(another) l28et 280z

[Jesse OBrien]

I've bought a number of vehicles in my time, but I'm looking for specific advice here.

Here's what I have:
1. 72 240z
2. n42 l28 with SU carbs (x2)
3. 4speed transmissions (x2)

It needs a radiator, all the hard lines, pedals, rear brakes, seats, and harnesses before it can move itself around. Because of that, I started looking for a parts donor for all the little stuff, to get the ball rolling.

I happened to find a 280z with an l28et in it and a couple manual transmissions attached. It has side skirts and bumper covers, which kind of concern me, and the engine wiring is incomplete. None of that concerns me much, but my previous experience with early Nissan EFI does. I haven't seen a reliable, effective l28et using the stock engine management. Therefore, the plan for this car would be to plop one of my SU-fed l28's in it and put the l28et on a stand as the more serious build for my 240z.

Here's the question of the day:
Aside from the obvious doglegs, frame rails, battery tray, engine rotation, brake line condition, etc ... what dealbreakers should I look for tonight?

Edited November 13, 2013 by Jesse OBrien

[Pac_Man]

You covered most of the things i'd point out in your post. I'd suggest looking at the interior floor under the carpet if possible. If you can't, look from underneath the car. At least that way you'd be able to tell if it's actually rusted through.

 

The EFI systems used on the L28s wasn't amazing by modern standards but it's not horrible. Even with the stock ECU the L28et can put down some decent power.

[Jesse OBrien]

It has plenty of rust in the usual places, but no scary rot. The floors look like they were jb welded in, so I'll revisit them before too long. The doglegs were much better than I'd expected (a small patch would be a good idea on the rearmost section of both). They had molded on Corvette (looked like c4) tail lights in, so I'll probably have to spend some time chipping bondo off and putting real headlights back in. I'd call the body an 8/10 for New England.

 

The l28et is in MUCH better shape than I'd expected. It looked like the BW t5 was in the trunk, with a 4spd mounted up. The motor is totally bone-stock, even has the injector cooling fan on it. The ECU and wiring is all there, and doesn't look molested at all, it just hasn't all been hooked up.

 

I've worked out a place to store it for a bit, while I get it streetworthy, so I'm going to pick it up later this week. It was too dark to get photos but I'll snap a bunch once I take possession.

[Pharaohabq]

Hey Jesse, Sounds like a good deal for a parts car.  Now you know the L28et is lower compression than the NA cars right?  So if you are just swapping your carbs over you may have some issue.  Though the L28et isn't that hard to get running on the stock electronics assuming it's all there.  There's a lot of Turbo swap threads on here so I won't go into that. but another option is always Megasquirt.  It's much more modern EFI that's been proven to work really well with these engines.  

 

As for what to look for to resurrect the Parts car, is all the regular rust locations, but also just look for completeness, you don't know what they've taken off the car. So that could be a factor.  It sounds like a deal though.  Oh Let me know if you need any other parts designed.

[Jesse OBrien]

Hey Jesse, Sounds like a good deal for a parts car.  Now you know the L28et is lower compression than the NA cars right?  So if you are just swapping your carbs over you may have some issue.  Though the L28et isn't that hard to get running on the stock electronics assuming it's all there.  There's a lot of Turbo swap threads on here so I won't go into that. but another option is always Megasquirt.  It's much more modern EFI that's been proven to work really well with these engines.  

 

As for what to look for to resurrect the Parts car, is all the regular rust locations, but also just look for completeness, you don't know what they've taken off the car. So that could be a factor.  It sounds like a deal though.  Oh Let me know if you need any other parts designed.

The l28et is separate from my two n42's with SU's on them, I would be swapping one of those into this. With the carb'd SU l28 under the hood, I could squeeze into U4 (unprepared 4) class on 14x7 street tires, where the l28et would have me planted firmly in SP2 (street prepared 2). Lower numbers are faster in that class.

 

It looks like I'm keeping both, the 280z with the l28et is complete with the wiring harness, ECU, and it looks like all the sensors except the AFM. In the long term, megasquirt is a bit of a no-brainer, and if all the electronics work to run the stock EFI I'll stick with that for a season or so, then pull the l28et off for the rebuild I'm sure it'll need and plop it into the 240z instead. I'm not sure I see a reason to go with MS3 over MS2 for the l28et though. If I'm reading the specs correctly MS2 can handle sequential injection just fine. That would be the main selling point for MS3, primarily to get better efficiency out of the engine.

 

Those door jamb reinforcements are holding up really nicely, despite a bit of unintended abuse. I may ask for another set for the 280z before too long, I'm impressed with how well that nylon has held up.

