North Idaho, Eastern Washington 280z l28et wiring gurus? Or anyone willing to help a knucklehead out?

[vale2489]

I picked up a 77 280z with l28et (from and 83zxt I believe) swap...the PO wired it up enough to hear it run before he got more involved with the car several years ago but I can't get it to fire for the life of me (cranks fine). I've been going through wiring diagrams and guides on here as well as zdriver and for the most part wiring looks to be correct  but there are a few things I just can't wrap my dumb head around.

 

I was wondering if there is someone local I can chat with over phone/email...or if worst comes to worst meet up and take me for a ride on the short bus (I'm seriously that horrible with wiring...my only other wiring experience is sr's into 240's which is about as easy at it gets).

 

If anybody else wouldn't mind communicating via phone or email from greater distances that would be fine too, I just don't want to clutter of this forum with posts and get flamed with links back to the guides I'm following (the youdamnfool one posted on here/fsm wiring diagrams).

[vale2489]

I've seen one swapped z cruising around as well as some clean restorations cruising around Moscow/Pullman area...must not be on here.

[loy]

Have you tried posting a topic of what you have done and what you have checked? You might get pointers to where to check and whatnot. 

[vale2489]

I'm in the process of putting together a large post with pictures of every connection made...but before I go through with it I'm gonna make sure the ecu isn't toast... I believe I've tracked down the wires that supply power with a multimeter but the green light on the ecu isn't turning on with the key is in the on position

Edited March 20, 2013 by vale2489

[cgsheen]

You've got the 1982 280ZX FSM and the turbo wiring diagram?  (I have the 1983 FSM as well but I find myself using the 1982 instead).  2 main power supply wires to the ECCS system:  1 Green, 1 Brown - in the ZXT they go through fusable links off the battery. 

 

Green is constant power (+12V to the injectors and is the only Green wire on the 3-row (17 pin) ECU connector),

 

Brown goes through the EFI relay and is switched ON at IGN ON.  The Brown feed comes out of the stock EFI relay as Black/White and also powers other ECCS components.  It connects to the ECU on 2 pins in the middle connector (16 pin) directly across from each other - I think the only Black/White on that connector.  It also powers the VCM solenoids and the Crank Angle Sensor.

Edited March 20, 2013 by cgsheen

[vale2489]

I have the 82 wiring diagram and i'm slowly making sense of it...my dillemma is I didn't do the swap my self so my familiarity with the setup is not favorable right now...the harnness wasn't hacked by any means but there is a few head scratchers (I.e. alligator clip on the starter running a yellow wire to the plug under the dash).

 

Thanks for the break down above, those are the little tid bits that help me out a bunch...I wish just I had a weekend to myself to sit down and figure this out (have some wife induced spring clinging that is taking away from my play time). 

[vale2489]

Hit the efi relay with the multimeter and nothing with the key on...ran the black and white wire straight to the brown wire and behold! Ecu power ( the green light finally came one). It will crank but no fire and no fuel pump prime (I'm guessing this is because it was running 12v constant and not ignition switched so it is not switching off when it needs to?) does it sound like new EFI relay time?

[cgsheen]

Dang!  Just wrote a longish reply and lost it!  Gist: EFI relay should have GND on one side of the coil, no voltage on the other with IGN OFF, battery voltage with IGN ON (B/W from ignition switch).  The Brown wire is source voltage for the internal switch - constant battery voltage at it's connection to the relay.  The other side of the switch is output to the ECU - no voltage with IGN OFF, battery voltage at IGN ON (B/W wire to ECU).  If all that is true - bad relay.

[vale2489]

^ Bingo! The EFI relay was not grounded on the coil... Fuel pump still does not turn on, although it did fire with a little help from brake cleaner. Lost spark for some reason after the second attempt to fire it up. Also I did not hear any turbo spooling upon startup ( I did prime it several times before starting) The PO said he could hear it clearly when he got it to run years back...must be sludged up or seized somehow...gonna have to pull the inlet tube and check it out.

