Bad fuel economy 84 MKSD33T

[84mksd33t]

hey guys,

im getting pretty bad economy from my 84 swb sd33t

From a full 60l i struggle to get 420kms - I shift at around 1900rpm

So no thrashing

I noticed that the pressure release plug on the inlet manifold is very easy to pull out (fingers can pull it out with ease) Is this normal? or could i be losing boost because of this? (boost gauge reads 4-5psi - stock is 8?)

I have a friend with an aftermarket turbod sd33 - he gets 550ks to the tank thrashing the pants off it :(

What are some things i can check?
- Fuel filter (where is it located?)
- Do they have a TPS?
- Do they have a thimble like on the TD42?

Any suggestions or help is much appreciated as Going through 100$ of fuel in 4 days isnt fun :(

Cheers,

Cody

[NZ4x4]

I get about the same as you but drive it a bit harder.

If you are running bigger tires or carrying heavy loads it could hurt your economy.

[pongo]

Maybe your injector pump needs some adjusting. Check air filters,etc. Mine might get close to your figures, but im running 4.6 centres. You will be able to hear your pressure release working if its letting out air. Mine is bloody loud.


Cheers

[badger]

mates mq runs a huge after market turbo and 35's get better econamy than that and enuf power to spin em in third

mab needs a tune up or injector clean

[zer0]

try putting a bottle of diesel power into it next time you fill up (its and additive that cleans and makes things run better its preety much the diesel version of spitfire for petrol engines) you can get it from pretty much every store like auto barn supercheap etc etc

Heath

[DR Frankenstine]

If your changing at 1900 rpm your turbo would only be just starting to come in. At least rev the thing to 2800 rpm get the thing working.
Turbo diesels hate being laboured.

[gurumon]

that's only about 15l / 100 klm.

my na sd33 chews about 18 or so per 100klm on the highway (much worse off road).... i don't have a tacho so i rev it till it stops accelerating

i also use about 1 litre of oil every 400k's

[badger]

you will get that when u rev it till it stops thru each gear lol

[84mksd33t]

So you think i should hold gears until 2600-2800RPM?

I dont like the amount of noise the engine produces ay...

Too loud

Ill trry it and see how i go!!

[festy]

hey guys,

im getting pretty bad economy from my 84 swb sd33t

From a full 60l i struggle to get 420kms - I shift at around 1900rpm

So no thrashing

Me too. I used to get better than 12l/100km, now only just managing 15l/100km

I noticed that the pressure release plug on the inlet manifold is very easy to pull out (fingers can pull it out with ease) Is this normal? or could i be losing boost because of this? (boost gauge reads 4-5psi - stock is 8?)

4-5 is stock. You'd know if you were losing pressure via the pressure relief valve, there's a big 'sneeze' and you lose *all* boost. If you keep your foot into it, it sounds like a steam train tshhh-tshhh-tshhh-tshhh

What are some things i can check?
- Fuel filter (where is it located?)
- Do they have a TPS?
- Do they have a thimble like on the TD42?

Fuel filter - there's one on the firewall behind the injector pump, and there's another filter in a banjo joint on the injector pump itself.

TPS - I don't think so
and no idea what a thimble is.
Check compression? Fuel pump timing? Have you had the injectors serviced?

[Patroldude]

Stock boost is like 9psi according to Nissan.... we cranked it up to like 13pound - never cooled one, got the cooler sitting there but never got around to it hey.

Your economy sounds like crap but... NA diesel used to use less than 3/4 of tank to get from Sydney to Cooma and TD uses just over 3/4 on highway - this is on stock 4.33 diffs with good 31 inch rubber. Sutherland to Cooma about 500kms I think.... 68 litre tank... so we be doing like 10l/100kms off road only chew little bit more....

My 5 litre though..... different story!

Mk

[84mksd33t]

Well when i increase the boost - max i get is 6psi and then the pressure release goes off.l

The car feels very slow - and doesnt pull likea turbo diesel :(

can someone post pics of where the filters are please?