hello all am a 3rd year apprentice in Sw ontario. Firday morning i got a 96 cavy on the back of a tow truck from another shop in town that was having a little trouble figuring out this no start.
it is a 2.4 DOHC btw. i dont know the whole background of the car for sure but it will not start an during cranking the exhaust just smells pig rich. i have good spark, good fuel pressure and volume. I tried pulling the fuel pump relay and running the engine on intake cleaner while my buddy craked the engine, IT DIDNT RUN and there is I REPEAT good spark on all cylinders with new spark plugs.
There are no codes stored in the PCM memory MAP, COOLANT, TPS and IAT all within spec. it injector pulse width for some reason during cranking is set at 30.2 ms.
all fuel injectors ohm at at 1.7 ohms.
im kinda thinking that this is a valve timing problem because the customer that owns the car said that just before the engine dies there was a loud screeching noise coming from the front of the engine and it wont run on intake cleaner. I guess the possibility of a bad PCM is real but the scanner data seems to be normal and no strange codes are appearing.
the car has 164,286 kms on it. it is an automatic.
MY QUESTION to you guys is : Does the timing chain commonly skip in these cars?
Is this an interference Engine?
Do you have any other suggestions as to what may cause this to happen.? thanks for your help.
IIRC the 2.4 is a non interference engine .... but I could be wrong .... as for the timing chain skipping ... I've never heard of it but if one of the tensioners lets go ... well I'm sure it's possible ... if it's got good spark and fuel I'd check the valve timing ..... not easy ... but it might help .... and you're sure the coil pack is alright ? that would be my first guess ...
Jay
i checked for spark by flipping the coil pack assembly upside down and putting four ST125 spark testers in the end of the the coil boots and put a jumper wire on every tester to ground. i spun the engine over and every one of the spark testers were sparking and makin a healthy snappin noise.
i would check for compression if compression is bad the plugs will still spark outside the block and the fuel will be fine, but you need 3 things for combustion and compression is one of them. i could also be the pcm though because of the injector pulse width and i believe that is controlled by the pcm but the cam sensor may take place as the signal. worse case pull the timing cover off and see if the chain broke because it would for sure not start then no matter what
I'd guess it's not firing when the cyl is full of gas. Everything can be working but if the spark is hitting an empty cyl you're going to get gas out the exhaust and it won't run on anything.
._____________________________.
Causa latet vis est notissima
DIY Clear 03+ Headlights
check to see if the cam and crank sensors have power going to them.
check fuses
-Cameron (CaliforniaCavalier)
Girls make me mad and break my heart, but my car is always there for me.
Timing chains in cavaliers is a common problem. Mine went after 57,000 miles and my brother's car just went after 96000. Mechanic I know said he's seen alot of them. He doesn't understand why GM didn't use a belt in this application. It sounds like it has all the symptoms of it. Lot of fuel cuz your cam isn't moving to open your valves, but your fuel pump is still pumping. When you try to crank it over does it whine or does it actually give an honest attempt to start? I noticed on my brother's car that when i tried to start it, it just didn't sound like it was giving a full attempt to start. It didn't have that powerful start-up sound if you will.
oh yea and if he was driving the car when it did 9 times out of 10 every valve got bent i had to replace all 16 of mine last year when my tensioner took a dump.
