No start condition after head, cam, and timing chain replacement.
What is your question?
The timing chain and the intake cam broke so we replaced the head both cams and tge chain. Check engine light is on and the engine will crank slowly but will not fire up. Just need an opinion as to if the crank position sensor or the cam position sensor would be more likely to be the problem. Hooked the diagnostic up under dash and could not pull any codes. Any ideas?
RepairPal Certified shops can diagnose and repair your 1999 Chevrolet Prizm. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.
Just curious , and it might be the answer to your question , but WHY did the timing chain and intake cam break? Oil starvation? What was inspected prior to installation of new parts?
The timing chain had been making noise for a while could have been oil starved its my daughters car so I usally have to check and add oil. But the camshaft broke I am guessing because of the cease of the chain. Thought maybe the cam some how gouged the cam sensor because of the scuff around the edge of the hole where the cam sensor is. But the engine is cranking irregularly like it is not firing right so I thought possibly the cranshaft position sensor may have been damaged. Note I thought being a late modwl car it had a timing belt so I just thought the noise was valve train noise and it needed oil if I would have known I would have changed it out.
Remove the spark plugs and see if it cranks any differently. The cam would not break because the chain stopped , it is driven BY the chain. IF engine was low enough on oil , you may have melted the crank or rod bearings , not enough to completely seize the engine , but enough to make the starter work extra hard to spin it.Do you still have the broken parts?
Makes sense if the crankcase was empty it could have partially siezed the motor enough, I still have the head and the old cams, the cam broke clean around the 3rd cap. The combustion chambers and the valves are not scarred or dinged. I dont have the old chain but the sprockets are in good shape. I may pull the oil pan and look at the rods and main journals but I will pull the plugs and turn it over a few times to see how she cranks. Good tip thanks. I will repost after I check it out.
Please do , you've got me curious enough now! (I hope I'm wrong) Let us know what color the main & rod caps are.DEPENDING on where the oil drain plug is located you might be able to get away with peaking through there to get a quick glimpse of the caps to see if there is bad heat discoloration , without pulling the pan.
Ok update remove I removed the spark plugs and crank it over and the engine spins freely took the plug wires all of the coil packs and checked them individually for Spark checked out ok. note only one off the plugs has appeared to be getting fire the rest are black so I'm thinking there is something throwing the timing off. by the way they are brand new I just bought them.
I just re-read your earlier statement and caught the part about it cranking irregularly , that's classic sign of valve timing being off/weak no compression in one or more cylinders. How much of a pain is it to re-check cams and crank line-up?
That was the first thing I did when they told me it would not start I had it towed here pulled the timing cover and it was off but realigned it correctly with the number 1 cyl tdc crank key at 12 oclock the chain sprocket has diff color links for the crank sprocket dot and the two dots on the exhaust and intake cams all that should be correct now. Gotta new batt put it in. Took out the plugs cranked it and she turned over easy and smooth. Checked for spark at the coil packs while someone else cranked it and I got spark. Plugwires are right it acts like it wants to fire up but I also hear a slight tick when cranking thats why I was thinking crankshaft position sensor or cam sensor. But its getting spark at the coil packs but not noticing any gas smell or unspent gas fume from the exhast. Can either of those sensors cause the ignition to cut fuel to the fuel injection. Plugs were black and not wet from fuel either.
Just another random couple of thoughts hit me (now I got a headache-THANKS!)----compression test and noid light to check injector pulse , if not already verified. Fuel pressure(PSI) , and last , those 3 black spark plugs , you did replace them(not try cleaning)? Well , I lied that wasn't last , this is a toyota engine your dealing with right? --All mass air flow lines/air cleaner hooked up nice and snug? No intake leaks?........again just random thoughts , maybe something will trigger your brain in the right direction , mine only goes there by accident!
Thanks for the input sorry about the headache. Just got done replacing the cam and crank sensors and no go. It has to be getting spark checked the coil packs they are sparking wires routed. I am gonna check what you suggested and hopefully find something I am running out of ideas. It has to be fuel or air related. Once again thanks for the input buddy. I am beggining to feel like one of those part replacer mechanics haha!!!!
