Forums/Z31P/z31-performance-upgrade-forums engine-management/Fuel Injection Wiring between Turbo and NA ECCSs
Imported from Z31Performance.com Forums{{#if:bemis| — original post by bemis}}{{#if:2007-12-04 15:17:19|, posted 2007-12-04 15:17:19}}{{#if:25| · 25 post{{#ifeq:25|1||s}}}}{{#if:/Z31performance_archive/forum/z31-performance-upgrade-forums/engine-management/3749-fuel-injection-wiring-between-turbo-and-na-eccss.html|
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bemis: (2007-12-04 15:17:19)
I thought that this discussion would be an important addition to Z31Performance.com, since there is alot of ECCS swapping going on between Z31's. From a general inspection of the ECCS wiring diagram in the FSM, it is very clear that the fuel injector wiring between turbo and na ECCSs do not follow the same pattern. If one was to install, for example, a turbo ECCS in an orginally non-turbo Z31, then changing of the wiring pattern on the ECCS harness is needed for correct operation of the fuel injectors and engine.
We all can agree that the Z31 ECCS uses simultaneous injection and group injection, in the former, fuel is injected into all six cylinders simultaneously twice each cylinder cycle. In other words, pulse signals of the same width are simultaneously transmitted from the ECCS to the six injectors two times for each engine cycle. In the group injection system, six cylinders are divided into two groups and fuel is injected into each group seperately once each engine cylce.
When any of the following conditions are met, fuel injection shifts to simultaneous injecton from group injection:
Engine speed is more than 3000rpms.
Injector pulse duration is more than 6.5ms.
Cylinder head temperature is below 60*C or 140*F.
When starting.
Having the fuel injectors wired up incorrectly will essentially make the fuel injectors stay in simultaneous mode for the whole range of engine operation. This will effect partial throttle operation, cruising*, cold starts, hot starts by making the engine run double the enrichment than intended.
- may not effect cruising if the added fuel enrichment is within the ECCSs scope of adjustment. In other words, the ECCS, using the 02 sensor, has a limit of how much it can change the enrichment from the base enrichment in order to acheive stoic.
From my inspection of the FSM, when converting from a 84 turbo ECCS to 84 NA:
Turbo-------NA
1------------no change
2------------3
3------------5
4------------2
5------------4
6------------no change
There may be differences in the other years, so examination of the applicable FSM is strongly suggested in order to get the swap right.
MrwassmanNA2T: (2007-12-04 18:59:16)
This is a simple Pin/injector clip swap after you have a z wired back to pre-recall?
Edit: By the way, thanks for the post. The wiring diagram to the injectors makes good sense now.
bemis: (2007-12-04 19:49:42)
As far as the injector campaign, I can't understand why Nissan engineers decided to wire up all of the injectors to one signal wire per side of engine, thus making the injectors run simultaneously and possibly overloading the current ratings of the injector drivers. Additionally, they did a piss poor job of connecting and sealing the wiring. The only thing I can think of is money. I takes more time to do the job right and time is money. They knew that Nissan would loose their ass in any type of lawsuit, so they quickly and cheaply put together a fix. Unfortunately, that's half the reason why everyone's Z31 runs like shit until the wiring is fixed back to the original configuration. The other half is 20 year old sensors and wiring.
dojunk: (2007-12-04 20:20:33)
In case this helps:
[archived image: INJ.jpg]
nutsaq: (2007-12-04 20:39:36)
Because 5 feet of wire is better than 15 feet of wire. 3 injectors per driver vs 3 injectors per driver. Same load. There are only 2 drivers in the eccs. Z-bum has posted multiple times, with pictures showing the pins entering the computer all ending up going to the two drivers.
As far as doing a crappy splice job, that lies more on the tech and proper shop practices. Nissan probably didn't tell anyone to do a hack job with poor splices, that's just what you get from a shop getting a set rate for their work regardless of time invested.
bemis: (2007-12-05 14:49:56)
Either way, why did Nissan even mess with the wiring. There was no need for it, since the campaign was done to replace the fuel injectors and hosing on the fuel rail to meet the current fuel standards.
MrwassmanNA2T: (2007-12-06 07:02:54)
Looks like there are two Main differences.
85
[archived image: 85Injectorpinout.jpg]
86+
[archived image: 86T-Injectors.jpg]
Maybe this explains why i can drop an 86T ecu into my 85NA harness and have it run with no issues? Because the 85T Ecu i bought sure doesn't work correctly.
jtz31ae: (2007-12-06 17:38:03)
Heh bemis,
When I install my '88 n/a ecu into my '84 turbo, should I be making an injector wiring change?
My injectors are still wired individually even though I did the injector campaign more than ten years ago :-D
Maybe they didn't change the harness in Canada, or just at the dealer I took it to …
Cheers
bemis: (2007-12-07 23:41:49)
Yes, you should make the wiring change when you install the 88 n/a ecu.
jtz31ae: (2007-12-08 01:40:25)
Thanks bemis
I didn't know about this injector wiring difference between the turbo and n/a
Cheers
Matt89: (2007-12-09 04:56:45)
I have an 89 na harness connected to an 85t ecu. I have always had problems with it running rich so maybe this it. Im going to try to find a complete 85t pre recall wiring harness to swap in…unless i can figure out the wiring change. Electronics is definitely not one of my strong areas.
phxZ31: (2007-12-09 20:02:55)
So my question is this:
It looks like above 84-85 and 86+ wiring schemes are reversed. So, if thats really the case, is putting a 1987 NA ECU into a 1985 NA vehicle not quite as plug and play as I was lead to believe? Do I need to rewire the injectors to ensure proper grouping?
