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Scott33

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  1. Scott33

    E36 PnP ECU questions

    Perfect, thanks!
  2. Helping out a friend, and before I make changes to the stock wiring I just wanted to check a couple things: 1. Pin 27 is supposed to control the engine module relay, but there isn't anything listed in the wiring pinout about pin 27. Similarly, pin 56 is ignition switch input, and nothing is listed in the wiring about that pin either. Are those two linked internally so that the ecu only has power when the ignition switch is on? 2. The oxygen sensor input is connected on the right pin (pin #13); does that mean the oxygen sensor relay (pin 38) is connected somehow? I don't see a connection listed in the help file. Is it only active when the car is running?
  3. In order to make sure the AEM UEGO controller is only running when the engine is running, one normally wires the power to the UEGO controller with a relay, which is controlled by an aux output of the ECU. However, the current requirements of the controller are pretty low - 1.2A. Instead, can we just wire the ground of the controller directly to the aux output of the ECU? Controller power will have to be switched so that it is not on when the ECU is off (otherwise ECU could receive phantom power). Also I would use CAN to communicate, not analog, in order to avoid the slight ground shift between the controller and ECU. To reduce the load on the aux outputs, the controller ground could be split between two aux outputs that are configured the exact same way. Not only would that divide the heat between two mosfets, but would actually cut the total heat in half (P=I^2*R - half current in each mosfet means a quarter of the heat per mosfet, 1/4 * 2 = 1/2).
  4. Thanks for all your help. I don't want to remove the pump as I have to replace a $70 fuel pipe if I do. Not sure why, but the factory manual says so. I looked at pictures of a cam on ebay and estimated the lobe angle. I also guessed that the lobe is a perfect sine wave. After that I started getting fuel pressure. I had guessed at the timing based on pictures from the factory manual on the position of the trigger wheels at TDC, combined with what I saw in the trigger scope. Something somewhere was wrong (either the factory picture, the Link manual on missing teeth + cam level, or my interpretation of one or the other) but once I reversed it 360 degrees it fired up every other time. I also lost GDI pressure. Then I realized since I changed the definition of TDC, I had to change the GDI cam lobe position and now it starts and runs perfectly. Now on to the fun stuff!
  5. FYI you can use a 74HC393 which has two 4-bit counters in one package. Saves space if you need all 4 wheel speeds. In a TSSOP package, the board fits on the end of an AT04-12PA-BM* header, making for a compact addition to a wiring harness.
  6. Thanks for the responses. My take away is I need a whole lot more fuel. I had hope I could run it without high pressure. I haven't characterized the pump or the cam profile at this point, and was hoping to do it through deduction on the running motor (see what duty cycles are needed to maintain the right pressure at various angles, and use linear regression to estimate the profile). I have gotten pops and even had it run for a second or two after I ran the injector test. I think the residual rail pressure was enough that the cylinders got some fuel. But maybe the injector time limit of 20-24ms will be too short to get enough fuel when the rail is at 5 bar. Given the occasional pops I've heard I also think I've gotten the air out of the system by now. Do you have any crank/start logs from the VW GTI GDI or Ford Ecotec GDI motors? I'd take anything at this point just to understand what "normal" is.
  7. I'm trying to get a motor running with Force GDI. I haven't gotten it to start yet, though I have verified that injectors and spark work. I wanted to verify a few assumptions before I push forward. It's a street car motor without any internal modifications - a BMW N26 if it matters. Unfortunately I don't have much technical data to go off, so I'm trying to derive as much data as I can from the motor itself. I started with the VW GTI map and have been making modifications along the way. 1. The MAP sensor never reads much vacuum when cranking. The lowest I've seen is around 60kPa at 270RPM. Is that normal? I assume more vacuum is generated at proper idle and especially at high RPM. Because of this, I added an extra column to the fuel map at 400 RPM so I could enter much lower VE %. Otherwise I was getting "injector duty cycle too long" error messages, which is what led me to think that 60kPa is actually not normal. I did open valvetronic up (before that, MAP read 97-99 kPa). 2. Is it possible to run a GDI motor without controlling the GDI pump? When I run the fuel pump, I see both the low and high pressure gauges read 5 bar, which tells me fuel is getting to the injectors even without controlling the pump. I recognize I won't be able to run at a high RPM or open throttle but it should be enough to start and idle, right? If it matters, I adjusted injector timing to be 180, so that the injection happens when there is relatively little pressure in the combustion chamber. 2b. If I get a "GDI pump failed to maintain pressure" error, will the ECU still try to run the motor or will it give up? AFAICT it was still trying to inject fuel but I just wanted to make sure. 3. What's a ballpark injector duty cycle for start at 5 bar on a 2L 4 cyl? I recognize this heavily depends on the injector flow rate (which, of course, I do not have), but I know an N55 (same injector, but 6 cyl instead of 4 cyl) has a duty cycle of around 1.8ms at idle. I scaled that up assuming idle is at 50 bar to be 5-6ms at 5 bar. I guess my next step after this is to get a timing light. I was hoping to avoid it but I'm running out of things to check/fix and it's still not starting. I've attached my attempt to start log in case anything jumps out (note this one has the injector pulsewidth at around 1.5-2ms instead of 4-5 but I've tried bumping it 20% at a time up to 10+ms and it still didn't fire). Do you have a log file from starting a GDI motor, and if so could you post it? Attempt Start Log 2020-03-31 5;38;56 pm.llg
  8. I have seen multiple comments that Link G4+ includes a CAN terminating resistor. However is that just for CAN1 (the separate 6-pin connector) or does is that true for CAN2 (the one that doubles as digital inputs) too? I have a G4+ Force if it matters. I don't think I can measure this - I assume the resistor (if it exists) must be disabled when using the digital inputs as inputs, which I assume is the default state when the ECU is unpowered. Once I power it though, then the CAN driver will take over the pins, and my multimeter won't be able to induce a voltage difference across the pins in order to calculate the resistance.
  9. The cams are stock, but the engine does have VVT. No ITBs. Is MGP still the preferred load axis for fuel?
  10. I will be tuning a turbo direct injection engine where it may be necessary for me to change the boost levels from race to race. Rather than retune the engine, my plan is to use TPS as the main load axis in the fuel table and use a 4d table to compensate based on MGP, or possibly MAP/BAP if I can make it happen. This is the suggested setup for turbo engines with unreliable MAP pressures, so at least I'm not going too far off the beaten path. My question is what to do for the ignition table load input. The manual suggests using MAP, as opposed to MGP, which I guess makes sense as it should be more related to the quantity of air entering the chamber, while MGP is more useful for determining how efficient the engine is. (Side note - the VW GTI Force map uses MGP as the load axis for ignition). It seems there's another input that is reasonably related to how much air is going into the engine, or at least related to how much air we THINK is going into the engine -- Inst Fuel Consumption. Would tuning based on fuel quantity be a reasonable idea, or should I just stick with MAP? Or should I go with MAP + TPS as suggested by the help file?
  11. bump.. I think I posted this when everyone was still on vacation.
  12. Scott33

