Poor cold starter - computer diagnostics? Can mechanics think for themselves?

Geodark

skivenov wrote: »

His car won't have a distributor as such any more. The crank sensor gives a signal to the ecu which talks to the coil packs.

If you asked me to place a bet - Modern engine and a poor cold start is going to be the crank sensor more often than not.

Have to say I had exactly the same problem with my Zafira back end of last year, replaced the crank sensor and all has been well since. But I have to say that this was detectable from the diagnostic logs.

m0nkeylover

A squirt of this may help ..

https://www.youtube.com/watch?v=PGMUGjlV5HU

arcon5

Technicians are called technicians because nowadays they are trained beyond mechanical technology, thus including electrical systems. Not because they are any less qualified than a mechanic.

So basically from this thread we've learn't ops problem could be caused by a vast number of things for which reading live data could help the technician eliminate things.

As for the fuel pressure, well pressure the valve to see if fuel comes out merely checks the flow, not the pressure. Although the pressure on a petrol isn't that high, 2-4bar maybe, to doesn't have a high pressure pump as suggested.

=rizla=

I had the same with a crankshaft sensor on a Cavalier, cold mornings after it had been left for a day or two, sometimes after a lot of turning over it would fire. Once it had started it ran fine and would always restart.