speedyxjs
|
| posted on 13/4/11 at 02:31 PM |
|
|
Sensors that affect starting but not running
My dad has a 1.8 TDCi transit connect which has developed a strange problem i cant figure out.
It wont start hot or cold but you can start it on easystart and it will run and drive as normal although it occasionally will cut out but bump starts
fine.
I have replaced the crank sensor, done a compression test (25, 27, 24, 26bar) and tested the air temp sensor. I have also put it on the diagnosis
equipment but no faults come up.
Does anyone have any idea where i should be looking next apart from replacing random sensors one by one till it starts?
[Edited on 13-4-11 by speedyxjs]
How long can i resist the temptation to drop a V8 in?
|
|
|
|
|
RickRick
|
| posted on 13/4/11 at 02:37 PM |
|
|
camshaft position sensor
had same sounding problem on wifes freelander
[Edited on 13/4/11 by RickRick]
|
|
|
dlatch
|
| posted on 13/4/11 at 03:08 PM |
|
|
crank sensor is a suspect for sure not upto date on the tdci but there must be a fuel stop switch somewhere too so check any sensors/switches on the
fuel pump
|
|
|
coyoteboy
|
| posted on 13/4/11 at 03:16 PM |
|
|
Usually the only sensors used to start engines are the crank and cam shaft position sensors (temp sensors obviously but don't usually stop
things starting even when dead), the rest is guessed until the engine is up to idle as the readings would be nonsensical.
[Edited on 13/4/11 by coyoteboy]
|
|
|
blakep82
|
| posted on 13/4/11 at 03:20 PM |
|
|
is there not some kind of automatic thing that pumps a bit of extra fuel in for starting only. i know they used to have them on some carbs (or was it
for acceleration?) injection's not quite the same, but is there anything that controls extra fuel going in for starting anywhere?
edit, my thinking with cam sensors or crank sensors is they'll either work or they won't, so if they don't work for starting, i
wouldn't think they'll work for running
[Edited on 13/4/11 by blakep82]
________________________
IVA manual link http://www.businesslink.gov.uk/bdotg/action/detail?type=RESOURCES&itemId=1081997083
don't write OT on a new thread title, you're creating the topic, everything you write is very much ON topic!
|
|
|
coyoteboy
|
| posted on 13/4/11 at 03:21 PM |
|
|
Depends on the engine but usually there's a cold start injector/enrichment. Older engines have an injector, newer just use the stock injectors
for longer (based on the temp sensor reading). However that's only to help things, most cars will still start without the CSI operational, just
cough a bit.
|
|
|
norfolkluego
|
| posted on 13/4/11 at 06:02 PM |
|
|
Glow plugs surely, no expert on tractor engines but surely dead glow plugs are the most likely suspect for a diesel not starting or don't modern
engines have them
<I sort of know I must have misunderstood>
|
|
|
speedyxjs
|
| posted on 13/4/11 at 06:09 PM |
|
|
quote:
Originally posted by norfolkluego
Glow plugs surely, no expert on tractor engines but surely dead glow plugs are the most likely suspect for a diesel not starting or don't modern
engines have them
<I sort of know I must have misunderstood>
Glow plugs have been changed and arn't needed when the engine is warm. Have also checked the wiring and timing for the glow plugs so its defo
not them.
How long can i resist the temptation to drop a V8 in?
|
|
|
coyoteboy
|
| posted on 13/4/11 at 06:53 PM |
|
|
Looking at all the info you gave us, and assuming you've not missed a tempramental one, could you be looking at a failing fuel pump (would have
thought it would flag an error) or a power feed to/from the injectors?
Is there a spill valve/solenoid (not sure of the common rail equiv) on this car?
If it starts on easystart and runs, it's fuel related or a position sensor. If you've replaced the position sensor it's fuel
related.
|
|
|
speedyxjs
|
| posted on 14/4/11 at 06:52 AM |
|
|
quote:
Originally posted by coyoteboy
Looking at all the info you gave us, and assuming you've not missed a tempramental one, could you be looking at a failing fuel pump (would have
thought it would flag an error) or a power feed to/from the injectors?
Is there a spill valve/solenoid (not sure of the common rail equiv) on this car?
If it starts on easystart and runs, it's fuel related or a position sensor. If you've replaced the position sensor it's fuel
related.
That was one of my first assumptions but why would it then run and drive as normal with no loss of power on only cut out once in a 10 mile drive? One
of his other vans had a fuel pump fail a few months back and the van wouldn't even hit 30mph (not joking!!!)
How long can i resist the temptation to drop a V8 in?
|
|
|
coyoteboy
|
| posted on 15/4/11 at 12:11 AM |
|
|
A spill valve fault is essentially electrical, it could be that getting the engine spinning helps the solenoid function properly with vibration/higher
voltage? We had one fail on a non-common rail car and it was completely intermittent - some weeks it would fire and run fine, some it just
wouldn't start at all for minutes, then i t would fire up and run as normal. Or it would just drop dead while driving along. Toyota had the car
in for 2 weeks and couldn't find it, it took some more detective work on our part.
|
|
|
mad4x4
|
| posted on 15/4/11 at 06:16 AM |
|
|
"Easy Start" - This is the Devils Tool - Don't use it.
Reslove the problem, Could be low compression , or Fuel Starvation or Air in the Fuel Line casuing you to crank until it is bled. Sounds like Low
Compression to me or Injectors sticking shut when cold.
Low compression can be rings or cracked head. Get a compression test done on each cylinder.
The Easystart is far more combustable that diesel so will ignite and then the mechnics of the diesel engine will keep it going.
Easystart is also like heroin to an engine once you start using it then the engine will always require it....
[Edited on 15/404/11 by mad4x4]
Scot's do it better in Kilts.
MK INDY's Don't Self Centre Regardless of MK Setting !
|
|
|
coyoteboy
|
| posted on 15/4/11 at 03:10 PM |
|
|
I'm not a believer of the easy start myth I'm afraid, there's absolutely no science behind engines getting hooked on the good stuff
lol. It's just that whatever problem caused you to use it in the first place doesn't go away and doesn't improve, so you have to
keep using it or use more.
|
|
|
hicost
|
| posted on 15/4/11 at 04:15 PM |
|
|
Leak Back
Could be an injector leaking back but probably the cam sensor.
Always keep a can of easystart in your disiel car gets you out of trouble instantly.
James
"I cant do that without accidentally grabbing hold of the work of the divine potter"
 
|
|
|
paulf
|
| posted on 15/4/11 at 08:41 PM |
|
|
I would go for an injector leaking back,I had a faulty cam sensor on my car when i first bought it and it would occasionally not start when hot.Easy
start would start it but it would not keep running as the injectors were not in sync.
if you remove the leak back pipes from each injector when the engine is running you can see how much leak back there is on each injector.
I did find the easy start was handy as I used it to cool the cam sensor when it refused to start when hot and it then allowed the engine to start.
Paul
quote:
Originally posted by hicost
Could be an injector leaking back but probably the cam sensor.
Always keep a can of easystart in your disiel car gets you out of trouble instantly.
James
|
|
|
.jpg)
