fuel injection to carb ?the do"s and dont"s

[limey]

Has anyone done the conversion from fuel inj to carb?

I'm thinking of replacing the injected system for the 4 barrell Holley.

If you have or can give any pointers ie(what sensors and wiring can be discarded) . the reason i'am doing this is that I am feed up of the electrical

failures in the system and feel that the carb method will bring reliebility

Please if you have done the swap' walk me through it .

thanks :cheeky: the Limey

[Arne]

You might want to try using the search function here on the site, I'm certain you'll find some good info. I have gone from injection to carbs, but not the 4 bbl, just the stock SUs. The tech article I wrote on the subject is at:

http://classiczcars.com/forums/showthread.php?t=21574

You may want to consider using the SUs, the performance is about the same, probably better economy, and cheaper, even if you go all the way and have a set remanufactured (see ZTherapy). I'll be posting my spare set on eBay soon, complete with manifold, heat shield, linkage and springs.

[daddz]

Clive,

What electrical problems have you been dealing with? The fuel injection when sorted properly is much more efficient than the carburettors. If you must go backwards then at least employ the factory twin Hitachi S.U.'s. I have driven a few cars with properly set up S.U.'s including a friend's MGB with HS6's and the response and drivability was very close to fuel injection.

Tell us what year 280Z you have and I am sure you will get some very good advice with regard to your 'electrical problems'. The biggest pain with the fuel injection systems in my experience has been the BCDD valve but even that can be bypassed by running a hot wire thereby bypassing that nuissance.

Another two items that a few will overlook is the water temp. sensor and the thermo time switch located just under the thermostat housing.

[limey]

the 280z i have is 1976 the fuel injection wires are hard and brittle

the water temp switch is shot (wire broken)

[daddz]

Clive,

I don't know where you're located but the parts you need are as close to you as a telephone (Olympus--www.forparts.com--just ask for Ralph Bull) or a local NAPA parts store or an equivalent. If you want to do it right and not to have mess with it for most likely the rest of the time you will have the car (imagine your 1976 everything has lasted this long) a visit to your local Nissan dealer will get you the parts you need. If you're still not interested then a call to Mike McGinnis at Banzai Motorworks (301-420-4200) will get you the factory Nissan parts or better.

In any case I imagine by your post that the "fuel injection wires" that you are referring to are the injector sub-harnesses which Nissan sells in a Lawson box (about $17 each) or you can go the Banzai Motorworks route as he has found a good supplier and they are a bit more expensive. There will be some soldering involved to do the job right. The "water temp switch" or water temperature sensor should be replaced and the wire can be replaced as well. While you're at it you might consider replacing the thermo time switch since they practically sit on top of one another. I forget the exact prices but from Nissan one was about $40 and the other was about $20. I would also suggest that you have a look at your fusible links (under the white plastic covers which may have turned brown or disintegrated by now). At the very least remove the fusible links and sand the contacts--I would replace the links as they about $12 total from Nissan and the fusible link covers are about $1.xx each. I would be interested to hear the history of your car (has it been sitting for a long time, high or low mileage, and ideally if you could post some pics of the engine bay a picture can tell alot of the story).

It sounds as though your Z just needs some quality time spent under the hood to freshen up those old parts that want to be replaced. You may want to have a serious look at your injectors and all of the attendant rubber hoses including the air flow meter boots (look closely for any cracking like you might find on an old set of tires); some people remove the injectors and you can send them a couple of places spotted throughout the U.S. that can clean and "balance" your old injectors (Marren Motorsports did a set for my old RX-7 awhile back for $25 per injector) or you can replace them but this can get expensive (Nissan injectors list for a little over $100 apiece but my local dealer sells them to me for about $65 each (I have bought a few sets in my time). This can be expensive depending upon your budget but once you have sorted the engine bay area you can be assured of enjoying your Z for quite awhile.

In summary it's tough to 'diagnose' your car without ever having seen it in person or otherwise and before you jump to carbs at least try to post a pic of your engine bay so that we can all give you some good advice.