The 75 and ZT Owners Club Forums - View Single Post - MG ZT 2004 Facelift Diesel not starting. Help Please!

PaulE · 5th April 2021, 11:45

I'm still trying to save this MG ZT whilst still viable.. Appreciate any help / suggestion at this stage to save the car!

I have now made a YouTube video showing the condition of the ECU, attempted starting and attempted starting with easy start, along with TOAF readouts.

Video here:
https://youtu.be/k2dvIdLi30A

Upon further investigation, it appears that the Plenum had been blocked for a while and part filled with water. (Slapped wrists,

it was cleaned out a year ago, but has been parked under trees over a wet year..!)

The glow plug relay was badly corroded and inoperable. This has now been replaced. No change when attempting to start the car.

The ECU had been partly under water.

Although the car had been starting and driving in that condition

I removed the ECU from its housing in an anti-static environment, and cleaned off Water corrosion. It appeared the lower third had become dipped, particularly when going round corners. I've attached some high res pics of the front and back of the ECU in its current state.

Referring to : https://www.the75andztclub.co.uk/for...splay.php?f=11
“B) Check your plenum drain
There will likely be a host of other symptoms available to confirm that your ECU is playing up such as erratic dials, malfunctioning electrics.”
There are no other apparent symptoms – Dials all operate as expected and hadn’t shown any issues. Electrics all seemed function perfectly. TOAF managed to talk to and configure ECU.

Back to the mechanics:
The fuel filter, oil filter and oil had all been changed within the last few months in a service - Although we decided not change the pollen filter, hence not noticing the build-up of dirt in the plenum water runoff.

Looking at low pressure side fuel flow, we removed the fuel connector both sides of the filter and there is good flow. The In-tank fuel pump does not seem to struggle in flow or sound.
The high pressure pump was replaced a few years back, and sounds OK. I have not tried opening the high pressure common rail to check we actually have pressure there.

Given the sounds (see video) Our current thought is there is no fuel getting into the engine - the sound with / without easy start seems to suggest that, plus the lack of diesel smell at the exhaust.

We're exploring the idea that parts of the ECU may be misbehaving as a result of its recent swimming lessons..?

Is there any information on how to safely measure the signals at the injectors with an oscilloscope? I will have a read through the forum, but if anyone knows or has a link, that would be greatly appreciated. It would be useful to know if the ECU is not reading data or controlling IO properly. E.g. TOAF comms OK, some starting actions seem OK, but has some IO function to sensor / injectors failed?

An EWS Immobiliser fault registers under TOAF as shown, but the immobiliser is allowing starting. I did remove the chip from the key and try starting, and the immobiliser appeared to function as expected, not even a cranking sound. Returning the chip returned cranking as expected. What might cause that?

The temperature sensor was replaced and the temperature showing correctly in dash a few months ago. But the temperature sensor error is confusing - is the ECU not seeing or reacting to that hence the TOAF error?

I do have some electronics experience and test equipment and would rather not just write off the ECU - it would be very useful to know if there is damage and what that manifests in, and if it is repairable. If there are a stock of new unprogrammed 75 / ZT ECUs, what is the going rate of supply and code?

Would a T4 session provide more insight into wellbeing of the ECU? We are in the Buckinghamshire area.

On another note, I do have a Rover 75 diesel we can borrow parts from. The engine works beautifully in it, but sadly that car suffered severe internal rot to the upholstery before I received it and rust in the sills. It has been useful maintaining our other 4 Rover / MGs as a donor. Its sat there for a year and a half and a quick flip of the key and it started

. But it's sadly no longer viable as a road car. We used this as the donor for the glow plug relay, for instance.

