Timing Belt problem! Or something HELP!

[Napster]

okay so im about to trade for a 98 gst. The guy and his friend just put a new timing belt on it. ever since they did the timing belt, when the engines rpms get high enough for the turbo to kick in, it boggs down. now is the timing waaaaayyy off or is it a boost leak?

 

[Meh987]

If the timing were off, even by a tooth, the engine would either not run or run badly. Chances are its a boost leak.

 

[Napster]

could it be anything else besides boost leak or timing?

 

[oldman]

could it be anything else besides boost leak or timing?

Why don't you check those and post back.

 

[Nanan]

Actually you can run a tooth off and almost not notice it. On my first engine my exhaust cam skipped a tooth, the result was abnormally high EGT, hard to control boost creep, and knock. The car ran that way for several months driving me nuts trying to cure the symptoms without knowing the cause, I only checked the T-belt after a suggestion on dsmtalk on a post I made about the issues and lack of ability to fix.

 

[oldman]

Actually you can run a tooth off and almost not notice it. On my first engine my exhaust cam skipped a tooth, the result was abnormally high EGT, hard to control boost creep, and knock. The car ran that way for several months driving me nuts trying to cure the symptoms without knowing the cause, I only checked the T-belt after a suggestion on dsmtalk on a post I made about the issues and lack of ability to fix.

I agree with this, a good percentage of members here are probably running with one tooth off without knowing, a very common installation mistake even for some DSM pros.

 

[nates6969]

Sorry to revive a dead thread but I noticed lately that my engine vacuum at idle (~900rpm) is sitting around ~10in of Hg. I've tried leaning it out or richening it up to try to resolve this but really had little to no change. I'm running a speed density conversion on a dsm eprom so boost/vac leaks should not play a role. At first I thought it was an ignition issue as it sounds like it has a bit of a miss at idle but now I think my exhaust cam has skipped back one tooth and noticed a nice 1.5" crack down the center of the timing belt! I also have 264s on both intake and exhaust. Has anyone had experienced this before. Could one tooth cause such a large vac drop with 264 cams

 

[Turbo Talon DL]

Sorry to revive a dead thread but I noticed lately that my engine vacuum at idle (~900rpm) is sitting around ~10in of Hg. I've tried leaning it out or richening it up to try to resolve this but really had little to no change. I'm running a speed density conversion on a dsm eprom so boost/vac leaks should not play a role. At first I thought it was an ignition issue as it sounds like it has a bit of a miss at idle but now I think my exhaust cam has skipped back one tooth and noticed a nice 1.5" crack down the center of the timing belt! I also have 264s on both intake and exhaust. Has anyone had experienced this before. Could one tooth cause such a large vac drop with 264 cams

I have experienced a similar event. My $150 Power Enterprises timing belt got slightly chewed up because of an installation error that didnt really show until about 14,000 later. The tensioner pulley bolt vibrated loose because I probably didnt torque it down properly. The timing was waaayyy off, the crank was past tdc when the cams were lined up, but didnt effect the gas mileage any and the car was still quick so I didnt really care. I had intermittent mis-fires that I couldnt figure out. My engine vac is pretty normal most of the time, about 8-10in/hg when its winter and about 13-14in/hg in the summer time. I can almost peg the bottom of the boost gauge in the summer when coasting about 3000 rpm. I have the 264/272 and they will drop your engine vac from stock specs. Change your timing belt and buy the special tools to install the new one. VFAQ Site - Visual Frequently Answered Questions has the how-to on the timing belt. Its identical to whats in the service manual. Hope this helps.

 

[nates6969]

So I did the timing belt the other day, I'm getting pretty good at it as I've done it about 8 times now on different dsms, so it was pretty painless HOWEVER when I got in there I saw one freaky sight! the balance shaft belt was completely shredded and just by chance did not get caught in the timing belt! Put the new belt on and now my idle is dead steady with 15.5-16 inches at idle. The difference in idle is night and day. I really wonder how many people are driving around with similar scenarios.

 

[92AWDHX40]

I drove around with my balance shaft belt shredded for a while, dont know how long
i didnt know it until i changed my water pump.