Dave M
Isuzu Baby
'89 Bighorn 2.8 LWB
Posts: 22
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Post by Dave M on Apr 8, 2004 20:44:27 GMT 11
On my 2.8 Bighorn, I recently cranked up the fuel delivery adjustment. A couple of guys at work have done it on a few other mates diesels, all with good results. There's 2 solenoids on the fuel pump. Just under the top one is a tin cover pressed over an adjusting bolt. After prising off the cover and taking careful note of where the slot is, I backed off the locknut and screwed the adjuster IN a quarter turn, locked it up and drove it. Much better power at all throttles. Screwed it in another quarter- better again but a bit much smoke. Settled on three eighths of a turn. Good power gain, earlier turbo boosting, just a wee haze of smoke on full noise and economy seems unchanged. Now, I'm not saying all race out to your garage and do this thing, cause I'm not sure about the long term wisdom of it, but it worked for mine and I am happy to risk it. Enjoy!
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Post by mudgrip4 on Apr 15, 2004 17:32:33 GMT 11
This works pretty good on mine also - I experimented and settled on a half turn - any more and it looked like a coal locomotive out the back. I combined this fuel increase with a slight advance of the fuel injection timing - not enough to make the engine rattle - and the result is VERY good increase in power - about 10-12% I estimate. Now a grunty 2.8. Fuel economy still 52km per gallon or 32 mpg. Very worth a look and safer than boosting turbo further etc - Mike A.
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Post by wiseman on Apr 16, 2004 0:20:54 GMT 11
Interesting information, I paid about 130 US dollars for something they call diesel pump optimisation. A performance company does this here in South Africa and it was a mystery to most vehicle owners as to what this optimisation entails, now I think I know. In my vehicle the smoke increased at heavy throtle under stress. Thanks to Club Isuzu again
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Len
Isuzu Baby
Posts: 13
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Post by Len on Apr 28, 2004 12:47:43 GMT 11
Sounds good. Can I do that to my 3.1 Wizard?
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Post by tourist on Jun 7, 2004 14:46:06 GMT 11
I wouldn't over do it personally. The excess diesel might wash off some of the lubricant clinging to the combusion chamber wall leading to more wear & tear. My 2cts.
On the other hand, I will have a look at cleaning the EGR valve or disable it altogether but may be bad for the environment with increased NOX emission. In my country, NOX is not a legally restricted emission so I have mine disabled.
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Post by namic69 on Jul 16, 2004 14:50:14 GMT 11
how did you manage the slight advance of the fuel injection timing ? I have a 96 bighorn and am lookin for more power after the 2.5" job.
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Post by namic69 on Jul 16, 2004 14:50:35 GMT 11
how did you manage the slight advance of the fuel injection timing ? I have a 96 bighorn and am lookin for more power after the 2.5" job.
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Post by ben on Aug 10, 2004 21:04:37 GMT 11
Just out of curiosity, isnt there a nut/screw on the back of the injector pump that does the same thing as what was described,
am going to look at doing some thing like this to my 2.8 intercooled turbo bighorn
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Post by Bruce on Aug 11, 2004 13:16:43 GMT 11
Does anyone know how their adjust the fuel delivery on the 3.1 injector pump?
Cheers Bruce.
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Post by HappyJack on Aug 11, 2004 18:02:11 GMT 11
A word of caution. To my understanding overfueling on boost can cause huge damage to the internals - such as piston tops through overheating and valves through carbon build-up. I'd be wary of trying to get cheap HP by pumping up your fuel delivery.  |
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Post by Bruce on Aug 12, 2004 18:54:45 GMT 11
Thanks for the reply mate and I do understand what you are saying, so will be doing a fare be of reserch on it before going any further.
Cheers Bruce.
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Post by Harry on Aug 18, 2004 20:56:35 GMT 11
Playing around with fuel delivery last weekend found that if you take the diaphragm cover off the injector pump,take out the diaphragm and remove the nylon spacer from the plunger and leave it out and reassemble the rest the truck goes heaps better.When I replaced the swb motor I noticed the replacement motor didn't have the spacers but the old motor did.In my wisdom I swapped them over and made the truck go all tired.Now it's only slightly slower than the intercooled lwb but that's with 32'' muds on.Can't take them off yet cos last weekend's club day is now this Sunday.