Although I've put the screengrabs in the video, here's the TOAF readout:

===
TOAF Readout after clearing errors but before turning over:

0100 - air mass meter
0110 - temperature sensor

Expanding the 0100 - Air Mass Meter:

Errors count 3
Sporadic error

Error 1
Engine speed : 0.00 1/min
Engine coolant temperature : 10.86 c
Injection volume 26.63 mm3
Rail Pressure : 0.0 bar
Current odometer : 331550 km

Error 2
Engine speed : 0.00 1/min
Engine coolant temperature : 8.81 c
Injection volume 28.67 mm3
Rail Pressure : 0.0 bar
Current odometer : 331550 km

3505 Glow Device.

==================
After turning the car over, as per video, the following error added:

1DF5 - Electronic car immobilisation system (EWS)

Errors count 1
Error Present
Error 1
Engine speed : 0.00 1/min
Engine coolant temperature : 14.95 c
Injection volume 23.55 mm3
Rail Pressure : 12.05 bar
Current odometer : 331550 km

=====

I have checked each of the points in the non-starting guide:

“A How much fuel do I have?”
Top quarter (see video). No variation on performance if tank if full or part full. We don’t run our diesels below bottom quarter.
“You should be able to hear the rear pump making a high pitch whine by listening to the rear wheel arch or pressing your ear to the rear seat base. If still unsure, remove the rear seat and feel the access panel for vibration. This will indicate that the pump is working.”
We can hear this. Sounds fine.

“B) Check your plenum drain. There will likely be a host of other symptoms available to confirm that your ECU is playing up such as eratic dials, malfunctioning electrics.”
Half filled with water. Drained and left for two weeks.

“C) Start the car with Easy Start
ii) If the car does not start on ES”
• Battery – fully charged.
• Synergy Box – not fitted.

I’ll try these things next:
• Fuel Pressure Sensor – Replace
• Cam and Crank sensor

And then will look costs for:
• Serious High Pressure Control Valve Regulator Seal .
• ECU / ECU Capacitors - Replacement ECU and a session on T4.

Any help appreciated, I would dearly love not to scrap the car, we have a bit of a history and has very recently had a new complete clutch and tyres! When it drives, it’s really quite punchy and fun, so worth saving if possible

I also promise to come back to the forum with the resolution / outcome.

Thanks,

Paul.

