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Post by rick1970 on Jan 11, 2006 19:18:22 GMT 11
Just incressed boost pressure on my '99 Rodeo 2.8TD. Went from 6psi (a bit to low???) to 12psi as recommended by diesel injection specialist. He said to increase fuel pressure by turning adjusting screw by one flat on lock nut MAX. If to much black smoke, back it of a bit.
Done this, very little change and no black smoke. Went another flat, bit better but still no black smoke!
Anybody done this or had this problem?
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Post by Graham on Jan 11, 2006 21:53:00 GMT 11
12psi is what my 3.1 MU has run since I got it. I guess if there's no black smoke (and that's under heavy acceleration) then it's not too rich. The question is, is it a problem to run a diesel lean? It might increase heat and reduce lubrication, further increasing heat. Excessive heat is a killer of diesels, so you want to avoid it. me personally, I'd consider a dyno tune.  |
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Post by geeves on Jan 12, 2006 6:59:19 GMT 11
Diesels always run as much air as possible Only thing that adjusts is the fuel. Only mixture that matters is the maximium or richness. Beyond a certain point theres not enough air to burn the fuel.
If its running better but still no smoke flat out through the whole rev range then turn it a little bit more. If it doesnt improve or starts to smoke then wind it back. Its a rare 2.8 that doesnt smoke a little
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Post by rick1970 on Jan 12, 2006 7:04:01 GMT 11
Owers manual said boost should be .5 Bar (7-8 psi), but injection specialist told me the ones thet see usually have about 10psi boost and run fairly lean from the factory.
Keeping an eye on temp guage, running as usual. Still think its running to lean, would likr to see a very small amount of black smoke.
Employee at specialist has his running at 14psi, with custom intercooler, has done 150,000k with no problems! He said it eats factory TD landcruisers and patrols easy.
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Post by mudgrip4 on Jan 12, 2006 9:10:35 GMT 11
Some isuzus ex Japan are definitely adjusted to run very lean. Continue to adjust your fuel delivery screw inwards (clockwise) at one eighth of a turn each time, and test for performance and smoke. When you see it begin to blow heavy black smoke at about 3000rpm, come back one tweak. From putting mine on the dyno and running through this process, the point of maximum horsepower is when it has begun to blow a bit of smoke under power but just a fraction before the real black cloud sets in - not after it. Once into heavy black the hp/kw actually started to go down a bit. Gain with my 2.8td by adjusting fuel delivery on dyno was 13 hp.
Mike
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Post by geeves on Jan 12, 2006 11:22:53 GMT 11
Ill have to tweak mine one day. Im running 13.5 boost but dont know if thats because of a fault or previous owners intention All Ive done in 8 years and 90000km to effect boost is 2.5 inch exhaust, snorkle and finner filter
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Post by rick1970 on Jan 14, 2006 18:45:09 GMT 11
Had a bit more of a fiddle with the fuel adjustment, screw now about 1/3 of a turn in on original. Just a hind of black smoke under full load and much improved power!
Mid-range torque well up, overtaking much easier and stay in 5th gear on most hills ;D
Just need to save for a snorkle and intercooler now!
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Post by mudgrip4 on Jan 16, 2006 12:51:44 GMT 11
From your description you can probably give it a bit more diesel again - power increases steadily up to black cloud point. However, too much unburnt diesel (Black smoke) can pollute your oil so don't go too far, or if you've got the diesel delivery fairly advanced, only use as much as much throttle as you need to. The first inch of throttle is plenty for most driving, good for economy and won't smoke. Even when diesel well advanced, motor will generally only smoke heavily when you are flooring it - so save the hard acceleration for when you need it -special circumstances. Like blowing Toyotas.
And you don't need to drive off down the road after each small tweak of screw. Just get a friend to blip revs up to and hold motor for a second or two at 3000rpm. This will show you clearly your smoke flow. When you feel you've got this right, then go road test it.
Mike
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Post by rick1970 on Feb 2, 2006 5:20:03 GMT 11
Thanks for the advise Mike, done what u said. Its going very well now! Love to drive behind 75 series toyotas up hills, watch for them to drop down to 4th (or 3rd), then pull out and overtake them, still in 5th! ;D
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Post by mudgrip4 on Feb 2, 2006 11:39:16 GMT 11
Cheers - it does make them pull well. Just remember to be pretty strict on oil and filter changes at 5000ks in case any unburnt diesel affecting oil. Advancing injection timing on diesel pump also lifts them quite a bit - but unclear exactly on this process - had a diesel specialist do this. Have to be clear not to advance to the point of any rattle or unbalanced sound in motor.
Mike.
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