High fuel consumption and lots of black smoke, what to do first? (1 Viewer)

[Cañonero]

Hello.

I have a HDJ81 from 1991 with the 1HD-T engine.

As you can see in the title, I'm getting high consumption and lots of black smoke. Nothing dramatic (still more economical that any of the three Nissan Patrol GR 2.8 diesel of my friends).

But, comparing with other 80 series of the same year and characteristics (I run 285/75/16 BFG A/T, 3.5" lift and Safari Snorkel). They are getting about 3 l/100 less than me in the same situations.

For instance, driving on 90% on the highway, always in overdrive at 110 kph mesured with GPS (about 70 mph) and 10% around town, I get 14-15 l/100 km (15.5-17 mpusg).

If I do off road and mountanious road driving fast, I easily get 18-19 l/100 km (12-13 mpusg).

I also get lots of black smoke.


The question is what can I try first?. These are the questions I can think of:


1) Everybody tells me to close the pump to reduce fuel flow (my pump is a little bit tweaked), but I don't want to lose performance (the other 80's I've checked with the same equipment, spend less fuel and are as fast or faster as mine).

2) Replace injectors. Mine have about 160000 km (about 100000 miles). But my mechanic says that there isn't any indication of injector failing.

3) Put more pressure in the turbo. Some people have reported better performance and fuel economy after increasing turbo presure. Reliability is my concern here.

4) Install an intercooler. Do you think it would help to reduce fuel spending and black smoke?. Maybe combined with higher turbo pressure?


Any other options would be greatly wellcome.


By the way, apart from this, my engine seems to be in a great conditon. It only has 160000 km on the clock (I think it's true as I have all the records) and it sounds great and smooth (everybody is impressed about how good it sounds). It also starts great at first time even if it's been unused for one month and it's freezing outside. It doesn't spend a drop of oil in 12000 km.


So what would you do?

 

[amaurer]

1) Everybody tells me to close the pump to reduce fuel flow (my pump is a little bit tweaked), but I don't want to lose performance (the other 80's I've checked with the same equipment, spend less fuel and are as fast or faster as mine).

Your tweaked pump is the problem, nothing else. You're being silly.

 

[Cañonero]

Your tweaked pump is the problem, nothing else. You're being silly.

Oh, thank you. You are so nice.

I know that the tweaked pump increase the consumption and black smoke, but it also increased the engine power A LOT.

The question is: is it too tweaked?, I mean, can I get the same or similar performance without so much consumption and black smoke?

As I told you before, some of the guys I know with the same car and setup I got have the pumps tweaked and perform as good or better than mine, but without so much smoke and consumption.

 

[R2HKS]

2 options.

1. Turn the fuel back down, less smoke but will lose power.
2. Increase boost. Less smoke and may increase power but won't lose power.

 

[jake2far]

You could try a propane injection and back off the injection pump. It would increase your power decrease fuel consumption and eliminate any smoke. Contact crushers (Wayne) who is a regular on this site he sells complete kits. The propane will give you everything you desire without any penalties.
Jim

 

[Cañonero]

Thank you R2HKS.

If I increase the boost, would the fuel economy be better also?.

Is it safe to increase boost without an intercooler?

 

[Dougal]

Thank you R2HKS.

If I increase the boost, would the fuel economy be better also?.

Is it safe to increase boost without an intercooler?

To find what the problem is, you need some gauges.
Boost and EGT would eliminate the guesswork, tell you if your current turbo is working properly and show how close to meltdown you are with your tweaked pump.

 

[roscoFJ73]

1) Everybody tells me to close the pump to reduce fuel flow (my pump is a little bit tweaked), but I don't want to lose performance (the other 80's I've checked with the same equipment, spend less fuel and are as fast or faster as mine).

2) Replace injectors. Mine have about 160000 km (about 100000 miles). But my mechanic says that there isn't any indication of injector failing.






So what would you do?

I would get it back to stock and go from there.
The injectors are a 100000 klms service job. Your mechanic cant tell if they are good unless they are removed and tested
I had mine done at 100000klm,no smoke, but the springs were weak allowing them to open a little too early.

If you drive it hard ,it will suck the juice and wear out the injection pump prematurely

There is an excellant tech article on 80scool on how to get the most from an 80 series turbo diesel.

 

[Radd Cruisers]

Black smoke = over-fueling

Over-fueling = high EGTs, bad mileage, a poor image of a diesel truck that should burn clean, & pollution that is toxic

High EGTs = early engine failure

Turn your boost up to about 10 or 12 PSI

Turn your fuel down

Check the timing of the pump. A slight advance over stock may help a touch.


~john

 

[Garry]

Black smoke = over-fueling

Over-fueling = high EGTs, bad mileage, a poor image of a diesel truck that should burn clean, & pollution that is toxic

High EGTs = early engine failure

Turn your boost up to about 10 or 12 PSI

Turn your fuel down

Check the timing of the pump. A slight advance over stock may help a touch.


