Diesel Smoking

Submitted: Thursday, Jun 24, 2004 at 20:13
ThreadID: 14102 Views:3637 Replies:10 FollowUps:0
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Hi guys,

I guess this is probably a repeated question (about every hour or so!)

My 1984 2.4Diesel 4runner is getting a bit cloudy in the rear view mirror when driving to work in these dark mornings. The smoke is only bad under load at higher revs but any hill and that is it - cloud city! (Note - it is black smoke but looks light in the headlights of a car behind me!)

I bought the truck in march, there is a receipt for a fuel injector pump removal and recon from February so I am hoping that is OK. I am trying to decide the best option - should I get the compression tested and valve clearances checked ($300-500) adn then look at getting the injectors changed ($500+). I am reasonably handy with the mechanics but have never had a diesel before so am getting nervous. Never trust the garages to charge a fair price. (Any recommendations in Sydney - Northern Beaches)

There is no oil lost and when driving offroad down a real steep hill, low range 2nd gear allowed me to engine brake all the way down without any use of the foot brake so I am hoping that compression is good? Fuel economy seems OK too - about 10liters per 100km. That is driving in the city traffic!

Hope that I don't subject anyone to driving behind me!



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Reply By: Andrew - Thursday, Jun 24, 2004 at 20:44

Thursday, Jun 24, 2004 at 20:44
It may just need the fuel injectors cleaned. Did that with my old diesel Rocky and it fixed the smoking problem.
AnswerID: 64941

Reply By: ianmc - Thursday, Jun 24, 2004 at 21:03

Thursday, Jun 24, 2004 at 21:03
$300-500 to adjust tappets, no way. About a one hour job on most trucks.
My Triton was getting smoky & I found how to adjust mixture & it reduced
smoke to hardly noticeable. Lean it off too much & performance drops off.
Also have the pump timing checked.It may be retarded, fairly simple & reasonably quick to do. Is air cleaner clean? It may restrict the air & run the motor rich
although your city fuel of 10kml sounds OK!
AnswerID: 64947

Reply By: SupaMav - Thursday, Jun 24, 2004 at 22:06

Thursday, Jun 24, 2004 at 22:06
Might not be anything wrong with it. Diesels normally do blow soot when under load. Mine did, had the injectors done and it didn't make any difference to how much smoke it blew.
AnswerID: 64964

Reply By: Bilbo - Thursday, Jun 24, 2004 at 22:27

Thursday, Jun 24, 2004 at 22:27
Diesels consume about 3 to 5 times more air than petrol engines. They thrive on good volumes of clean air. Ever noticed how a deisel engine runs betterat night or when it's cold. The air is denser when temperatures are cooler. Better thermal efficiency.

First check the air filter(s). Dirty filter equals black smoke. Have the timing checked. This is best done by a GOOD diesel workshop. If you want to go "cheap", try advancing the timing yourself. Different engines have differing ways of acheiving this. It's quite common that in an older vehicle such as yours, the amount of wear in the fuel pump drive train can result on retarded fuel pump timing - and it doesn't have to be out by much to give black smoke. Advance it bit by bit and see if the smoke disappears. Look for a slight power loss if you've over advanced it. Than back it off a bit.

It's doubtful that it's low compression that's doing it. If it starts OK in the morning, then your compression is ok. Early cold starts is where low copmression will show itself by having to crank longer to get it going.

Get the injectors done last. Like others, I've had injectors done and nothing changed. Still black smoke when pulling hard. The old diesel mechanics maxim " If ain't misfiring, leave the injectors alone". I had the original injectors in my SD33 Nissan engine for 275,000 kms- not a problem. Had the injectors done on my TD 42 Nissan/Maverick at 150,000 kms - and it still made black smoke. Wasted my money there.

AnswerID: 64973

Reply By: Biggus - Thursday, Jun 24, 2004 at 23:48

Thursday, Jun 24, 2004 at 23:48
Give "West End Diesel" at Wetherill park a ring, ask to speak to Davesh, very knowledgable and happy to provide you with any info, unfortunately it's bit of a hike from N/beaches but you will only need to go there once !
AnswerID: 64989

Reply By: banjodog - Friday, Jun 25, 2004 at 06:29

Friday, Jun 25, 2004 at 06:29

Sounds like good advice has been given above. I have a similar vehicle - 2.4L, done 254,000km, gets the same litres/100km and it will do the same as yours - under load slight black smoke. Normal really as it's an enriched fuel mixture under those conditions.