    Water Pump PWM

    I don't think you want to use a high side output for this. The aux outputs have built in pull up resistors, which AFAICT is enough to pull the pin high. Then the low side switch is used to pull the pin low.
  13. My engine doesn't have any timing marks that I can find. I do know, however, where TDC is relative to the first tooth after the missing tooth (60-2 configuration on the crank). If the first tooth after the missing tooth is, say, 50 degrees BTDC, then do I enter 50, -50, or 310 (360-50) in the 2nd field in "Set Base Timing"? ECU is Force GDI if it matters.
  14. I'm curious why it's recommended to use MGP instead of MAP as an axis for the fuel table. If we consider two scenarios, both with the same MAP/IAT value, both with the same Fuel pressure level, but at different BAP values, then IMO: 1. The mass of air in the manifold is the same (same MAP/IAT = same mass, unless the manifold changed size?) 2. The mass of air in the cylinder is the same, for the reasons above 3. The fuel injected for a given pulsewidth is the same (same fuel pressure as stated above, and same pressure where the fuel is being injected into due to 1/2 above depending on whether direct injection or not) The only things I see being different are exhaust backpressure (but that just affects how much effort it is to push the mixture out) and different crankcase pressure (but I don't see why that matters). I do think it's important to take BAP into account when creating target boost levels (since the turbo may not be able to generate high boost levels at altitude simply due to the lower density of air, which may result in the turbo heating up), but that's not actually configurable AFAICT. Anyways, if you could clarify how MGP results in better fueling tables for turbo engines, direct injection or not, I'd appreciate it. Thanks!
  15. True (though I'd use oil temp, not engine temp, in order to compensate for the change in oil viscosity). It'd just be nicer to have pid capabilities available in a generic way. What do you control with that output? Water pump speed, or thermostat heater?
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