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davidb98
Isuzu Baby
Isuzu Mu 1990
Posts: 3
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Post by davidb98 on Feb 1, 2006 18:48:12 GMT 11
I also would like to ask the question about advance of injection timing..... I have a 1990 Isuzu Mu 4JB1-T did you take off the timing cover and the pump drive pulley and rotate the pump slightly? is it possible to take off only the section of the timing cover that covers the pump pulley without disturbing the section behind the crankshaft pulley, etc? (if so it will be much easier to do the timing adjustment) rgds how did you manage the slight advance of the fuel injection timing ? I have a 96 bighorn and am lookin for more power after the 2.5" job. |
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Post by mudgrip4 on Feb 2, 2006 11:57:24 GMT 11
Guys - I can't exactly recall the process with advancing injection timing on pump. Had mine done 2-3 years ago. Can confirm it took only 20 -30 minutes to tweak at Turbo Tech in Chch, cost very little and gained about 10-15hp, notably extending rev range grunt from 3000 to 3500rpm (unlike bigbore which gives more grunt 1500-2000rpm). Needs to be done in conjunction with fuel delivery increase for best effect.
Cannot advance timing to point motor rattles or sounds unbalanced. Seems a safe mod - my motor has done 60000ks with this tuning and going well. I see from blurb sheets the new mitsi 4x4s all have this standard now - helped them gain 10hp increase for their new (triton?) model. I think they also called it diesel pump optimisation or some such thing.
I would call your local diesel shops and ask them re process and cost.
Mike.
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smithy
Isuzu Baby
lets get dirty !!
Posts: 10
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Post by smithy on Feb 20, 2006 15:14:13 GMT 11
Just wound the fuel pump screw in 1/4 turn and found it now gets off the line alot easier and with less revs.My 2.8t was very flat untill 2000 rpm when the turbo tooks over.Now it will respond in 4 th gear with 1500 rpm much better than before.Thanks for the tip ,it has made town driving much easier.Cheers.
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Clark
Isuzu Baby
Posts: 25
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Post by Clark on May 16, 2006 15:31:34 GMT 11
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Post by mulover on May 16, 2006 17:48:59 GMT 11
Sorry to tell you clark, but that anit it, that one is in a way too easy place!! The actual screw is a screw, not a bolt, it has a solt in the end of it, not a hex head, and has a thin hex lock nut on it, and it is underneath where you are and towards the motor, its a real prick to get at!!
I will take a photo when i take my wheel off next, but that won't be for a while.
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Post by Graham on May 17, 2006 0:17:51 GMT 11
Cool, let's play where's Wally? Or I'm Wally and I'm wondering where this adjusting screw is. How about this photo? (click for a bigger image) Is it the one at 12 o'clock, just below the black fuel line?  The front of the vehicle is to the left and the passenger side front shock is just on the right - there's a rubber 'blind' separating the wheel arch from the engine bay, I just lifted this out of the way and took the pic from almost ground level and the chassis rail is visible in the foreground. If I have found the right adjustment point, then next up, how do I adjust it? There was no movement in that arm. Do you just loosen the locking nut and turn the threaded bolt by 1/12th turn or is there more of a trick to it? Cheers, G. |
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Les
Isuzu Baby
Posts: 28
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Post by Les on May 17, 2006 12:41:27 GMT 11
Graham no thats not it in pic and its real hard to spot. Where your fuel supply pipe in the pic connects to pump is solenoid a wire runs of it immediatly below this is another solenoid with a wire
if you have taken egr valves of your truck get a top veiw down onto pump on the engine side of pump and just below the fuel inlet solinoid u should be able to see a metal cap which extends out of pump its above the pipe work which gos to injectors if u find the cap the screw and locking nut is inside the cap i tried to get pic for u but its almost impossible. im hoping this description helps if you are looking thru the rubber blind unless you know where to look its very hard to see I hope this description helps you
cheers Les
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Clark
Isuzu Baby
Posts: 25
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Post by Clark on May 23, 2006 22:21:29 GMT 11
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