Edited October 31, 2013 by Jesse OBrien

[Pharaohabq]

No problem, I'll print up another set, I've got black ABS plastic now too, so it'll be less obvious than the white. You'll have to send me your address again.   I keep looking for the article about the fabrications, so I can see what your TIG girl can come up with.  Though, I'm not sure that the 280Z uses the same latch setup if I remember correctly. I can look at my 280Z tonight and clarify that.  These are also uploaded to Shapeways so we can have them printed in metal if you want.

[Jesse OBrien]

Let me get the driver's door lined up, it won't even close on the new 280z. Then we'll get back to making/installing worn parts. 

No problem, I'll print up another set, I've got black ABS plastic now too, so it'll be less obvious than the white. You'll have to send me your address again.   I keep looking for the article about the fabrications, so I can see what your TIG girl can come up with.  Though, I'm not sure that the 280Z uses the same latch setup if I remember correctly. I can look at my 280Z tonight and clarify that.  These are also uploaded to Shapeways so we can have them printed in metal if you want.

I've had too many projects up in the air, so I haven't had a chance to wrap up the fabrication series yet. Right now, there are 5 articles remaining. The goal is to have them finished for the new year, and wrap up the entire series then.

 

Update time!

The money shot:

I used an array of high-precision rust-identification tools (screwdrivers) to identify any potential rust problems, and this was all I found:

I'll call that a win, and an easy fix.

 

There's a nice MSA (I think) downpipe that could use some header paint, and an o2 sensor!

 

The most damaged of the wheels. These things weigh NOTHING, and they're currently fitted with 195/75-14 tires. Haven't checked their width yet, but the lack of heft has me a bit excited to use these for race wheels.

 

I couldn't find the l28et afm, but I found a stock l28 one (I think?)

 

I really hope this is an l28et ecu, not an l28e:

 

Correct me if I'm wrong, but BW t5? I think I'll keep the Datsun 4speeds I have, and put this up for sale. What's the going rate these days?

 

I have some major server changes to push out this weekend, so I won't have much time to work on it, but I may hire someone to rewire the l28et for me. Being colorblind and working with wires that have been fading for the past 40 years isn't a good combination, overall. Has anyone put together a minimal l28et wiring diagram with the 'bare essentials' and nothing extra?

[Jesse OBrien]

The body kit is sold to a fellow hybridz'er that I'm hoping to meet up with this weekend. All that's left to do to get ready for him is jack up the rear end so I can drill out the rusted sheet metal screws in the wheelwells. I half-repaired the passenger's window today so it would stay up and keep rain/snow out.

 

I mocked up the air dam, but it really doesn't look like it's going to fit without some modifications:

 

By the feel of things, I'll have to remove the tab that sticks out from the front of the lower radiator support and move the horns out of the way, then I can secure it and start drilling some mounting holes.

 

Hopefully I can get the passenger's door lock off so I can have a key cut, I couldn't find the code in the glovebox, and the ignition tumbler isn't bad enough that I can turn it with any key.

[1 tuff z]

BW 5 speed, if you could verify; condition, miles, etc. could bring in the 350-400 range.  Without all that, $150-200?

[Jesse OBrien]

BW 5 speed, if you could verify; condition, miles, etc. could bring in the 350-400 range.  Without all that, $150-200?

see http://forums.hybridz.org/topic/115530-nh-280zx-t-t5-and-driveshaft-400/

 

verified 55k miles on the 82 zx-t donor. Haven't cracked it open, but it looks/rotates as a 'used but serviceable' transmission. The car had been last registered in 2010.

[Jesse OBrien]

I finally got both bumper skirts/covers off, along with one of the side skirts. The driver's side skirt is being somewhat problematic, so my drill is charging and my stepper bit is waiting for action.

 

Something was living in one of the rocker panels, and had nested in there. That nest absorbed some water, and ... you know where this is going.

 

I found another small patch that'll need to be cut and welded in under the front wheelwell also:

 

In more positive news, my first look under the car was really encouraging. The frame rails are reinforced and extended to the back of the car. It looks like all they need is paint and underbody coating, and I'm in business.

 

It's nowhere near as bad as I had expected, and replacement panels are available, inexpensive, and straightforward to weld in. I'll visit Bad Dog soon to pick up a pile of little things I need. Most of the other rust is just going to take some wire wheeling and a fresh coat of paint, but I'm sure there are a couple other spots I'll have to patch. I certainly didn't expect perfection out of a near-40-year-old car for $1k.

