'71 240Z w/ '82 280ZX L28 MRE project

[XplosiveLugnut]

Hi,

I have a Datsun 240Z. It's my fun little money pit.

The carbs are fantastic, except when they vapor lock. What a shame. If only the head was crossflow.

I've wanted EFI for a while, but it either required coming up with a custom intake for the early (pre-EFI) head or modifying the head to accept the intake I had off a '75 280Z (drilling a different bolt pattern and slots for the injectors).

Last year I solved that problem. I rebuilt an '82 280ZX L28 and swapped it for the perfectly good L24. Still running the carbs though (the EFI head accepts both manifolds). Wanted to get the car back running as quickly as possible. It was only off the road for a couple days. And I now have an engine the EFI intake will bolt up to.

Anyway, my strategy is to change as few variables as possible to keep the downtime as short as possible. I like to drive it after all.

So I now have a MicroRusEFI.

I'm going to leave the mechanical/vacuum advance dizzy in place and run the MRE in parallel. Hoping the VR sensor will work like that anyway. If not, I'll get some kind of tach signal into the MRE.

To address the 6 injectors / 4 injector drivers issue. I'll be running batch injection (my only choice while using just the distributor).
I plan to pair the drivers up to drive 3 injectors per pair. 2 injectors is a bit much for a single driver, but 2 drivers should handle 3 injectors.

As far as sensors go, I have a MAP and a wideband. I have a throttle position switch too. Not sure if that'll be useful yet.

If I can get fuel working with this rudimentary configuration, I'll go for a DIS in the near future.

I almost have all the plumbing sorted out.

Hopefully going to start testing the electronic side of things this week.

My goal is to get the EFI working before Hot Rod Power Tour in August.

[stefanst]

Welcome to rusEFI!

That sounds like a fun and interesting project. The 240Z is one of the best looking cars ever to come out of Japan and that straight-6 is silky-smooth.

I didn't quite understand how you were planning on getting a crank or cam signal into the MRE unit. Can you please elaborate?

Also: I don't think the injector drivers on the MRE were ever tested for running two injectors each. They may very well be able to handle it, I just don't think it was ever tested.

Also: Please post pictures! And where are you located?

[XplosiveLugnut]

Oh, yeah, I didn't explain the ignition much at all. It's an electronic distributor from the same car as the EFI intake ('75 280Z). It has a single VR coil that I have wired to a 4 wire Chevy HEI igniter. The igniter is driving an MSD Blaster II.

I ordered the MRE configured for a VR sensor. My plan is to wire the MRE to the VR sensor in parallel with the Chevy igniter. Hoping both inputs are high impedance enough that the VR coil can still drive them at cranking speeds. And that there's not some sort of ground related incompatibility. If this doesn't work, I'll try getting a conditioned signal from the negative side of the MSD. Works for the tach.

The injectors will all be fired together every 3 spark events (I think? Maybe every 6? However the L-Jetronic did it).

The injectors are about 12.5 ohms. On paper, this puts the current of two injectors a bit beyond what a single driver is rated for.
The injectors are 440 cc @ 3 bar with a 3 bar regulator. My napkin math says they'll never go beyond 30% DC (not counting dead time) to keep the 2.8 fed. So the injector drivers might very well be able to handle 2 each at such a low duty cycle.
I figure driving 3 injectors with a pair of drivers would be "safer". I definitely could be wrong though.

I shall post pictures soon™.

I'm in Huntsville, AL.

[mck1117]

Awesome project!

Two injectors per channel on an MRE should work, but hasn't been extensively tested.

[XplosiveLugnut]

Yeah, the Chevy HEI module doesn't like to share.
Wiring the MRE in parallel with the HEI on the VR pickup wires resulted in the HEI getting really hot and the engine not cranking (still carbureted).
It ran after I removed the MRE, so at least I didn't fry the HEI.
I guess it got at least one good falling edge and then dwelled indefinitely. Thought that was something HEI wasn't prone to. I wonder if I leave the ignition on after a stall if the HEI would cook itself?

