General D5252T - 96' 850 TDI, Hot Start Issue... Help!

[TomFitch]

Hi Chaps,

Wondering if any one might be able to help out with abit of a conundrum i've got with my old 850.

Issue:
After making a journey of greater than say 10mins, so the engines upto temp and the gauge is at 3'oclock; if i then park up and stop the car, in say a petrol station or to pop to the shops, on returning the car it refuses to re-start.

It just cranks and cranks... by cranking for 30secs, stopping, cranking, stopping and cranking it again, it does occasionally pick up and fire; but sometimes it will just run the battery flat without firing. If i leave the car for say an hour or 2, it will normally start without too much hassle. So i'm lead to believe its got to be a heat issue...

I've tried numerous ideas, and am going slowly mad trying to suss this out.


Idea's Tried:

Fuel Pump, Injectors and Timing, all checked by M&B Injection in Eastleigh
(highly recommend, but even there stumped by the hot start issue!)

New Thermostat
Engine Coolant Sensor checked
Wiring between ECU Connector and ECT checked
Wiring between ECU Connector and Air Temp Checked
Wiring between ECU Connector and Fan checked
Fan Relay checked, working happily at Low / High Speed

Just checked between the ECU Connector and the Fuel Temp sensor, which for the given resistance vs temp graph that I have for it, is about 10deg C out. (Actual temp 35c, res/temp graph reckons it should be 45c)

Would it be worth replacing this sensor?

Any other suggestions or ideas that you chaps might have are very welcome!

Cheers!

Tom

[outnumbered]

has the dynamic pump timing been checked , if this is out this can give you hot start issues as well as cold and also poor running. either volvo bosch or an indi can do this for you or volfcr.
mike

[The Hooded Claw]

Originally Posted by outnumbered

has the dynamic pump timing been checked , if this is out this can give you hot start issues as well as cold and also poor running. either volvo bosch or an indi can do this for you or volfcr.
mike

Wot Mike said ^^^^^ the pump timing needs to be checked using a "proper" Volvo diagnostic Comp/Reader the ONLY way to set it is with the Engine Running

Keith

[TomFitch]

Cheers for the replies! Just double checked with the injection people, and they confirmed the pump timing was setup and checked when they did the injectors etc. So unfortunatly that rules that one out... have ordered a new fuel temp sensor on the offchance, but yeah, any other possible ideas please do shout!

Current thinking is that either the ECU is not responding correctly to the temp information its recieving, oorr... something else..

Cheers,
Tom

[TomFitch]

So, after taking onboard what was suggested, and still not 100% conviced that my timing is right. I decided to lump it and buy a cable and a copy of Vol-FCR.

The new version is cracking with the live data readout. Which has thrown up an intresting one...

On running a timing test, it takes the engine upto about 1200 revs and the timing is spot on, desired value of -0.3 and actual of -0.1
(albeit im on old belt)
This is also true up at around 1800 and above.

However. At idle revs of 800. The desired value is 0.0 and the actual value varies from about 1.8 to 2.2 !

So, i guess its back to garage to get that one checked out!

[outnumbered]

Hi Tom
The figures you have quoted should be at the test standardr,iwould have the garage re do it or seing as you have the kit now you can do it yourself if you are unsure the garage will do it properly.its not a difficult job.
Mike