 

I temporarily repaired the passenger window (it's up, but only two of four tracks are attached, so it doesn't move from 'up'), and found that the ratcheting latch mechanism on the driver's door is broken. It's kind of a pain to remove, but I'm going to pull it this weekend and see if it's salvageable or if I need to order a replacement.

 

I haven't tried starting it yet (I'm slightly nervous to, if I'm honest) and haven't tried the brakes yet. I'll bleed them this weekend, hopefully prime the fuel pump, and possibly start it up.

 

After that, I think the tail lights are going to have to go back to stock. Corvettes can get away with Corvette lights, I don't find them pleasing on an s30.

[Jesse OBrien]

I have a confession to make.

 

I'm colorblind

 

I know, it's hard to just come out and say it, but we all have things we need to admit to. Now that I've got that off my chest, I need to ask the really stupid questions. Partly because my previous owner didn't pass on any wiring documentation on his progress, partly because I don't know what year this engine's from, partly because the WEALTH of information about the l28et takes days to paw through, and partly because I'm colorblind ... but also because my landlord pulled the rug out from under me and surprise! I no longer have a garage bay to work on this car. That means it needs to be inspected by this weekend, or it gets towed. To get it inspected, it pretty much just needs to be able to sputter around on its own power in only two (20-degree) evenings. I really need your help.

 

Let me start with a lay of the wiring land. Here's what I know for sure:

1. This engine only appears to have one fusible link box (pictured at right, 2 inputs, 2 outputs, 2 wires connecting the two). One of those circuits has continuity (closer to the camera), the other does not.
   
2. My ignition tumbler has no power coming in to it, and therefore does nothing at all.
3. As far as I can tell, the ECU also has no power.
4. When I received it, there were 3 wires connected to the battery + terminal, connected via a yellow crimp connector:
   1. white (it's a trap!)
   2. green
   3. red
      (blurry, but you get the picture - ha! pun!)
      
5. Because nothing appears to work, I thought I'd start there, hoping to uncover some obvious fix. Unfortunately, now I'm just more confused than ever. The red and green wires appeared to run to a relay just off-camera, so I pulled back the looming, and uncovered these disconnected leads:
   
   The more observant among you may notice that there are more than three now.
   1. red - already discussed, connected to +
   2. green - already discussed, connected to +
   3. color? was disconnected
   4. color? also disconnected
   5. is actually an IMPOSTOR (it was never white after all! it was [insert color here])
   6. and the 6th is new, but was also disconnected
6. Here's the wiring mess that's looming (ha! pun again!) before me ... it's what's coming out of the loom.
   
   (left-to-right)
   1. yellow(?)
   2. color?/color?
   3. color?
   4. black(?)/white
   5. color(?)
   6. white
   7. green(?)
7. Finally, here's the backside of the relay in question.
   
8. Coming out of the loom, but not connected to anything at all:
   
   (top to bottom)
   1. color?
   2. color?
   3. color?
   4. color?
   5. white

I'm sorry for the piecemeal photos, I'm working on a proper wiring diagram, but needed a good way to identify all these wires. I'll work on a numbered wiring diagram with a bunch of question marks shortly.

 

I know the fuel pump is a concern, and the igniter is a concern based on the research I've done. How concerned should I be about them? Am I risking lighting fires or frying the ecu (assuming it's a working unit to begin with) by getting everything else hooked up first? I have 0 problems with wiring virtually everything into toggle switches and running a screwdriver across the starter posts to start it up ... as long as it starts up. Once it's running, I can probably work my way through any body wiring that the car might need, but I really need to solve this part of things RIGHT NOW.

 

Thanks, guys. Please come through for me.

Edited November 14, 2013 by Jesse OBrien

[Jesse OBrien]

Maybe I'm getting closer to figuring this out. My girlfriend was good enough to try identifying which wires were which colors, and I organized them a little better into a micro-diagram:

 

I'm relatively sure that this "brown" color the wiring diagram speaks of gets constant 12v directly from the battery. I'm still poring over it to figure out which components I really have, though.

 

I also discovered that the ring terminal that's attached to the + lead of the starter apparently provides power to much of the car. Anyone know what color that wire is, or where I might find it on the wiring diagram?

