MAJOR hesitation after installing timing belt.

[Deadly BlaZe]

Ok after I installed a new timing belt, I noticed my car hesitates like crazy when i start approaching 2.5k rpms. I changed the timing belt, water pump, balance shaft belt and timing belt tensioner and all the necessary seals. Before the installation, my balance shaft belt was broken, but didn't seem to hurt the motor. Anyway, what could be the problem?

 

[oldman]

Didn't I tell you to check timing marks before you take off the old belt? Time for a compression test, what you're looking for are bent valves. This of course is ASSuming the timing belt job was done correctly. I would first check the timing marks again, then perform that compression test.

 

[Deadly BlaZe]

Well I already had the old belt off by the time you told me that. And since I won't be able to do anything until monday, I have to ask, assuming the valves are bent, what other negative symptoms would i feel? The car seems to run just like it did before, minus the hesitation after the 2.5k rpm point.

 

[oldman]

How much vacuum are you pulling at idle?

 

[Deadly BlaZe]

vaccum at idle is 18-20 inHg. Hasn't changed at all.

 

[oldman]

vaccum at idle is 18-20 inHg. Hasn't changed at all.

Then it's probably something else which is good but you still want to run that compression test to verified. What else was done/removed/changed?

 

[Deadly BlaZe]

Well I hope you're right. Nothing else was changed except for what I mentioned in the first post.

 

[Deadly BlaZe]

One more question Oldman, i noticed today that right when i started up the engine, I heard a CLANK CLANK. Any thoughts on what that could be?

 

[DJYoshaBYD]

bent valves... didnt line up those marks?

Do a compression test....

 

[oldman]

One more question Oldman, i noticed today that right when i started up the engine, I heard a CLANK CLANK. Any thoughts on what that could be?

I wouldn't start the car again until

1. Rechecking of your timing marks.

2. compression test.

 

[Deadly BlaZe]

Well I really did it now Oldman. I know you said not to start the car until i checked all those things but i had no choice; I had to get to work some how.

Anyway, after work I tried to start the car up..and it refused to start up. I tried again and it was turning and turning and finally started up roughly. Both times I tried to start it, it was accompanied by the CLANK CLANK/Rattling sound (which may be completely unrelated to my motor because i was also having exhaust work done on the car a couple days ago and it might be a heat shield rattling). Anyway, i shut the car off immediatley after i got it started. This sucks cause now i gotta take it to the shop and have the head removed to check the valves. Yes i know, i'm a stupid noob for even driving the car considering the circumstances. We'll see on monday how bad the damage is.

 

[oldman]

Is there a reason why you can't do a compression test yourself? If need be, go buy one from Sears then return it if money is an issue.

 

[Deadly BlaZe]

Well I figured either way, compression being bad or good, I have to get to work. I have a tester at the shop and I didn't wanna have to deal with buying a new one, or driving to the shop (which is a good 20 miles away) and whatever else. Considering that my car barely started, what kind of damage do you think i'm looking at? Is there a chance my pistons could be hit bad too?

 

[oldman]

Assuming that is the problem, the piston top definitely need to be inspected.

More importantly, don't make the same mistake twice. If the compression numbers indicates problem, perform a leakdown so you can conclude what was damaged before you pull the head.

 

[Deadly BlaZe]

Ok oldman.

I took the car to the shop. I had my dad's mechanic inspect the belt since i didn't wanna mess with it anymore. The belt jumped a few teeth and he said i did something wrong with the timing belt tensioner. He fixed up everything that looked wrong with it. I checked compression, and each cylinder had 120-130 psi. I figure the numbers might be a bit low, but nothing to really worry about.

So i started up the car..started up fine. Idled fine, vacuum was still the same. I took it for a test drive, car didn't buck or hesitate at all, didn't make any strange noises and it still hit max boost before 3k. All seems well. I guess I can conclude that the valves are fine and the jumping of the belt happened when i started the car so it didn't cause any major issues.

Oh and the clanking/rattling sound from before was a loose exhaust shield.

 

[oldman]

The compression numbers were low probably because the test was not done right, was the car in operating temperature, throttle fully open during cranking and battery fully charged? Repeat the compression test with the car fully warmed up, 120-130 really isn't something to be thrilled about since the service limit is 121psi.

 

[Deadly BlaZe]

The compression numbers were low probably because the test was not done right, was the car in operating temperature, throttle fully open during cranking and battery fully charged? Repeat the compression test with the car fully warmed up, 120-130 really isn't something to be thrilled about since the service limit is 121psi.

Ok I wasn't aware of some of that. The car was still some-what cold, battery was fully charged, and no i didn't keep the throttle fully open. I'll try doing it again. The car runs great though. Just like it did before the whole timing belt change. We'll see again tomorrow about the compression.