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Nissan diesel engines, and the people who love them
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Post Number:#1  PostPosted: Thu Mar 29, 2012 1:44 pm 
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Joined: Thu Sep 08, 2011 5:01 pm
Posts: 17
Location: SE Pennsylvania
Not Nissan, but hoping that someone here can help me.

I have a 4 cylinder 2.2 Isuzu diesel with a Diesel Kiki licensed Bosch VE pump.

I installed an Eaton blower, and can get 6-7 psi boost at the rpm's that I want to run at. Injectors have been cleaned and popoff pressure set at a reliable injection shop. I cannot get enough fuel thru the pump to make anything more than a barely noticeable difference--I have a manual way of dumping boost, and doing this while under load, there is so little difference that it may be attributed to the frictional load turning the blower without making any boost. I have the fuel screw cranked up so far, it is affecting the idle. I have never seen black smoke. I sent the pump to the same shop and explained what was going on. The head guy there, a friend, put in a larger pistoned pump, checked it over and returned it. While he had it, he removed the aneroid capsule, and raised the pin that it moves to the top of it's travel with a relatively stiff spring- stiff enough that I can not imagine the aneroid capsule moving it, if it was still there. All of my driving is below 1K sea level anyway. Bottom line is that even though the pump put much more fuel on his test stand, there was zero change in the way the engine acted. My reason for wanting to see black smoke is only then will I know that the engine is getting all the fuel that the increased amount of air can burn, and I can turn the fuel screw down a little from there. My pump man is stumped.

Does anyone have any ideas--especially stuff that I can do myself? I am a machinist, and have a complete shop here.


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Post Number:#2  PostPosted: Fri Jul 05, 2013 1:01 am 
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Joined: Fri Nov 26, 2010 2:51 pm
Posts: 15
Location: Middleburg, Fla., U.S. of A.
15 months & no anything?

This is merely deductive, but makes sense.
I don't know the proper name, but would call it fuel delivery profile.
Can/did your shop increase the delivery capacity of those injectors? They're really very fancy valves. A 1/4" valve on a 12" pipe will only flow it's maximum volume (though pressure might be astro-comical). Replace it with a 1/2" valve and flow volume quadruples.
Your pump pushes (now more) volume, which produces pressure, but the extra fuel has to enter the engine to burn.

That's where things went crazy on my SD22. The pump got drunk, went ber-zerk, and tried to kill the engine.

It's not an answer . . . more of a question that might go unanswered.

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'82 Datsun 720 SD22, '81 Toyota HiLux (proj)'77 Fiat 124 Spider trike project.
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Post Number:#3  PostPosted: Fri Jul 05, 2013 6:56 am 
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Joined: Thu Sep 08, 2011 5:01 pm
Posts: 17
Location: SE Pennsylvania
Ron-

Thanks for the reply--yes, 15 months.
The rebuilder redid the injectors with the same nozzles and whatever that the injectors that the later turboed 224 used. Lines from pump and fittings on ends are visually the same diameter that all my other larger per cylinder (Nissan,Deutz, Ford Dagenham) use.

I have an electric pusher pump at the tank that gives 2 psig positive pressure at the pump fuel inlet, with a 3/16 return line to the tank--that runs constantly filled of fuel.Inlet fitting to pump is stock. I have tried bypassing the booster pump with no change.

One fellow that I know, who is experienced with Isuzu 224's, both NA and turboed says that the pump timing is off one tooth on the belt. I have been off the project (putting a Deutz FL512 in a 60's Willys wagon) so haven't checked this--which I will-- but it would seem to me that if this were the case the engine would lack power, but still smoke from excess fuel. I have to think--since the pump was checked on a test stand with aprox 60% more delivery than stock 224NA--that the lines to and from the pump are the problem--but with fuel delivery pressure and quantity so much over standard-and??? I set the project aside. I would VERY much like to solve the problem, but other than the pump timing (which I am 90% sure is correct)and the internal pump pressure--which was checked at the shop-- I have no ideas.

PS--built a trike once long ago--HD engined copy of a Morgan. It has gone through a number of owners-the last that I heard(couple years ago now) it was in upstate PA


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Post Number:#4  PostPosted: Mon Dec 16, 2013 12:29 am 
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Nice post !


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Post Number:#5  PostPosted: Mon Dec 16, 2013 8:16 am 
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Joined: Thu Sep 08, 2011 5:01 pm
Posts: 17
Location: SE Pennsylvania
Problem solved a month or two ago.

Having no new ideas, but wanting to do something--anything--I started taking sections of the fuel system back to the tank apart one piece at a time, inspecting and blowing through them. Every thing from pump to tank either looked like, or was new. The tank, while old, had no rust inside, and looked exceptionally clean for it's age. Laying under the car, wondering what the %#(*%%] to do next, I put the air hose on the fitting at the tank and gave it a shot of air. There was a loud pop, followed by the sound of violent bubbling. It seem that, even though all the old Chevy "experts" say that the pickup inside the tank was just a tube going to the bottom, mine had a screen that had gotten partially blocked as the gas that was in the tank evaporated while the car sat for years in storage. I took the fact that the return line from the pump back to the tank had fuel running out of it at any speed that I could run the engine at with the car stationary--that fuel volume could not be a problem--but when the engine was under load, the amount that could get through was only enough to get 60-70% of the power.

Problem solved--and I hang my head that it was such a simple thing!

Gromit


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Post Number:#6  PostPosted: Wed Dec 25, 2013 11:34 am 
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Joined: Fri Jun 29, 2012 8:47 pm
Posts: 87
Location: Peyton Colorado
If you do any mechanicing you find this to be so true, the old KISS principle. I've had so many of these, it's a good reminder for all of us. I find the culprits to be, dirt, dirty connections, loose connections, I forgot to tighten this, the previous mechanic screwed this up-always assume that he or she didn't know what they're doing, the answers in plain sight in the shop manual, it's out of fuel the gauge isn't accurate, the battery that charges right up is actually bad, and there's many more! Duaneclark

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