Excellent info! You've answered all my questions. I am convinced I can make this work now.

 

Successful bench test! I put a rubber thing in a hand drill so I could spin up the CAS. Only managed 1k RPM but good enough to test both coils and primary injectors!

 

I discovered a bug in the FC ECU that is fixed by a simple turn off, wait a couple seconds, then turn on again. While experimenting, I'd unplug the trailing coil, spin the CAS so I could check the leading only, or check the injectors only, or listen for the BAC to make its oprational sound. When I'd hook the trailing back up, it would only spark up to 250 or possibly 500 rpm, at which point the sparks would disappear. Then I'd "reset" the ECU by cycling the power (the black with white stripe wire). This would fix the trailing no spark issue with repeatability. And I could repeatably cause the no spark issue by ungrounding the trailing ignitor base.

Maybe it's not an actual bug but interesting none the less.

Oh and here's my version of "bench testing" on the floor. lol

Notice the old school tach meter and the hand drill on the far right. This spins the CAS to 1k.

 

By chance did you ground the bracket to both coils when checking for dpark?
i had spark issues when I did a harness on a repu once and it was due too poor grounding of the leading coil.

 

By chance did you ground the bracket to both coils when checking for spark?
i had spark issues when I did a harness on a repu once and it was due too poor grounding of the leading coil.

 

Of course they were grounded. That was how I was getting spark. Now sure if it's the best way, but it was the easiest way to prevent spark too. Just unhook the ground. But then the trailing would malfunction. A simple power down then back up of the ECU would fix it.

Tell me more about your REPU.

 

neat, i should do that with my REW swap... if you push on the AFM, do the injectors click more?

 

it should if voltage is taken away from pin B on the harness for start signal. when 12v is applied to pin B the injection amount is static.

 

Wow, I never checked it. I just wrapped a little electrical tape around wire B so it couldn't make accidental contact.

But even if I didn't I don't think I could have heard an actual difference. The reason I suspect this is because the injectors would have only been open for a split second longer which I doubt I could have discerned audibly.

Now maybe if I hooked the injector connector to an actual speaker, maybe. I tested the MegaSquirt like that. Just not sure I'd mess up something in the FC ECU since I don't know what kind of protection diodes if any or whatever it has in there.

Man, should have opened up the AFM door too. Oh well. I'll just have to test this thing on an actual engine next.

 

you can hear the change but it isn't drastic, it also depends on the drill speed.

i did some playing around with an extemely basic harness to drive injectors for an injector test stand. you can get injectors to kick over and ignition with only the CAS hooked up.

 

Nice. Except my hand drill was so noisy I could'nt hear anything else while it was spinning.

 

It was a friends truck.i did a complete s4 turbo II swap on it running stock Ecu.turbo manifold had to be custom made for the s4 turbo.im also running the n332 Ecu right now on my 12a turbo,which I'm running all 13b turbo injection on.recently did a hybrid on the stock turbo and running 10 psi of boost and runs super strong.i have around six cars total running the stock turbo Ecu and they are all running good till this day.

Here's my build thread on that
https://www.rx7club.com/old-school-o...roject-928917/

 

Thanks for the link. That's a nice project. Since you've had success several times with stock stuff, I will too!

The banjo bolt arrived so I started taking off the carb stuff and will test EFI next!

 

no biggie, i think i would have just gotten curious, actually i AM curious, we have the rudiments of an ECU test board, and i might just finish setting it up

 

That sounds good. Pun intended?

I got all the carb stuff off the engine. Installed the LIM and injector diffusers with new o-rings. Test fitted the UIM but it's kinda hitting the rear lifting hook (1st gen style, which I bent out of the way) and the thermowax blockoff hose. Can't take it off because it's full of coolant.

Ok, managed to push it out of the way and got the UIM on with the vertical supports on the other side.

Then messed with the pulsation damper and threw on the banjo bolt. Thanks Karack! By the way the little screw was just lying in the plastic cap. Scary.

