Intermittent Non Starting after resting after a run. Engine warm but not hot.

[Ena II]

Hi,
I have a VX engine conversion in a transit van. Long story but I recently fixed an intermittent miss on one cylinder when cold. New Valley Gaskets, New Plugs, leads, coils and DFI module . New O2 sensors. And now new battery. Its a big DIN65L MF so plenty of cranking power. Vehicle has run fine for the last 7 years with usual services.

All was running fine, for about a fortnight, since the new Valley Gaskets, New Plugs, leads, coils and DFI module, until yesterday when it would not start and there seemed to be no spark even though it turns over fine. Tried the old DFI module no change. Got towed home, charged battery for a short time and it started fine. Put a new battery in, started fine.

Went to warm start today, no start, but was spinning fine. Put the charger on for 10 minutes. She started fine. Seems like an earth or a power supply problem?. Alternator charges up to 14.3V

DTC 31 and DTC 76 on Tuner Pro, but of course that is with the car running fine. Cant seem to get Tuner Pro to read anything unless the car is actually running but I am new to this. I am guessing some alarm inputs may be missing due to the conversion.

Ordered a crank angle sensor as that seems to come up in threads as a potential issue. However it is not a hot start issue.. But that crank sensor fault code was not present(when the car is running).

Can any one point me to chasing tha fault down please.

 

[Ena II]

OK, also replaced fuel filter, also closed contacts on DFI up a bit. Still waiting for the crank angle sensor to come before I am game to use the car. Seems to be starting OK however it is an intermittent fault so i am not confident yet.

 

[Lex]

OK, also replaced fuel filter, also closed contacts on DFI up a bit. Still waiting for the crank angle sensor to come before I am game to use the car. Seems to be starting OK however it is an intermittent fault so i am not confident yet.

Drive up & down the street or round the block for an hour? Testing takes time. No problem in the first hr. go a bit further. Not to far.

 

[lout]

if you have a heat gun heat up the crank angle sensor until just too hot to hold onto
then see if it starts

 

[Ena II]

Thanks Lout, I have a new sensor coming. But happy to try the heat gun. How do you heat the sensor or do you heat the general locality of the sensor just dont want to damage the wiring. I am aware the sensor is hidden by the Harmonic Balancer.

 

[lout]

just blow the hot air into the general area of the sensor
the wiring can handle an overheating engine on a 40 degree day
so unless you go crazy you wont harm anything

 

[Ena II]

Fixed. new crank angle sensor. thanks all.