x1/9 carb to fi conversion help

J

jcstuckinmuck

Daily Driver
Hi all iam new here, iam from the otherside of the pond uk, i have a 1979 1500 carb model and i would like to convert to injection, have the manifold,air chamber,injectors ecu, fuel rail and pressure regulator, cold start injector and wiring and air flow sensor and intake hose, i think i have most bits
What other items would i need for the conversion, i also would like a wiring diagram for the double relay pinouts, this coversion is not for power but better running and starting, any help and ideas, and any part numbers for the missing items, John
 
Welcome!

I think the E;ectrical Diagnostic Manual has the easiest to read diagrams - I thought it was available off the x1/9 Wiki, but I don't see it, so here i s a link to my copy: Pages 20, 21,22 have clear diagrams & the next page describes the circuits.

Pics of what you have laid out in the general placement as it would be on the motor make it easier to see whats missing :)

Sounds like you still need the Aux Air Slide. Do you have the lower runners (that the injectors mount in) and all the fitting pieces for the injectors (hold downs, phenolic spacers, etc)
 
What are your plans for the gas tank? Will you convert your existing one, or source an FI tank? The fuel level sender is also different. You didn't mention fuel pump and filter either, do you have those?

Pete
 
Wow thanksyou for you super fast reply lookforjoe, and pete whitstone, that manual is a godsend, iam truly greatful, here is what i have, i dont think i have the aux air side, i do have the lower runners, as for gas tank at the moment i only have carb unit,what do you guys think?
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Another issue is the intake ports on the FI head are different from a carb head. The FI ports have a cut out to facilitate the injector spray pattern. The carb head will not have these cut outs. I have been told that the carb head can be used with the FI set up, but obviously will not provide the full benefits of FI. IIRC, I was told it will run OK, just not as good as it could. I think that means you should get the desired drive-ability, but probably not all the "power" of the FI setup.

Here is an FI head with the cut outs:
tap_hole_9.jpg
 
I am sure you could approximate the cut outs on your own. As you said, time and patience would be key. You can get an idea of the shape you need from the end of the intake runners that hold the injector. Or perhaps from an FI manifold gasket, although I have found some of the gaskets to not be real precise in fit. So.. working off the shape of the intake runner is probably best.

Not exactly a precision cut on this gasket. :(
IM002826b.JPG IM002827b.JPG
 
I have been very slowly swapping a 1500/FI into my 78, but that is a much different project than yours. Hopefully I am not filling your head with extraneous info that isn't helpful. :)
 
You may want the OE aircleaner, it is large but effective with little restriction.

I also don't see the FI style thermostat housing which has a coolant temperature sensor in it. I also dont see the thermo time switch (that goes in the head) or the auxiliary air valve which gives you fast idle

You won't need the little cylinder with the two small ports and two electrical blades on the opposite end, that's used to boost the idle on a AC equipped fuel injected car.

You will be buying new 7.5mm fuel injection hose correct to put new hoses on the entire system? Hint hint. You can reuse the little steel rings that are part of the retention system for the hoses.

This is an image from the Bosch L Jetronic manual with all the parts. Twin cam but the parts of the system are the same.

IMG_1616.jpg
 
Last edited:
Guide to replacing fuel injection hose.
Bosch L-Jetronic Manual
 

Attachments

  • FI Hose Replacement.pdf
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  • BOSCH L-Jetronic Injection Manual.pdf
    6.1 MB · Views: 65
Get some Silly Putty and shove it in the intake ports of the head. Lay the manifold gaskets in place and mark the EFI notches. Remove the extra metal. Vacuum the ports and then remove the Silly Putty. Issue solved and you're good to go!
 
Good advice above - also you'll need a fuel pump, with mounting brackets and mounts. Don't sweat the AAV, you can probably get away without it, just plug the holes. You can always add it later if needed. Looks like you might be missing some throttle linkage too.
Take a good look at the rubber air intake hose - make sure there are no cracks.
 
kmead said:
You won't need the little cylinder with the two small ports and two electrical blades on the opposite end, that's used to boost the idle on a fuel injected car WITH AC.
Click to expand...

You'll need the FI-based Ignition distributor, wiring and box also - the carb advance curve is wrong for FI.
 
Brilliant guys, ive just done all the pinout for the double relay, and the silly putty idea sounds a good option, and yes i will check the intake duct for crack and holes, what is the little cylinder with two ports and electrical connector??
 
jcstuckinmuck said:
Brilliant guys, ive just done all the pinout for the double relay, and the silly putty idea sounds a good option, and yes i will check the intake duct for crack and holes, what is the little cylinder with two ports and electrical connector??
Click to expand...

It a valve to increase the idle speed to compensate for the load when the air conditioning is on.
 
jcstuckinmuck said:
what is the little cylinder with two ports and electrical connector
Click to expand...
I think you are referring to item 15 in the illustration? That is what Beezee described and what MikeHynes called the AAV (auxiliary air valve). Not to disagree with MikeHynes but I think it is necessary as it works in conjunction with other components to provide correct high RPM idle conditions. You might get away with your existing ignition distributor if you eliminate the factory ignition module (grey box) and use a modern (GM style) module. There is a thread on how it is wired to the stock wire-harness. It will provide a better advance curve than either of the stock ignitions.
 
Dr.Jeff said:
I think you are referring to item 15 in the illustration? Not to disagree with MikeHynes but I think it is necessary as it works in conjunction with other components to provide correct high RPM idle conditions.
Click to expand...

They're taliking about this, attached to the AFM, it's AC idle compensation:

He doesn't have an Aux Air Slide yet.

index.php
 
Dr.Jeff said:
You might get away with your existing ignition distributor if you eliminate the factory ignition module (grey box) and use a modern (GM style)..... It will provide a better advance curve than either of the stock ignitions.
Click to expand...

Jeff - forgot to comment on this - the advance is complete controlled by the mechanical and vacuum in the distributor - the module is only a power stage, there is no chip controlling advance/retard in these boxes.
 
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