ZFuel

[superlen]

Update.

I ran the Z again today (barely) with the HellFire board. Not as successful today as I hoped for, but I was able to grab some data points running the stock ecu I needed. It was still running way too rich. I had warmed up the shop to 75 deg so the cold temps that were working for me last weekend were gone. Today I ran with the map sensor connected so it should have pulled the pulsewidth down to something close, but I couldn't get it so stay running for more than a few seconds at a time.

I suspect it was the extremely long, extremely small diameter vacuum line I used to plumb the intake to the board for my impromptu test. I was worried about it being too small & causing issues. The MAP reading was very sluggish and wouldn't pull down to any appreciable vacuum at all. Therefore the pulsewidth stayed up there and was just too large & dumping too much fuel. In addition, the Map table I'm using is just a wild guess as to what the Z might need, however I'm sure the table wasn't the primary problem, it was the map reading.

Lenny

[JRSGTS]

Get lots of extra fresh plugs Lenny. All this rich running is going to fuel foul them and not help you at all.

[arts.zccm]

Tomohawk, Lenny emailed me last week, I will be talking to him this week and we will be getting an article in ZCCM. It will be more then 1 page for sure .

[TomoHawk]

I did a quick video this afternoon.

Thanks Lenny. Would you please get a photo of the intake manifold to see how it looks with the extra parts? I'm trying to take stuff off my for a clean look, and you need to add sensors for the new control system.

Perhaps the new sensor(s) are not very noticeable?

[FastWoman]

Tomo, Pomorza (Jan) posted this photo of his megasquirt setup, which would have the same MAP sensor as one possible configuration of Lenny's system:

https://fbcdn-sphotos-e-a.akamaihd.net/hphotos-ak-ash3/527276_10152006457680347_412958556_n.jpg

The beauty of these systems (either MS or Hellfire) is that they're configurable for what you have and what you need. The Hellfire can work as a P&P ECU with stock components (including the AFM) if you wish. Or it can be configured more like Jan's MS system with the MAP sensor. Or I *think* it can even be configured with a hot-wire MAF sensor, which would go in place of the AFM and would be maybe 1/4 the size.

If I understand the MAP sensor strategy correctly, it can be done with a small vacuum line running from the intake manifold to a MAP sensor placed on the circuitry board of the ECU. Or there can be a MAP sensor attached directly to the intake manifold, with wiring running to the ECU. (Right, Lenny?)

[superlen]

Tomohawk,

Yeah..what she said (points up) Sarah is exactly right. That's why I hang out here, there are so many smart peeps.

The intake on my Z in the video is 100% bone stock. Several Z lovers have expressed an interest in what it looks like under the hood. Not surprisingly they seem to all be in California. In the base configuration, HellFire just replaces your stock ECU and you party on with all you're stock sensors. For many owners, this will be fine. They now have an ECU they can connect a laptop to and read all the sensors, get error codes, tweak a little to accommodate that aging AFM spring, or adjust for that cam/header they just added, ect. No drastic changes, but you know have infinite tuneability and 2014 technology in your mid 70s car.

However.... I'm not one of those owners. I like to tinker, change, customize & like you, want a sleek clean intake/engine. For others that feel the same way, this would be my recommendation:

Stage 1 - Cold start valve...we doneed no stinkin' cold start valve. Lose it & associated plumbing. HellFire will monitor warm up temps and supply all additional fuel that the cold start did (programmable of course if your car needs a little more/less) Additionally, I know how to use a gas pedal to warm up my car & I don't live in Fargo, so ditch the AAR and water lines for the heater block under it. (how many times have we seen it leaking). Now we have the beginnings of a clean intake. Grind off all the associated mounting bosses of course. The beauty of stage 1 is that no part of your wiring harness needs modified. No sensors added, and you don't need to even know how fuel injection systems work at all. You will have some extra wires/connectors that were used by the old harness to hide or if you want to, just remove them and clean up the harness. I would still consider Stage 1 to be an easy DIY project and I would still call it plug and play. (yes it's a stretch as your removing a lot of junk off the intake)

Stage 2 (AFM Upgrade )

And when I say upgrade, I mean lose it! Turn it in to a coffee table, some yard art, or a boat anchor. The AFM in 1975 was a great thing & even now they can and do work (sometimes), but they are restrictive, have temperamental circuitry inside that has drifted/aged, and IMO are ugly. Stage 2 is for the serious Z hacker & depending on how you approach it, you are going to become very knowledgeable about how FI systems work. There are two options for replacing the AFM. As Sarah pointed out, you can use MAP or MAF. The MAP option is the cleanest install, as the location of the AFM is just replaced with a straight pipe. You will need to add into this pipe an Intake Air Temp sensor. (IAT), and a vacuum line from the intake manifold needs to be ran into the cabin and hooked to the ECU. The second option is to use a MAF sensor. It will plumb in the same place as the old AFM. They are not as restrictive, not as large, not as ugly, but not as clean as a straight pipe. It too will need an IAT. Either of these methods will require playing with the software some to dial in the setup depending on what parts you find. It's not rocket science, but it's not shake and bake either. I've tried to make the software as intuitive as possible & I will have a few pre-canned setups with some know parts that if you use these, all the calibrations will be done for you. Think Infinity Q45 MAF & GM IAT.

