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CAS timing problem won't start

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Hey guys so I have a problem with my timing and Crank angle sensor i've been trying to diagnose for the last week and its really got me stumped now.
Just done the head gasket on my car put it all back together and no start yes cas put in correct and at tdc. timing chain installed correctly.
car would turn over for about a second then stop turning over starter would just stop like the timing was so badly out and pressure overdid the starter causing it to stop.
I've pulled out the cas over 30 times and put it back in tried another second hand one off a mate and this time straight away car turned over normally and starter wouldn't stop but still not starting. Tried a stock S15 map on my link g4 ecu it started after a bit but barely ran only giving it revs and would idle at about 400rpm very rough. Put tuned map back on and it started now also maybe cause it was warm but still the same very bad. Next day wouldn't start again

I have no idea what it could be now and yes everything is working spark/fuel etc and car was running fine before i done head gasket. Have checked all earths plugs etc everything was put back together correctly. Anyone have any idea's what could be wrong im getting so annoyed haha.

Thanks heaps
 

S15_SAM

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The only thing it can be is the timing!! If you've got fuel and spark! You've had it running but rough! Then it's the timing!
 
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hmm i heard its not possible for the chain to fall off the crank but who knows. Theoretically though if its at tdc and the cams are in the right position must mean the chain is correct on the crank right? running out of ideas tempted to take front cover off to check but don't want to waste my time because I highly doubt its off
 

S15_SAM

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I'm afraid I don't know the timing marks on a sr20. But your right if you've got TDC (assuming sr20 uses TDC for setting timing) and the marks on your cams/chain line up then all should be ok. Do you have standars cam gears? I.e the standard vct?

other option is you didn't plug all injectors in properly? But that wouldn't stop it from cranking. When you say CAS is it a sensor on the flywheel/front pulley.
 
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I've experienced the same problem with a friend's SR when the head got built, somehow the timing chain got off by 1 link and the car would rumble once or twice but would never start. We had the timing chain ziptied up tight when the head was off but while pulling it up through the head it must have slipped a link down on the crank or something.
 
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I've experienced the same problem with a friend's SR when the head got built, somehow the timing chain got off by 1 link and the car would rumble once or twice but would never start. We had the timing chain ziptied up tight when the head was off but while pulling it up through the head it must have slipped a link down on the crank or something.
how did you end up fixing it taking front cover off while leaving head on? I mean thats kind of what im thinking because yes it splutters and wont start. but marks on the cams are perfectly positioned so don't see how it could be
 
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I'm afraid I don't know the timing marks on a sr20. But your right if you've got TDC (assuming sr20 uses TDC for setting timing) and the marks on your cams/chain line up then all should be ok. Do you have standars cam gears? I.e the standard vct?

other option is you didn't plug all injectors in properly? But that wouldn't stop it from cranking. When you say CAS is it a sensor on the flywheel/front pulley.
everything is plugged in correctly definately spark and fuel on all 4. and yes stock vct the cas that inserts into exhaust cam sprocket
 

drifter

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How do you know you've put the cas sensor back on in te right place? Pretty sure it can go on more then one way which will screw up the timing. When my engine was built it didn't start, the guy took the cas off, twiddled it and put it back on and away it went. I think there's a guide in the workshop manual :)
 

immy21

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No need to take the front cover off.
Make sure piston 1 is up top with a long screw driver down the bore, then line up the TDC mark on the crank pulley, 2nd to the left iirc
Count the links, lean down so your level with the head a compare with the pic below.
If everything lines up then fit the CAS like in the video below. If the pulley is at TDC but piston 1 is at the bottom of the bore car will not start, so as mentioned it's easy getting it lined up on the wrong stroke.
Once running set the ignition timing, stop the timing jumping around by locking it using diagnostic software OR unplugging the TPS. My timing light is way off unless I leave the spring clip partially open for some unknown reason. Worth a try if you have the same issue.
If the cas isn't roughly central when a timing light is hooked up and 15* base timing is set, the CAS is a tooth out (easily done)


















 
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how did you end up fixing it taking front cover off while leaving head on? I mean thats kind of what im thinking because yes it splutters and wont start. but marks on the cams are perfectly positioned so don't see how it could be
No we didn't have take the front cover off. We lined the crank pulley up at TDC and looked at the markings around the cams/timing chain and realized we were in the wrong position by about a chain link, so we loosened the TCT, pulled the chain up off the cam gears, and moved the cam gears forward to the link on the chain that put the cams in the right position. When we were done, the dot on the cam gear wasn't lined up with the coloured link on the chain but it was timed correctly, it fired up first try after that.

I hope im making some sense, this happened a while ago so im trying to remember it all.
 
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