Fi Ecu Mods And Differences?

[wheee!]

Glad to help.

 

Forgot to ask before, but to double check... What you were originally saying is that you've got three ECU's in your possession and all three of them outwardly appear to be identical. Same part number on the outside of the case and all three "should" work fine in your 76. But you took the case off and found significant differences inside (at least between two of them). And you're wondering "What the heck? I thought all three of these were supposed to be the same?"

 

Did I get that right?

 

I'm intrigued by the ECU you have there that has DIP (Dual Inline Package) components instead of the round ones with the finned heat sinks. The parts I'm talking about have sixteen pins each and have a big "1", "2", "3" on them. Can you take a closeup pic of one or more of those for me? I believe they are semi-custom (not available off the shelf) Hitachi parts, but it would be nice to have the numbers off the tops. If you get a chance?

 

 

You are correct on all counts. I have to remove the third ECu and open it to inspect the internals. All three were in a box in the trunk of the car when I bought it.... and the car hasn't been run since 1996.

 

I will get some more pics of the DIPs for you soon. Unfortunately I reassembled them and took them back to the shop last night. All I had at work was my crappy cell camera. When I get the other one out I will photograph them both with my Digital SLR

 

 

Higuys,

 

There is a discussion on HybridZ by Braap regarding the L6 EFI system, including the ECU.  Basically, there are a few things on the ECU that you could change, but you won't really see any difference. 

 

It seems like the Hellfire replacement by Superlen is the best thing you can do, tuning-wise, but the engine is the real hurdle to overcome.  It's a very nice engine, but they didn't really design it to be really powerful, as we understand it now.

 

Thanks for the link, I will look into that!

 

I like the idea of the Hellfire as I have two engines and I would like to run the stock motor at first (for the wife) and then rebuild the other as a hi-performance overbore with carbs or ITB's. No point in doing that until I have a megasquirt or Hellfire to tune it....

[Captain Obvious]

I've been through that EFI thread on HybridZ and I wouldn't put any credibility into the validity of the information as it pertains to the guts inside the Z's ECU. The discussion of things OUTSIDE the ECU case are valid, but all the stuff about changing resistor values and such inside the case are suspect.

 

I've been through that info a couple times now and I believe he's working with a different ECU. Bosch L-Jetronic yes, but of a newer generation than what we're discussing here. Might even be a ZX, but I can tell you that it's not a first generation Z.

 

If I remember correctly... The pics are wrong. The resistor designations are non-existent. And there's talk of a lamda sensor. All that spells different ECU.

 

In other words, the overall system info by BRAPP is good stuff, but the resistor tweaking stuff inside the ECU case dug up by cygnusx1 doesn't apply to us. Unfortunately cygnusx1 didn't write it either, but dug it up somewhere else from what appears to be early internet days so it's very difficult to trace.

[Captain Obvious]

You are correct on all counts.

 

I will get some more pics of the DIPs for you soon.

 

Great, I'd love to have some better pics and some numbers from that newer ECU. No hurry... At your leisure.

 

As for the Hellfire... I believe the only thing holding it up is available time. Lenny keeps fading in and out of consciousness.

 

Maybe if I were to resurrect my somewhat similar project I was working on before he came along and seemingly made my project obsolete before it was ever completed. Maybe I should have never pulled the plug?

 

Maybe if I just TOLD him I was going to resurrect it...   ::

[rcb280z]

Go for it Captain. I need a tune-able system. Especially owning a FI Z here in CA where I can't have CO output of 0.5 and above! If I had the :hellfire" I bet it would make things easier for me.

[TomoHawk]

I read a write somewhere that was about L-Jetronic on a car that also has the Lambda sensor, so there definitely is more than one version of the L-Jetronic ECU.

[wheee!]

I read a write somewhere that was about L-Jetronic on a car that also has the Lambda sensor, so there definitely is more than one version of the L-Jetronic ECU.

, maybe it's my extra ECU, the lost holy grail!

Sent from my iPizzle ringy dingy device....

[Captain Obvious]

I read a write somewhere that was about L-Jetronic on a car that also has the Lambda sensor, so there definitely is more than one version of the L-Jetronic ECU.

 

Yes, there's no mystery there. It's not a version thing, it's a chronology thing. I've got one sitting in my driveway. An 83 ZX.

 

The 83ZX has a later revision of the Bosch L-Jetronic that includes a Lamda sensor. The point wasn't that it was hard to find... the point is that the ECU they were tweaking in that HybridZ thread by changing the resistor values doesn't apply to us with the first gen Z's.

 

wheeeeeeeeeeeee, Haha! I don't think yours is the holy grail of ECU's. It wouldn't have the same P/N on the outside if it were. I just think it's a newer produced version for the older cars. I'm thinking that in 1990 the factory still had to supply ECU's for people who needed them and there had been so many technological changes in electronics between 1975 and 1990 that the newer ECU's changed some with the times. Form, fit, and function identical to the old ones, but different inside.

 

I'm just wondering if Hitachi decided to get away from the completely custom IC's used in previous versions for more readily available silicon. Or maybe they thought they could sell some of the components on the open market to other manufacturers and started offering them for sale outside Hitachi.

 

I really doubt it, but it doesn't hurt to check into it.

[wheee!]

I will remove the unit still in the car as soon as it warms up enough to get into the car. It's been -27 degrees celcius around here for the past few days. My workshop isn't heated yet... Supposed to warm up soon.

 

I will take it apart as well and get a picture of the inside of the newer C-12 board with it.

 

[Captain Obvious]

Great. When you get a chance.

 

On a related note... I popped the case on my spare ECU and went hunting for date codes on components and found nothing easily distinguishable.

 

So remember when I said it would be likely that you could be able to closely estimate the dates of production by determining the manufacturing date of some of the parts used on the boards? Apparently not!  

 

I was planning to find a couple easy spots to guide you towards so you could do the same...  That's not gonna happen.
 

[TomoHawk]

So remember when I said it would be likely that you could be able to closely estimate the dates of production by determining the manufacturing date of some of the parts used on the boards? Apparently not!  

 

You forgot to factor in the primitive 1970s overseas materials and manufacturing methods and 40 years of degradation?

 

OTOH, what if they build the L-Jectronic ECUs today?  It would be 1/2 the size, very much customizable, and they'd probably call it "Hellfire!" 

[Captain Obvious]

Naa. It's not materials used or degradation. It's more the fact that these things were built as IC technology was in it's infancy and some of the standards that are ubiquitous today were not yet in effect yet. Things like "mmyy" date codes that are printed on almost all IC cases don't exist when you don't have IC's in cases.

 

Prior to that standardization, there were other more cryptic methods employed. Usually three characters with coded info that is undistinguishable without the decoder ring that goes with it. Adding to the issue is that every manufacturer used their own Rosetta Stone for translation. For example, NEC's date code encoding wasn't the same as Hitachi's.

 

So while I did find some three character markings on the transistors that are probably date codes, I don't have anyone's Rosetta Stone to do the translation into a date.

 

The best chance for an easy to distinguish date code comes off markings from wheee's newer ECU with the DIP's.

 

Oh, and we've gone full circle on the component markings as well... With the advent of tiny surface mount stuff, many manufacturers don't have room for full info on the parts anymore and have gone back to cryptic markings. More cryptic than ever before. In fact many times there isn't even room for a part number, let alone a date code. Full circle and beyond.

[wheee!]

They didn't have the printer technology either ....

I will get some hi res shots of the dips soon. Maybe this afternoon if I get off work early

Sent from my iPizzle ringy dingy device....

Edited March 6, 2015 by wheee!