5th April 2021, 11:45	#5
PaulE Regular poster MG ZT 135+ (04), MG ZT-T (06), Rover 75 (01) Join Date: Jul 2012 Location: London Posts: 63 Thanks: 7 Thanked 7 Times in 4 Posts	We now know the ECU has been under water... I'm still trying to save this MG ZT whilst still viable.. Appreciate any help / suggestion at this stage to save the car! I have now made a YouTube video showing the condition of the ECU, attempted starting and attempted starting with easy start, along with TOAF readouts. Video here: https://youtu.be/k2dvIdLi30A Upon further investigation, it appears that the Plenum had been blocked for a while and part filled with water. (Slapped wrists, it was cleaned out a year ago, but has been parked under trees over a wet year..!) The glow plug relay was badly corroded and inoperable. This has now been replaced. No change when attempting to start the car. The ECU had been partly under water. Although the car had been starting and driving in that condition I removed the ECU from its housing in an anti-static environment, and cleaned off Water corrosion. It appeared the lower third had become dipped, particularly when going round corners. I've attached some high res pics of the front and back of the ECU in its current state. Referring to : https://www.the75andztclub.co.uk/for...splay.php?f=11 “B) Check your plenum drain There will likely be a host of other symptoms available to confirm that your ECU is playing up such as erratic dials, malfunctioning electrics.” There are no other apparent symptoms – Dials all operate as expected and hadn’t shown any issues. Electrics all seemed function perfectly. TOAF managed to talk to and configure ECU. Back to the mechanics: The fuel filter, oil filter and oil had all been changed within the last few months in a service - Although we decided not change the pollen filter, hence not noticing the build-up of dirt in the plenum water runoff. Looking at low pressure side fuel flow, we removed the fuel connector both sides of the filter and there is good flow. The In-tank fuel pump does not seem to struggle in flow or sound. The high pressure pump was replaced a few years back, and sounds OK. I have not tried opening the high pressure common rail to check we actually have pressure there. Given the sounds (see video) Our current thought is there is no fuel getting into the engine - the sound with / without easy start seems to suggest that, plus the lack of diesel smell at the exhaust. We're exploring the idea that parts of the ECU may be misbehaving as a result of its recent swimming lessons..? Is there any information on how to safely measure the signals at the injectors with an oscilloscope? I will have a read through the forum, but if anyone knows or has a link, that would be greatly appreciated. It would be useful to know if the ECU is not reading data or controlling IO properly. E.g. TOAF comms OK, some starting actions seem OK, but has some IO function to sensor / injectors failed? An EWS Immobiliser fault registers under TOAF as shown, but the immobiliser is allowing starting. I did remove the chip from the key and try starting, and the immobiliser appeared to function as expected, not even a cranking sound. Returning the chip returned cranking as expected. What might cause that? The temperature sensor was replaced and the temperature showing correctly in dash a few months ago. But the temperature sensor error is confusing - is the ECU not seeing or reacting to that hence the TOAF error? I do have some electronics experience and test equipment and would rather not just write off the ECU - it would be very useful to know if there is damage and what that manifests in, and if it is repairable. If there are a stock of new unprogrammed 75 / ZT ECUs, what is the going rate of supply and code? Would a T4 session provide more insight into wellbeing of the ECU? We are in the Buckinghamshire area. On another note, I do have a Rover 75 diesel we can borrow parts from. The engine works beautifully in it, but sadly that car suffered severe internal rot to the upholstery before I received it and rust in the sills. It has been useful maintaining our other 4 Rover / MGs as a donor. Its sat there for a year and a half and a quick flip of the key and it started . But it's sadly no longer viable as a road car. We used this as the donor for the glow plug relay, for instance. Although I've put the screengrabs in the video, here's the TOAF readout: === TOAF Readout after clearing errors but before turning over: 0100 - air mass meter 0110 - temperature sensor Expanding the 0100 - Air Mass Meter: Errors count 3 Sporadic error Error 1 Engine speed : 0.00 1/min Engine coolant temperature : 10.86 c Injection volume 26.63 mm3 Rail Pressure : 0.0 bar Current odometer : 331550 km Error 2 Engine speed : 0.00 1/min Engine coolant temperature : 8.81 c Injection volume 28.67 mm3 Rail Pressure : 0.0 bar Current odometer : 331550 km 3505 Glow Device. ================== After turning the car over, as per video, the following error added: 1DF5 - Electronic car immobilisation system (EWS) Errors count 1 Error Present Error 1 Engine speed : 0.00 1/min Engine coolant temperature : 14.95 c Injection volume 23.55 mm3 Rail Pressure : 12.05 bar Current odometer : 331550 km ===== I have checked each of the points in the non-starting guide: “A How much fuel do I have?” Top quarter (see video). No variation on performance if tank if full or part full. We don’t run our diesels below bottom quarter. “You should be able to hear the rear pump making a high pitch whine by listening to the rear wheel arch or pressing your ear to the rear seat base. If still unsure, remove the rear seat and feel the access panel for vibration. This will indicate that the pump is working.” We can hear this. Sounds fine. “B) Check your plenum drain. There will likely be a host of other symptoms available to confirm that your ECU is playing up such as eratic dials, malfunctioning electrics.” Half filled with water. Drained and left for two weeks. “C) Start the car with Easy Start ii) If the car does not start on ES” • Battery – fully charged. • Synergy Box – not fitted. I’ll try these things next: • Fuel Pressure Sensor – Replace • Cam and Crank sensor And then will look costs for: • Serious High Pressure Control Valve Regulator Seal . • ECU / ECU Capacitors - Replacement ECU and a session on T4. Any help appreciated, I would dearly love not to scrap the car, we have a bit of a history and has very recently had a new complete clutch and tyres! When it drives, it’s really quite punchy and fun, so worth saving if possible I also promise to come back to the forum with the resolution / outcome. Thanks, Paul.