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Re: Project 4ktq update
Todd Phenneger writes:
> [ KH engine install in 4KQ ]
> On the list for this weekend is to get the downpipe in and install
> the CIS system and wiring hooked up. The under dash wiring is basically
> done except for the light to pull the codes. (I'm ocnfused on this) I
> though I just needed to wire the wire into a light socket like the OXS
> light since its disconnected on my car. Then use the fuse to plug into
> the relay to flash it. But there has been talk of needing a seperate
> Intermittent switch to do this. why do i need this???
If you're running the KH engine ECU (MAC-07A) then the code dumping
stuff is very different than the MC engines. The tachometer and
the "check engine" light are the display for this, and the brake
pedal is the control.
On the KH with MAC-07A:
1. Start engine, run until warm, hopefully with boost.
2. Close both the full throttle and idle switches for at least 3 seconds.
This sets the ECU into fault memory dump mode. The tach should read
7000 at this point and the check engine light should be on.
3. Press brake pedal once.
4. If there are faults, the tach will indicate anywhere between 1000
and 6000 and the check engine light will be on or off. You look this
up in the table below for the fault. If there is no fault, the tach
will indicate 7000 and the check engine light will go off. You can
switch off ignition to exit the diagnostic mode.
5. Loop back to step 3.
Here is the fault table:
Tach CE light Sourc
--------------- --------------- --------------------------------
1000 Off RPM sensor
1000 On Knock control
2000 Off Ignition timing sensor
2000 On Knock sensor
3000 Off Hall sensor
3000 On Intake air temp sensor
4000 or 6000 Off Vacuum hose from intake manifold to ECU,
or short circuit in idle switch or wiring,
idle switch stuck.
4000 On Coolant temp senser
5000 Off Pressure sensor in ECU
7000 Off End of diagnostic sequence
7000 On Beginning diagnostic sequence
The Bentley manual for the 84+ 5000S/T/TQ has more details about this.
What this all means as far as wiring is that the tachometer on
the KH (and MC) cars are connected to the ECU, as opposed to the
ignition coil as on the 4KQ. I don't know if the 4KQ tach can be
re-wired to the MAC-07A ECU and read correctly, but you can try.
Also, there is a wire that runs from the MAC-07A to the brake light
switch you need to add to make this all work.
You really do need to study the wiring diagram of both the KH cars
(84/85 5000S turbo) and the 4KQ carefully and make sure you got all
the details worked out.
96 A4 2.8 quattro
84 5000S 2.1 turbo
80 4000 2.0
/// Ti Kan Vorsprung durch Technik
/// AMB Research Laboratories, Sunnyvale, CA. USA