Difficult starting -checking Crank & Cam sensors

mro

m_c wrote: »

The fault codes could be symptoms and not faults, as some older Vauxhalls would show those faults whenever the engine was not running.


Some vehicle detail would help.

It's a Vauxhall Cavalier 1995 2.0i CDX (X20XEV engine)


I've put in another new Crankshaft sensor, but still getting difficult starting, although does seem better than previous new Crankshaft sensor I tried and have returned.


The Camshaft sensor fault code strangely now seems to have disappeared for some reason.

92 Camshaft sensor Incorrect signal ==>not getting this now

m_c

From what I remember, getting a crank shaft or camshaft sensor fault when the engine wasn't running was normal. They would disappear as soon as the engine was running.


Personally, given your symptoms, I would be looking at the coolant temp sensor for the ECU. That failing would give the symptoms you describe. They had a habit of failing in a way the engine would think it was either hotter or colder than what it really was without triggering a fault, so fuelling would be wrong until the engine somehow started and entered closed loop mode. After which it would run fine.

AndyPK

Is it a Vauxhall 2.0 ?

AndyPK

cam sensors were very problematical on those engines.

I think you get code 31 if its not running.

Yeah I think the problem maybe else where.

mro

AndyPK wrote: »

Is it a Vauxhall 2.0 ?

AndyPK wrote: »

cam sensors were very problematical on those engines.

I think you get code 31 if its not running.

Yeah I think the problem maybe else where.

See post #12.

It's a Vauxhall Cavalier 1995 2.0i CDX (X20XEV engine).


The Camshaft sensor fault code 92 strangely now seems to have disappeared for some reason.

92 Camshaft sensor Incorrect signal ==>not getting this now

mro

Saw something on Youtube about sensors like Air Mass Flow & Air Inlet Temperature, if they are faulty and you disconnect them, that can stop difficult starting, as ECU uses default settings.


Tried disconnecting these 2 sensors one at a time, then both together, that didn't solve problem.

khcomp

Odd question: How long has the cambelt been on the car? If there's a problem with the belt's position or tension, its possible that the ECU will throw up camshaft & crankshaft sensor faults as they are not producing synchronised pulses...

mro

khcomp wrote: »

Odd question: How long has the cambelt been on the car? If there's a problem with the belt's position or tension, its possible that the ECU will throw up camshaft & crankshaft sensor faults as they are not producing synchronised pulses...

Cam belt has just been changed, engine running lovely, nice, smooth & stable once it has started.

It now seems pretty consistent, I keep cranking engine for say 10-15 seconds & it eventually starts.

Strider590

I assume you've done the obvious checks first? Spark plugs, leads, etc?

ECU based diagnostics, even now can be hit n miss, but back in the mid 90's? I'd use a large pinch of salt.....

thescouselander

I still think you need to check the battery even if it's relatively new. What is the voltage while cranking? Also check the battery terminals are done up nice and tight.