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June 2009

Just installed Bosch 1600cc Injectors (5 Ohm)and we are now running E85 fuel.

The Honda resistor pack failed today, one channel very high resistance, is it possible to run these injectors directly from the ecu? (NO Resistor)

<<<With no PWM-ing and no series resistors (but 30V unidir transient-diode flyback)>>>
  • Yes, you most certainly can run those injectors (those are the only mid-lowZ injectors though) without resistors.
  • yes, possible to run the 5.5 Ohm injectors without series resistor, but RUN ALL OF THEM without resistor.
If you run only one of them without resistor, that cylinder gets more fuel and cheats the average lambda reading.

It would be most dangerous to run just one injector with series resistor (and blow up that cylinder).

End 2008

Car is running very well, see Dynos page. Best 1/4 mile E.T.=11.4 , best MPH=128



TODO: organize

Custom EC36/EC18 Wiring harness

custom FJO fuel injector driver

Symptoms that might have predicted a problem

1) TPS signal very very dirty For the first day of running/driving, the TPS signal was erratic and caused very poor driveability. I moved the spark plug wires away from the TPS but it didnt do much. The problem "went away" the next day or so with no changes to the TPS enrichments or the VE table.

2) Wideband/lambda readings very spikey The lambda readings from the beginning were ok at and near idle rpm, but get very dirty when driving. The sensor is new and has been calibrated to 20.8-20.9% O2 and the Pumpzero_PW and Nernst values were supplied by the Webshop.


Many 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.

  • In my case it cost me a USD $280 Bosch LSM11 O2 sensor!! Also new oil for the engine (twice), and several hours lost (work and sleep).
- 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.

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.
  • 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 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

- Overkill, please see Wiring details above
  • 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 ?)
- Engine to Chassis Ground present

- Only thing I can think of is I used chassis ground for my Autronic air/fuel analyzer

- Connected to EC36-23 and to FJO injector driver. - Autronic meter supplies 0-5 volt only - confirmed.

- Launch Control Pull-up is to Pin 29 5v

- No switch used
  • 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:

- I am using a custom .ini file (by me). I will e-mail this to the Webshop as the File Manager will not allow it to be uploaded.

- At the top of the .ini file this appears:

"vems.ini for Megatune2.25 + vems firmware 1.0.x (stable1_0 branch)"

- Yes, the car has a small battery that went low 20+ times in a week. Battery charger was used, jumper cables were used only AFTER the second ECU lockup.

MCP3208 damaged

- Simply turn off Ignition Switch and wait the first time. The second time I unhooked the Battery because I was fearful of the ignition coil possibly being stuck ON (wired to battery that day, long story). (Ignition is now a VW VR6 2x3 coil pack(using only 2x2), using coil drivers 2 and 3, 3.0 to 3.5 ms dwell)
  • this shows that quite certainly something was connected wrong. Bad grounding ? or >5V (+12V ?) applied to extra analog input ?
- Please see wiring details and timeline below. - Note that the fuel was injected Twice, the first time (days before) there was no issue with the analog inputs, so maybe this timeline will help you diagnose the chain of events?


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.

- Wideband problem was from the start, mcp3208 did not "die" until 7 days later. - Any more information? Are you thinking the voltage spiked over 5v? How can I prevent this from happening?

Minor Questions

1) Map Multiplication

- 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

- TODO: find out is 255 ohm works and then specify that from now on for all orders (I have many applications using VAG COP coils)

- 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 ?
- TPS signal was originally very dirty, caused poor driveability. thought cause was possibly TPS near spark plug wires, moved the wires away from each other but this did not directly co-inside with "fixing" the problem. The problem "went away" by itself.

- Maybe that was a "red flag" to a bigger problem?

- Current TPS Enrich Settings:

- Bins: 1,5,20,40

- Amount: 0,1,2,4