Nigel

I've got my Tech Edge Version 2AO DIY kit on order. I hope to assemble it over Christmas. I still have to buy a sensor, but I'll probably go with the cheap VW sensor. I ordered both the VW and regular Bosch sensor connectors just to be safe. The kit was $300CDN including a 2.4m cable, the two connectors, and the DIY display. I probably could have bought a used Palm Pilot for the display, but I'm not sure if I want to permanently mount the o2meter in the car. Nigel '73 240ZT

The Innovative Motorsports meter is nice, but if you want auxilliary inputs, then you have to purchase one of their input cable. The basic 6 input cable is only 25 dollars, but if you want RPM input then the price jumps to $99, and for RPM, thermocouple and map input it jumps to $199! So, now you're looking at $450 for diy with rpm input vs ~$150 (+ sensor) for the techedge with rpm input and datalogging. Nigel '73 240ZT

I'm not all that familiar with the ZXT ECU, but a lot of factory fuel maps are pretty conservative (ie, pretty rich at full throttle). So, you can get away with a few extra pounds of boost. But you're not going to be finding anyone running 15#'s of boost on a completely stock ZXT fuel system. Probably beyond 9 or 10#'s you're looking at tweeking the air flow meter, adding a rising rate fuel pressure regulator, or adding some additional injectors and a separate controller to meet the increased fuel demands. But, as for the ECU, it still thinks you're only running stock boost. Nigel '73 240ZT

Just to elaborate a bit on what Xander was saying, stoichiometric (14.7:1 AFR) is the ideal for low HC and CO emissions, but best fuel economy is slightly leaner than that, and best power, somewhat richer. Factory ECUs run off the O2 sensor at idle and cruise for best emissions since this this where the output of the O2 sensor is most meaningful (averaging at stoich by bouncing between rich and lean as Xander stated). But at full throttle, they switch to a pre-programmed fuel map because the output of the O2 sensor doesn't provide a very meaningful output in the rich range (or the lean range for that matter). Like Xander was saying, you could be running 12:1 or 14:1 and not really be able to tell the difference from a nb sensor. I found that I was running too rich when I tried out the wb sensor. My readings were in the 10:1 range at full throttle! Better than being too lean, but still pretty far off the mark. This is where the wideband sensor is critical. Incidently, the new Dodge turbo 4 cylinder (found in the Neon and PT Cruiser) is designed to run at full throttle at Stoichiometric! Nigel '73 240ZT

I don't think sub $100 diy wb is that unreasonable anymore. The diy-wb.com kit for use with the ntk sensor is only $18! If it worked with the bosch sensor, then that would come out to $80 or $90 with shipping. I'm familiar with the innovativemotorsports.com unit as well. $130 for the techedge 2.0 kit is an awesome price for what you get, but that would be closer to $200 with the sensor. And I'm in Canada, so the price for me would be closer to $300. Come spring, I wont mind spending that kind of money, but I've been spending pretty hard this year. However, if I could put something together cheap before the trip to the convention in October, then I'd do it. I have a nb gauge in the car right now. I'm very familiar with the limitations of nb (rich, lean or somewhere in the middle, and that's it), but at least it's kept me out of trouble. At the time I got the car running, wb was just not an option. I'd have been looking at $800+ CDN. My engine builder has an fjo wb meter, and I did some tuning with that recently. Without question, wb is the way to go. Nigel '73 240ZT

Does anyone know of a cheap DIY wideband controller for the Bosch LSU4 wideband O2 sensor? You can get these sensors super cheap ($50US and less!). I'd like to get something up and running quick for under $100US. I'm familiar with http://www.diy-wb.com/ and http://www.techedge.com.au but diy-wb.com only talks about the more expensive NTK sensor, and techedge wants around $130 just for the kit (admitedly a nice one though). Any suggestions? Nigel '73 240ZT

Oops! When I said that the max temp out of the turbo has to be 50 deg C, I shoud have added that that was the max temp just cruising around. That's not the maximum temperature for under boost. What makes the wax so effective is that it remains at the same temperature (52 deg C) as it changes state from a solid to a liquid. It's the same principle as packing an intercooler with ice, except unlike ice, the wax will solidify again. Nigel '73 240ZT

