superlen

Zed, I have you covered on the injectors. I can control all six separately, so if we know the offenders, we're good to go. I agree that it's a rabbit hole on figuring out who/what/how much. Your idea on increasing pressure works too, from what I have read online. This makes sense as the higher pressure in the rail will require higher soak temperature to cause vaporization. I don't know if 45 psi will completely solve it, but it should definitely help. HellFire will run at 36, 45, 50psi, or whatever you want to set it at. I ordered an adjustable FPR for testing the stock injectors at different pressures. This may turn out to be the easier/better solution. Another thing I thought of is that when we try to purge the fuel fail by running the pump for a bit of time, I'm not convinced that it is sweeping the entire rail. Looking at where the FPR is located and the circular nature of the rail, it may just be bypassing some/all the rail. If this is true, just re-plumping the rail such that the prime condition forces fresh fuel to completely replace the warm fuel should help as well. I have to do some tuneup on my system before I can get some good numbers for HellFire testing, and one of the items is installing the FPR & building a new rail. I'll post back what I find. Lenny

Just a quick update that I've done nothing on the HellFire for the last week, save for a tiny bit of cleaning up the code. I should have more time this week I hope. Lenny

Zed, Yes, I agree with you. I kept thinking about the stub (it's just a short amount) & I think I was off the deep end. With some experimentation one may be able to find where the heat is getting in and causing the issue, but I think with a little characterization of how much additional fuel needed in a hot start/soak it would be a moot point. Just have the ecu dump additional fuel for x amount of revolutions/x time. It may take a bit to figure out the table, but makes for a simple solution when the work is done. Len

Zed, What about the fuel that is trapped in the short hose from the rail to the tip? (lets call it the stub) Could that amount of fuel represent the 10-20sec of run time? This fuel would not be flushed back to the tank during the prime function as it would simple be bypassed. We could do the math on the flow rate and the ID/Length of that stub to see if the numbers are half way close. Also, if the entire car, or more importantly the injectors themselves, cool back down, I'm assuming the 20sec stumble is gone or at least greatly reduced. Does this agree with what you have seen? Len

BTW. I would shoot for 2-3sec total of fuel pump priming. More won't hurt anything.

If you go the insulation route, you will have to test as I think it's possible that you might make the problem worse. If the heat is being from convected around the fuel lines them selves, this will help. If it's leeching (conducted) up through the injector body, this insulation will just make it harder for the heat to conduct *out* of the fuel itself. One of the feature of the ECU I'm working on is a fuel pump prime feature to see if topping off the pressure with a few secs of fuel pump activity at key switch "ON" will help this common Z ailment. I believe that people have ran a hotwire switch bypass for just this function and reported back good results. That might be a good thing for you to try as well. You could do a quick test, just: start, warmup, stop, wait..... unplug starter solenoid wire and try to start (which will ONLY run fuel pump because of disconnected solenoid). This should ensure the line is primed as good as it's going to be..Then reconnect starter and give it a try. I personally would be interested in the results of this test on your car since it's behaving like a nice test subject currently. Lenny

Zed, The test harness I'm using for HellFire has white wires coming out for the altimeter not black. Go figure! That's why I assumed that the white wires from the OPs was the same. I have no idea what year this harness is from, it was just in a pile of them I had. Thanks for posting the pics showing the "Control Unit Checking terminals". I have never seen those referenced before. I'll also double check my white wires to make sure they are in fact going to the altimeter switch. Len

JR, I'm not 100% sure, but I believe the single pickup disty will work. The second pickup I think is only used on CA models perhaps??? The two pickups are some fixed degrees apart (maybe 6 or so) & the ignition module decides which one to use . Sorry for the vague info. I've not looked at the ignition circuits in a while. Others here will be way more up on that than me at this point. Hopefully, they will chime in. Good luck with the weather & stay warm. Len

Bummer! The sad thing is that, depending on how hard they worked at covering it up, it wouldn't have taken them much more time to just patch in the few pieces of sheet metal. I had a very similar experience as well & still have a little rust there. it's just a small amount on mine, but still...it's annoying. Lenny

Chas, I'm not sure how I missed this post earlier, but very nicely done. Mine is a 77 as well & when you get everything to your liking, I would be interested in a set. Lenny

Que evil slow voice and fingers tapping together...."Excellent." Thanks JR. I'm glad the spare ECU got you farther down the road. I've been watching the thread & your follow on ignition woes. It sounds like you're just about there. Lenny

