Timing belt change experience
04-27-14, 06:10 PM
#1
10th Gear
Thread Starter
Timing belt change experience
Hey folks, I just changed my SC400 timing belt, water pump, tensioner and belt idler bearings and although the engine purrs, these two codes show up after about 20 miles of driving. For those who had a similar situation,..what ended up happening?
I've changed dozens of timing belts and never seen an engine run smoothly if even one tooth is skipped.
I've cleared them twice and it takes a little longer for them to show up again. I'm wondering if the ECU is "learning" the characteristics of the new belt and since it saw a sudden change between the old one (which might have stretched) and the new one, it thinks something is wrong.
Each time I reset it, the car drives longer than before and I'd think a timing belt error would be more severe and show up sooner than this. Plus miss-aligning by even a single tooth should make it run terribly.
I'd hate to dive all the way back in far enough to see the dot on the crankshaft and find everything still perfectly aligned and that I could have just cleared the codes and tried waiting a few times.
I've changed dozens of timing belts and never seen an engine run smoothly if even one tooth is skipped.
I've cleared them twice and it takes a little longer for them to show up again. I'm wondering if the ECU is "learning" the characteristics of the new belt and since it saw a sudden change between the old one (which might have stretched) and the new one, it thinks something is wrong.
Each time I reset it, the car drives longer than before and I'd think a timing belt error would be more severe and show up sooner than this. Plus miss-aligning by even a single tooth should make it run terribly.
I'd hate to dive all the way back in far enough to see the dot on the crankshaft and find everything still perfectly aligned and that I could have just cleared the codes and tried waiting a few times.
05-07-14, 12:45 PM
#2
10th Gear
Thread Starter
Guys,
I found the problem. The timing belt needs to be installed the other way. My belt had arrows on it, not “L Cam, “ “R Cam” and “CR” marks. I’d assumed that the arrows needed to face the engine and the print on the belt should be in the direction so the installer could read it while facing the car. I thought the arrows in the Alldata instructions were just illustrator’s arrows and not the same ones printed on my belt. Plus the instructions that came with my belt did not mention that the belt had to be installed in a specific direction. I’d replace many timing belts in the past and these were the rules I used. Also there is no marker on the block that aligns with the one on the crankshaft gear as with all of the other cars I ‘ve worked on so you have to completely rely on the belt marks. After going through the whole mess again and turning the belt around, the CEL codes never reappeared.
A few things that might be helpful to others if you decide to do this. The Alldata manual says “remove the compressor and set it aside.” The whole job is really not bad except for this step because reaching the rearmost compressor bolt is almost impossible. I was able to get to it through the wheel well on the driver’s side and had to use 2 extensions and a universal joint. Plus, when you go to re-install the compressor, you’re on your back, trying to lift the compressor up (heavy) while aligning the holes enough to get the threads started. My hand fatigued several times. In reality, you only need to remove the front two bolts (one by the oil filter mount and the other on the top of the compressor near the fluid lines). Just loosen the rear bolt but don’t take it out completely. This will allow enough clearance to get the hydraulic pump off. When you reinstall the compressor, it is easy enough to just snug up the rear bolt to get the compressor to align enough to get the other two started. Then you can tighten all three.
You do not have to remove the camshaft pulleys….therefore you don’t have to buy the dreaded “special tool.” Also, the power steering pump pulley and the crankshaft pulley bolts came out easily with an impact wrench. You will have to use a harmonic balancer puller to get the crankshaft pulley off, but these are inexpensive. The power steering pump pulley might be a little stubborn because of oil deposits but it isn’t as if it is press-fit on or anything. You may have to use a puller to remove it the first time.
The other messy part is removing the alternator because the wiring harness wants to keep it captive. The bolts holding the wiring harness are difficult to reach. If you clip the outside most (plastic) retainer that holds the harness to the alternator, it will allow enough freedom to move the alternator off of its mounts. When you re-install, a zip tie works great to reattach the harness to the attachment point.
Some other advice: Pay attention to the routing of the wiring harness around the compressor, especially the crankshaft position sensor wire. It needs to go behind the compressor bolt boss and into the channel on top of the compressor.
Hope this helps someone.
I found the problem. The timing belt needs to be installed the other way. My belt had arrows on it, not “L Cam, “ “R Cam” and “CR” marks. I’d assumed that the arrows needed to face the engine and the print on the belt should be in the direction so the installer could read it while facing the car. I thought the arrows in the Alldata instructions were just illustrator’s arrows and not the same ones printed on my belt. Plus the instructions that came with my belt did not mention that the belt had to be installed in a specific direction. I’d replace many timing belts in the past and these were the rules I used. Also there is no marker on the block that aligns with the one on the crankshaft gear as with all of the other cars I ‘ve worked on so you have to completely rely on the belt marks. After going through the whole mess again and turning the belt around, the CEL codes never reappeared.
A few things that might be helpful to others if you decide to do this. The Alldata manual says “remove the compressor and set it aside.” The whole job is really not bad except for this step because reaching the rearmost compressor bolt is almost impossible. I was able to get to it through the wheel well on the driver’s side and had to use 2 extensions and a universal joint. Plus, when you go to re-install the compressor, you’re on your back, trying to lift the compressor up (heavy) while aligning the holes enough to get the threads started. My hand fatigued several times. In reality, you only need to remove the front two bolts (one by the oil filter mount and the other on the top of the compressor near the fluid lines). Just loosen the rear bolt but don’t take it out completely. This will allow enough clearance to get the hydraulic pump off. When you reinstall the compressor, it is easy enough to just snug up the rear bolt to get the compressor to align enough to get the other two started. Then you can tighten all three.
You do not have to remove the camshaft pulleys….therefore you don’t have to buy the dreaded “special tool.” Also, the power steering pump pulley and the crankshaft pulley bolts came out easily with an impact wrench. You will have to use a harmonic balancer puller to get the crankshaft pulley off, but these are inexpensive. The power steering pump pulley might be a little stubborn because of oil deposits but it isn’t as if it is press-fit on or anything. You may have to use a puller to remove it the first time.
The other messy part is removing the alternator because the wiring harness wants to keep it captive. The bolts holding the wiring harness are difficult to reach. If you clip the outside most (plastic) retainer that holds the harness to the alternator, it will allow enough freedom to move the alternator off of its mounts. When you re-install, a zip tie works great to reattach the harness to the attachment point.
Some other advice: Pay attention to the routing of the wiring harness around the compressor, especially the crankshaft position sensor wire. It needs to go behind the compressor bolt boss and into the channel on top of the compressor.
Hope this helps someone.
05-07-14, 06:08 PM
#3
You never mentioned what two codes you had, but I am positive the belt being on 'backwards' had zero to do with the cel. The belt would still function as designed. I recently did a 100 series cruiser (2uz) which is largely the same where they had put the belt on same as you and lasted 80k according to the sticker. Customer had just bought the truck and wanted general maintenance done. Ran fine coming in. Also, depending on mileage, you really really should have pulled the cam gears and replaced the cam seals. This particular truck was leaking from the cam seals pretty good.
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