2.8 Hilux engine performance

[xfman87]

Hi all

I have a 2.8 hilux on 33s. As expected it's pretty gutless and only just gets to 100km/h n hills aren't fun. On occasion it will run worser that other times. Engine has a new head, airfilter fuel filter and good compression.

Yesterday after doing a rough 4wd track in the snow that ended with a steep decline of the track for about 30min, we headed home. The hilux has never run as good as it did for this hour drive home, it lost bugger all speed on hills and water temp was read about 72 degrees. Today it's back to its old slow 2.8 ways.

I was interested to know if anyone has any ideas why it may have run so well after the hill decline?

[tweak'e]

what diff gearing does it have?

cool conditions will allow more air flow into the engine. on gutless engine any minor improvement is noticeable.

when was the last time the injectors where reco'ed ?

what does the engine sound like in the various condition?
is it rattly in warm conditions, quite in cold?

[xfman87]

It has 4.55 diffs, wouldn't know when injectors had been rec'D as has 400,000 kms on the truck. It probably should have 4.8 diffs running 33s I guess. Engine sounds the same in either conditions. Doesn't burn much oil. Its a lot quieter than a 2.4 2wd hilux i used to have.

[tweak'e]

its going to be slow with 4.5's.
injectors would be a start, possibly injection pump. IP may still be untouched and struggling to pull diesel up from the tank. thinking along the lines of cold conditions may mean slightly thicker diesel which is easier to pump up to pressure.
the lack of engine noise could indicate timing is not advanced enough. if fuel pressure is down (eg from blocked fuel filter, tank pickup or worn IP) timing tends to retard.
also check for air in the fuel line.

the other thought is to check valve clearances. also check when cam belt was last done. it may be a case of not breathing to well and cooler denser air helps.

[xfman87]

Injection pump has been changed at some point, it's probably out of a hiace as doesn't have rev counter sensor on it so timing could be out. Valve clearances should be good as I put a new head on 4 months ago from cylinder head supplies in Auckland, cambelt done at this time as well. I've changed fuel filter a few times to eliminate that as an issue. I have a snorkel an airfilter is new.

Is there any easy way you recommend to check IP timing?

Appreciate your advice

[tweak'e]

timing is a bit of a pain to check as you need to get a dial gauge fitted into the back of the injection pump and measure it.
i think toyota have a special tool for it so you don't have to pull the starter motor out.
see a diesel injection crowd.

tho i have heard of guys who do it the crude way and simply turn the pump until it sounds right !
not recommended be cause there could be other issues. possible belt not lined up quite right, wrong injection pump fitted, worn out pump etc.

i noticed with mine that a fuel lift pump made a big difference. i suspect my pump is fairly worn.

[xfman87]

The timing of the cambelt is done correctly on all 3 marks so that shouldn't be a problem. I think I may book in with toyota and get them to adjust the fuel screw on IP.

I am contemplating throwing a turbo on it. When you install a turbo do most people generally change the injectors and IP to the ones off the 2.4?

What do you mean by a fuel lift pump?

[tweak'e]

the fuel screw is easy enough to do yourself, hardest part is getting the anti-tamper bit off.
but EGT's go up really easily on atmo's. you need to have an EGT gauge installed.
if you fit the gauge will tell you if its under fueled or not.

stock injectors are fine with a turbo.
you can run standard pump, but there is limits to how much you can wind it up.
as there is no boost comp you get the same fueling with or without boost. so at times it will over fuel and can cause damage if its wound up to much.
you can get boost comps fitted to your pump, or fit a 2lt pump. might be better to reco the pump and fit a boost comp on at the same time.

a lift pump is an electric fuel pump which sucks fuel from the tank and pumps it to the injection pump.

[xfman87]

Thanks for that mate. What egt range is underfuel - overfuel?
I have got a spare 3l pump floating around as well.

One thing I thought I would ask is do you know if a 2ct injector pump boost compensator would fit a 3l injector pump? In photos they look very similar to a 2lt. I know where a 2ct pump is and 2lt pumps are getting harder to find.

[tweak'e]

egt, you want to keep it to a max of 700c pre turbo. technically you can go a bit more but i like a bit of headroom.
theres no minimum as such.

but a small catch is the egt gauges do not react fast enough to pick up short stints of overfueling. an AFR gauge is generally better in this respect.
without a boost comp you just have to keep in mind your going to overfuel for a short amount of time and try to be easy on the throttle.

no idea on the 2c injection pumps.
it can also come down to the setup on the inside of the boost comp to. pay to talk to injection guys.