Sarah, I will definitely video the first start attempt & post for posterity. No cheating, I'll post it as it's shot. I have a high confidence that it will at least cough, sputter, backfire, foul the plugs, or in fact even catch fire! And to answer your question on ignition... The HellFire Hybrid will be able to do COP. You would of course have to use an additional ignition harness (will be supplied with the HellFire Hyrbrid version). This harness contains the inputs needed as well for the Crank position sensor, cam if desired, ect. I haven't detailed yet exactly what the ignition harness is going to look like, but it will exit out the back of the ECU case and have an appropriate automotive style connector & appropriate cabling/ends. TBD COP is the ultimate goal on my personal Z so when I get it dialed in, I will most likely offer a complete kit as well with all coils, brackets, exact lengths of cables, and plug and play connectors. I'll be back on job bright and early tomorrow morning....or maybe I'll just write code all night. Len

@Captain. Yes, the bat volts is only for offsetting any sagging/excessive voltage that the injectors see. I did connect the AFM reference voltage wire to an a/d input, but I'm going to use it for MAF or any other analog signal we may need/want from the engine bay. @CG. Your avatar makes me jealous. If only the bottom of my car looked that good. General Status Update. - I'm firing injectors. (well five out of six, something on one channel has an issue I need to chase down) Woot Woot! - Just for grins, I did a quick code hack to make the pulse width vary linearly with the AFM input. This allowed me to watch the injector PW on the scope vary as I moved the vane in/out. It's obviously not accurate at all, but for me was fun to see some actual real world feedback. I do have all three Injection methods (MAP, MAF, & stock AFM) simulated and tested on the PC but without any base map at all to start with, or half way close AFM calibration numbers, it's a moot point to try them in the car yet. Plus, I have a lot of cleanup to do on the interrupts that fire the injectors & general testing. I'm getting closer though!!! I was shooting for New Years Day to have the first in car test, but I think that's slipped now. Len

Great. Sounds like you're finally making some progress. I'm glad the spare ECUs I have lying around helped out. Lenny

An old thread but for posterity...Those wires are for the altimeter switch. CA models monitored altitude and would adjust the fuel pulse width if above a certain altitude. If yours isnt a CA model, the altimeter switch isn't there and the wires just hang. Len

JR GREAT news! I missed your call yesterday & got tied up with family and was hoping you were calling with good news. So the new plugs helped out after the new ECU was in? Lenny

Blue, I forgot to add. Have you seen this forum: Home There is lots of good info there and seem to be a friendly bunch. Len

Blue, I do measure Battery + on board the ECU. I need it for modeling the injector dynamics for a low/high battery. The stock ECU does this too, but I'm assuming because of the lack of technology at the time (or maybe "complexity needed" is a better term) they couldn't use the same reference on the AFM input circuit so they had a sensor in there as well. I suppose possibly the ref sensor in the AFM is what they use to determine their BAT + for injector dynamics, but I wouldn't understand why they stuck it there if thats the case. Len

I created my table, but I haven't downloaded yet. I need to change out a pullup to adjust my range some & I built the table around the new pullup. I'll test tomorrow. Also, it seems plausible the reference is also used for drift, but I don't recall coming across that anywhere. I do have it wired up in the stock configuration so I could use it if necessary, I just chose to ignore it. Len

Captain, FYI, I keyed in the equation so I'm good to go. No need to email something. Thanks, Lenny

Sarah, I said we *can't* easily tell if the injectors are delivering the proper amount. At least that's what I was trying to imply. I have thought about selectively disabling injections to check if a cylinder is misfiring/injector clogged, ect, but I haven't spent any time on it. What's more interesting to me is rotating through a squirting sequence in an attempt to do sequential injection. Without a sync pulse of some sort, I don't know which cylinder is where so sequential isn't really possible. However, if I rotated through all 6 possibilities and monitored rpm and MAP I *might* be able to detect which of those sequences resulted in the most stable idle & then use it. From my research sequential doesn't buy a whole lot, but it does help make a nice stable idle. BTW, I was unfamiliar with the fuel pump switch touchiness on some models. The user would just have to make sure that their switch was adjusted so that it operated at idle or just turn over fuel pump control to HellFire and forget about the AFM switch. Note: There is a slight caveat with the HF taking over fuel pump control. The Z's wiring harness is wired for the ECU to control the relay if it likes (via pin 20), however Bosch didn't load pin 20 on all ECU's. Even ECUs with the same exact part number don't necessarily have that pin loaded. So depending on what ECU someone sends in as a core they may/may not have that functionality out of the box. Because of this, I routed the signal to both pin 20 & pin 11. Pin 11 is unused in the harness, but is always loaded on the connector. So...if one desires fuel pump control, but has pin 20 missing they need to move the wire in their harness connector from pin20 to pin 11. There's no soldering or cutting & the harness will appear perfectly stock afterward. Taking the connector apart & moving the wire/pin from one location to the other & putting back together is all that is required. A small sharp pick/tool will be needed to let the pin release from the body. Lenny

