TD5 Overboost problem.

**Rosscoe68** · 8th February 2010, 12:04 PM

so tday my D2 decided to start hitting overboost. never had it happend before today at all. it is fine on mild throttle but if i floor it, the nanocom read the boost going to 1.40 and then drops to 0, and will stay at 0 for as long as i leave my foot flat. is this normal ? i was under the impression the overboost modulated, not totally shut down. from reading several posts on TD5 overboosts, i can't see anyone with the same problem i am having, more people seem to be having surging problems, which is what i would have expected through the modulation of overboost.

i suspect the waste gate modulator. will disconnect it and see if it does tha same thing. guess its the cheapest place to start anyhow.

i have Tommey ECU upgrade.
Big intercooler
Silicon Hoses
3" Exhaust.
EGR removed.
New AFM (plus a spare , the old one which i suspected was a problem but never confirmed,. may change it back and see how it goes if modulator doesnt make any difference.

**crash** · 8th February 2010, 03:32 PM

If you try and accelerate quickly, does the vehicle seem to become gutless and struggle to gain any speed but if you accelerate slowly you can reach 100kmhr without issues? If so I had similar problem and it was my boost controller that was faulty.

**Rosscoe68** · 8th February 2010, 03:53 PM

yep. thats exactly what its doing. light throttle is good, but heavy throttle is gutless.

**woko** · 8th February 2010, 04:27 PM

I have had troubles with the waste gate sticking. Test with a blow gun on a air compressor. Be gentle with it. is should move freely. if it jerks open you will need to free it up

**Rosscoe68** · 8th February 2010, 05:19 PM

so anyone know where i can get a waste gate modulator on the southside of bruisbane?
i am in logan city until end of week then on sunday heading for harvey bay. i only know of MR auto and British Offroad on the northside.

**woko** · 8th February 2010, 05:35 PM

What you can do to get you running is run a hose from the steel turbo pipe to the waste gate (this is how TD5 Defenders are) It will run fine like that and you can organize one when you get home

**Rosscoe68** · 8th February 2010, 09:24 PM

sweet. thanks. will try that. now anyone care to elaborate on how the nanocom and ECU read the turbo pressure ?
i now suspect the wastegate is sticking. as tonight i took it for a drive and it is going very well indeed. and i am getting a turbo whistle i haven't had before, although the nanocom shows Tp going up to 1.40 and then imediately down to 0. although i am definately still getting positive Tp, and a nice turbo whistle. perhaps the wategate modulator is shutting down, showing the nanocom 0 Tp but the wastgate is sticking open and giving me more. i suspect more than 1.40 so i am not going to be driving it like that as i dont want it to grenade.

**Urban Panzer** · 9th February 2010, 12:31 AM

If Nanocom ever shows 0 under "Load" ( hard throttle) then the modulator is duff, had exactly the same symptoms a week or so ago......

www.discovery2.co.uk / Waste Gate Modulator - Over boosting

**Rosscoe68** · 9th February 2010, 08:29 AM

so that would also go back the other way if the solenoid was stuck open the car would get no boost as the wastegate is open all the time, if its stuck shut, the car would get more boost than it should. all makes sense now. i have just bypassed the solenoid using the hoses and joiners that fit it into the inlet system and will take it for a spin and see. i imagine it wont be as nice as the wastegate will always be getting some boost feedback and so will get the old fashioned wastegate creep but it should isolate the problem hopefully.

**Rosscoe68** · 9th February 2010, 08:56 AM

so bypassing the wastegate controller seems tro have fixed the problem.
heres an easy fix for anyone on the side of the road. took 2 minutes to do and i reckon it is safe enough to drive on until i can find a new solenoid, although my suspicions were right, i dont get as much boost now, maxes out at 1.06.
forst thing is to take off the flex hose from the AFM to the turbo and allsmall hoses attached. then theres 2 bolts holding the solenoid onto the engine block. take em both off and keep one of them at hand. undo all the small hose fittings. theres a white elbow fitting that presses into the flex hose right next to the AFM. take it out and put in the bolt you kept handy, it screws in nicely. then use the white elbow you just took out to bypass the solenoid. put it back together and test drive.
heres pics., cos it didnt happen.......

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