Uhmm.....parts replacers are just that-parts replacers , mechanics are just parts replacers that proved a VALID reason , for replacing the parts..........uhmmmm....sort of---I don't know , I'm not a mechanic , i've just been succesfully working/fixing cars (mostly) for over 30 years...........I'm 'bout worn out!.........Please keep me updated on your progress , like I said , I'm curious. AND , thanks , it's OK now , my headaches gone.
Ok decided to pull the cover and recheck the alignment of the cam sprockets let me know if I am wrong. With the no 1 cyl at TDC, there are 2 dots on the intake sprocket that should line up with the colred link on the chain around the 1 oclock position and the next colored link goes to the 2 dots on the exhaust sprocket on the exhaust cam in the 11 oclock position as far as the middle of the two sprockets there are imprinted int and exh on both cams with marks that should align directly across from each other. The crank sprocket mark is around the 4 oclock position with the colored link on the dot and the keyway at the 12 oclock position then with the tensioner pushed back in and hooked reinstall after a little oil on the oil O ring, right or no? Just racking my brain trying to make sure this is done right and I have not screwed up.
The procedure sounds right , as long a smarks are correct and all the slack is on the side with the tensioner. ...After you have it all set up , with plugs OUT (no compression to fight against) try slowly turning the crank in the direction of normal engine rotation - two full turns of the crank-- and then make sure all the marks still line up.IF that all checks out , I guess next step is to go ahead with the rest of the re-assembly and give it a try. Make sure to use fresh plugs! Last question for now( I think) , adjustable or hydraulic lifters? Don't remember on that on .While cover is off might want to give rocker arms a fresh look.
Well timing chain jumped pulled the tensioner. I could put the thing in a bind and push it back by hand. So replaced it,also pulled the oil pan no pieces of piston or rod or evidence of damage, rotated it while the pan was off looked ok and put everything back together spun it by hand seemed ok but it gets tough to spin over on number 4 cylinder when the cam lobe reaches it. Gave it a crank battery is dead as a doornail.Battery is on the charger now. No rockers DOHC and the lifters are pretty much cups that sit over the springs, really cheaply designed engine. I have a sneaking suspision I may have a bound up lifter or a bent valve on the POS junkyard head this guy slapped my daughter's car not sure yet.
The timing chain had been making noise for a while could have been oil starved its my daughters car so I usally have to check and add oil. But the camshaft broke I am guessing because of the cease of the chain. Thought maybe the cam some how gouged the cam sensor because of the scuff around the edge of the hole where the cam sensor is. But the engine is cranking irregularly like it is not firing right so I thought possibly the cranshaft position sensor may have been damaged. Note I thought being a late modwl car it had a timing belt so I just thought the noise was valve train noise and it needed oil if I would have known I would have changed it out.
Remove the spark plugs and see if it cranks any differently. The cam would not break because the chain stopped , it is driven BY the chain. IF engine was low enough on oil , you may have melted the crank or rod bearings , not enough to completely seize the engine , but enough to make the starter work extra hard to spin it.Do you still have the broken parts?
Makes sense if the crankcase was empty it could have partially siezed the motor enough, I still have the head and the old cams, the cam broke clean around the 3rd cap. The combustion chambers and the valves are not scarred or dinged. I dont have the old chain but the sprockets are in good shape. I may pull the oil pan and look at the rods and main journals but I will pull the plugs and turn it over a few times to see how she cranks. Good tip thanks. I will repost after I check it out.
Please do , you've got me curious enough now! (I hope I'm wrong) Let us know what color the main & rod caps are.DEPENDING on where the oil drain plug is located you might be able to get away with peaking through there to get a quick glimpse of the caps to see if there is bad heat discoloration , without pulling the pan.
Ok update remove I removed the spark plugs and crank it over and the engine spins freely took the plug wires all of the coil packs and checked them individually for Spark checked out ok. note only one off the plugs has appeared to be getting fire the rest are black so I'm thinking there is something throwing the timing off. by the way they are brand new I just bought them.