I just read an interesting article on the Autospeed.com website about sealing an intercooler in parifin wax! Unfortunately, you do have to subscribe to view the whole article, but Autospeed is one of the best magazines on-line or off that I've come across. Their tech articles are excellent, and it is well worth the subscribtion fee. Anyway, apparently the wax can absorb a large amount of energy over a long period of time, making it ideal as a heatsink. There are some limitations, like your temps out of the turbo have to be max 50 deg C (melting point of the wax is 52 deg C). And it's not suitable for continuous boosting (like on a race track). But for a street car, it's an intriguing idea. The article is here http://autospeed.com/cms/A_1815/article.html Nigel '73 240ZT

Hey Scottie! I understand the theory behind what you are saying, but I have a question about the following statement... "IMPORTANT (and I think I tell this to everyone who has asked): The RPM FUEL curve should be built to match the engine's torque curve NOT the HP curve. The highest map value should be at about the same RPM as your peak torque." Now, I'm not going to disagree with you. What I want to know is, is there some trick to approximating this on the street? Or, can this only be done on a dyno? I kind of know what the torque curve is going to look like, and as for where the peak will be... I've no idea how to determine that. Would it be sufficient to rev the engine up to redline in neutral in stages, making adjustments to the RPM FUEL values at each increment? My understanding is that the RPM FUEL values are meant to represent the fuel requirements of the engine at no load (ie to compensate for the variance in flow of the engine through it's operating range). Am I making any sense? It's 12:30am Nigel '73 240ZT

Are you running a heated or un-heated O2 sensor? I have a heated sensor, and I tried it without the heating element hooked up. The readings showed rich no matter what I did, because the sensor just wouldn't get hot enough idling in the driveway to read accurately. I don't know if the same problem would occur with an un-heated 02 sensor. Your MAP FUEL values aren't so far off that I would expect them to make up that much of a difference between your RPM FUEL values and mine. You should be able to turn the mixture knob equal amounts to the left and right before the engine starts to stumble if you have your RPM fuel value set right. What kind of fuel pressure are you running? I don't want to send you off on a wild goose chase here, but it just seems odd that you are able to run such low RPM FUEL values with stock 280ZX turbo injectors. I don't recall my ACC settings off the top of my head. I can check them Saturday at the earliest. Nigel '73 240ZT

I think the idea is that you get a different response when you snap the throttle open from idle than from when you're cruising at say 3000 rpm. So you program in how much extra fuel you want it to add at low rpm and at high rpm. The sense value allows you to set how quickly you have to open the throttle for the extra fuel to kick in. I don't have my values handy, but I can post them this weekend. You were asking for comments on your maps... I noticed that you have much lower rpm fuel values with stock injectors than I had. I think 100 was the lowest value I could go at 1000 rpm for a decent idle. Even with my 460cc injectors, low 70's is the best I can do. I also see that you've apparently changed your MAP FUEL values from the base settings that SDS supplies. How did you get fractional values? Also, I see that you're a few points higher than the base map up to about negative 10.5, and then you're a few points lower above that. In effect, you're running richer at idle and cruise and leaner under acelleration? Finally, you have your MAP limit set at 23? You should have this set to a few points higher than your maximum boost... Nigel '73 240ZT (SDS EM3-6F with V11 software)

The cold start injector is a totally different design to the other six. It's just a small solenoid with a skinny tube with a hole in it that sticks into the intake. I seem to recall hearing that it only flows something like 75cc's. Hardly worth it, as has already been mentioned. Nigel '73 240ZT

Hey Bastaad... I sympathize with what you're going through. I've never tuned an engine before in my life (running SDS EM3-6F), and it's very hard to get definitive answers as to how to go about it. As for EGT vs. NB A/F Ratio, I have both, and as a novice, I find myself looking at the A/F gauge the most. At the very least, it tells you if you're rich, lean, or somewhere in the middle, and it tells you instantly. With the EGT guage, a lot of interpretation is required. Temperatures go down as the mixture gets richer OR leaner. So, how do you know which side you're on? Furthermore, depending on the quality of the probe (which you may have to buy separately) there is a delay in the response time. I went with the Autometer Competition probe. That's their mid-priced probe. From memory, I think it was $100 for the probe and $100 for the guage. Placement also makes a difference, but before the turbo is the best idea. Anyway, I've been driving the car for a couple of months, and I'm jsut starting to try to figure out what kind of usefull information I can get from the EGT guage. I've noted that I get temps of around 1200 to 1300 cruising at 75 MPH. Idle is around 800+ if I've been driving for a bit. At full throttle it peaks at 1400. I've been told that 1400 is the max I should want to see, but others have said 1500+. Regarding A/F guage accuracy, there are two primary problems. One is that the output of the 02 sensor is very non-linear. The output goes almost from one extreem to the other around stoich, and has very little change at richer or leaner mixtures. So, it's very difficult to tell if you're at say a 13:1 or a 10:1 A/F ratio. The second problem is that the output is very much affected by the temperature of the probe. What makes wide band sensors so effective is that they are temperature compensated. Nigel '73 240ZT

