fault codes

Richarddiscoverytwo · Oct 19, 2016

good morning all

Its been a while since I posted because all is going good with my disco two td5 ...but I have a cold starting issue and could do with some decent advice.

I connected my Lynx diagnostic interface in - and got 2 codes.
3012 driver demand 1 low fault logged
3016 inlet air temperature high

I don't believe either of these codes are to do with my cold starting problem - but does anybody know what they do mean?

And second question - does anybody have advice on cold starting problems?

ps I have already changed glow plugs and checked they are working before fitting, swapped relays - but still have the cold starting problem.

sierrafery · Oct 19, 2016

Hi,
1. first replace the air bleed valve in the rear wheel side port of the fuel filter housing(WJN500110), the driver demand code is related to the throttle position sensor, might be hystorical if it doesnt come back after you cleared it, if the IAT code is current that one can affect cold starting and it's time to change the MAP/IAT sensor in the inlet manifold though if this one is hystorical too and if still no joy do the following test: first time in the morning(when it used to start hard) dont crank it, put ignition on II and push completely the throttle 6 times in a fast sequence then wait untill the MIL warning stops flashing...if then will start easy it's time to replace the injector washers/seals,

2. unplug one glowplug no matter which one and put multimeter or controll lamp across it's terminal and body then turn ignition on to make sure the plugs get feed

3. check the ECU's red plug, if there is oil replace the injector loom ASAP and keep cleaning the plug with contact spray once a week untill all the oil leaves the harness.

Richarddiscoverytwo · Oct 20, 2016

thanks for quick reply

air bleed valve - I replaced this just over a year ago - but it may be worth revisiting
I have cleared the fault codes after a short run so they must have been historical
bleed test - I have purged the fuel system as suggested - made no difference
ecu's red plug - there was no oil in red plug, loom was replaced a couple of years ago, tested power at glow plugs - all fine
glow plugs powered for 4 secs only - 4 secs seems a bit short to me - any idea how long should they be on for?

I still have cold starting problem, although when it has started once it is fine on subsequent starts - the search continues - any help appreciated.

sierrafery · Oct 20, 2016

then measaure voltage on battery at cold start while you crank it, if the voltage drops below 10.5V then you'll need a new strong battery ...or leave a charger over night on the battery and if the cold start issue is gone after that it's certain that you need new battery, dont fit anything below 100AH/900CCA(both values are minimal requirement)

if this test is passed again and no change with fully charged battery connect the tester and read the fuel temp live input in the morning with stone cold engine.... it must be equal with the coolant temp reading, if it's not replace the fuel temp sensor(in the FPR)

Richarddiscoverytwo · Oct 20, 2016

Thanks again for advice, you have given me a few leads which I will be working on over the next few days
I have ordered a gen LR bleed valve as advised - just in case
I will check the batt first thing tomorrow when its cold

am still wondering if glow plugs powered for 4 secs only is too short?

and how can I check the fuel temp and coolant temp...sorry if this question is a daft one...but I have a better understanding of the mechanicals than the electricals

brian47 · Oct 20, 2016

Richarddiscoverytwo said:
glow plugs powered for 4 secs only - 4 secs seems a bit short to me - any idea how long should they be on for?

The glow plug time is variable and dependant on the coolant and therefore the engine temperature; the colder the engine, the longer the glow plugs will fire for.

sierrafery · Oct 20, 2016

I presumed that the lynx tool is your's ...if it is there is a "live data" section where you can see sensor inputs

Richarddiscoverytwo · Oct 20, 2016

hmmm goes off to check my Lynx, thank you again

Richarddiscoverytwo · Oct 20, 2016

brian47 said:
The glow plug time is variable and dependant on the coolant and therefore the engine temperature; the colder the engine, the longer the glow plugs will fire for.

a little more knowledge gleaned, thank you

Richarddiscoverytwo · Oct 28, 2016

sierrafery said:
then measaure voltage on battery at cold start while you crank it, if the voltage drops below 10.5V then you'll need a new strong battery ...or leave a charger over night on the battery and if the cold start issue is gone after that it's certain that you need new battery, dont fit anything below 100AH/900CCA(both values are minimal requirement)

if this test is passed again and no change with fully charged battery connect the tester and read the fuel temp live input in the morning with stone cold engine.... it must be equal with the coolant temp reading, if it's not replace the fuel temp sensor(in the FPR)

measured voltage and it was 9.7 - so ordered and now fitted a new battery
read fuel and cooling water temp - 15.2 and 15.8 respectively, I think that is probably fine

fuel bleed valve - I ordered one, fitted it and took a short drive, engine cut out 4 times due to fuel starvation. Contacted seller he sent another one...fitted it...engine cut out again, so old bleed valve is back in place.

I still have the same problem (cold starting) any suggestions what to try next?

sierrafery · Oct 28, 2016

next move should be injector copper washers(and o-rings) then

fault codes

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