Still fuel lines to run, wiring harness to install, um... Probably should just pull the engine to prep it for the REPU now. Then I can run the fuel lines and wiring harness for real and save time in the process.

I don't really need to test the FC EFI stuff in the GSL-SE do I? I mean what's the difference between one chassis and the other? One has a Walbro (too big). The other will get an MSD pump (just right).

 

just go ahead and put it in the truck now. I honestly didn't understand when I read it earlier. it seemed like wasted motion to me.

 

Thanks for the advice. The truck actually already has a 6 port in it. A fresh rebuild too. Just needs a 225mm clutch disc and an injector diffuser (cracked one removing it). I'll have to post a wtb soon.

As for the GSL-SE, might as well leave the 6 port in it and develop an intake scheme. I came across a set of high impedance injectors with a matching '88 NA harness that I can strip of all but the basics for a MegaSquirt install! For the MS, I think all I need are the injector connectors, BAC, water temp, air temp, and maybe a TPS. I also have an S5 LIM/UIM and wide TPS that I might swap on to the S4 TB if possible.

The reason I don't want to run the actual S5 LIM/UIM/TB etc is because it needs an air pump to open the aux sleeves and has no OMP lever. I also don't feel the need to have a VDI. Am I selling myself short? Should I give the S5 stuff a try? Will it make enough additional power to justify any of it?

Hmm, I know the stock S4 NA made 145HP at 6k. What did the S5 make?

 

this exact question has been dropped in front of me several times over the last maybe 6-8 weeks and I must say I think i'm turning into a convert. I usually don't dance over factory parts just because the newer version made "some more" power over the old. however, I seem to learn a newer, small tidbit everytime it comes up.

Iotus (check his Gen I SE thread) was actually the one that started it for me, and I think i'm probably going to go ahead and start casually searching for an S5 N/A intake setup soon. I can't say for sure if it will be worth the hype and effort, but at this point, I do think it's worth giving a try.

160 at around the same RPM (may have been a few 100s higher).

 

i believe it's worth it if you're at that starting point. if the engine was already in and running then the benefits would be questionably worth it to swap them all out.

 

the S4 works great from idle to about 6500rpm, the VDI on the S5 gives you another 1000rpm on top of that, and the net result is about 10-15hp.

a stock port S4 with an exhaust will generally do about 150-155rwhp, and an S5 will do about 160-165

 

Thanks guys! Do I need to grind down part of the top of the rear iron to get the S5 manifolds to fit? I seem to recall someone needed to do that. It was hornbm on the forum when he had an S5 manifod on his FB. Don't recall the type of engine, but could have been a GSL-SE or S4 NA?

Karack, the engine currently has Pinapple sleeves, an S4 NA LIM and injector diffusers installed. That's it so far. I also installed the Earl's banjo bolt in the primary rail! Thanks again. So yes I am just starting out.

Exhaust is a full RB "streetport". Also has an RB light steel flywheel.

For power increases beyond stock, I planned on using the pineapple sleeves with a feed pipe from the header. The exhaust diffusers have been modded to T2 style. The intake ports have been smoothed but timing is still stock. No AFM so that adds like what 1HP?

However if the S5 manifolding and such is truly the better choice, especially for my situation ei MegaSquirt, high impedance injectors and all that, am I supposed to wire the aux actuators open? I don't really want to run an air pump and some sort of solenoid? Or just hook it straight up?

But if it avoids me having to add a sensing tube to my header, it may work out.

I think I have an S4 air pump somewhere.

One more question. Will an S4 primary rail fit under an S5 manifold?

 

IMO i'd just start with the S4 stuff, it runs really nicely. the S5 upper intake does make more power, but swapping it in is more complicated than you'd think.

 

Sounds like I'll stick with S4 stuff then.

Any idea whether an S5 TPS will fit?

 

as I understand it, the S5s use two of them and one of the two will fit the S4.

 

you could splice the 3 wires off the narrow range sensor on the S5 TPS to run into an S4 connector and it will work just fine.