Edited November 14, 2013 by Jesse OBrien

[NewZed]

You should change the focus of what you're trying to do.  Don't worry about wire colors or what this plug connects to or any of that.  Sit down with the wiring diagram, the big connector to the ECU, some tape or stick-on labels and a pen, and an ohm-meter or continuity tester.  Test each pin in the ECU plug for continuity to every wire end.  Some of them will be pretty easy, like the pin for the CHTS should be connected to an EV1 style connector.  Others might require a lot of probing.  Or do it backwards and pick a wire end and just stab your probe in to every ECU plug pin until you get a hit.  When you figure one out, label it with the pin number and/or (preferably and) its purpose to the ECU (example: injector ground, CHTS connection, etc).  When you're done you can decide how to connect each component or power source to the proper pin at the ECU.  Fuses, relays, etc. will be easier to figure out once you know each wire's function. 

[Jesse OBrien]

Figure N

Ok, this is in the same loom as the FI relay. There are 3 wires that you will need to cut and splice. First off, don't cut any wires that are going to the plug for the FI relay, those need to stay intact. There are 5 other wires not attached to the relay. They are from left to right;

 

-Green - Constant power (Needs to be run to a 12+ volt constant)

-Black with white strip - Switched power (Needs to be run to a 12+ volt switched power)

-Blue with red stripe - is switched power for your fuel pump relay (has 12+ volts when key is on, will have power for 5 seconds if car is not running to prime the fuel system, and will have a constant 12+ volts when car is running.)

The yellow and white wires you see bent off to the side you will not need and wont be using

 

Figure O

This plug is for fusible links. Those white wires on the left you will not be using,

but the brown and green wires go to the + post on the starter.

 

And that is it for your FI harness.

I hate being colorblind. Are these the wires I'm looking for? The names of the colors sound the same.

 

You should change the focus of what you're trying to do.  Don't worry about wire colors or what this plug connects to or any of that.  Sit down with the wiring diagram, the big connector to the ECU, some tape or stick-on labels and a pen, and an ohm-meter or continuity tester.  Test each pin in the ECU plug for continuity to every wire end.  Some of them will be pretty easy, like the pin for the CHTS should be connected to an EV1 style connector.  Others might require a lot of probing.  Or do it backwards and pick a wire end and just stab your probe in to every ECU plug pin until you get a hit.  When you figure one out, label it with the pin number and/or (preferably and) its purpose to the ECU (example: injector ground, CHTS connection, etc).  When you're done you can decide how to connect each component or power source to the proper pin at the ECU.  Fuses, relays, etc. will be easier to figure out once you know each wire's function. 

My multimeter died, apparently it's too cold for it. The LEDs don't give meaningful output any more. It's starting to get chilly now (21F currently on my thermostat) so sitting down and spending a lot of time stabbing in the dark driveway.

 

My test light is the best diagnostic equipment I have available for tonight, but I'll try to make time to replace my multimeter tomorrow if that's what it takes. No wires on the ECU connector or the ignition terminal have continuity with the battery. Once I have some continuity, troubleshooting becomes much easier (it might actually even run at that point).

 

Finding facts on how this was supposed to be is still proving difficult. This image:

indicates that I should have two fusible links on the passenger's side, but I only have one. I assume that's an indication that I have a year of l28et that this person doesn't have, but I don't know if that means I have an 81, 82, or 83

 

seems like a fairly straighfroward diagram, but it's incomplete. I need to know what color the fuse link that powers everything in order to trace it to the fuel pump relay or ignition relay (I still need to identify which relay is which, as well).

 

I also took a look at the starter motor, where I realized there's a ring terminal on the + lead that burrows away into the wiring harness. I've been trying to cut back the cold, crunchy electrical tape to see where that wire goes, but it's very slow going, even with snips.

[NewZed]

Well, good luck then.  The feeling of knowing the function of the wires and that they're connected correctly is much more satisfying, to me, than the thrill of connecting the battery or turning the key with no firm knowledge that things won't go up in smoke.  But I'm kind of boring.

[Jesse OBrien]

Well, good luck then.  The feeling of knowing the function of the wires and that they're connected correctly is much more satisfying, to me, than the thrill of connecting the battery or turning the key with no firm knowledge that things won't go up in smoke.  But I'm kind of boring.

If I don't have it running in two evenings (around 6 hours of work in the cold with a flashlight in my mouth), it gets impounded and I never see it again. At the moment, I really just want it to limp, so I can work out the details later when I'm not directly under the gun. I appreciate the recommendation of striving to do things right and invest time to understand systems, but I don't really have the luxury of time at the moment.

[Namor]

I have a confession to make.

 

I'm colorblind

 

I know, it's hard to just come out and say it, but we all have things we need to admit to. Now that I've got that off my chest, I need to ask the really stupid questions. Partly because my previous owner didn't pass on any wiring documentation on his progress, partly because I don't know what year this engine's from, partly because the WEALTH of information about the l28et takes days to paw through, and partly because I'm colorblind ... but also because my landlord pulled the rug out from under me and surprise! I no longer have a garage bay to work on this car. That means it needs to be inspected by this weekend, or it gets towed. To get it inspected, it pretty much just needs to be able to sputter around on its own power in only two (20-degree) evenings. I really need your help.