I just re-read your earlier statement and caught the part about it cranking irregularly , that's classic sign of valve timing being off/weak no compression in one or more cylinders. How much of a pain is it to re-check cams and crank line-up?
That was the first thing I did when they told me it would not start I had it towed here pulled the timing cover and it was off but realigned it correctly with the number 1 cyl tdc crank key at 12 oclock the chain sprocket has diff color links for the crank sprocket dot and the two dots on the exhaust and intake cams all that should be correct now. Gotta new batt put it in. Took out the plugs cranked it and she turned over easy and smooth. Checked for spark at the coil packs while someone else cranked it and I got spark. Plugwires are right it acts like it wants to fire up but I also hear a slight tick when cranking thats why I was thinking crankshaft position sensor or cam sensor. But its getting spark at the coil packs but not noticing any gas smell or unspent gas fume from the exhast. Can either of those sensors cause the ignition to cut fuel to the fuel injection. Plugs were black and not wet from fuel either.
Just another random couple of thoughts hit me (now I got a headache-THANKS!)----compression test and noid light to check injector pulse , if not already verified. Fuel pressure(PSI) , and last , those 3 black spark plugs , you did replace them(not try cleaning)? Well , I lied that wasn't last , this is a toyota engine your dealing with right? --All mass air flow lines/air cleaner hooked up nice and snug? No intake leaks?........again just random thoughts , maybe something will trigger your brain in the right direction , mine only goes there by accident!
Thanks for the input sorry about the headache. Just got done replacing the cam and crank sensors and no go. It has to be getting spark checked the coil packs they are sparking wires routed. I am gonna check what you suggested and hopefully find something I am running out of ideas. It has to be fuel or air related. Once again thanks for the input buddy. I am beggining to feel like one of those part replacer mechanics haha!!!!
Uhmm.....parts replacers are just that-parts replacers , mechanics are just parts replacers that proved a VALID reason , for replacing the parts..........uhmmmm....sort of---I don't know , I'm not a mechanic , i've just been succesfully working/fixing cars (mostly) for over 30 years...........I'm 'bout worn out!.........Please keep me updated on your progress , like I said , I'm curious. AND , thanks , it's OK now , my headaches gone.
Ok decided to pull the cover and recheck the alignment of the cam sprockets let me know if I am wrong. With the no 1 cyl at TDC, there are 2 dots on the intake sprocket that should line up with the colred link on the chain around the 1 oclock position and the next colored link goes to the 2 dots on the exhaust sprocket on the exhaust cam in the 11 oclock position as far as the middle of the two sprockets there are imprinted int and exh on both cams with marks that should align directly across from each other. The crank sprocket mark is around the 4 oclock position with the colored link on the dot and the keyway at the 12 oclock position then with the tensioner pushed back in and hooked reinstall after a little oil on the oil O ring, right or no? Just racking my brain trying to make sure this is done right and I have not screwed up.
The procedure sounds right , as long a smarks are correct and all the slack is on the side with the tensioner. ...After you have it all set up , with plugs OUT (no compression to fight against) try slowly turning the crank in the direction of normal engine rotation - two full turns of the crank-- and then make sure all the marks still line up.IF that all checks out , I guess next step is to go ahead with the rest of the re-assembly and give it a try. Make sure to use fresh plugs! Last question for now( I think) , adjustable or hydraulic lifters? Don't remember on that on .While cover is off might want to give rocker arms a fresh look.
Well timing chain jumped pulled the tensioner. I could put the thing in a bind and push it back by hand. So replaced it,also pulled the oil pan no pieces of piston or rod or evidence of damage, rotated it while the pan was off looked ok and put everything back together spun it by hand seemed ok but it gets tough to spin over on number 4 cylinder when the cam lobe reaches it. Gave it a crank battery is dead as a doornail.Battery is on the charger now. No rockers DOHC and the lifters are pretty much cups that sit over the springs, really cheaply designed engine. I have a sneaking suspision I may have a bound up lifter or a bent valve on the POS junkyard head this guy slapped my daughter's car not sure yet.