NA6 stock ECU tuning - definite torque flat-spots etc.

[StanTheMan]

is it normal for a mechanic to overtighten a timing belt to allow for stretching?
when i got my car back from having the waterpump, plugs, air filter etc replaced, he told me there's a "bit of a whining noise, because i found the timing belt was loose after i replaced the waterpump..." (der)
the noise almost sounds like it's supercharged haha. i freaking wish!

unlikely.
The timing belt runs around the crank shaft & cam gears. Along the way it also passes over some runners which automatically tension the timing belt. The water pump gets dríven by aaccesory belt.

Usually when there is a noise like you describe. The first suspect I'd have is the water pump. closely followed the runners.

The water pump has allegedly been replaced......
Over tightening the belt? sh*t......is that possible? or is he talking out of his arse? one of the runners is kind of pre loaded it has a specific spring loading within it to keep the cam belt tight & allow for stretching.

I have a feeling he's kept the original runners. which are making that noise & if he's managed to tighten that runner more than what its meant to be....it can't be good. Its probably then making that extra supercharging noise because its too tight( if he's managed to tighten it more than its supposed to be)

I'd almost put my bet that the runners are out......or will be very shortly.

As far as the tune goes. I doubt the runners, even if he's managed to over tighten them, will affect the tuning issue.

if the runners do break or loosen too much.....the engine will be pretty noisy. You will now about it. I doubt they will break. They just sound like they are worn out.

ohh and as far as the O2 sensor.....yes very small chance but would probably be one of my last things to check.

I would certainly check your leads & plugs

[Juffa]

Actually I had one thing around the wrong way. I said you have to remove the timing belt to get at the pump. It is other way around.

Anyway to Stan's point. There are two pulleys that the timing belt runs through. One of these uses spring tension to press against the timing belt. Without this tension the belt could slip. If it slips the cams get out of Sync with the crankshaft...not good for the engine or you (worst case). Anyway get yiurself and the car back to the shop and get it looked at.



http://www.miata.net/garage/timingbelt.html

These are usaully replaced every 100,000Km (major service) with the timing belt (and water pump (sometimes)).

[ampz]

Just adding to Juffa's and STM's post.
Overtightening of the timing belt is possible, it may also be a tooth out, making your engine work a little differently to what it was designed for.
If your injectors are in need of cleaning, they may be spraying irregular fuel patterns (running a little rich as the fuel dribbles out rather than spraying out).
I noticed this when i changed injectors, which i had cleaned prior to installing them.
My idle was a lot smoother and so was light throttle driving.
Maybe one thing to check.

[93_Clubman]

is it normal for a mechanic to overtighten a timing belt to allow for stretching?
when i got my car back from having the waterpump, plugs, air filter etc replaced, he told me there's a "bit of a whining noise, because i found the timing belt was loose after i replaced the waterpump..." (der) the noise almost sounds like it's supercharged haha. i freaking wish!

short nose crank problem also starts with a bit of a whining noise, but you'd hope that when the waterpump was being done that would have been noticed...

[bensale]

Its also possible the whining noise is coming from the accesory belts. Spray some water or maybe wd40 at them and see if it goes away. I fitted a certain brand of belt (can't remeber) and it made one hell of a whine (like a s/c) when not tensioned perfectly.