rory McMeeken · May 16, 2019

Just had a disco 2 transfer box put in and a larger inter cooler also got a stage 2 tune truck goes good but seems to cut out at around 80km in 4th gear and also cuts out at around 120km in 5th gear with original transfer box it used to pull right up to 130km in 5th. The waste gate on the turbo has been adjusted from 11 threads to 6 threads anyone know why it would be cutting out doesn't feel like a rev limiter just goes flat almost like there is not enough fuel or turbo boost

johnlad · May 16, 2019

Probably using more air than the maf can read( only goes upto approx 650) or with the amount of threads wound in on wastegate over boosting.
Try unplugging maf sensor and see how it is, failing that the ecu can be fooled using maf clamp, and boost box or new pirated map sensor to help with the boost

rory McMeeken · May 16, 2019

johnlad said:
Probably using more air than the maf can read( only goes upto approx 650) or with the amount of threads wound in on wastegate over boosting.
Try unplugging maf sensor and see how it is, failing that the ecu can be fooled using maf clamp, and boost box or new pirated map sensor to help with the boost

cheers man if i unplug the maf sensor is there any risk of over boosting and braking something because the ecu wont put it into limp mode i have a boost gauge turning up in about a week might put that on before i try anything

Bennehboy · May 16, 2019

You won't break anything but it might use a bit more fuel as it won't be able to calculate what effect the EGR is having (assuming it's still fitted).

The ECU will fall back to using the MAP & IAT to calculate the air mass being ingested.

Overboost cutoff protection works purely on the readings from the MAP, so the ECU can still cut fuelling if need be. It's pretty brutal when fuel cutoff kicks in, but it won't damage anything.

rory McMeeken · May 16, 2019

Bennehboy said:
You won't break anything but it might use a bit more fuel as it won't be able to calculate what effect the EGR is having (assuming it's still fitted).

The ECU will fall back to using the MAP & IAT to calculate the air mass being ingested.

Overboost cutoff protection works purely on the readings from the MAP, so the ECU can still cut fuelling if need be. It's pretty brutal when fuel cutoff kicks in, but it won't damage anything.

Sweet might have a play tomorrow the TD5's that were shipped to New Zealand never had a EGR valve fitted

ozzyboydeano · May 16, 2019

sounds like boost creep

when adjusting waste gates or playing with turbo configarations a boost gauge is needed or a map KPA reading under all loads and gears
please guys dont just geuss on thread counts then hope for the best

ps dont also be lazy when installing a boost gauge you need to monitor manifold pressure hence map location

sierrafery · May 16, 2019

rory McMeeken said:
The waste gate on the turbo has been adjusted from 11 threads to 6 threads anyone know why it would be cutting out

IMO the bolded part is the gist of it... at 6 threads it's so tight that it would definitely go to overboost so bring it back to 11 and see then

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