The season is over for this car, there has been an issue with the fuel injectors and finally the Genboard died.
Even if the board can be fixed, two of the 1600 cc injectors are fried or unreliable. Back in June, the injectors used were 4 x 900 cc (Accel brand) and they started leaking through an internal seal, they probably couldn't take 5+ bar fuel pressure (1.5 bar boost + 4 bar fuel pressure) and the swedish gasoline with added toluene. The 1600 cc injectors have been run on regular 98 octane with no toluene or octane boost added, but we suspect it could still suffer from the same problem even this time - only now the plastic on the coil is the victim (probably). Cyl 1 and 4 have measured as low as 1 Ohm and 2.3 Ohm, but up to 7-8 Ohm and up to infinity as well - normal impedance is 4.9 Ohms which cyl 2+3 still consistently measure to be.
The unlucky part about searching for the error was that the high load put on the Genboard by the failed injectors (low impedance = short) was that we got serious trigger errors. On an engine that cost more than a couple of new Autronic ECUs you don't want any of that. The bad running engine was blamed on problems with the trigger, and we searched for something that would disturb the signal but never thought to look at anything but the sensors - only to turn out to be the injectors. I don't wish to count the hours spent on this one.
- Install 4 x 1600 cc of another make/brand, as we suspect fuel incompatibility to be the cause of failure last time.
- Jörgen recommends separate fuses for each injector to protect the FET drivers in the future.
- The fuses are placed on the wires going from injector- to the Genboard, 3A would be good enough and readily available. A 10A fuse would be used on the injector common.
- A repaired and tested box, these have been measured and seem damaged and needs to be replaced:
- All FET drivers (1 of 4 has made it, but all will be replaced)
- At least one FET (I think the rest are ok)
- The transient suppression diode on the back of the board
The only trouble is having faith and energy, hoping that no time and money is wasted yet again on another set of fuel injectors and chasing strange problems. The owner of this car has spent time on problems that shouldn't be.
Fixed C44/C55 problem with EGT, capacitors were soldered in place. Apparently this was a bug according to information found here GenBoard/UnderDevelopment/VerThree, and should actually be jumpered. So I jumpered them and got EGT1 and EGT2 working. Yay!
One of the problems from this weekend was that the fuel pump output (P259_5) didn't switch to ground for pump priming on initial power-on of the Genboard.
But this only occured with the serial cable connected to the board, but this was becuase the board entered BootLoader. The long serial cable acted like a loopback: without anything driving the input, the cable makes a capacitive coupling and the signal the bootloader uses for loopback-test is high-freq enough for this.
Tip from Emil: Try a big resistor (~100kohm) between pin 5 and pin 3 in the DB9 to drive the input low.
Due to a fuse problem (injectors), a very irritating laptop and running out of time - we decided to post-pone the 15x15 test until later. Too bad.
Information about the installation
Emil Larsson made the initial install:
Genboard serial no: 204, with pump_zero_pw=0x65
Firmware wishes, more or less needed for this car.
- Exhaust backpressure input
- both EGT channels on LCD, best would be with current and max reading
- Extra temperature inputs, most important is for automatic transmission temp
- EGT based enrichment (if egt goes over a configured value, start adding more fuel to cool.. With the automatic transmission, the engine goes on full load for the full quarter mile, more fuel is needed to keep the engine from detonating, currently tuned to run too rich off the line)
- Cold engine ignition retard, Maybe not too important with the adv. based idle control.
- Some sort of check engine light/warning light, configurable for different temperatures and pressures, also when trigger/camsync problems appear, maybe with one led that says "hey, check your LCD", and one huge lamp / loud summer that says "switch off now, somethings is blowing"
This car is using a MSD 6 ignition system and distributor.
- Engine spec.
- 4 cyl B23 block
- Marine 2.3L 16V volvo head
- Custom made cam shafts
- H-profile aftermarket rods
- Holset HX55 turbo, 66 mm inducer and 82 mm exducer, with an advanced manifold and wastegate system [Picture of engine bay]
- Trigger setup:
- Main trigger is a pulley on the crankshaft, aluminium with 2 8mm (square or round), 8mm high iron pieces, to trig a Honeywell GT1 sensor.
- Cam trigger is not implemented yet, but will be easy. Change one of the M8 bolts on the adjustable camsprocket to a longer one, a GT1 will be used here too.
Alubos case front [Picture]
Alubos case rear [Picture]
- Serial jack (6.3 mm stereo plug)
- LCD (DB25 used instead of DB9 for LEDs and switches on LCD case)
- K-type thermocouple connectors (female chassis)
Q: Can you please tell me what are your injector related settings for the 1600cc injectors? Thanks,Peter
A: I will have to get back to you in a couple of days for the real facts, below you can see what I found in an old config from May 2005.
req_fuel=11 injopen=0A injocfuel=19 injpwm=3C injpwmt=0F injpwm6=64
From what I remember injopen and injocfuel were relatively long periods of time compared to what I've seen with much smaller low-Z injectors. This could partly have to do with the coil being about 5 Ohms (usually 2.5 Ohms) and not as fast as it could be with a lower impedance, perhaps the size and weight of the pintle is involved here too.
Thanks!I have a problem with my 55lb/hr Siemens low impedance 3ohm injectors,and want to know which settings will work.Peter