View Full Version : Strange XE starting problem when warm
Car starts fine first thing in the morning and I drive to work. If however I have to stop for petrol or whatever and turn the car off it is really strange starting it again. It fires up but revs hunts up and down and it stinks of fuel. Try and rev it and it coughs and splutters and then cuts out. If you then try and restart it it might do it again or it might run fine.
It does this every time I start it for the first time when warm so now I just turn it straight off and try again. Once I get it running normally it will run perfectly until I turn it off again.
This one has me really confused, it's like something isn't resetting properly but no idea what it could be.
No fault codes and no ecu light when problem occurs.
Any ideas?
I am sure you have a few spare CTS's lying about - anything temperature related and I would change it!
david dixon
19-05-10, 08:33 AM
its not a faulty water temp switch is it?
David.
Changed the cts for a brand new GM one a few months ago. Fitted old one last night and still same problem. Should have mentioned that.
ICV sticking, faulty AFM lee.?
Can't see why the afm would keep changing between being ok and faulty and not cause any issues once running.
Did think about the icv maybe sticking but couldn't think how it would make it overfuel so much. Might take it off and change it tonight though.
Southie
19-05-10, 12:58 PM
Could a dodgy fuel pump or fuel filter be the fault or even the earth to the fuel pump?
Can't see why the afm would keep changing between being ok and faulty and not cause any issues once running.
Did think about the icv maybe sticking but couldn't think how it would make it overfuel so much. Might take it off and change it tonight though.
Has it got a lambda sensor lee could be that at fault it may not be showing a fault as its plugged in????
Could a dodgy fuel pump or fuel filter be the fault or even the earth to the fuel pump?
Wouldnt be affected by the engine temp.
Only other thing is lambda as mentioned - that and CTS are the only things that require a temp reading...
craig green
19-05-10, 06:14 PM
What about the wires to said CTS sensor??
Looked at timing marks just to be sure it hasnt jumped a tooth?
craig green
19-05-10, 07:07 PM
Hot start issues always stem from a crank sensor, 99% of times.
andy22sri
20-05-10, 12:20 AM
I would go with the crank sensor too your engine light will not come on unless it see fault 3 time one after the other, If you have the use of scan tools use ODB and look at pending faults.
Changed the idle control valve last night and it seems to have cured it for now. Drove it all the way to work and restarted it and it started fine.
Hot start issues always stem from a crank sensor, 99% of times.
Why? All the crank sensor does is read the teeth on the trigger wheel... Heat wouldnt affect it - unless teh sensor itself is fecked - then they tend not to start at all...
Stuck in major traffic for an hour or so on the way home tonight, was reading 26 degrees on outside temp gauge.
Turned car off when I got home and it restarted a few times over a ten minute period with no problems so thinking it might be cured.
MattBrown
20-05-10, 07:54 PM
Stuck in major traffic for an hour or so on the way home tonight, was reading 26 degrees on outside temp gauge.
Turned car off when I got home and it restarted a few times over a ten minute period with no problems so thinking it might be cured.
Good timeslol
djbrowney
20-05-10, 11:32 PM
try your lambda sensor, they dont work until the engine is warmed up, would explain the over fueling aswel !
Maybe it isn't sorted. Started doing it again tonight when I got home from work. Inside temp sensor is reading 31 degrees though and it's too hot to even touch the powercap so wondering if engine bay heat is causing the issue.
djbrowney
21-05-10, 06:27 PM
you tried lambda sometimes dosnt bring an ecu code up either !!!
Tried unplugging the lambda while its running, car runs the same and the engine management light doesn't come on which I though was strange?!
djbrowney
21-05-10, 06:53 PM
have you not got a second hand one to try ???
Tried unplugging the lambda while its running, car runs the same and the engine management light doesn't come on which I though was strange?!
It would have if you would have driven it down the street lee think somebody once said they dont work until you reach 1500rpm but dont know how true this is....
craig green
21-05-10, 07:25 PM
Why? All the crank sensor does is read the teeth on the trigger wheel... Heat wouldnt affect it - unless teh sensor itself is fecked - then they tend not to start at all...
Just speaking from experience Will. & agree it dosent really make sense. lol
have you not got a second hand one to try ???
Yes, just couldn't be arsed going under it tonight when it was so hot. Might throw my spare on tomorrow when I get the car back from its MOT retest.
djbrowney
21-05-10, 08:10 PM
lovely weather certanly not for working in lol
Problem has got worse this morning. Started doing it while I was driving. Swapped the afm at the side of the road and no difference. So I unplugged the air flow meter and it idles ok and got me to work.
Surely this points to the air flow meter or loom being the problem. More inclined to think loom as it's random when it does it?
djbrowney
27-05-10, 12:43 PM
have you changed the lambda yet :)
Can't get my spare out of the turbo elbow it's currently in. If afm unplugged is lambda ignored?
djbrowney
27-05-10, 01:00 PM
no i dont think so mate, im 100% certain its your lambda playing up thought :)
I tested it with a sensor tester and it performed how it should. Strange how problem is so random but obviously getting worse now. Will try and get a lambda too!
checked for air leaks post AFM ?
Does the XE have a hot restart valve... thats a first port of call if it does
Renault Clios suffer from overheated cranksensors.. they run fine when cold then wont restart when hot. Its to do with the magneticness of it all lol
Just gone to start it at lunch and it's running like a bag of nails with the afm unplugged? Could be until it warms up?
If I plug afm it won't rev at all.
david dixon
27-05-10, 07:03 PM
Have you tried a AFM on it? and maybe a lambda?
David.
Tried 3 air flow meters now.
Decided to try a mates ecu tonight and discovered a lot of water in the ecu plug and the pins were shorting out. Think I might have solved the problem although god knows how water gets inside the ecu plug.
david dixon
27-05-10, 11:37 PM
it must be running between the loom wires, i have seen that happen before after washing!
David
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