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Old 6th September 2018, 13:03   #21
Jules
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Get OBD hooked up to diagnostics to measure low and high fuel pressures.

It's a big guessing game if you don't!!
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1. Plenum drains..all 3 or 4 year dependent
2. Cooling fan..All speeds functioning
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Old 6th September 2018, 13:24   #22
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Quote:
Originally Posted by Jules View Post
Work down this list for a non starting diesel

This is how a non starting CDTi should be trouble shooted.

A) How much fuel do I have?
This is the first thing to check, especially if your car is pre-facelift and has two low pressure fuel pumps. These are located in the tank on the drivers side and under the bonnet next to the battery (left of). Post facelift have a different single intank fuel pump which to date seem to be more reliable.

Both pumps prime for between 30 seconds and 1 minute when the ignition is turned to position II.

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.

You can hear the underbonnet pump from within the car but check by opening the bonnet. It should make a continuous noise. If it is gurgling loudly, this is a sign that something is not quite right.

If your car is not starting and your fuel guage is below half it is worth adding 5 to 10 litres to the car and trying to start it again. If it does start, this is a clear indication that your intank pump may have stopped working or is on its way out. This will place more strain on the under bonnet pump which will become apparent with increased noise. Usually only the intank pump will need replacing. This can be found on ebay for around £200 and fitted with minimal mechanical knowledge. A dealer is likely to charge upwards of £350 for the part and labour.

B) Check your plenum drain
This is where the ECU is stored. Without appropriate maintenance the drains in this are become blocked and no longer allow water to be removed. As the water level grows the threat to the ECU becomes greater. Even if the ECU has not been submerged but there is water in the plenum the damp moisture can be enough to cause problems.

There will likely be a host of other symptoms available to confirm that your ECU is playing up such as eratic dials, malfunctioning electrics.

C) Start the car with Easy Start
Easy Start is a simple chemical process which allows the car to start by igniting across the top of the cylinders with a low flash point. It should not be religiously used as it can damage the engine. Due to the massive inlet tract of the diesel engine (some 5 or 6ft before the air actually reaches the engine) it is best to remove the engine cover and unscrew the jubilee clip holding the large intercooler pipe to the EGR valve assembly at the front right of the engine.

Spray a sniff of easy start into the EGR valve and get someone to crank the car over. Do not continue to spray.

i) If the car starts and runs
You can rule out any electrical component such as the Cam and Crank sensor but you cannot rule out the ECU as its capacitors could be dying.

You can (with large probability) rule out both low pressure fuel pumps as fuel starvation will not magically be cured and the engine will stall.

So what do I Check?
If you can get the car running on Easy Start, replace the Intercooler hose to the EGR valve assembly. Turn the car off, wait a minute and try and start the car normally. Chances are it will not start.

Start the car again using Easy Start and take it to your local Bosch Service Agent. These are far more competent diesel specialists than your old Ex MGR service garage and are able to diagnose with better equipment.

Possibilities now are: ECU Capacitors, High Pressure Control Valve Regulator Seal, Injector Leakback.

Associated costs are: ECU = £650 and will need T4 session to match it to the car. HPCVR = £250. Injector Leakback = from £85, FPS = £100

ii) If the car does not start on ES
If it catches but does not idle (as in, it stalls) unfortunately you are in the worst possible situation. Try the Easy Start again but do not proceed beyond this point.

You have a few choices here and there are some gambles. Personally, I would immediately get the car collected and taken to a Bosch Specialist. Recovery can cost as little as £40 if the garage is local (within 15 miles).

Alternatively you can purchase parts yourself and hope you pick the right one. Here is a list of things that will need checking / replacing.

Fuel Pumps (as earlier, make sure they are working).

Fuel Pressure Sensor - Replace

Change your Cam and Crank sensor (£110 for both as parts, Cam is easy change, crank is relatively easy but takes a bit longer as it is situated below the starter motor).

Serious Injector Leakback - If your injectors are seriously leaking, Easy Start will be useless, however there would be a very strong of diesel from the engine bay if this was the case. Suggest diagnosed / replaced by garage.

Serious High Pressure Control Valve Regulator Seal - If the seal has deteriorated and/or actually blown through then Easy Start will be useless. It will need to be addressed by the garage.

ECU / ECU Capacitors - Replacement ECU and a session on T4.

D) What other possibilites are there?
Very little other possibilities. However, you can't even rule out the battery. This is true especially if the ECU capacitors are not cranking at their correct voltage.

Synergy Box (if fitted) - Its highly unlikely that this has caused the problem or is in anyway stopping the car from starting. However it is important to remove it and return the car to standard before carrying out the above checks.

Pumps playing tricks - Attach the front underbonnet pump directly to a 5litre can of diesel and try and start the car. This will highlight a poor intank or underbonnet pump.
--
Regards
Jules
That's a pretty comprehensive list posted by Jules and you need to work through it slowly and carefully to find the results.

If it's none of those, then you have a bit of an anomaly!
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Old 1st September 2020, 15:06   #23
Don.Hasi
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I had warm start problems from the start of my 75journey. With the climate going nuts and therefore more degrees in the enginebay, it went worse. After reading most of all threads I was sure, that I have leaking injectors.

I didn't fix them until now but my fan did go pop and was repaired with the gold resistor and got fixed on the motor again, which made it better but I still had to crank a lot on very hot days.

Now the aircon went also with a system almost empty. Got it to a service. Now I have an ice cool interior with a fan which adjusts all speeds AND the car has no problem to get started in the hottest days these year and we had a lot very hot days in my surrounding.

I don't know which was the culprit at first but in the end these things are minor maintenance things which can obviously get a bad chain reaction starting. Maybe this is of any help for others.

Thanks to the community all around for giving hints on many of these things.
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