2004 Manual TD4 in 5th gear.

Hi,

Are other owners able to drive their cars at 30 mph in 5th gear, and accelerate on the flat?
I find that 5th gear is too high and can only get to 4th at 30 mph without the engine /transmission humming excessively.
Once I am above 30mph there are no issues.

Any ideas, or is this the norm.

Regards.

:welcome2:

op2:

going down hill yes try going up hill it is a big fat no no even going along the strait is really a no unless you like replacing the bottom end.

Ok thanks for that, I was starting think that there may be an issue with the variable turbo vanes, or mass airflow sensor.

*30mph in 5th be @ 1287 rpm* for a manual gearbox .. ( my tyres are 225/55 H 17 )

the *turbo is just starting to boost at about 1200 rpm*

on the 'flat' .. mine will accelerate from that in 5th gear .. albeit at a moderate pace 'till the rpm climb higher ..

had reason to do it today .. on a relatively flat 'A' road .. traffic at about 45/50 mph ..
van in front was turning into a side road .. i slowed down 'till 30 mph .. in 5th ..
then got going again .. no complaints from the engine .. or transmission ..
( er .. actually .. only did that 'cause i read this thread yesterday
( thought i might check rpm and boost data .. before posting ..
( already knew it would pick up from 1200 rpm in 5th on the flat .. but double checked anyways

however i wouldn't make a habit of being in 5th @ 30 mph ( on the flat )
hardly flexible .. eff all engine braking .. .. not so kind to the engine ..
certainly wouldn't try climbing a hill @ those rpm either

30 mph for me is ..
flowing traffic .. then 4th gear @ 1500 rpm
congested traffic .. 3rd gear @ 2000 rpm ..
if i need to get the AC working fast .. then 2000rpm does the job quicker

climbing any long steep hill .. i won't let the rpm drop below 1800 ..
( 1750 rpm being peak torque on a standard td4 )
although generally it usually works out @ between 2000 to 2500 rpm
( except 'M' ways roads or dual.c. roads in which case 3000 rpm = 70 mph in 5th )

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** data read from a ScanguageII

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'synergy2a' and 'egr delete' units fitted

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disclaimer: i doubt there are any absolute 'n totaly flat roads in west yorkshire ..
however above example were on a 'as-flat-as-it-gets' just before a gentle incline

gilbertian said:

Ok thanks for that, I was starting think that there may be an issue with the variable turbo vanes, or mass airflow sensor.

Click to expand...

low torque might be signs of bad fuel flow due to blocked filters or failing fuel pump.

Keep an eye on it

I have to say I would normally be in 4th at 30 on the auto hippo, using 'manual mode'

5th is just a bit too low for it.