*Almost* timing failure - Page 3

bholmes · bholmes's Garage

John that was exactly my thoughts about the balance shaft belt when I said the balance shaft belt "is not as important, but important none the less" I was just to lazy to type it, thanks for adding that.

I'm not absolutely sure about the motor needing to be on TDC or not, but it seemed to me when I was tensioning my belt that I could get a different reading on my belt at different points in the rotation due to the tension the cam would put on the belt at different points in it's rotation. However if it's loose enough to slap, it will be rather obviouse regaurdless of the cams position. Again, to be on the safe side and since it's not to hard to do I'd just put it on TDC and have no worries.

Icey1174 · 06-21-2007, 10:05 AM

Agreed

It can be done off TDC, but for the piece of mind it is well worth the extra time to set it to TDC.

rcrguy24 · 06-21-2007, 01:54 PM

ok. so i am really confused now, i don't know what is wrong with my 944. heres the low down: I was driving the car car home, it was fine at first but i stopped at a stop sign and took off and the car seemed to have a less power than normal, then right after that there was another stop sign so i went to stop and the car stalled out on me when i pushed the clutch in. i immediately opened the hood and looked for anything abnormal but i couldn't find anything. so i started it back up(was a little harder starting) and slowly took off when the car was low on power, squeling, and making a ticking sound so i quickly slowed down to stop and the car stalled out again, which is when i towed it home.

Now that the long story is over, while in the shop i realized the tensenior for the power steering was cracked, so it would tighten up completely(squeling problem). I took off the cover and checked timing and balance belts and they seemed tight to me and even fairly new. Now i don't have a clue what is wrong with it!
any help would be greatly appreciated and thanks so much for reading all this!
joe

bholmes · bholmes's Garage

I am no expert. My 944 ownership only goes back ohhh about two months LOL. However, sounds to me like you may have jumped time. I have never had my timing jump on my car, so I can't tell you for sure. This would explain being low on power and if you jumped time it would tend to stall out etc. This could be due to a loose timing belt. Also when was the last time your water pump was replaced? The timing belt runs the water pump and if the water pump is worn and seizes it will mess up alota stuff with your timing. If you belt is loose enough it would likely cause the belt to jump time. If the belt it tight enough it is likely to shear the teeth off of the belt and cause valve damage. Lets hope you didn't have any of that if that's your case.

Are you working on the car yourself or having someone do it for you? If you are doing it, it's fairly simple to just remove the front cover and atleast have a look about the timing belt. No matter what, you should check the belt anyways just to be safe, an ounce or prevention is worth a pound of cure. If the belts haven't been replaced recently I'd replace them as a starting point, make sure you get TDC set correctly and the balance shafts in proper sequence, inspect all your idlers and tensioners. If any of them sound like a roller skate wheel when you spin them they need replaced. If you have the money to spend get all new belts, idlers, tensioners and water pump, then you know where you stand and have some peace of mind about what is some of the most important maintance of these cars. If you don't have the money, also be sure to check the waterpump, look for seapage, feel for any resistance/wear/loose/rough bearings. Check to make sure the shaft is square with the housing. Keep us posted, don't be afraid to ask any questions.

bholmes · bholmes's Garage

If any of you more experienced guys have any ideas please chime in!

rcrguy24 · 06-22-2007, 07:07 AM

thanks for the ideas! but when i really got confused was when i set it to tdc, took the cover off, and didn't find anything wrong with the belts or rollers. The timing belt did have a little bit of play but not what i thought would be excessive. are these suppose to be really tight? good idea with the water pump, i forgot about that going bad.
thank you

bholmes · bholmes's Garage

They aren't supposed to be really tight in my opinion, but I supose that is a little bit subjective to what you consider really tight. Did all the timing marks line up? There should be a mark on the cam that will line up with the cam tower and a mark that says "OT" on the fly wheel that will line up with a mark on the top of the fly wheel housing. If these two don't line up you're out of time...you may have checked both of those but I just want to make sure.

Once you have that checked see if you have either fuel or spark. While cranking the motor over, ground one of the spark plugs to the engine and look for spark, if may have to be dark to see. To check for fuel I'd just pop the cap off the end of the fuel rail and see if you get sprayed in the face with gas, if you do you know you have fuel to the rail and can proceed with checking the injectors. It would probobly be better to use a fuel pressure gauge if you can, either way, you should have pressure on the rail. I've never done that so hopefully someone can fill in a little for me here (John?)

Be sure and check out clarks-garage.com if you haven't already, the shop manual section is great and may have the proper procedures for what I am sujesting.

Icey1174 · 06-22-2007, 07:17 AM

They say you can check the tension of the timing belt by twisting it 90 degrees. anything more it's prob a little too loose, anytyhing less and it's prob a little too tight. I have read this in several places and that is how I checked my timing belt. Not very accurate, but better than nothing.

When you set the crank to TDC, MAKE SURE the cam is also at TDC.

Icey1174 · 06-22-2007, 07:28 AM

Try truning the car over or start it for a few seconds. I don't remeber if your car started or not.

This will turn on the fuel pump to charge the fuel system. If you don't have a gauage you could just crack the end of the fuel rail to see if you are getting gas out the end. With the car off it will not spray, but you will lose a fair amount of gas, so have some rags ready. If you are only getting a couple drips of gas or no gas at all then you are not getting fuel the the rail. It should spill a few table spoons at the very least if you are getting proper pressure to the fuel rail.

Are you using a flywheel lock when you set to TDC? Make sure that cam mark lines up for you too. The crank turns twice for every turn of the cam. So just setting the flywheel could leave you on BDC. I don't think you could possibly get the cam to turn that far, 180 degrees. The valves would hit the pistons before then. And turning it with your hand should not cause any problems unless you are really strong and really cranked on it.