 

Looks like I'm gonna have to go through the fuel pump wiring and figure out why I lost spark. Thanks for the info cgs!

 

Also, here is a link with pictures of what I'm dealing with

http://www.zdriver.com/forums/240z-260z-280z-motor-swaps-non-v8-269/new-site-new-77-280z-l28et-swapped-kinda-owner-37362/

Edited March 29, 2013 by vale2489

[cgsheen]

The fuel pump should be wired similar to the EFI relay except it's a signal (voltage) from the ECU that sets the coil and turns the switch ON.  So, fuel pump coil should be GND on one side, connected to ECU pin 16 on the other side of the coil. Pin 16 will control the relay (which turns the fuel pump on and off...).  You'll find that this is one of the ECU wires that goes to either the #2 or #3 connector which connects to the main harness in the 280ZX.  That's normally one of the wires you have to connect into your own harness to get it to your fuel pump relay.

[vale2489]

Went through fuel pump wiring, getting power for 5 seconds with the key in 'on' position, no fuel pump prime...hard wired the fuel pump and doesn't make a sounds, time for a new one.

 

Also, is this the  ballast resistor? It connects to the bottom of the distributer (near the CAS I believe) I thought it was fried so I ran the wires straight with no resistor and it got really hot, put the resistor back for now and doesn't get hot. Could that be part of my no spark issue?Would the GM HEI upgrade eliminate the need for this?

Edited March 31, 2013 by vale2489

[cgsheen]

It's a condensor to help eliminate electrical noise (like the one over on the alternator).  Has nothing to do with spark and nothing to do with the Ignitor.  Just leave it bolted up to GND and look elsewhere.  Have you checked your CAS signal?

 

(just looked at the pics you posted @ zdriver...  sorry man...  that's gotta be a little confusing.  the last post made over there is WRONG about the ECU light.  Ignore that comment.  The exact function of that light is well documented in the FSM (wish I could post over there and tell him to stop posting incorrect info - might have to register...)

 

I probably have some suggestions on the wiring.  (I'd re-do most of it if it were mine.)  You need to have a pretty good understanding of the wiring in BOTH cars (your early Z, and the 280ZX Turbo that the engine came out of (at least the ECCS harness and how it connects to the 280ZXT main harness) - be sure you have both FSM's.

 

Did you really get it to fire with starting fluid?

[vale2489]

Yeah, I blew off the green light comment on zdriver. Turned out the ignitor must have gone bad,i found a goody going through extra parts... the PO had a gm hei unit all put together so i wired it up and the car fires everytime now ( w/ starting fluid...new fuel pump on the way). The pictures make it look pretty bad but most of the connections are correct, ive been doing alot of cleanup and looks much better now. It fires right up and idles surprisingly well, but alot of hesitation when given throttle... Will dig into it more when i have a working fuel pump. Thanks a ton for the help so far!

[vale2489]

Found a working fuel pump in the heap of spare parts that came with the car, fuel getting to fuel rail now but runs horrible. All injectors are clicking but one, gettin 12v constant on both sides of plug when not running. Would a clogged injector still try to pulse or does it shut down altogether?...when i was running the car on starting fluid all cylinders were firing. I thought this was gonna be a wire it up and go project...boy i was wrong,lol

[cgsheen]

The injector is a coil (electromagnet).  It does have a constant +12v to one side, the other side is grounded by the ECU when it pulses the injector.  Because it's a coil, when the connector is plugged in, the voltage will pass through and show on the other side when you test it with a meter.  That's normal.  Test that it's being pulsed by the ECU with a "noid light" (or get a 12v bulb in a socket with the wires attached, remove the injector connector, and push the wires into the connector).  The light should flash as the other injectors click.  While the connector is off, "Ohm out" the injector - they're low impedance so I think they should read about 2.3 Ohms across the two spades.  (the FSM will have the exact value).  If the injector checks out in that regard, you know it's coil is intact.  Then it could just be stuck.  I've had to manually work some of these old injectors to get them opening again.  Being stuck closed is probably more likely than it being clogged, but you'd only know that if you pulled the fuel rail and watched it spray or pulled the injector out and had it flow tested.  If you did that you'd want to do them all...

