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I Love The Fuel Injection Bible


Mr.INSANE

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congrats! :-D

 

man, i had a fit trying to start mine, until one day I says to myself "it's that bloody fuel pump!". so I disassembled it and and gave it a good cleaning, purged it with some solvents, and BAAAM. 10:30 at night, my exhaust broke off its rusty bolts to the roar of all 6 cylinders at 6,000 RPM after a 20 year hiatus.

 

Nothing quite like that first-time feeling.

(and just for good measure)

"That's what SHE said"

*ahem*.

 

congrats =)

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'Bout bloody time. :-P

 

So what all was wrong?

 

Ahh lets get started

 

First off there where to many fuel related problems i swear, a few injectors where stuck and leaking but thats been fixed. and old fuel line in the back finally burst after 20 years (since then ive replaced all fuel line's) The starter I got for it awhile back was bad.

 

After i got it running i ended up replacing the intake/exhaust manifold gasket becuase of vacuum leaks. I think i need a new TPS and AFM still too :P

 

All in all i still have a lot of buttoning up todo. Alternator need's replacing etc etc etc

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I'd hold off on the AFM replacement. Odds are it's fine, just needs to be cleaned up/rebuilt. Easier to do that yourself before trying to find a replacement, though I come across them EVERY time I'm at picknpull if ya need one.

 

Yeah, I'm still not entirely sure its the AFM i really think there's a vacuum leak I haven't caught yet. I don't have any starter fluid or WD40 to find it though.

 

Oh yeah found out my cold start injector is gone too :(

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you should check your throttle position switch for proper functioning.

 

MY favorite way of finding a vacuum leak is to use a mechanic's stethoscope (less than ten bucks at harbor freight) or a piece of tubing with one end in my ear, and listen around anywhere air flows or vacuum pressure is established, listening. I know it must sound strange, but i trust this method MUCH more than I trust haphazard spraying of combustibles.. not over a safety factor, simply far easier to reproduce results, and cheaper in the long run than wasting can after can of carb cleaner or starting fluid.

 

The mechanic's stethoscope is a GREAT tool.

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you should check your throttle position switch for proper functioning.

 

MY favorite way of finding a vacuum leak is to use a mechanic's stethoscope (less than ten bucks at harbor freight) or a piece of tubing with one end in my ear, and listen around anywhere air flows or vacuum pressure is established, listening. I know it must sound strange, but i trust this method MUCH more than I trust haphazard spraying of combustibles.. not over a safety factor, simply far easier to reproduce results, and cheaper in the long run than wasting can after can of carb cleaner or starting fluid.

 

The mechanic's stethoscope is a GREAT tool.

 

Mine doesnt seem to want to come apart. Just buy a new one?

 

Ill look into that method it seems cheap and I'm trying to keep costs down as it is

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first test it for proper function; read the bible for details, but there are three terminals. at zero throttle, there should be continuity between A and B, at part throttle there should be no contact, and at WOT there should be contact between B and C. I cant recall which wires are A, B, and C, but thats the basic version of the test.

 

If it functions appropriately, then its good. if it doesnt, get a flat screwdriver and pry the black plastic cover off. Its glued on. ALOT of hitachi FI components are assembled in this same way; it WILL just come off. If it doesn't work, what do you have to lose?

 

Once you get the cover off, you discover how rudimentary this thing is; its so blatantly obvious i wont even describe it. More modern vehicles use a throttle position SENSOR (not switch) that is essentially a "volume knob" (potentiometer) indicating the position of the throttle.. but this is literally just two contacts. One indicates idle, no contact indicates "running" and the other contact indicates WOT-Full Enrichment.

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first test it for proper function; read the bible for details, but there are three terminals. at zero throttle, there should be continuity between A and B, at part throttle there should be no contact, and at WOT there should be contact between B and C. I cant recall which wires are A, B, and C, but thats the basic version of the test.

 

If it functions appropriately, then its good. if it doesnt, get a flat screwdriver and pry the black plastic cover off. Its glued on. ALOT of hitachi FI components are assembled in this same way; it WILL just come off. If it doesn't work, what do you have to lose?

 

Once you get the cover off, you discover how rudimentary this thing is; its so blatantly obvious i wont even describe it. More modern vehicles use a throttle position SENSOR (not switch) that is essentially a "volume knob" (potentiometer) indicating the position of the throttle.. but this is literally just two contacts. One indicates idle, no contact indicates "running" and the other contact indicates WOT-Full Enrichment.

 

If seen the Innards before, I was under the impression that they where a bit more complicated than that. As in the tell they Ecu about throttle changes before the Ecu knows to compensate for fuel and air and the such.

 

Edit: Tested, it wasn't working right, Turns out theres another Unit besides the Hitachi The JECS one. It has rivets that most be drilled out to open it :P

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Edit: Tested, it wasn't working right, Turns out theres another Unit besides the Hitachi The JECS one. It has rivets that most be drilled out to open it :P

 

Bah, I forget sometimes that alot of the datsun FI stuff was JECS and not Hitachi sourced... its all so similar looking anyhow, and i do more work on my subaru than on my datsun, I just inserted the name "hitachi" without thinking. It still shouldn't be too difficult to pull apart, and if you have to zip tie the cover back on, or glue it with a light bead of silicon or something, hey.. you still might be able to make that part work until you can get another one cheaply and easily (read: junkyard, on a lucky day)

 

I know how its worded in the book makes it seem like there is more to that, but seriously.. thats it, just three possible conditions. sounds like you got the (a?) problem traced, in any case. That book was written for technicians who had grown up in a world where computer controlled EFI did not exist.. they "jazzed it up" a bit in some places :P

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