New plan. This distributor is supposed to have 2 VR pickups. And it did, until I, in my infinite wisdom, removed the extra one.
I know I didn't throw it away, but that was almost 3 years ago and it's nowhere to be found.

Got a new VR pickup on the way. Time to wait for shipping.

If nothing else, the MRE did pick up the VR signal while I was cranking it and cooking the HEI, so that's nice.

[XplosiveLugnut]

Got the second VR pickup in the dizzy. Twisted some wires together and got the MRE showing the correct RPM. Progress.
Now I gotta get the engine/transmission out to modify the fuel lines and exhaust. And fix the oil pan leak while I'm at it.
Nothing to it but to do it.

The dizzy

PXL_20210701_034344106.jpg

The "setup"

PXL_20210701_034052831.jpg

The Z

PXL_20201125_012058862.jpg

[AndreyB]

ECU PCB color matching vehicle color... that's a serious rusEFI commitment!

[XplosiveLugnut]

The blue was a nice surprise. I'd only seen pictures of the MRE in red or green.

[blundar]

https://forums.hybridz.org/topic/115112-rb-efi-system-retrofitted-on-a-l28et/

There's a thread about putting a Z32 ECU on the L28ET. I wonder if you might be able to steal a few tricks to use to get a better engine speed sensor set? The nissan CAS are essentially optical hall effect.

I'm jealous of your 240Z. (I have a R32GTS4)

[XplosiveLugnut]

I have a scheme cooked up for running COP and sequential injection eventually.
These engines (the old non-fuel-injected ones) have their fuel pump ran off an eccentric that mounts on the front of the cam.

I figure it would be pretty easy to mount a trigger wheel in place of the eccentric and poke a hall sensor up through where the fuel pump mounts.

95d79a206eb79a6ac0c832c494d8a094.jpg

There's an R32 that gets driven around here. Some kind of dark grey. Guessing "Gun Grey Metallic". Beautiful.

[XplosiveLugnut]

Man, done this like, 3 times now. Pulling a motor is still a ton of work.

The O2 sensor bung is in.

PXL_20210711_013138981.jpg

Think the angle is good. Should live comfortably between the trans and the tunnel.

PXL_20210711_055304998.jpg

The front ends of the fuel lines have been terminated.
The supply line is 8mm. A 5/16" compression fitting is perfect.
The return line is 5mm. Close enough to 3/16" that I could give it a 3/16" 45° inverted flare. Welding the end of a brake hose to a 6AN fitting to adapt it to the 6AN hose I'm using everywhere.

PXL_20210711_005144375.jpg

Still have to terminate the tank side of the supply line and get the fuel pump in.
Oil pan still needs to be re-sealed.
Getting there.

PXL_20210711_011242445.jpg

Here's a pic of the intake I test fit before yanking the motor out.

PXL_20210708_015538711.jpg

[Simon@FutureProof]

just to confirm a couple of things, I checked out the MRE drivers for batch injection a while back.

They are OK for 2 injectors at about 14ohms but 3 injectors is nogo.
Looked into it for the stock e30 injector wiring.

If you have an MRE with the "aux reuse" additional lowside drivers then you should be able to run 3 off those.
They should be at minimum an 8 amp VNLD5160.

[XplosiveLugnut]

I'll have to check to see if I have the 8 amp low side outputs, that's definitely an option if that's the case.

My original idea was to pair up the 2.2 amp outputs and use each pair to drive 3 12.5 ohm injectors.
A pair should handle 4.4 amps and three injectors should require around 3.6 amps at, what I'm calling a worse case scenario, 15 volts.

[Simon@FutureProof]

If you open the case and hold the ECU with the plug at the top, the two VNLD drivers are on the top right above the large square TLE chip.

[XplosiveLugnut]

Yup, got 'em.

image.png

And they're VNLD5090's which are apparently good for 13 amps. Sweet.
Not sure if it's a good idea, but I could fire all 6 injectors at once with a single one of these.

