jack

An unusual thing happened today when I floored my 1st gear (I don't usually do that, not in 1st anyway :P). Upon reaching 4000rpm or so, the engine seemed to skip a heartbeat before continuing the rush to redline. The hesitation was accompanied by a little shrill chirp. I repeated it several more times, and it's always at or around the same rev range (4000-4500rpm), around the time when the TD05 turbo gives you the savage kick in the back. Then I experimented with lifting off the throttle at very high revs and the chirp came on again, so I concluded the sound/problem(?) was the result of a sudden change in the car's momentum? Second gear up, the problem is a lot less frequent, almost non-existent.

Any idea what is causing it? Belts? Leaking BOV? I'm driving a MY94. Any advice would be appreciated.


Best rgds,
Jack

Gerg2

Hows it goin Jack...had a merry christams I hope.

I have the exact same car as you with the exact symptom. I can get this to happen every time floor it in first and is like you describe a very noticeable hesitation in delivery.

It happens to mine no matter what temp, fuel etc I use.

I have put it down to the ECU but I could be wrong. I havnt found any other explanation other than a characteristic if the car so I dont really worry about it.

Mines due for its 100,000 km service and am having the cambelt changed as well.

jack

Hi Gerg2,

Merry christmas to ya too!

I just remembered something. The problem only occurs if I floor it fully. If I bring the revs up to redline gradually using part throttle, there's no hesitation at all. It became more obvious after I fitted the A'PEXi AVC-R boost controller and caused the boost response to jump (improve) dramatically. I have a Superchip fitted and I've set boost to 1.2, 1.1, 1.1, 1.0 and 1.0 bar for first to fifth gear respectively.

I'm worried about it because I'm bringing the car to the local short-distance drag meet soon. If the problem is actually a feature, I might as well just give up now. *sigh*

Right now, I'm leaning towards a faulty set of coil packs and plugs. My car has done 67000 miles (about 110000 km) and I've been told wear-and-tear items like the coil packs are known to give way around now. Can anyone confirm this?

Sorry for all the bitching, but I get really frustrated when something goes wrong with the car. :P

Anyways, a happy new year to all!

Scott.T

iTrader: (2)

Has anyone solved this problem as I think I have the exact same thing on my MY94

Blackscooby

I'm not sure whether mine is exactly as you describer, but as the revs go over 4200 in first the acceleration is best described as frantic. I also have a TD05 with apexi AVC-R and an AFC running 1.3bar.

I don't have any noises (apart from the scream from driver).

One thing I do know is that the engine moves on the bushes pushing the intercooler into my strut brace as the turbo kicks at those revs causing a squeak. Putting some rubber sticky pad on the IC has stopped it

Mark

Scott.T

iTrader: (2)

See my other post on the same topic .....

jack

Hey Scott,

Turned out the chirp/squeak was totally unrelated to the hesitation/surge. The squeak was due to a poorly tensioned aircon belt. :P The hesitation was due to settings on my AVC-R because it simply couldn't react fast enough in 1st gear. I played around (mainly) with the duty cycle, start duty and feedback speed until the problem has more or less gone away. Still happens once in a while, but I've given up hope on eliminating it completely already.

In my search for a solution, I have been advised by many that the few common causes for this problem are the fuel delivery (does it happen when the tank is near empty?), plugs and especially the coil packs.

If you do eventually find the cause and/or solution, would appreciate an update, thanks and good luck!

[This message has been edited by jack (edited 09 August 2001).]