Excellent feedback everyone. Captain, Yes please email me the xls you have if you don't mind. I remember you saying the points shown in the FSM were not quite spot on. My readings confirm that. Sarah, I agree with this.. I have looked at the Atlantic Z site before, but I didn't realize it was Blue's creation. I also agree with your thoughts about a loosened clock wheel is going to peg out at higher RPMS. With the stock ECU we just had to live with it. For HellFire the simple solution is to tighten the clock spring until the 4500-5000rpm range does NOT peg it. Then we can calibrate the lower portion no problem. Poof! Now we have a nice full scale to use. As for the inputs being spot on in order to have it work perfect out of the box, I totally agree. However, If you have a good running Z now & you plug & play a HellFire, you will still have a good running Z(and you can tweak it to a great running Z). The same goes for a crappy running Z. Assuming it wasn't the ECU just being thrashed, plug & play HellFire will still result in a crappy running Z. However, this is exciting to me as now you can get all kinds of feedback via the GUI to troubleshoot your engine. we can validate your temp sensor(s) are close or waaaay off. We can validate your AFM doesn't have dead spots & we can validate the clock spring adjustment is reasonable. We can validate your idle switch & WOT switch operate properly. HellFire can also read shorted and open injector circuits. We can't *easily* tell if your injectors are spraying correctly, but if one want's to pull the rail & stick a graduated cylinder under each injector (one at a time of course) you can run an injector test and it will tell you the exact flow of each injector using *your* fuel pressure. This would even calibrate out an adjustable regulator if someone was running 40psi or something silly. I need to get busy. I have lots to do. Blue, I have been thinking about building a flowbench as well, but too much to do. My redneck solution was to use the Infinity Q45 MAF plumbed in front of my stock AFM. The Infinity MAF has a know transfer function that I can read on the fly & then do the math using that output plus IAT to derive the CFM of the stock AFM. My software is written to support MAF anyway so it's not much extra work. The MAF sensor reading comes in on the wire that used to be the AFM Reference voltage so the wire is already right there at the correct location in the engine compartment. ( I don't need the reference as I'm sending regulated +5V to the AFM, not bat voltage) It would be awesome to compare the graph I get with your flowbench measurements. We could send some AFMs back and forth to compare apples to apples too. As you mentioned VE would work too, but I don't have a starting map for the VE of a stock LJet. I'm sure people have them from MS installations that would be close. My VE tables are 16x16. (smaller works too, it's configurable, just max is 16x16) Zed, I agree with you and I'm sure I'm going to be doing some of that, but I would still like to know as close as possible the real numbers. That way I won't be tuning the AFM thinking it's off when really it's some other issue I have that's causing the AFR to be off. I do think there is still going to be some "seat of the pants" tuning. Or is it playing? I'm not sure. haha. Lenny