You said you have a receipt for the injector pump - any warranty still current? If so, give the repairer a ring and ask for a check up of the pump timing, won't hurt. As already mentioned air flow is a must - if in doubt replace the air cleaner - they're about $32.00ish for a Ryco paper one, $65.00ish for a Finer Filter reuseable foam one. Snorkles are good too but won't give better fuel consumption - just cleaner, cooler air.

If you don't know the vehicle history, for piece of mind start from scratch in the service department. Change the oil and filter but use a good quality oil for diesels. Give the fuel tank a bottle of diesel fuel conditioner - again many brands to choose from. With the tank full tip in the whole bottle even if some claim the 300ml will treat 300 litres. Won't be as good as removing the injectors for a proper clean but it's easier - you can do this for every 3rd fill up if you wish.

Stick to a fuel outlet that has a high volume diesel turnover as they tend to have fresher fuel rather than somone that may be cheaper but hardly sells diesel - as diesel goes off. BP claim to have the cleanest diesel in Oz.

But before you race out and pay lots of money just monitor the engine yourself for a while and don't panic too much too soon about exhaust emissions. Ever been behind the latest turbo diesels from Nissan or Toyota when they put the boot in? That really is a worry with emissions - but more grunt needs more fuel.

If still in doubt get the tappets adjusted - won't take more than 30mins to do but you may be charge a rounded up one hour labour fee. Any longer and you're being ripped. But aks the first how long to do if you wish for piece of mind.
AnswerID: 64996

Reply By: Utemad - Friday, Jun 25, 2004 at 08:31

Friday, Jun 25, 2004 at 08:31
My work runs two new F-250 7.3litre intercooled turbo V8 4WDs. Heaps of grunt but plant your foot and watch the smoke! Was concerned when I first drove them (I own a petrol Rodeo) but diesels do that. Although good advice above if excessive.

AnswerID: 65005

Reply By: Member - Jeff M (WA) - Friday, Jun 25, 2004 at 11:31

Friday, Jun 25, 2004 at 11:31
Mate Diesel's smoke, some worse than others. Toyotas (Daihatsu's same thing) seem to be good at it from my expereince. Worry about it when you can't see the driveway when backing up. LOL

Headlights from behind really showup the smoke, you'd find that the person behind you probally can hardly even notice it. When I bought my first diesel I was paranoid about it, I got my girlfirend to drive behind me at night, she said "what smoke?".

If you're not 100% convinced, get a mate to drive it around the block, follow him in another vehicle, you'll see what I mean.

Also, when you get the rev's up on a tojo with your foot planted, yeah it's gonna smoke, it's gonna smoke heaps. That's why when someone tail gates me, I just hit the overdrive button and plant my foot for about 5 seconds, they soon back off!

If it is starting to get excess get some injector clean, it really does work, just don't get that crappy spitfire brand, go to the auto shop and get Nulon at the very least, instead of a whole bottle per tank you're looking at about 5 tanks per bottle for th same price. Use it every tank until it's gone, don't be shy, put a fair bit in and after a few tanks it'll clear up. Keep an eye on it, if it get's bad, so it again.

You'll also find the fuel you buy will make a massive difference to smoke. Not so much the brand (alot of them do come from the same suppliers, I know this because I have fitted cameras for work to the depots where all the tankers fill up) it's more to do with how old the tanks are at the servo. If you've seen a servo around you're local area recently getting new tanks put in the ground, that's where you go to fill up.

Long runs. If you are a suburb bashing kinda guy (like most of us are) injector cleaner may be required more often, if you do a lot of long runs the Tojo will be much happier.
AnswerID: 65019

Reply By: -OzyGuy- - Saturday, Jun 26, 2004 at 20:27

Saturday, Jun 26, 2004 at 20:27

I drive a 2L diesel and I had the same hassle now I can state to you the answer is simple from experience, first thing to do is change where you buy your diesel!

I now buy mine from the local Caltex depot, I was using BP low sulphur till I was informed by an employee that it is gr8 fuel, but not suitable for my engine when I complained about the smoke.
The air filter is important, but the Caltex fuel is what works for me...

AnswerID: 65252

Reply By: Matt 4Runner - Sunday, Jun 27, 2004 at 15:15

Sunday, Jun 27, 2004 at 15:15
You guys are all great for the information. Have decided that the first thing to do was get the missus to follow me as suggested. Just as you all predicted it is not so visible even in her headlights. I can see loads but she said "what smoke".

So I will buy better diesel, try some nulon and generally worry more about not breaking the poor truck next time I go play in the bush!

Thanks fellas, (and female fellas)

If you see a black tojo with a welsh flag on teh back going slow somewhere then hoot!

AnswerID: 65350

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