~john

Sound advise! and get some guages on there

 

[blis]

definately get atleast boost gauge and egt too... I would also check the valve clearances... on my hj61 before adjustment i was doing around 14-15l/100km and after adjustement its down to 11-12l/100km (which is quite normal figure for hj61)...

 

[Cañonero]

It definetly looks like the EGT and Boost Gauges are the first step to make a good pump and turbo setup. And also it's clear that my pump is over-tweaked.

I think I will get one of these McNally dual Boost/EGT gauges to save space in the dash: McNallyelectronics.com : Boost/EGT combo kit 30 PSI EGT Deg F

I also have a chance to get a cheap air/to water intercooler kit from a guy that bought it and is not going to use it.

Would an intercooler help to reduce black smoke and fuel consumption?

 

[Volcano cruiser]

Man, tha gauge looks nice but as a friend of mine often said when he spotted a really pretty girl, "man that aint no cheap date..". I'm gonna really have to star paying attention to this stuff now. more c r a p to budget for.

 

[Cañonero]

Do you think $244 is too cheap?

Well, it depends on what you compare it with. For what I've seen, it's easy to find EGT gauges under $100 and even some cheap ones for $60. Also, boost gauges under $25.

If we talk about dual EGT/boost gauges, here are some cheap examples:

Boost gauge (15 PSI) + EGT Combo, Koso Analog:eBay Motors (item 110362753853 end time Jun-09-09 13:09:11 PDT)

Zeitronix ZR-2 Multi Gauge (AFR / Boost / EGT):eBay Motors (item 260413659836 end time Jun-18-09 13:19:16 PDT)

http://cgi.ebay.com/52mm-DIGITAL-LE...3.l1177&_trkparms=240:1318|301:1|293:1|294:50

 

[Cañonero]

Just seen an interesting statement in an australian diesel website:

Diesels already have a strong bottom-end coping with 500 PSI engine compression. Low boost in diesel engines is classified as 10 to 11 PSI and high boost is classified as 16 to 18 PSI. The lower the boost the richer the mixture. The richer the mixture the hotter the engine temperatures.

Berrima Diesel Service - Turbocharging


I didn't boosted it up cause the mechanic told me it would raise the EGT'S without an intercooler, he said that it was more safe and reliable (but less economical in fuel terms) to tweak the pump, and in this website they state that is just the opposite way!

 

[mainlander]

EGT's are all about the amount of fuel going into the combustion chamber and raising the exhaust gas temperature. So, more fuel = higher EGT. Boost can raise the EGT too but it has much more to do with the amount of fuel you are putting in. Think about a diesel engine without a turbo at all. It can also have too much fuel sent into the combustion chamber thus, raising the EGT's and possibly causing damage.

Black smoke is unburned fuel and that is also why you are getting poorer economy. Turn down the fuel. Get the gauges then you can play with the fuel and boost level. Without knowing what the EGT's are, why would you 'tweak' the fuel? That's just a big repair bill waiting to happen.

It's better to get the boost you want and than to tweak the fuel to the type of driving that you do. More hills, keep the fuel closer to stock as you will put your foot down more as you climb the hills, thus putting more fuel into the system and raising the EGT's. Moderate to no hills, raise the fuel more and note the EGT's when driving at full load.

The proper gauges will tell you what you need to know to move forward. And you don't need to spend that much on good gauges either. I got my VDO gauges for a total of $125 USD for the pyro and boost gauge. They work perfect.

 

[Cañonero]

Thank you mainlander.

Where did you get such cheap VDO gauges?. That brand is one of the most expensive here in Europe.

I also heard good things about the prosport ones.

Have any of you tried them?

 

[mainlander]

I got my gauges from Summit Racing.

Here's my post on the exact specs for you IH8MUD Forums - View Single Post - Planning my turbo install - What gauges please?

And here's the entire post on the gauges and my questions https://forum.ih8mud.com/diesel-tec...ning-my-turbo-install-what-gauges-please.html

 

[Cañonero]

Thanks a lot mainlander.

There are real good prices for the VDO's there. They are freaking dear here in Europe. (I've seen advertised the VDO pyrometer kit for €400 = about $500).

The only thing I don't like is the fact that the VDO boost gauges are all mechanical, so that means there is a hose coming into the cab.

My cousin had one of those (from another brand) and he found himself cleaning oil inside his cab twice.

Do that happens usually?. Aren't the electric boost pressure senders safer and easier to install?

 

[Cañonero]

Another option I like a lot are the Prosport premium gauges.

What I really LIKE on these is that you can set an alarm when they reach certain ETG or boost level, so yo don't have to keep an eye on the gauges when driving hard.

Another feature that is great is the possibility of recall the peak temperature reached.

I've read some reviews and they don't seem to be bad quality gauges, but there's something I don't like at all and I'd like to ask your opinion:

The EGT gauge goes from 0 to 2200ºF. Being 1300ºF the maximum recommended temp for our diesel Toyota engines.

I suspect that this could make this gauge not enough accurate for this engine.

What do you think about this?

EGT gauge -Prosport Gauges Peak & Warning EGT gauges Stepper motor

Electric Boost Guage - Prosport Gauges Peak & Warning gauges