Sarah, I was hoping to have at least a steady state baseline map running (read Idling with at least a halfway close 14.7 AFR) in the Z by New Years. It's still a possibility, but with some Christmas travel and such, i don't think I'll make it. And, I'm still laughing at even the thought that I would have a calibrated AFM. :) As you probably guessed,like most all of us, I have an old worn out AFM that who knows how much it has drifted/spring weakened or how much the spring has been tinkered with. I have several thoughts on this: 1. My assumption is that most don't have a clue where their AFM is really at. 2. My GUI can easily adapt to any slight (or even fairly major) drift as long as the internal wiper is smooth and doesn't have dead spots. However, tweaking a bunch of numbers that aren't even close to linear by hand doesn't sound fun or productive at all. 3. In the GUI, I'll have a virtual "wheel" that the user can advance or decrease. This will simulate popping the cover & manually changing the spring rate. It will adjust the numbers on the fly for you. The benefit is that a) it's easier You don't have to worry about risking the integrity of the seal on your cover & use gobs of silicone to make sure it's water tight when done. c) you can easily go back to stock by clicking a button as opposed to remembering where your wheel started at. d) It's far easier to click a button while the car is idling, than to loosen the bolt adjust, retighten, ect. (usually with the car off) I feel this virtual feature will allow the user to "tune" their particular AFM's drive in pretty good. Experimentation will tell. I can't wait to get to that point. 4. How do we know if our AFM has dead spots? Testing with a voltmeter is a great start, but somewhat time consuming, and I never know if indeed there was a tiny dead spot I just missed. Plus, what if the dead spots only show up during vibration. People who have investigated their AFM internals know that the wiper is just held in place by the pressure of the arm. What if your wiper is just barely touching and sometimes you get a hiccup? Wouldn't it be nice to know the overall AFM Wiper health? I have a great solution. Anytime the HellFire is running, it will be building a histogram of all the data points it sees on the AFM input. The GUI can show a bar graph of where the AFM mostly hangs out at. Obviously down at the rest position & idle there will be much greater activity & then one should see a somewhat smooth bell curve. The key is that if you see one spot in the middle of that smooth bell curve that is down in the weeds. Voila! That's a point where the wiper has a dead spot! 5. Ok, all the cool stuff aside, we still have the problem of whats the calibration supposed to be? What is the standard? Two possibilities: a) calculate/measure what a factory tuned brand new AFM is & use that as the gold standard. Measure as many unmolested 40yr old AFMs as possible to calculate what the normal drift is for these things and use that as the standard. For now, I'm leaning towards a. (with a caveat). The base calibration should be as close to possible as a factory new AFM. However, I would like to ship the HellFire Classic configured with the golden calibration, but with the virtual wheel set to what is most likely the best setting for a tired old AFM. In reality that may just not work perfect, & some tweaking of the wheel may be necessary for the absolute *best* setting. However, one thing for sure is that it will work better than the stock ECU hands down. Blue, Thanks, I'll try and post later today my input circuit & a picture of the calibration screen for the IAT/CLT. Here are some quick details. I have a 6.2K pullup to 5V, the sensor is of course the other resistor to form the voltage divider. The 12bit A/D maxes out at 3.3V. (0- 4096 counts = 0-3.3V input) Lenny

Here's another status update for anyone following. Today was a small milestone as I connected a full EFI harness to the HellFire. For a few weeks now, I've been playing with the software and sensor calibration routines. The stimulus to the board has always been my breakout/simulator board. Additionally, I wasn't running +12V power. The usb connection was providing +5V that powered all the circuitry. I did this just for ease of development (no need for lab supply on desk, no extra pesky wires in the way, ect). This morning, I connected a stock harness ( I think from a '75) & powered up. All sensor inputs worked flawless!!!! WOOT WOOT. The IAT, CLT, TPS (idle & WOT switches of course), cranking signal, Battery voltage & AFM output were all showing on screen as they should. I have an AFM lying on my desk with the cover off. I can move the vane from 0 to full scale and watch my sensor input go smoothly from 0 - 100%. Changing the scaling works great and I can scale it to give me raw A/d Counts, or the voltage at the ecu pin, % full scale, or cc/sec of air flowing through it. I still need to calibrate to determine the cc/sec of air. This is of course the critical measurement we need but for now it's set to just show voltage. The IAT was showing 28.9 deg C which is a little high for my office but I am running a space heater below my desk keeping my feet warm. More likely I thought was that my calibration numbers that I calculated based upon the FSM are a little off. They are definitely coarse as I'm only using 5 data points and I need more. Both Captain and Blue have volunteered to calculate some better numbers & I'm ready to take them up on it and buy some beer. For grins I took the AFM and set it down in front of the space heater & immediately the IAT on the computer screen started rising. The on board MAP sensor is tested and working great as well. I have also ordered a MAF sensor off a Infinity q45 to test as well. I already know the transfer function of it in grams of air/sec, so I'm going to plumb it in front of my stock AFM while the car is running and use it to get a baseline calibration curve on the stock AFM flowrate vs output voltage. The next thing is to test the circuitry that detects the coil firing and test the injector drivers. So far knock on wood, No smoke from the prototype board, and not even any blue wire jumpers needed. Lenny

I bow down before the master. Sarah, that was awesome! Thank you. Len (who's off to find a fur Santa suit to wear while writing software)