to get help from all the technical gurus and Mahindra Logan owners if they have faced the problem.

10 days back we got a Mahindra Logan. The problem reported was that the engine stalled all of a sudden. The Engine overheat light had flashed when the engine stalled. The vehicle was taken to Mahindra dealership. They have advised to replace the HP pump. The customer brought to me the HP pump & injectors for repairs. Ontesting the same they were found to be in perfect condition. Even then the vehicle did not start and the dealership is adamant on replacing the HP pump.

I personally checked the vehicle and found the engine timing OK. When I attached the scanner onto the vehicle it is showing 2 errors,
1. Coherence between Camshaft & Engine Speed
2. Preheating Unit Diagnostic connection open circuit.

Thinking this to be a problem with the vehicle electronics I suggested the customer to bring the vehhicle to my workshop for further diagnosis. When the vehicle was brought to my workshop I rechecked the injectors and serviced them again. On fitting the Injectors the vehicle started immediately. Now when the vehicle was completed after fitting the engine foundation and other fitting which has to be removed for removal of the HP pump the vehcile is not starting again. On hooking the scanner again the same above two errors are displayed.

Now with the 2nd error which is displayed I think there is some problem with power supply from the ignition switch to the ECU or something like that

I have checked all the connectors in the wiring cleaned them with WD-40. In the meantime I called a similar Logan from one of my friends and swapped the HP pump and Injectors on this vehicle still the vehcile did not start. The Pump and Injectors of the failed vehicle were fitted on to the other vehicle. It started instantly. So there is no problem with the HP pump & injectors.

Now the only part remains is to swap the ECU. But for this you have replace the entire lock swtich unit and the speedometer console.

Has anyone faced similar problem or can anyone guide me in this regard

Thanks in advance and eagerly waiting for response.

Samir

[wild child]

Dear Samir

Strange complaint indeed.
Anyways, I don't own a verito/Logan, nor do I run my own garage.
But, with the little mechnical knowledge I have, I guess something could've gone wrong with the following:
1. Check for diesel filter clogging.
2. Check for battery charge/Try swapping the problematic car's battery with another car's.
3. Donot swap the ECU because the ECU's hardware is built to last. Anyways, as widely known, softwares are prone to house bugs of all sort. So try flashing the ECU and reload the software.
4. Check for any broken/ torn diesel supply hose. This could suck in air while cranking the engine thereby creating an air lock resulting in starting trouble.

One more question. You had mentioned that the car doesn't start. Is the starter motor rotating the flywheel or is there only a click sound when the key is turned?

Will update the possible remedies as they keep coming to my mind.

Cheers

[bejoy]

Originally Posted by CRDIsamir

Now with the 2nd error which is displayed I think there is some problem with power supply from the ignition switch to the ECU or something like that

Second error has to do with the glow plugs. Check the condition of them and see if power comes to the leads while ignition is ON.

But I am confused, you say that the engine started after cleaning the injectors and later it does not. Was there any sensors re-connected after that? Check the RPM sensor, as the first sensor points to it indirectly.

[CRDIsamir]

Originally Posted by bejoy

Second error has to do with the glow plugs. Check the condition of them and see if power comes to the leads while ignition is ON.

But I am confused, you say that the engine started after cleaning the injectors and later it does not. Was there any sensors re-connected after that? Check the RPM sensor, as the first sensor points to it indirectly.

Thanks Bejoy.

Heres a update. This afternoon I swapped the ECUs of the two vehicle and found out that thers nothing wrong with it. The problamtic cars ECU working fine on the other car.

After that I tried pulling the vehicle with my Sierra. Still the Logan did not speak a word. But while doing this I noticed one thing that is the RPM meter is not showing any movement. Though the vehicle speed was around 20kmph the battery charging light gone, engine oil light gone still the RPM meter was at 0.

Then just to confirm we gave a bit of petrol dose in the inlet manufold just to forcibly start the vehicle momentarily and check for the RPM. Even on the scanner it is not showing any RPM reading at all.

Can you tell me where the RPM is sensed. Is it in the camshaft sensor or the crank sensor or from the alternator.

Thanks again

Samir

[bejoy]

Originally Posted by CRDIsamir

Can you tell me where the RPM is sensed. Is it in the camshaft sensor or the crank sensor or from the alternator.

It is the crank (TDC) sensor, but there could be a cam sensor also. Definitely not from the alternator. Sorry I don't know its location in Logan, but RPM sensor is generally a solid state (hall effect) sensor in the shape of a small cylinder that goes into the grove normally to the side of the engine.

