Help with hot start 1.6 petrol 'Engine Malfunction'

[fordlynx]

my fathers 2009 1.6 petrol 100,000 miles

once the engine is hot and he turns it off and returns from shop etc. and tries to start it will not....

He has to wait 20-30 mins to cool down before he can start it again...??

Jobs done:

New Coolant Temp Sensor

New Thermostat

New Coolant

Gets Engine Malfunction on display

No Fault codes registered 

am at a loss now on what it can be any pointers in the right direction would be great

cheers in advance

[unofix]

20 minutes ago, fordlynx said:

Gets Engine Malfunction on display

No Fault codes registered

That just means your using a generic code reader that like most it can't read Ford specific DTC's.

Use the software FORScan on a laptop with connection lead to the OBDII port and there will be a DTC.

FORScan: https://forscan.org/download.html

vLinker FS cable: https://www.bmdiag.co.uk/forscan-diagnostic-cable-for-ford-vgate-vlinker-fs

[fordlynx]

I try that i do have forscan 

but he lives a way from me so i told him to buy a generic rac one to check

alot of people keep telling me crank sensor??

[unofix]

Don't keep guessing, you have already found that it doesn't work. Get the DTC and then you will better know the reason for the starting problem.

It might be the crank sensor but then again it might not, it could be fuel pressure, injector problems and a couple of hundred other things.

[fordlynx]

i know i will have to do big trip at the weekend

[fordlynx]

put forscan and it had near all all codes on every module cleared them then it started then when i turned off engine malfuction no start and forscan wouldnt connect to car ....???

Is this a signn that ecu or wiring has had it?

[isetta]

Did you have fault codes starting with a u?  It sounds like it has a fault on hs canbus wiring / connectors. The wires from the obd socket to the ecu takes a long tortuous route via many connector plugs. Canbus wires carry computer type signal , like hundreds of pulses of data per second.  The slightest bad connection and the data falters and doesn’t make sense so ecu says no. 

[isetta]

I know this thread is long but it does have some stuff in there about using ohmmeter on the obd socket to try to find where the fault is and also locations of troublesome connectors.   Of course it might not be the same problem.

[fordlynx]

yeah some of the codes began with U

[isetta]

U is communication faults do that does tie In with Canbus wiring / connectors.   The ecu is like a computer,  the fuse box under glove box has a load of gubbins inside and is like a computer.  The instrument cluster is like a computer.   All three pass computer data between each other in a continuous flow.  Any slight blip  and it doesn’t like it.   There is the well known problem with the soldering on the pins in the main connector in the instrument cluster but it’s not always that, and wasn’t in my case. I have seen others spend money on getting the cluster resoldered only to find that wasn’t the problem.   Don’t leap to that conclusion.  Do the ohm test on obd socket with the instrument cluster connected and disconnected