How about a leak somewhere in your intake plumbing that's venting boost? Nigel '73 240ZT

SOLVED!!! I can't believe this. Hours of head scratching and it turned out to be something stupid. I had reached a point where I was grasping at straws, and so I replaced my plugs and removed the filter caps from the ECU that SDS had given me. Of course, that made no difference. So I was sitting in the car reving it up 'till it stumbled, trying to think of what was wrong. I noticed that it seemed to always cut out by around 2000 rpm on the tach. Could I have accidentally set the RPM FUEL CUT at 2000...? Nope. Damn. So I was thinking, what else causes a fuel cut. Manifold Pressure... it's set to 8.5 psi. That's not it... Throttle position...? That's it! Throttle position! I had noted that the engine would only cut out if I reved it up slowly. So, I watched the TP value when the engine was stumbling, and sure enough, it was the same value that I had entered for TP FUEL CUT! Typically, when you rev the engine up, you pass through the value almost instantly, so it's never an issue. But just by chance, I reved the engine up slowly enough (just opening the throttle a crack) that it was staying on that value. Un-freaking-believable! Nigel '73 240ZT

I got my two spare injectors cleaned and I installed them this morning. The miss at idle seems to be gone but I'm still getting this... I don't know what to call it exactly. It's like power to the injectors is momentarily being cut off when I hold engine speed in the 1750 to 2250 RPM range. I see a lean blip in the air/fuel ratio, the EGT blips lower as well and the engine briefly stumbles. Fuel pressure pauses on the low side of the range it normally fluctuates at. It'll do this repeatedly every 1 to 2 seconds. I've crimped off all the vacuum lines to see if it's getting a gulp of air from somewhere, but I could find nothing. Disconnecting the vacuum line on the pressure regulator does nothing. Manifold pressure is constant. RPMs don't fluctuate. Duty cycle and ignition timing are constant. I need some ideas on how to troubleshoot this! Thank you to all who reply! Nigel

On a whim, I checked the plugs last night, and once again I have 4 that look normal (in fact they're bordering on carbon fouled), and two that are white (with a bit of depositing on what I'm guessing is the shadow side of the electrode). I had checked the plugs earlier in the day before I did all the testing as described in my previous post, but I guess there hadn't been enough time for the deposists to build up on the 4 and burn off on the 2. And once again, the white plugs correspond to the 2 questionable injectors (ones that I had been told flowed as well as the others). I moved these 2 injectors to different cylinders than they had been in before (cylinders 3 and 4 instead of 1 and 2), so I don't think there's any question that these two injectors are not flowing as well as the other 4, despite what the injector rebuilder said (if they actually bothered to test them). I still can't quite figure out how this would translate into the symptoms I described, but I'm going to ditch these two injectors and try to find some more. Nigel '73 240ZT

I got the latest chip from SDS and I installed it along with two filter caps on the board. I took the car for a spin and I'm still seeing occasion knock sensor activity at full throttle. I went to go out again to try some new settings, and I notice what sounds like an occasional miss while it's idling. I don't know if was there before or not, because it's very subtle. But I decided to investigate further. I reved up the engine to 2000 rpm and held it there to see if it would be more obvious. Sure enough, instead of getting a constant vrooooooooooom, I get vrooom, vrooom, vrooom, vrooom! I see the air/fuel ratio guage spiking lean in time with cycling engine note. Upon further investigation, I noted that the fuel pressure, which normally pulses in time with the injectors, pauses with the cycling engine note. The period is roughly around 1 second. I listened to each injector while it's doing this, and it's not obvious that one is cutting out. Disconecting one injector at a time also shows nothing conclusive. The cycling is also not 100% repeatable. Some times I can rev it up and I can only detect an occasional miss. Other times, it's like clockwork. WTF is going on! On the plus side, I fixed the rpm error from the fast idle solenoid shut of with a diode. Nigel '73 240ZT

