Jump to content
Click here if you are having website access problems ×

Throttle body airflow and accelerator sensor setup


anthonym

Recommended Posts

far as I know the airflow is the same and the other part is setting the TPS where memory fails me.

note to self from http://www.emeraldm3d.com/faq

Throttle pot recognition: how to tell which wire is which?

Any Throttle Potentiometer (TPS) has three wires - which are:

+5v

Signal

Ground (GND)

Disconnect the TPS Sensor and work on the TPS sensor plug – not the wiring harness plug.

Using a resistance meter (automotive multimeter) find the two wires which do not vary their resistance when you move the TPS spindle.  These two wires are the +5v and GND - you just don't know which way round they are!  To determine this connect either one of the +5v/GND pair to the remaining wire – which by default must be the signal wire.  Note the resistance value you see and operate the TPS spindle.

If the resistance value INCREASES as you operate the pot then the wire you are working with is the GND
If the value of the resistance DECREASES as you operate the pot then the wire you are working with is the +5v

Emerald ECU connections are:

+5v = pin 9

0 = pin 30

signal = pin 8

If your engine is using independent throttle bodies it is vital that they are well balanced.  The most useful tool is a synchrometer (small air flow tool that you just hold into the trumpet with a needle that indicates air flow on a 1-10 scale) - they're useful for both carbs and throttle bodies so you may already have one or have access to one (if not, the old pipe to the ear trick is fairly good!).

Link to comment
Share on other sites

You'll want an air flow of some 5.5 kg/h per cylinder at idle (1000+-50RPM)

Later I'll see if I can remember to upload the guide to my server. I'm in the garage at the moment and don't have access.

 

Link to comment
Share on other sites

  • 4 weeks later...

The latest question is whether my having set the TPS has caused my emissions test to fail by ten timesthe HC limit. 

What is unclearis whether having done this without reference to how it was set when the maps werecreated, mean# all the maps are out.

It is realeasy to do. Whether it was wise remains to be seen.

 

Link to comment
Share on other sites

My understanding is that high HC readings are caused by 1 of 8 things.

 

Poor spark.

Ignition timing too advanced (linked to cam belt change?)

Lean air/fuel ratio too much air, not enough fuel. Faulty lambda?

Very rich fuel/air ratios- too much fuel, not enough air.

EGR issues - not relevant here.

Engine issues - cylinder sealing, low compression, valve timing.

Faulty cat.

Restricted or plugged injectors.

 

I would be looking at my valve timing as the cam belt has recently been changed as my first step.

Link to comment
Share on other sites

There is a crib sheet on the Emerald website on how to align the throttle pot, it takes no more than 30 seconds once the  ECU is connected.

Once this is done the origin of the map and origin of the TPS are in sync. As is the throttle progression.

In my experience of 100s of Emerald equipped engines the high HC is most likely rich fuelling, it’s a fully programmable ECU, just lean it off a little at the load and speed sites where the test is done.

Unless your cam timing is an absolute mile out it will have little effect on HC on an Alpha-N system like the Emerald.

Oily

Link to comment
Share on other sites

Anthony, I believe you recently fitted a switch to allow you to switch between maps, and you confirmed on your laptop that it was switching between maps 1, 2 and 3. Are you absolutely sure that the map you are running on now is the same one that was selected by default before you fitted the switch?
Link to comment
Share on other sites

  • 3 weeks later...

MAP - Manifold Absolute Pressure. More sophisticated way of measuring engine air demand. Throttle, engine speed, temperature all affect the density of the air in the intake system. Density and engine speed give you a pretty good measure of the mass of air the engine is swallowing per second and therefore how much fuel to inject etc. In your case as you have separate throttle bodies and no plenum, the ECU uses a simpler / cruder approximation based on TPS to estimate load (on my car for example the TPS is used to detect closed throttle and rapid throttle movements but is otherwise ignored by the ECU whereas on yours it's the key input).

IACV - Idle Air Control Valve. A small ECU controlled valve that bypasses the throttle and let's the ECU modulate the idle speed directly. Again as you have separate throttle bodies you can't really run an IACV. Instead your ECU just has to set conditions that should give you a sensible idle and then you get what you get (or possibly it modulates the idle speed by managing the ignition timing only). Possibly more important in tintops where there a lot of other things that can load the engine at idle and need to be compensated for by the ECU such as electrical loads, power steering pump, air conditioning.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...