[Catalyst_delhi]

You might want to check if there is a VSS, usually on the gear box housing. Vehicle speed sensor.

[jatinpatel]

If the engine speed sensor thats the Crankshaft speed sensor is not working or is giving wrong values then the car will NOT start as engine speed plays a key role in managing the fuel maps injector timming and so on.

Try swapping the Crankshaft sensor and then observe.

Engine speed is given from crankshaft 99% of time as if its taken from cam-shaft the the speed will be half of that of actual crank speed hence suitable calibration would need to be done which inturn makes the process more complicated.
Cam-shaft sensor output decides the fuel injection timming and in case its a petrol car then spark timming too.

[Sankar]

Originally Posted by CRDIsamir

I personally checked the vehicle and found the engine timing OK. When I attached the scanner onto the vehicle it is showing 2 errors,
1. Coherence between Camshaft & Engine Speed
2. Preheating Unit Diagnostic connection open circuit.

Look like:
1) Camshaft/crankshaft sensor error. Swap and try. Swap the cam sensor first.
2) Probably the glow plugs or the glow plug circuit. Circuit not getting closed, meaning glowplug(s) not working? Check that out.

[CRDIsamir]

Originally Posted by Catalyst_delhi

You might want to check if there is a VSS, usually on the gear box housing. Vehicle speed sensor.

Originally Posted by Sankar

Look like:
1) Camshaft/crankshaft sensor error. Swap and try. Swap the cam sensor first.
2) Probably the glow plugs or the glow plug circuit. Circuit not getting closed, meaning glowplug(s) not working? Check that out.

I have already swapped the sensors with the other vehicle. Now I doubt the wiring loom which could be faulty

[SS-Traveller]

Originally Posted by CRDIsamir

2 errors,
1. Coherence between Camshaft & Engine Speed
2. Preheating Unit Diagnostic connection open circuit.

On fitting the Injectors the vehicle started immediately. Now when the vehicle was completed after fitting the engine foundation and other fitting which has to be removed for removal of the HP pump the vehcile is not starting again.

Originally Posted by CRDIsamir

Now I doubt the wiring loom which could be faulty

My thoughts exactly. Undo the wiring that was required to be done up after fitting the HP pump. Somewhere, there's possibly an invisible break in the wiring. Would be really tough to pinpoint. Wish you good luck!! (Look for areas with sharp bends - that's all I can suggest...)

Incidentally, do you get a part-harness for the Logan, or does one have to buy the complete harness?

[CRDIsamir]

Originally Posted by SS-Traveller

My thoughts exactly. Undo the wiring that was required to be done up after fitting the HP pump. Somewhere, there's possibly an invisible break in the wiring. Would be really tough to pinpoint. Wish you good luck!! (Look for areas with sharp bends - that's all I can suggest...)

Incidentally, do you get a part-harness for the Logan, or does one have to buy the complete harness?

Thanks for the suggestion. I am on the track as per you. But unfortunately part-harness is not available. You have to go in for the entire wiring harness. Anyway I am following all the wires as per the color code from the connector socket upto the ECU. Hope i will find some wire cut.

Regards

Samir

[Catalyst_delhi]

Originally Posted by CRDIsamir

Thanks for the suggestion. I am on the track as per you. But unfortunately part-harness is not available. You have to go in for the entire wiring harness. Anyway I am following all the wires as per the color code from the connector socket upto the ECU. Hope i will find some wire cut.

Regards

Samir

I am not sure with the Logan , in Fords there is an IFS inertial Fuel Switch , A high impact can upset it. This may be at the front left foot-well or in the boot right side. Or maybe the immobilizer is activated. I am not good with Renault's , I am more used to Fords.

[CRDIsamir]

Thanks everyone for the inputs. Today the Logan finally started. The main culprit was missing 12v supply from the ignition switch to the ECU and the IMV on the HP pump. It took almost 12 hours for the electrician to pinpoint the fault and rectify it.

Anyway thanks again for the support

Regards

Samir

[SS-Traveller]

Originally Posted by CRDIsamir

The main culprit was missing 12v supply from the ignition switch to the ECU and the IMV on the HP pump.

What was it? Broken wire? Your electrician needs special kudos for persistence.

[CRDIsamir]

Originally Posted by SS-Traveller

What was it? Broken wire? Your electrician needs special kudos for persistence.

Yes the connector at the ECU were bent and were not in good contact.

Hats off to the electrician. The guy was on the job for nearly 10 hours. But finally he got it right.

Delivered the vehicle to the customer yesterday.

Thanks again SS and regards

Samir