Problems
(Likely related to the mcp3208 damage)
Problem #1 Twice, shortly after making a change (what change?) in Megatune, the ECU "locks up" and causes the injectors to stay open and fuel pump to run, hydralocking the motor.
- Second time change was the Fuel pump power-up time, from 5 seconds to 60 seconds.
- First time, I do not remember, likely Start Fuel change though as I was tuning the startup.
These seem harmless.
- How can it be prevented?
- properly PLANNING an install before doing the wiring is the way to go, it often saves a lot of bucks.
- I don't know the difference between "planning" and "effective wiring". I am not a hobbyist, I do this professionally for 2 years and overall for about 8 years. I did plenty of planning, please see the wiring information.
- WHERE exactly ? This page looks like asking for help without describing the setup. No details (or link) for wiring and mcd / mct.
That means to plan
- wiring (inputs and outputs)
- choose firmware and trigger setups to start from (reference to similar setup)
- firmware and trigger same as VEMS #857, which has been running for about a month. This information is useless for helping.
- matching outputs h[0] and h[2]. If you instruct the ECU to activate an output and the outputs control injectors and fuelpump (it is possible to activate max 8 injector outputs at the same time, see GenBoard/Manual/DigitalOut/Table
- please see wiring details and MSQ file in link (WHAT LINK?) for output setup.
- in case of any output issue, all output channels are interesting (mcd dumpDone, variables ending with _channel except shiftcut_channel that is not output but input selection)
It is best to publish for review (split to subsystems at least trigger, inj and ign) before doing wiring and powerup.
- Felt it not necessary due to other successful project (that I made myself as a 100% plug in ECU)
HW connection problem is also possible
- bad grounding ?
- eg. "stealing input switch ground" (not from EC36pin26 ground but) from chassis while some or all grounds are missing (or chasses to engine ground missing ?)
- Only thing I can think of is I used chassis ground for my Autronic air/fuel analyzer
- flyback ?
- overloaded output ?
- Shift light to EC36-30 is close to max (~300 mA)
- this should not be a problem. Max current for one p259 output is actually 1A (if others are not loaded). Shiftlight is not inductive load, which makes it even less likely to cause problem, even with misconfiguration ("prelling")
- extra analog input out of range (pullup to +12V or direct +12V applied ?)
- Launch Control Pull-up is to Pin 29 5v
- perhaps using battery break switch to disconnect battery while engine (and alternator) is running ?
- This is only for accident. (especially if there is no external max 1A fuse and 18V transient diode in the harness)
other possible (though unlikely) causes:
- using different megatune (1.1.x for 1.0.x firmware ?)
- At the top of the .ini file this appears:
"vems.ini for Megatune2.25 + vems firmware 1.0.x (stable1_0 branch)"
- almost flat battery ?
MCP3208 damaged
- After turning the power OFF (how exactly?) for a few minutes, everything was fine the first time, however the second time I think the (edit) MCP3208 was damaged.
- this shows that quite certainly something was connected wrong. Bad grounding ? or >5V (+12V ?) applied to extra analog input ?
- I now have no 1) EGT 2) Launch Control stuck ON
- no surprise, this confirms mcp3208 was damaged. It is also possible that the main processor got partially damaged (could also explain the injector outputs)
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Problem #2 - perhaps also related to the same damage that damaged mcp3208 (although mcp3208 is not directly involved in wbo2 control).
The wideband O2 readings are OK at idle and low engine RPM, but jumps around greatly at medium RPM and higher, making the sensor unusable. The pumpzero_pw and Nernst values were used as supplied with the VEMS, and the sensor was calibrated to 20.9% O2.
- What could be the cause for this problem?
- first, compare wbo2 settings to a [known good] (pumppw zero, nernstdc target and wbo2 calibration will be your own of course)
- most likely: doing the wiring before planning it => killing mcp3208 and perhaps other internal with bad connection
- possible note is I used the Fuel Injector relay output (terminal 87, shared with fuel injectors and the FJO fuel injector driver), to power Pin #3 of the Wideband O2 Sensor
- good note. Unlikely to be the cause of the problem though
- To allow the car to be tuned, I used an analog input for my Autronic exhaust analyzer. I set the analyzer to 0-5v, 10-15 AFR so I could view the Megatune logs in voltage and add a "1" to get my AFR. However I could not do this after the (mcp3208 was damaged.
- this is one of the operations that could damage the chip.
Minor Questions
1) Map Multiplication
- What does the "Map Multiplication" in Megatune do exactly?
- the pulsewidth would be multiplied "behind the scenes" with MAP. The fuel VE table often becomes "flat", but not always very flat especially at low kPa. VE value approx. 50% at 40 KPA, 200% at 250 kpa.
- Injector Settings:
InjOpen: 0
Rampup: 1008
Battfac: 4080
Battfac: (us) 304
PWM DC: 0% (should this be 100%???)
PWM Peak Time: 25.5
Divider: 2 (using 2 Injector Outputs 10(8+2)and 5(4+1))
Fire Banks: Alternate
2) Ignition Output Power
- I found that the logic level Ignition output does not trigger an MSD ignition, I had to use a 12v power output.
- this is well possible, actually a common method to use IGBT power output
- I would prefer to use logic level (or stepper) to trigger MSD rather than IGBT (less heat(clamping platye is tricky to get "right" and not "bow up" in middle, more reliable as less components are being used)
- I ended up changing the ignition to a Webshop 2x2 coil pack using 2 12v drivers
3) TPS Enrichment
The TPS Enrichments are not working great (often adds fuel on small throttle transitions)
- what are the tps bins used? (the lowest one is most interesting, obviously). Is the TPS signal otherwise clean ?
- Maybe that was a "red flag" to a bigger problem?
- Current TPS Enrich Settings:
- Bins: 1,5,20,40
- Amount: 0,1,?,? oops
Essential info needed to investigate
Because fuel-dump can be caused by either misconfiguration, or it can be related to HW damage (perhaps at the same time as the mcp3208 damage), we need to be able to verify configuration with respect to wiring.
Please do not ask for help until this is filled in:
( IssueReports can give hints on other useful info )
- wiring (split to sections: injout / ignout / otheroutput / sensors / flyback / grounds / other ...)
- firmware version: 1.0.73 (if I understand right)
- mcd / mct dumps
- we will verify ... _channel and h[0] if some might open the injector and flood the engine