You asked about how visible the sensors would be. It will depend on what you do and how crafty you are hiding them. For the absolute cleanest look, run with MAP. You will have one vacuum line running from the intake through the firewall, and one IAT that I would add on the bottom side of the straight pipe were the AFM used to be. No one will see it on the bottom side. To me, this makes an incredibly clean intake.

Now, don't even get me started on the distributorless ability of the HellFire Hybrid version.

Lenny

[superlen]

Art,

I'm back from my business trip so we'll touch base when you have time, and I got my ZCCM magazine subscription in today. They look great. Thanks.

Lenny

[superlen]

Sarah,

I realized I didn't completely respond to the MAP statement/question you made. Yes. You are right (again ), the easiest way to get MAP is to use the MAP sensor that is built into the ECU, just run a vacuum line and connect.

If however someone has an external map sensor, they can wire it up & tell the software to use the external instead sensor instead of the the on board one. If they do that, then the internal MAP would then serve as a continuously monitored barometer (BARO). This would be nice if you lived in a mountainous area and started your car at one altitude and then drove to another. If you live in Kansas, well it's not much of an issue. If you run MAP the BARO is set when you start the car (actually when HellFire powers up & before the cylinders begin to turn) to whatever reading it's at and does not change until you turn off/back on.

You could also have continuous BARO if you are running the stock AFM, Alpha-N, or MAF, as the internal MAP sensor would be available in those cases as well. The stock ECU does have some limited BARO abilities as well. In the CA models there was the altitude switch that tweaked the fuel map at one particular altitude. Go above the preset altitude & less fuel is squirted, drop back below it and more fuel is squirted. On/off, Higher/Lower, leaner/richer. The BARO just gives a very accurate more precise ability in that department.

The flexibility to do this comes from the ability to re-arrange most all of the external sensors with respect to the wiring harness. For instance, you could wire the AFM signal to the TPS wires instead of the stock AFM wires, and vice versa (which would be silly, but you could do it). In the software setup for each sensor, there is a field to select an ECU pin number. If you tell the software that the AFM is attached to pin X instead of pin Y, it doesn't care how crazy your wiring scheme is, it will just read pin X and run with it. For the stock system, you obviously wouldn't need to do that, but if someone is customizing (as is my hope that many users do), this feature is awesome.

Len

[FastWoman]

"In the software setup for each sensor, there is a field to select an ECU pin number. If you tell the software that the AFM is attached to pin X instead of pin Y, it doesn't care how crazy your wiring scheme is, it will just read pin X and run with it."

NICE!

[TomoHawk]

I would stay with the OEM connectors and pin numbers. It'll Make any later diagnostic or trouble-shooting efforts easier. It's just a shame that you can't adapt a tubular AFM or MAF sensor to the original ECU (you probably can, but it's not easy.)

[superlen]

TomoHawk,

Yes. Staying with the original wiring is waaay easier & that's what most everyone will do, but there are those out there (I'm one of them, go figure) that will want to change/tweak/play/customize and never leave it alone. They need the ability to be more flexible in their wiring. It's been way hand for my testing, although I must confess I spent 1/2 hour yesterday wondering why my target pulsewidth looked wrong when I realized I had changed the AFM's pin over to the one where the MAF should be. What was that you were just saying about about troubleshooting Tomo?

As for adapting a MAF. You're right, it can be done, and it's not as simple as one might think. The AFM measures airflow in volume such as CFM, the MAF actually measures airflow in MASS. The stock ECU has to take volume flow and convert to mass flow. For this it needs air temp via the IAT. If you simply replace the AFM sensor with a MAF sensor, the output (no matter how much you scale it) is already corrected for air temp. The stock ECU would then correct it AGAIN, which obviously isn't correct. You could make a circuit that reads the MAF in, reads the IAT (with yet another sensor) then un-corrects for temperature, then scales the output, then sends the signal to the ECU. Then the stock ECU would then correct back and work. Of course you would need a GUI to tweak and calibrate your MAF to your car as well. I have considered doing something like this to offer for other cars that use an AFM, but it's just not as much fun as the HellFire is.

Len

[TomoHawk]

The point was that when you stray from the OEM wiring, you are responsible for documenting changes, or even the entire new system, for future reference, or even the next owner. The factory wiring diagrams are readily available, complete, with notes and without any errors.