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Still getting my head round the whole fuel injection principle thing, just when I can feel proud that I understand carbs, now I have baffled myself by choosing to do fuel injection.
I have this list of sensors (from howstuffworks.com) :
# Mass airflow sensor - Tells the ECU the mass of air entering the engine
# Oxygen sensor(s) - Monitors the amount of oxygen in the exhaust so the ECU can determine how rich or lean the fuel mixture is and make adjustments accordingly
# Throttle position sensor - Monitors the throttle valve position (which determines how much air goes into the engine) so the ECU can respond quickly to changes, increasing or decreasing the fuel rate as necessary
# Coolant temperature sensor - Allows the ECU to determine when the engine has reached its proper operating temperature
# Voltage sensor - Monitors the system voltage in the car so the ECU can raise the idle speed if voltage is dropping (which would indicate a high electrical load)
# Manifold absolute pressure sensor - Monitors the pressure of the air in the intake manifold The amount of air being drawn into the engine is a good indication of how much power it is producing; and the more air that goes into the engine, the lower the manifold pressure, so this reading is used to gauge how much power is being produced.
# Engine speed sensor - Monitors engine speed, which is one of the factors used to calculate the pulse width
Do you need them all for a Fuel injection system? Dom only listed a couple that you need when I asked before. Can I rip sensors out of scrap cars, or is it worth buying them new/off ebay. Will an Oxygen sensor from a Mondeo/Bentley/Charade be suitable to use in another car, or are they sized ... ??
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Most standalone stuff (Megasquirt/emerald etc) will work on: Water Temp Engine speed (Crank trigger) Throttle position Ambient Air Temp (Possibly) MAP sensor will be needed if Turboed/supercharged Oxygen sensors are useful for tuning but not needed in a lot of systems. As I understand it, Wideband oxygen sensing is one of the best methods of realtime mapping, hence why its the latest Buzzword ;D OEM stuff requires many more sensors, as they have to comply with all sorts of weird emmissions drive cycles, like running incredibly lean on cold start to light off the CAT, doing that, the ECU requires a greater knowledge of whats going on, hence more sensors. They also have knock sensors which are generally a good thing and used to retard the ignition if detonation is detected. Most of this has come about because to meet current emmissions regs the engines have to run so close to detonation, that you then need some means of controlling that, you cant get away with putting more fuel in on an OEM vehicle like we can on standalone. The ClubGti FAQ`s have got a great "Cheap" ECU thread, just to confuse matters further ;D Got me thinking where can I find Software to remap Bosch and Mag-Marrelli ECU`s ;D HTH Dom EDIT: Whichever ECU provider you decide on will specify the sensors you will need, they are pretty common, most of the differences is in Plugs for different manufacturers. There are only really a few Sensor suppliers, Bosch, Nippon Denso, Valeo, visteon and they all do the same job. Resistance or values vary sometimes. New is nice...... scrappy is usually a lot cheaper, or more to the point, you can raid 3 or 4 cars worth of sensors for the cost of 1 or 2 new. giving you spares or a variety of different values to play with. HTH Dom
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Last Edit: Nov 9, 2005 10:46:38 GMT by CR500Dom
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I've got a copy of Dave Walkers Haynes Fuel Injection book here somewhere, a freebie when I subscribed to CCC once. It's well worth reading if you can get hold of a copy! Even I could follow it ;D
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Need to get the book, thats for sure.
So whats the deal with sourcing sensors?
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ImpManiac
Part of things
Imps... Imps... Imps...
Posts: 868
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I found the following link useful: hometown.aol.com/dvandrews/Dave Andrews' page gives loads of interesting and useful information about setting up Weber and Dellorto side draft carburettors and EFI too, including factory type Lambda feedback running, etc. I don't think it goes into wideband O2. As has been said, WB-O2 is a very useful tool for tuning engines, including carburettor-equipped units. I bought WB-O2 for the Imp because I plan to invest some time getting the Weber DCOEs running just right. For that, you need exhaust gas measurement (e.g. on a rolling road) and data logging on the road suits me better than paying out for rolling road time. Lambda sensors need to operate within a narrow temperature range. WB-O2 can operate at almost any temperature as it has a controller that not only conditions the signal from the sensor but also heats the sensor as well. Another type of sensor is the camshaft position sensor, necessary for sequential port fuel injection. Hope the link proves useful. I'm
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1966 Singer Chamois sprint/hillclimb car in white over blue two tone 1975 Triumph Stag long term project (over 20 years so far) in colour TBA 2003 Vauxhall Vectra GSi 3.2 in black sapphire
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I might be preaching to the converted here but the megasquirt site is excellent for this kind of information. Its a bit biased towards the MS but the information is the same no matter what system you use. The forums pretty cool too. www.bgsoflex.com/megasquirt.htmlWith regards to using bits from other cars, as long as they operate within the right parameters you shouldnt have any problems. I know with megasquirt you can actually alter the ecu's code to suit the sensors your using.
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Last Edit: Nov 9, 2005 17:29:11 GMT by rustingdeathtrap
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If you are running a set of throttle bodies (as opposed to a single and plenum) then I guess you wouldnt need a MAP or MAF sensor as you are running. So as Dom says you would just need Water Temp, Engine speed and throttle Pot.
A mate of mine has done a few now using emerald ecu`s (the first he did was about 8 years ago on his Fiat Uno rally car) and thats all he normally uses. He uses a boss welded into exhaust for fitting a Lamda sensor when setting it up, starting from full load through the range and then going through the part throttle positions. He says the emerald software is a doddle to use.
Normally carbs have no sensors to help with fuel flow so a simple system like this can easily be as powerful as a good side draft setup and still be more fuel efficient.
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if you are running ITBs then you would normally use Revs (for speed reference) and Throttle pot (for load reference) as the two for your maps
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***There are few of life's problems that can't be solved with sufficient application of High Explosive***
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John
Part of things
Posts: 347
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My Weber Alpha set up use individual throttle bodies, throttle pot, crank position sensor, water temp, and air temp sensor. Inlet pressure sensor is optional for boosted setups.
If I inject another car I will look at the Mega Squirt unless I am seriously minted then Motec will get my cash.
John
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