75 EFI on a 77 Z.

[rcb280z]

I have a chance to buy a 75 EFI "matching" system complete for my 77. The only reason I'm considering using the 75 is because my 77 EFI has been butchered by previous owners and I have searched a long time for a complete 77 and have come up with "0". This 75 system looks to be in really good shape. Harness doesn't look butchered, AFM cover is still siliconed on, can tell it hasn't been removed, etc. Correct me if I'm wrong but as long as its a complete 75 system it should fit my 77 right? As long as I use all the 75's system I should be good. I'm pretty sure this is correct but verification would be nice. Thanks in advance.

[Zed Head]

I think that it should work fine.  You could even mix and match AFM and ECU, I believe.  I have an assortment of ECU's and AFM's, from 75 to 78, that I have run together in various configurations.  No significant differences, besides small effects of age and wear and tear.

 

Wasn't it you that had the altitude correction on your car?  You might lose that if the 75 ECU doesn't have it.  But you could still run the AFM.  And the ECU would work it just wouldn't do anything with the altitude switch.

 

If the price is reasonable and the parts are in good shape you might buy it just for spares.  I was just looking at my new MSA AFM that I bought five years ago but haven't really used much and it's already showing a good amount of wear.  I don't think the reman parts are anywhere near as durable as original Nissan parts.  A 100,000 mile Nissan AFM might have another 150,000 miles in it, while a reman AFM might last 50,000 only.  Mass manufacturing has its benefits.

[SteveJ]

Things to consider:

1. Was there a California emissions version of the 75?

2. If so, will it have the same equipment as a 77?

3. Will it pass the visual test on smogging?

4. Didn't the fuel pump relay, etc., change between 76 & 77?

[rcb280z]

ZedHead, I did think about the altitude switch. I'm at sea level so the only time it is working is as you increase altitude so no worries there.

 

SteveJ, Nothing visually different between the 2. Yes the efi relay is different (2 different ones available) but if I use the 75 with all its other components it should be fine.

 

Thanks guys. 

[Captain Obvious]

I've not investigated the differences between years, but I gotta believe that if you ported the entire system over it should work.

 

I also don't know if there were any performance or emissions tweaks from one year to another. At that point in time, electronics technology was changing pretty quickly and I wouldn't be surprised if there were some changes between years. However, a perfectly working 75 system is still better than a questionable 77 system though, right? 

[FastWoman]

I would think it would work, perhaps with some minor mods (but probably no mods needed).  I think the fuel pump shutoff is a non-issue, because that's handled outside the EFI system on '78 (and I think '77).  In '78, the fuel pump will run with signal either from the alternator or the oil pressure sender or both.  The EFI doesn't matter in that scenario.

 

I think there are also differences in the EGR, but again, that's not handled by the EFI.

 

The '75 system might be an upgrade because of the Bosch (vs. Hitachi) ECU, which doesn't seem to have the same leaning-out issues with age.

 

The '75 AFM would be a downgrade if original, because it doesn't have the backfire relief valve.  Backfires can actually bend the AFM vane.

 

But overall, I'd say to go for it.  You can deal with a '75 EFI one way or another.

[rcb280z]

Perfect. Thanks guys and gal. The intake manifold I will not use, keeping my 77 intake intact. This way I can keep the EGR which I need for visual inspection. I'll use everything else from the AFM to ECU and the dropping resisters, EFI relay, etc. I'll have to look at the wiring schematic to see if there are differences on the dropping resisters between the years. Maybe there isn't. Would make it easier for me and the person I'm buying it from. Unless someone already knows this info.

 

BTW, anyone recall why there are 3 and 4 mounting bolts for the AFM? Mine has 3 bolts and the 75 AFM I'm buying has 4.

 

FastWomen fuel pump shutoff is a non-issue. Correct, the safety switch is in the AFM on my 77

 

CO yes a perfectly running 75 system is for sure better than what I have!

[rcb280z]

....and there are no external components like tach or speedo issues with the EFI swap is there?

[SteveJ]

You have to swap the right rear tire from the donor car to yours.

[rcb280z]

Haha! is that why it won't start, too funny Steve. Just realized I neglected to answer your questions in post 3.

 

Things to consider:

1. Was there a California emissions version of the 75?

2. If so, will it have the same equipment as a 77?

3. Will it pass the visual test on smogging?

4. Didn't the fuel pump relay, etc., change between 76 & 77?

 

1. Yes there was a 75 version of smog, but I am using my 77 intake with the smog equip.

2. Is answered with question #1

3. Which means it will pass a visual.

4. Yes, relay is being supplied with the transplant.

as well as the dropping resisters. I think all years of 280z used the same dropping resistors. Only one "set" listed on my microfiche. 

 

Thanks for the laugh, I needed it.

[FastWoman]

Shouldn't be any tach or speedo issues.  Tach gets input from the coil.  Speedo gives output to the BCDD, which operates independently of the EFI.