Thread: Hunting throttle D2a TD5

Originally Posted by discorevy

Boost controller?, try to bypass and see if your symptoms are still there

Agree boost controller could be the cause. When mine started to go, it began to momentarily cut fuel supply. Fairly cheap to buy and easy to replace. Good tute and info for this on Urban Panzers website

Are you talking about some genuine boost controller? Because I don't have an aftermarket one fitted.


I hope it isn't the fuel pump, it was replaced not that long ago. The boost controller makes a bit of sense because it has shut the turbo off on 2 occasions since I started this thread.

The last time that happened was when I turned the boost up on the waste gate. I've turned it back since then, about 3 months ago.

Im def eager to hear how you go on this one, mine has a really similar problem around 1800-2000rpm.

OK , to at least see if boost controller is the problem , you can bypass
to diagnose , to do this you need enough vacuum line to go from the take off point which is on the metal pipe between turbo and intercooler about half way along , remove vacuum line from there and the turbo modulator and fit new line between these two points , but before you do , check to see if existing lines haven't split as this could also be your problem , jazzman you do have a boost controller , only the defenders don't, follow the line up from the metal pipe and you will find it . it has three lines . let us know how you get on cheers

Originally Posted by discorevy

OK , to at least see if boost controller is the problem , you can bypass
to diagnose , to do this you need enough vacuum line to go from the take off point which is on the metal pipe between turbo and intercooler about half way along , remove vacuum line from there and the turbo modulator and fit new line between these two points , but before you do , check to see if existing lines haven't split as this could also be your problem , jazzman you do have a boost controller , only the defenders don't, follow the line up from the metal pipe and you will find it . it has three lines . let us know how you get on cheers

I"ll have a shot. Cheers for the help. I'm going to China for 2 weeks leaving Friday night. Might not get back to you until i'm back in Aus.

Just got my car back today after having some pannel work done to it.

Today I disconnected the MAF just to isolate it. The problem became worse and more aggressive. I've since plugged the MAF back in and the problem is the same as it always was.

I'm going to have a look at what discorevy has suggested this weekend at the latest. Cheers for your input.

OK so that didn't take long. I have bypassed what i'm pretty sure is the boost modulator. It is a little black cylinder shaped thing the that resembles an old camera film canister. It had 3 vacuum hoses. two on the top, one on the bottom.

1: off the bottom to the metal pipe between the turbo and the intercooler.
2: off the top to the vacuum diaphragm on the turbo waste gate.
3: off the top to the intake piping behind the MAF.

I disconnected 1 and 2 from the boost modulator and connected them together. (Hopefully bypassing the modulator) 3 I did not touch.

The result - Symptom of hunting throttle gone. So I guess this means I need a new boost modulator?

Just as a side note. Once this symptom had gone I also disconnect the MAF to see if there was any change. There was a minute increase in performance. To be specific i'd put it down to the pause between gear change 1 to 2, it was much shorter and in turn the engine revved up smoother. I don't think it is an issue but thought i'd mention it anyway.

What rpm range does it do it? Mine at around 2k mark, still not sure what the go is with mine????? just waiting to get someone to have a look at the driving data ive got on my nanocom.
let me know

cheers

bronson