Edit: Typo

[XplosiveLugnut]

Last weekend I ended up helping with my friend's project. A '74 Dodge D100.
We went and got a 5 speed for it. Going to do a manual conversion.
But that's for another weekend.

This weekend end I've "finished" plumbing the chassis.

The pump.

PXL_20210725_002130986.jpg

The pump side of the supply hard line. Wasn't tight and was leaking a bit during this snapshot.

PXL_20210725_002205681.jpg

Looks like 3 bar. This is a temporary setup to pressure test the supply line fittings.

PXL_20210725_002042166.jpg

And last, the engine is back in it's home.

PXL_20210725_023233063.jpg

Hopefully a full fuel system pressure check will happen tomorrow.

That friend I helped get the transmission. He's the one that's been helping me get the engine in and out of this thing.
He also has a '96 S14 that'll likely be a future RusEFI project. Stock KA runs great, but it'll need a standalone and some forged bits before we put a turbo in it.

[XplosiveLugnut]

It lives! It's a twisted together electrical taped temporary mess, but it works.
Fuel rail leaks on the end fittings, so I've gotta fix that. And I must've screwed up configuring the 02 sensor pin 'cause I was reading 0v in TS while reading 5v on the multi-meter.
Otherwise, it was really easy. Configured my pins (MAP, injectors and EGO), generated a VE table, and boom, running engine, first try.

Screenshot_20210815-224813.png

Was helping convert my friend's truck to a 5 speed manual the past couple weekends, but I'm back on track.
Will post the video at some point.

[XplosiveLugnut]

Took the Z around the block for the first time. It's running too rich, but a successful first run nonetheless.
Going to add the cylinder head temp sensor before the trip to improve cold starting.

A bit cleaner than the last post. Now with more PVC and zip ties, but less fuel leaks!

[XplosiveLugnut]

Victory. The Z made it through Hot Rod Power Tour 2021. The MRE ran perfectly for what was at least a 2000 mile road trip; and not once did the engine act up, while idling in the heat, like it did with the carbs.

I ended up running with the bare minimum for the entire trip.
Used the wideband to tune it for a couple days, then just let it rip with only the MAP.
Would've been nice to wire up the cylinder head temp sensor, IAT, TPS and set up closed-loop, but ran out of time.

The biggest driveability issue I had was a sticky throttle. Looking forward to TBW.

PXL_20210827_180348756.jpg

[AndreyB]

Thank you for reporting your positive experience! It's those warm words which are moving rusEFI forward.

[XplosiveLugnut]

Well, I'm not good keeping stuff like this up to date.

Happy to say the EFI setup has been working fine. I tracked the Z at Atlanta Motorsports Park in 2022 and did another Power Tour in 2023.

I did make a few minor changes during that time.
After Power Tour 2021:

• Changed from using 2 of the VNLD5090 outputs (driving 3 injectors each) to using 3 outputs (driving 2 injectors each). Current limiting was causing the engine to hit a wall at ~4200 RPM at WOT. Couldn't get past ~33% duty cycle on the injectors.

After AMP 2022:

• Added a TPS.

• Added a surge tank.

Otherwise the Z's been stuck in the garage while I struggled to work out a bunch of kinks with the aftermarket suspension I first put on in 2022. And, of course, while working on other projects.


Present day:

After finally sorting out my suspension, I added coil-per-plug ignition. I have a 24-1 tooth wheel with a hall sensor in place of the dizzy.

PXL_20240717_203748569.png

And a set of used LS1 coils. Ran out of time, so they're zip tied for now.

PXL_20241008_042615914.png

I had to do some soldering to convert the MRE from VR to hall. Also soldered the J2 pads to set GP_Out_6 and GP_Out_5 to 5 volts in order to get 6 ignition outputs.


It's not pretty (it will be! eventually!), but it made it through another track day at AMP a couple weeks ago. Drove 6 hours there. Tracked it the next day. Drove 6 hours back the day after that. No problems!