1995 cavalier CDX 2ltr..cold-start hell...please read..maybe u can help!

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Hi, my up-till-now reliable CAVALIER CDX 2ltr (1995, April) has developed a cold start problem.....It just about starts b4 the battery dies when cold. When HOT it will restart easy. If LUKE-WARM its touch and go.

IF it starts from cold it instantly runs perfectly over all op conditions. The same apples with starting from HOT or lukewarm.

IF it starts from cold or lukewarm...the energy management light will come on and stay on.

WHEN it starts first time from HOT, no energy management light comes on.

I had a diagnostic test which threw up just CAM AND CRANK SHAFT SENSORS as the problem....

BOTH have been replaced with new ones but the bloomin problem is still there.

Please help save my family's christmas - I am the driver for 4 elderly parents on the day and I'm hoping the car will get fixed!

My electronic diagnostic man is now saying it WILL be 1 of two problems:

1/ a loose chink of metal in the engine that has stuck to the crank MAGNET? i.e. the thing the new sensor is trying to read!!??

2/ The ECU is faulty, so will now need to be NETWORK 500 read at great expense and delay

I am worried that these drastic routes might be overlooking a few simple problems......whats wrong with a fuel injection relay not working for example? Could it just need tuning?!

I'd dearly love to hear some tips so I can help steer the repair to a happy and least expensive solution AND...SAVE CHRISTMAS FOR OUR FAMILY!


posted by  ASHTONY

sounds more like a charging system(which includes battery) problem to me if it really had a problem with the crank or cam sensor I doubt the temperature would have an effect on them

posted by  carlos

how long are you cranking it b4 the battery goes dead?
is it just a short time or all morning?
im not sure here but im pretty sure the crank sensor is the magnet
the wheel on the crank is just metal with notches in it that the sensor reads
but as i say im nor sure on that one
as for the ecu
i think thats under the dash on those but another uncertainty
im full of usless no knowledge tonight

posted by  windman

I had a similar problem with an Astra I had a while ago. It sounds to me like it could be the Temperature Sensor, do the revs climb excessively high when the car is warm?

Oh, and I presume you mean the engine management light, the yelloow one with an engine symbol displayed, and not the energy management light, as the latter doesn´t exist, unless you mean a battery warning light :thumbs:

BTW, my engine management light was also illuminated, if this light goes out, and the fault is intimitant, chances are the car will run fine :thumbs:

Oh, and Happy Christmass to you, too :thumbs:

posted by  Cliffy

Thanks people!

In response to comments so far:

1/ No the revs dont rise when the car gets warm....IF it starts it runs perfectly well and stably

2/ This theory that my electrics guy has re swarf/bits of metal stuck inside the engine worry me of course so any further light on confirming or scotching this train of thought gratefully accepted!

3/ If it were the temp sensor playing up, would that not come up as a fault via the Engine Management Light or another indicator?

Do keep the respnses/help coming, just woke up baffled and worried about how the hell i'm going to get everyone chauffered to christmas w/o the car..all the hire places are sold out round my way too! such a b**mer all this!

Ta, Ashtony

posted by  ASHTONY

is that what you call a check engine light? what codes did you get exactly? or did you even have em checked

posted by  BanffAutoSpa_ap

Hi Banff Auto...

Well, yes I had them checked. My diagnostic man did what he called a manual read of my system. I watched him apply some sort of short to a junction / terminal box under the bonnet near/behind the washer bottle. He then counted the EM light flashing and then went to his computer and declared that the readings were showing the
Cam Sensor AND crank sensor

He said from his experience if one shows they both show but his gut feeling was to try just the CAM change 1st......did this = no change

so, changed the crank sensor too = no change to start problems.....

He then worked further and put a scope on to look at the crank sensor signal and reported that it was very intermittent/all over the place. Oh, and the computer is now only recording a CRANK sensor problem

This leads him to think it could be the two problems listed in my original posting: metal in engine or faulty ECU

i do not know u see. I 'm just a currently hard up & worried car owner and am 'out here' on this forum to a/ try and not feel helpless and help the repair along, b/ avoid major expenses by connecting with a wizard who may know what my problem is, c/ save my family's christmas!

B great to hear more from you. Thanks , Tony

posted by  ASHTONY

when he tested the crank sensor with his scope did you see how he hooked it up? it is possible there is a loose terminal in the connector to the crank sensor? and im not sure this type uses a magnet i would have to lok it up but the magnets have been know to break before causing erroneous readings.

posted by  BanffAutoSpa_ap

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