 

It may take a bit to get the cobwebs out...  Get it running, get some injector cleaner in it (or Marvel Mystery Oil - or both), and let it burn a few tanks af gas. 

 

Oh, you've pulled apart all of the electrical connectors on the engine harness & ECU, checked them for corrosion, and cleaned and de-oxidized ALL of them , haven't you?

[vale2489]

Ive checked all the connections and they look surprisingly good, but a good scrub and clean certainly would not hurt...the battery terminal wires are pretty bad and are soon to be replaced.

[vale2489]

One other thing, ive read some info ( very possibly missinformation on other forums) that if the tach is not hooked up it can cause issues also?

[cgsheen]

One other thing, ive read some info ( very possibly missinformation on other forums) that if the tach is not hooked up it can cause issues also?

 

 

Not on the L28ET.  And not on a '77 Tach.  Wiring the Tach is a simple process - the Tach feed is the post on the Coil that has the blue wire attached (should be 2 blue wires - one from the Ignitor - the 2nd one is the Tach signal.  It just needs to be connected to your existing Tach signal wire BEFORE the in-line resistor.

 

But, that wire is simply a signal to the Tach - has nothing to do with the ECU or engine electronics.  The ECU has it's own "Tach" - the C.A.S. tells it all it needs to know about engine rotation.

[vale2489]

Cleaned up a few grounds and re-soldered a few connections and all injectors are firing and almost idled well. Still would hesitate/stutter/ backfire given any throttle...any way, i was so proud it would fire and idle i went to fire it up to hear it run and lost spark! I replaced coil/ hei module and still nothing. Im guessing CAS is the culprit? Also i noticed some people are running n/a distributors...is that a good alternative if my CAS is bad?

Edited April 23, 2013 by vale2489

[cgsheen]

Or...  Just replace the CAS optical module in your distributor.  Can't find one for an L28ET?  Or, too expensive?  Go to the pick-a-part and find a late 80's early 90's Nissan with a distributor model VG30e (3 liter V6 engine).  Infiniti M30, Nissan Maxima, 300ZX...  The optical module in any of those will drop in the L28ET distributor.  Oh... Don't tell anyone else, most people think that isn't possible.

 

Pull the cap and rotor, remove the protective metal plate, unscrew the top mount for the stainless steel optical disc, remove the disc and it's lower mount (and associated brackets and washers).  You'll see that the newer style optical module is encased in black plastic, mounted to the distributor body by 3 screws.  The L28ET module is held in place by 3 screws that go UP through the bottom of the dist.  The VG30e style are mounted such that the screws go DOWN from the top of the module into the dist. body.  That's the only difference.  To mount one of those in your L28ET you'll need some long skinny bolts with nuts and washers that will go all the way through the distributor body and the optical module so you can put them down through both and get a washer and nut on the bottom of the distributor...

 

The Infiniti M30 FSM describes how to test the CAS -  you need to remove the distributor so you can turn it by hand.  The 4 wires that go to the CAS are these:  Red = +12v,  Black = GND, White & Green are signal wires - one is the 60 degree signal (six slits in the circle), one is the 1 degree signal (360 slits in the circle).  As the optical wheel turns the slits allow light to pass (while the solid metal blocks the light).  When the optical sensor gets light it sends a 5v signal, no light = 0 volts...  If you pull the dist, turn the IGN to ON and spin the dist by hand you can test the output on the white and green wires with a meter.  As you turn, you should get alternating +5v and 0v.  The 60 degree signal should be easy.  The 1 degree could be more difficult - you'll need to turn slowly and carefully as 1 degree will probably happen very quickly...

 

My point?  make sure the optical module is bad and that it's not something else causing your problems...  Electrical can be a nightmare on these - but you already know that, don't you.

 

I haven't told you that I was raised in Idaho Falls have I?  Haven't lived there since 1972 though...  Been back any number of times, but now that my Parents have passed and I don't have any more Family there, not much reason to go.