Hot fault

[lbrogs]

Ive got a caddy 2008 van lwb, when i go i short or distance runs and the van warms up, if i stop starting is a real problem, the engine struggles to turn over like the batteries flat but its definatley not, in most cases if i wait 20 minutes it starts again, the fist couple of turns of the engine seem to be a real strain??? I changed a sensor, (cant remember what it was) located below the cam belt..... what a job that was! but still happening, any ideas, she goes on a jump start but the battery reads full?????? very often when this happens I jump it if I cant be bothered to wait, today for the second time I got stuck at a busy set of lights which is bloody annoying and embarrassing. Also when i start now I keep the key turned when starting after the van has fired up, only for a second, just to be sure, in the past the van starts and if it cuts out restarting can be a nightmare, Im a one man outfit self employed, just gone out on my own and hope Ive not invested a load of cash on a dog of a van. Any suggestions are welcome but please talk to me like Im a child, I really dont understand engines. Cheers Lee.

And a special thatnks to Pappa Bear, a member here who told me about this site and stopped to see if he could help.

[Doc]

Hi, welcome to the forum.

The hot start problem is a strange one on those engines. Essentially, the engine ECU must see a engine speed above a certain threshold before it will permit injection of fuel. There are a few theories.
1. Battery is weak, not supplying enough current to turn the engine over fast enough.
2. Starter motor weak, again not turning over the engine fast enough.
3. Wiring fault, causing high resistance on the supply to the starter motor and thus reducing overall output and starting RPM.

People have fitted new batteries, new starters, cleaned up wiring terminals, all seem to help.

The one solution that always works is to have a specialist change the setting in your engine ECU to permit start of injection while hot at a lower RPM. Software like VCDS which quite a few forum members have, can make this change.

[Papa Bear]

Welcome to the forum, glad you got home ok.
@Doc, what is the entry in VCDS that needs changing and what value would you recommend?
@lbrogs, I have VCDS but I’m no specialist!

I think it will need the other things checking as well though as it was really struggling to turn over.

[Doc]

With VCDS:
1. select engine module
2. Security login (code 12233)
3. Adaptions, read channel 1
4. Increase channel 1 value and save.
5. Test.

Channel 1 can be set 0-100 if I remember correctly. From experience, you don't need to set the value very high to resolve the hot start problem but the option is there.
Google search "VCDS EDC16 hot start fix" to satisfy yourself that this is a viable solution.

If the engine is struggling to turn over even on the first attempt, that would suggest a battery issue.

[lbrogs]

First thing all is normally well, its only when i stop start between jobs and quotes, do you think it could still be a battery problem?? I have to pop out in a mo, when i get back Ill check what battery I have

[Zeberdeecaddy]

Not sure if this’ll help , but i had a very similar problem .

I changed the temp sensor , next to the thermostat , & that cured it .

Would take ages to start when hot & when it did there was a lot of exhaust smoke .

[Doc]

Was your coolant temperature sensor reading incorrectly to warrant changing it?
I've seen this mentioned a few times but never read of anyone checking if it's reading incorrectly to begin with. On the EDC15 controlled engines, the fuel temperature sensor used to give trouble and cause a similar problem but this is not common on the EDC16 controlled engines.

[Zeberdeecaddy]

I didn’t , I don’t have access to it .

I went old school diagnostics .

It would always start fine when cold & slowly started getting worse when the engine was warm . When it faulted , it always had excess black smoke when it finally started , so pointed towards excess fuelling .

As we started to get into summer & the outside air temp started to rise , it got worse on cold starts .

I had a similar issue before with a Skoda pickup diesel .

Replaced the temp sensor with a new genuine one & it’s been fine since , no matter how hot the engine gets .