Matt89: (2007-12-13 01:40:55)
I just did the conversion. I took apart the wire loom and moved the injector connectors over to their proper location and rewraped everything. The car runs so much smoother and my richness problem is fixed. Thanks Bemis, this is a big help to the z31 community. EVERYONE who has a turbo ecu connected to a na harness really needs to do this.
MrwassmanNA2T: (2007-12-13 03:38:35)
The 86-89 ECU's have the same injector configuration.
Timbo_021: (2007-12-14 10:06:43)
Done,seems to run alot better..Doesnt run rich coming onto boost anymore.Not sure about the running rough when starting the engine when its still warm.See how we go tomorrow.
Jason84NA2T: (2007-12-14 18:27:34)
Wow. I never even noticed that difference in the wiring; thanks for the info! Though as far as I can see it really only changes the injector firing sequence? I'll try re-pinning one of my nistuned cars this weekend and see what kind of a difference is shown on the wideband. If I can ever get my laptop running again I'll post some logs.
On a side note I appreciate your active work on this. I've had so much going on in the last year that there has been almost no time left over for Z stuff. I know I need to update some of the information on the redz31.com website BADLY (havent touched most of it for 2+years) do you mind if I use your images/text?
phxZ31: (2007-12-16 02:51:54)
confused!!
the 86+ ECUs have the same injector configurations as what? Do you mean all 86+ ECUs use the same configurations whether turbo or not? Or did you mean that they have the same configurations as the 84-85s?
Basically I'm trying to figure out if this is something I'd need to look into on my 1985 N/A engine and wiring harness that is running a 1987 N/A ECU.
MrwassmanNA2T: (2007-12-17 20:09:35)
That 86 diagram i have is the exact same as the 87-89. No changes, instead of posting up all the pictures, i posted 1 and saying they are the same.
Jason if you were asking about mine, go for it man!
RocknTommy: (2007-12-17 20:23:07)
http://www.tboz31.com/300ZX/Z31EFIHarne … wiring.htm
phxZ31: (2007-12-18 03:30:04)
You mis-understood what I'm asking. Your first pic shows that pins 101, 102, 103, 104, 105, and 106 correspond to injectors 1,2,3,4,5,&6 respectively on an NA for 1985. Your second pic shows that on 1986+, those same pins correspond to injectors 1,3,5,2,4,6 respectively for an NA.
Here is my question: I had previously re-wired my injectors BACK TO FACTORY as shown on Jasons site. But then later I swapped in a 1987NA ECU for my 1985 one… so, according to your pictures, when I installed the 1987 ECU, I actually UNDID that and put them right back into the same firing groups that Nissan did when they changed the injector groupings when they performed the recall. Does this make sense??
So, in order to change my groups back to 1-2-3 and 4-5-6, I would need to redo it all over again. Currently, I should still be using groups 1-3-5 and 2-4-6 due to the difference in pinouts from the ECUs.
Or am I not understanding anything here at all? Somebody help set me straight!!
phxZ31: (2007-12-18 03:46:16)
Actually on second thought, I now question the validity of those diagrams, at least for NAs..
Here's my reason (and I'm considering ONLY an NA car in this):
When Nissan rewired the injectors for ANY Z31, they grouped injectors 1,3,&5 to injector 3's leads, and they grouped 2,4,&6 to injector 4's leads.
Based on your diagrams, if it were a 1985 NA Z31, that means all injectors on the passenger side (1,3,&5) connect to pin 103, and all on the drivers side (2,4,&6) connect to pin 104. Also, if we look at your diagrams for 1986+, that means that Nissan would have wired injectors 1,3,&5 to pin 102, while injectors 2,4,&6 were wired to pin 105. All the other wires were simply cut and covered in tape and shrink tube.
The only problem with that is, it would be IMPOSSIBLE for any 1984 or 1985 NA Z31 to use a 1987 NA ECU because the leads going to injectors would have been cut due to the different pinouts, and none of the injectors would ever fire. (If 1987 truly drove injector 3 with pin 102, that lead was cut off and just tucked up not connected to anything, hence no injectors)
Well, that means that in either scenario, 1984-5 and 1987 MUST use the same pinouts and wiring.. if they didn't, those who haven't rewired back to factory wiring (undoing the injector campaign) would NOT be able to do the ECU swap which is relatively well known to work.
MrwassmanNA2T: (2007-12-18 06:31:29)
I was just trying to make things clear, as in get a picture of wiring out of ECU w/ color and a simple chart.
The Wiring diagrams came from 2 big companies. Mitchall on demand and Alldata pro. I printed out all the engine harness diagrams from alldata pro at school on paper to look at all the differences and then copied the diagrams off of ondemand5.com for the pictures you see.
I can't explain the campaign or the wiring differences. Just showing what i can.
Matt89: (2007-12-18 14:10:37)
I just swaped the actual injector clips to the proper injectors. Is it ok to do it this way? I think it fixed my rich problem but now i have a slight hesitation right after 3k rpm.
noel9914: (2008-02-19 08:14:28)
I put in a 87 T to a 88 NA is the wiring need to be changed ? If so were is this located? Im realy having trouble with the idle and it cuts of around 5psi 3500rpm on semi load. (T3 T4 intercooled pathfinder manifold,stock injectors and computer) . thanks
bemis: (2008-02-19 12:14:09)
Yes, your wiring will need to be changed. The wiring is located at the connectors that plug into the ECCS. As far as what needs to be done, that information is written within this thread.