Thanks Tim. I hauled out my electronic devices theory text and read the section on reverse-bias condition. I'm up to speed now I guess I probably don't need knock sensing with 94 octane pump fuel and 7 psi of boost, but I've never tuned an engine before so I don't have any experience to fall back on. I've read the SDS manual several times, and everything else I can find on tuning, so I'm well acquainted with the theory of it all. The experience is building with practice. I have an EGT gauge with the probe mounted just before the turbo, but I don't find it all that helpfull. How am I supposed to know what my peak temperature should be without running the car on a dyno (which I eventually hope to do)? Nigel '73 240ZT

The stock 240Z 5/16th supply line is ok but the stock return line is way too small . That's why your pressure went up with the high flow pump. The pressure went down under boost because you are effectively bleeding off the excess pressure through the injectors. Definitely use the 3/8 line for the supply and the 5/16th for the return. However, you are also going to have a problem with the fittings on the tank (not to mention the stock tank is not properly baffled for FI applications - assuming you still have the stock tank installed). I would recommend having a sump welded to the bottom of your tank. Nigel '73 240ZT

Just a regular diode then? I don't think you ment to say "reversed biased" in that case, which would be a Zener. I've got lots of regular diodes kicking around. So, it would have to be the white stripe (I always get cathode and anode mixed up) to the solenoid terminal. Makes sense... I emailed Ross about the discount... Thanks for all the help Doug. I hope this finally gets the car running the way I know it can. Are you going to Cayuga? Hopefully we can actually meet in person one of these days. Nigel '73 240ZT

I was thinking over the fast idle situation this morning, and the same thing occured to me. I do have the power wire for the fast idle solenoid bundled with the crank angle sensor cable. The solenoid is switched through a relay, so it's not affecting the ECU directly, but the noise pickup in the CAS cable appears to be enough. Are you talking about a Zener diode to correct this? I can get my hands on say, a 16 V Zener easily enough. I e-mailed Ross today, and he got back to me already. Apparently the price has gone up... it'll be around $100 for the chip, tool, shipping and tax. Or, I can send it to them and they'll install it for $75 plus $15 shipping (not to mention my shipping cost there), and they will install some filter caps on the CAS inputs to the microprocessor. I think I may ask if they can just mail me the caps and directions where to put them. I've populated surface mount circuit boards by hand, so I'm sure I could handle the installation. Nigel '73 240ZT

I suspected it may just be a chip swap. But I wasn't sure if they'd trust the customer to do it themself. No biggie for me though. We have the pullers at work. I'll talk with Ross tomorrow. I should get the chip before the end of the week. With any luck that will cure my fast idle shut off RPM ERR problem too. Nigel '73 240ZT

Hi Doug! I was hoping to see you at the track last week. I heard something about a coolant leak? I was talking with a friend of yours there. I forget his name. He has a blue 240 Turbo. I believe he won the eliminations? Well, for $45CDN, I'd be willing to give the software upgrade a shot. I guess it would it be reasonably safe to give the car a run with knock sensing turned off to test the hypothesis that the knock sensor is overreacting. With 94 Octane gas and only 7 psi, it does seem unlikely that it would detonate without some really screwed up programming. How long was the turn around time for the upgrade? Nigel '73 240ZT

Well, so much for that theory... I got the injectors back today. Aparently, the 2 injectors in question are flowing as well as the others. So, now I have no idea what's going on. I'm going to run those 2 injectors on different cylinders and see if the apparent leaning out follows them. I may try replacing the knock sensor too. Does anybody know a year and model of GM vehicle to give to the parts guy to get a replacement? Also, what knock sensitivity are you all running? I've also considered crank angle sensor problems, but I never get an RPM ERR message (except when my fast idle shuts off, but that's another story ). You could lift the engine with my sensor mouting bracket and the gap is within specs. The wires and sensor are no where near the ignition or alternator. I never get any display wierdness. I'm running out of ideas. And I'm getting very discouraged... Nigel '73 240ZT