Disco 3 2.7 tdv6 wont start 😬

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Graculus said:
Which is why I asked you to put a pressure / vacuum gauge on the inlet to see the suction (or pressure) created. If there was an exhaust issue, there would be an old DTC. In any case, you could just stuff some newspaper up the exhaust pipes, crank it and see if they blow out, it might take a few seconds as it's cranking not running speed.
Click to expand...
Yea easy to check that but worth it. I know you said about vacuum test, I just don't have a guage yet. Also my batteries don't seem to turn it over that fast or for that long. I have a 95ah Halford battery that came with it and a less than a year old napa from my x5 and neither last that long before needing charge. I'm sure it's unrelated but weird as it spun my 3.0D six cylinder engine up for ages.
 
Do a volt-drop check between the engine and the -ve battery terminal, it should be less than 0.5V during cranking.
It could also be the starter is getting tired...
 
Starting issues can be engine earth strap related, but as this cut out....
BTW, what is the measured voltage during cranking a) at the battery, b) at the ECM c) at the VCV or PCV? use a ground point on the body, not directly to the battery -ve. Also check something like the fuel rail pressure sensor across the 5V & sensor ground (pins 3 & 2 respectively) also whilst cranking.
It's worth doing a volt drop check between the battery -ve and the engine, just to have a measurement to eliminate as a contributory factor.
 
Graculus said:
Starting issues can be engine earth strap related, but as this cut out....
BTW, what is the measured voltage during cranking a) at the battery, b) at the ECM c) at the VCV or PCV? use a ground point on the body, not directly to the battery -ve. Also check something like the fuel rail pressure sensor across the 5V & sensor ground (pins 3 & 2 respectively) also whilst cranking.
It's worth doing a volt drop check between the battery -ve and the engine, just to have a measurement to eliminate as a contributory factor.
Click to expand...
Yes ok I'll do some poking tomorrow. Er...ECM...engine control module, VCV or PCV ?? Control valves.....volume and positive crank ventilation? Is that the one in the top of the y piece? I took that out and it was all cruded up with black stodge. Sorry I'm not used to the terms... I do air cooled VW's with points and carburettors 😆
 
Engine Control Module, Volume (Pressure) Control Valve - both on the HP fuel pump. Don't measure across it / them as they have a variable ground connection, they have - or should have an ignition +ve, measure from there to a good body ground.
 
Graculus said:
Starting issues can be engine earth strap related, but as this cut out....
BTW, what is the measured voltage during cranking a) at the battery, b) at the ECM c) at the VCV or PCV? use a ground point on the body, not directly to the battery -ve. Also check something like the fuel rail pressure sensor across the 5V & sensor ground (pins 3 & 2 respectively) also whilst cranking.
It's worth doing a volt drop check between the battery -ve and the engine, just to have a measurement to eliminate as a contributory factor.
Click to expand...
So interestingly battery just been fully charged ignition off 12.5v, ignition on 12.1v, cranking 9.9v !! I am presuming that's not really enough to make it go broom. It is sort of trying with every rotation.. I must admit it sounds like it needs a boost pack on it but sadly mine has died. Is it OK to jump these or a big no no? Cheers
 
charlie@autoworxengineeri said:
So interestingly battery just been fully charged ignition off 12.5v, ignition on 12.1v, cranking 9.9v !! I am presuming that's not really enough to make it go broom. It is sort of trying with every rotation.. I must admit it sounds like it needs a boost pack on it but sadly mine has died. Is it OK to jump these or a big no no? Cheers
Click to expand...
9.9V is either a battery on the way out or the starter drawing excessive current, neither will help as the voltage at the control modules will be below what is required.
You can jump start with proviso's...
Connect to donor vehicle (DV) with good jump leads, direct to battery terminals on both vehicles, start engine on DV & turn on heated screen, put cabin blower fan at full, attempt start on Disco3 - for no more than 10 seconds, then 'rest' for 1 minute - repeat as required. When finished, turn off engine of DV first, wait 30 seconds then disconnect jump leads.
 
Graculus said:
9.9V is either a battery on the way out or the starter drawing excessive current, neither will help as the voltage at the control modules will be below what is required.
You can jump start with proviso's...
Connect to donor vehicle (DV) with good jump leads, direct to battery terminals on both vehicles, start engine on DV & turn on heated screen, put cabin blower fan at full, attempt start on Disco3 - for no more than 10 seconds, then 'rest' for 1 minute - repeat as required. When finished, turn off engine of DV first, wait 30 seconds then disconnect jump leads.
Click to expand...
Wow, ok..so just to be sure do you mean turn on heated screen and blower on dead disco while attached to donor vehicle?
 
charlie@autoworxengineeri said:
So interestingly battery just been fully charged ignition off 12.5v, ignition on 12.1v, cranking 9.9v !! I am presuming that's not really enough to make it go broom. It is sort of trying with every rotation.. I must admit it sounds like it needs a boost pack on it but sadly mine has died. Is it OK to jump these or a big no no? Cheers
Click to expand...
It is easy to go off at all sorts of angles you must remember that it was going along the road and died this is not going to be a tired battery, (this maybe another problem) when I was working on my van I disconnected a injector (with everything off) and used a volt meter on 250v ac to see if I got any sort of input into the injectors, I have also used a meter on Hz, all you are looking for is signs that something is being sent to the injectors if no volts then that point to the problem being electrical of some sort, normally if this is a problem it will fire on easy start
 
Ian M in France said:
It is easy to go off at all sorts of angles you must remember that it was going along the road and died this is not going to be a tired battery, (this maybe another problem) when I was working on my van I disconnected a injector (with everything off) and used a volt meter on 250v ac to see if I got any sort of input into the injectors, I have also used a meter on Hz, all you are looking for is signs that something is being sent to the injectors if no volts then that point to the problem being electrical of some sort, normally if this is a problem it will fire on easy start
Click to expand...
Ha, yes can't help but get back to the topic of easy start 😆. Still cannot understand why it doesn't fire with it, but will remove an injector if I get chance tomorrow and check functionality. Cheers
 
Maybe the x5 requires less power to turn the engine at a sufficient speed, possibly it can cope with lower voltage at the ECUs
Anything under 11v is considered a weak battery. Assuming it is fully charged to start with
 
kermit_rr said:
Maybe the x5 requires less power to turn the engine at a sufficient speed, possibly it can cope with lower voltage at the ECUs
Anything under 11v is considered a weak battery. Assuming it is fully charged to start with
Click to expand...
Mm, ok. Yeah literally just come off charge. I have two decent (well they test as decent) batteries and they are both the same with regards to voltage drop.
 
kermit_rr said:
That should be fine, what voltage does it give?
Click to expand...
Well actually the one that came with the truck is showing 12.2v and 11v under load, which should be fine. The one from my X5 now seems knackered so maybe a battery is in order before moving much further on with this. I thought I had that covered but apparently not. It's not the root of the problem but won't help.
 
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