 

Let me start with a lay of the wiring land. Here's what I know for sure:

1. This engine only appears to have one fusible link box (pictured at right, 2 inputs, 2 outputs, 2 wires connecting the two). One of those circuits has continuity (closer to the camera), the other does not.

   

2. My ignition tumbler has no power coming in to it, and therefore does nothing at all.
3. As far as I can tell, the ECU also has no power.
4. When I received it, there were 3 wires connected to the battery + terminal, connected via a yellow crimp connector:
   1. white (it's a trap!)
   2. green
   3. red (BROWN)

      (blurry, but you get the picture - ha! pun!)

      

5. Because nothing appears to work, I thought I'd start there, hoping to uncover some obvious fix. Unfortunately, now I'm just more confused than ever. The red and green wires appeared to run to a relay just off-camera, so I pulled back the looming, and uncovered these disconnected leads:

   

   The more observant among you may notice that there are more than three now.

   1. red - already discussed, connected to + (BROWN)
   2. green - already discussed, connected to +
   3. color? was disconnected (Yellow)
   4. color? also disconnected (Blue w/ Red Stripe)
   5. is actually an IMPOSTOR (it was never white after all! it was Green)
   6. and the 6th is new, but was also disconnected (White)
6. Here's the wiring mess that's looming (ha! pun again!) before me ... it's what's coming out of the loom.

   

   (left-to-right)

   1. Yellow
   2. Blue w/ Red Stripe
   3. Green
   4. Black/White
   5. Black
   6. White
   7. Green
7. Finally, here's the backside of the relay in question.

   

8. Coming out of the loom, but not connected to anything at all:

   

   (top to bottom)

   1. Yellow
   2. Green
   3. Green
   4. Blue w/ Red Stripe
   5. White

I'm sorry for the piecemeal photos, I'm working on a proper wiring diagram, but needed a good way to identify all these wires. I'll work on a numbered wiring diagram with a bunch of question marks shortly.

 

I know the fuel pump is a concern, and the igniter is a concern based on the research I've done. How concerned should I be about them? Am I risking lighting fires or frying the ecu (assuming it's a working unit to begin with) by getting everything else hooked up first? I have 0 problems with wiring virtually everything into toggle switches and running a screwdriver across the starter posts to start it up ... as long as it starts up. Once it's running, I can probably work my way through any body wiring that the car might need, but I really need to solve this part of things RIGHT NOW.

 

Thanks, guys. Please come through for me.

 

 

I entered and bolded the wire colors as they appear to me.  I hope this helps.  

[mattb3562]

Why not just bolt one of the carbed intakes on and crank it with a screwdriver and some gas in the carbs to get it primed? U can run a fused hot wire to the fuel pump on a switch and manually regulate it...

[Jesse OBrien]

Why not just bolt one of the carbed intakes on and crank it with a screwdriver and some gas in the carbs to get it primed? U can run a fused hot wire to the fuel pump on a switch and manually regulate it...

Retuning them to run on a turbo block along with getting the n/a ignition to run on a turbo block would take more than today. It would also require rewiring the entire car, because the problem I have (as I've said several times) is that there's no positive anywhere.

 

I entered and bolded the wire colors as they appear to me.  I hope this helps.  

You sir, are a god among men. I can't express how much it helps.

 

I bought myself the weekend to finish working on it, so I cut back all the looming starting at the starter to see where power goes from there. After another hour of cutting through crunchy wires, I found an unidentified connector that went to nothing.

I have yet to see any reference to this in any of the wiring diagrams I've seen, and it's the 'weak link' that's keeping the block of 'fusible links' from running. Because the documentation doesn't explain this and I haven't had any responses explaining how the car received its +, I applied a logical temporary solution:

 

Suddenly, several of the car's systems started working. Now I get to put Namor's input to good use, and figure out how this mystery relay is intended to work, as well as where all these other miscellaneous wires go:

 

The wiring diagrams are absolutely worthless to me, as it doesn't indicate any physical locations of the wires. I'm going to ASSUME this relay is the EFI relay and wire it as such (receives signal from the ignition tumbler). I'm not sure where the 12v constant source is intended to be, but I'm strongly inclined to wire a fuse in before the relay. Does anyone know what kind of amperage the stock ECU requires?

Edited March 26, 2014 by Jesse OBrien