3b sensitive turbo

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Apr 8, 2013
Hi so i have a 3b diesel that i turboed a while ago using a td04l 13t and its very responsive which is great.

But i just drove it after 1 year (was doing rust repairs) and it accelerates nice but once at a constant speed on the freeway at 80kmhr at around 6psi the smallest movement in your foot or the smallest hill causes it to boost up to 15psi or more and take off.

I know being a small turbo its always going to be on boost on the freeway but is there a way to reduce its sensitivness as i constanly have to make corrections with the speed to stop it from taking off

Also i run 20psi max egts are 650 degrees celcius pre turbo

Someone with more knowledge will be along with a better answer but it sounds like your pump and not the turbo. The turbo takes fuel to spin up and you also said it "takes off." It seems like your injection pump has become touchy for some reason from sitting
It's possible too that you've cranked the wastegate so much that it just stays closed. Check that the linkage is free and not touching on anything or it can bind. I've found that running boost higher than 12psi on the stock wastegate and be able to maintain fine tuning ability you will need a stiffer spring. eBay has about half a million aftermarket bolt on wastegates for these. I've had good results from mamba.
To control the boost im using a manual boost controller tapped into the factory wastegate.

I no its working in terms of maximum boost control as i can get boost over 20psi and under it by adjusting the controller.

The issues just seems to be while cruising the throttle seems to touchy which as vw luv says may be a injection issues.

Fuel is maxxed and has a mercedes spring in the diaphragm housing.

Im thinking maybe the two hoses coming of the throttle body to the injection pump fittings may not be positioned in the air flow properly.

Should the holes in the fittings be pointed towards the airflow?
It may be worth considering the leather diaphragm in the injector pump.. when it fails you get significant fuel.

Is it dropping back to idle slower than usual or is it idling faster than it used to?
Ahhhaaa. Mercedes spring. I ran that and it made my pump feel like an on/off switch. Made it ohh so twitchy. You could try trimming the spring length and see if it helps. I put my stock one back in but the Mercedes spring sure increased the fuel.

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