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Reliably running a K24 engine OUTSIDE of a car

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#21 ·
yes, you need the female part and wire it according to the Doctronic schematics for wideband ECUs. In Europe at least, Doctronic sells the E, C101 and the lambda connector.
Or cut it off and wire in any other connector you can source. But I prefer to keep the engine loom as OEM as possible.
 
Discussion starter · #22 · (Edited)
Am I correct in understanding that the C101 and E terminal plugs should be wired on the 85 relay terminal? Isn't this usually a ground and should not be connected to anything but star earth point?

And shouldn't terminal 30 for the main relay be connected to the constant 12V supply, i.e. the battery? In the diagram it's connected to terminal 87 which I thought was an output, not input.
 
#23 · (Edited)
see page 2 of the Doctronic schematic pdf a few posts up.
The only ground you connect is from battery to the engine block and the engine loom with its ground strap to the cam cover or OEM intake manifold. No other grounds are used that you have have to route.
Then you feed battery 12V to the main relay switch input. The main really then provides "switched 12V" to the C101 once activated by the ECU.
You can skip the brake pedal switch. If you use a Hondata or Doctronic ProK ECU, as you can disable this function.
Ihr ECU sees ignition 12V from your ignition switch to E9. this then triggers the ECU to activate the main relay. This then powers the starter relay and the fuel pump relay.
The starter trigger is an other switch than then triggers the starter relay though C101 Pin 16.

It is really not complicated wit the doctronic schematic page 2.

For RPM, you can hook up any rpm gauge. The frequency output can be adjusted in the Hondata or Doctronic ECU.

30 and 87 are interchangeable on a relay. The Doctronic schematic states no numbers BTW. It just shows the switch portion of the relay. There is no polarity unlike with a solid state relay.
 
#24 ·
Lotus said:
PRA, PRB and PRC are K20 types.
if you are not competent in these type of electrics, I suggest you get a K20a2 or K20a (missing VTP sensor) engine loom such as one from an RSX-S and the ECU with it. Then it all works as in the pdf. Easy as thant and no engineering required.

If you attempt to reinvent the wheel, you need to sort it out itself. I don't have any other schematics than the RSX-S and the cars I put the engine in, i.e. a MK1 Lotus Elise or a S3 Lotus Exige.
I don't understand half the model designations in the USDM either, such as Civic Si etc. as we in Europe get them with a different name or don't have these K24 engined models at all.

I recently helped to drop a K20a2 into a 2004 Lotus Exige originally using a Toyota 2ZZ engine. The MWR conversion harness was next to useless for a european spec PRA ECU and on top of it, was not well thought through even for its original application on US spec PRB looms and US spec cars. It took me about 3 full days to document each an every cable to the ECU, the conversion loom and how the Toyota loom works, coming up with a schematic and rewire everything. And I roughly know what I am doing. If you are not into it, I'd say don't try or take your time.
PS are you sure the knock sensor signal runs though the C101 connector? why should it? These run straight from the sensor to the ECU though the engine loom.
Click to expand...
Lotus I attempted to send you a pm about your experience with the MWR harness. I will be doing a K-swap in an Elise also.
May you can PM me?
 
Discussion starter · #25 · (Edited)
On the last page there's a legend of the relay:

104436

Is it up to me to wire 87 and 30 for the fuel pump and fan relays? They are not connected to anything on the diagrams.

I'm trying to make this adapt to a test stand that is already pre-wired. However, this is prewired toward carbureted engines and not EFI. I have the schematics of that I could PM you if you would be so kind to look over.

I think I'm getting there. I have the parts on order and will inspect everything to see if I can figure it out.
 
Discussion starter · #27 · (Edited)
Here's my quick wiring diagram I edited that I currently have. Can anyone double check it to ensure I have everything correctly? Nothing has fried, so I think it's good... Fan, pump and starter all work; ignition reads as "on" in Kpro manager software. It turns over, fuel at the rail (was actually 5/16" EFI coupler, not 3/8").. but I forgot to change my throttle body from DbW to DbC. I ordered a Honda Accord 04 throttle body on Amazon that will come in a couple days. Once I hook up the MAP and TPS, I hope to the car gods that this thing runs!

104523
 
Discussion starter · #29 ·
The wiring for the fan and fuel pump switch were already done previously with the Easy-Run test stand, so I just wired the power and ground to the pump and fan. Would this cause problems with the ECU for the fuel pump? I figured since it was an OUT plug, that the ECU didn't need to detect if the pump was running or not, just if there's pressure at the rail.
 
#30 ·
No, but the ECU controls the fuel pump relay. It primes the pump for 3 seconds or when the engine is running . E1 is an out pin to control the fuel pump relay. Same for fan. You could run switch and ECU in parallel, if you want. Switch needs to ground the control line. Or be open
 
Discussion starter · #31 ·
I received the drive by cable throttle body, hooked up the TPS and the MAP, received an IAT and hooked that up too and still the engine will not start. Is there something wrong with my wiring? Are the injectors on a K24A wired differently than on the K20? Please advise!

For what it’s worth, when I press the start button the crank the engine, the Kmanager software displays the Ignition as OFF, but when I release the crank button, ignition is ON again.
 
#33 ·
The starter needs several amps of current. Are you sure your 12V supply is sufficient to drive the starter switch? Could be your "switched power" voltage drops so much while cranking that the ECU switches off. Normally this current is delivered though a dedicated starter relay with direct battery feed.
The ECU has no knowledge of the starter doing anything except of detecting the engine spins. There is no other connection that the supply voltage.

A resistor from switched 12V to E7 would simulate a main relay being present. It also provides power in the ECU for the memory storing the DTC codes.
Could be it is needed, but it would then not show "on" in the KManager.
 
Discussion starter · #34 · (Edited)
I wired the starter button directly to the 12V post of the battery and to the C103 terminal. Even with this, the ignition still displays OFF when cranking. I've noticed though, that when I turn the Fan relay switch or the fuel pump relay switch on, the ignition will also display as OFF.

I played around with the CKP sensor wiring to ensure that I didn't have it wrong when matching the K24 vs K20 wiring. Ignition will be OFF if any of the wiring of the CKP is incorrect, so that was somewhat reassuring.

Do I need more power to the C101 - 9, 14, and 20 wires that I have connected to a shared fused power distribution rail (this rail also shares the fan and FP relay power)? Will the ignition still be displayed as OFF with no fuel to the injectors? I also obtained the Hybrid-Racing Universal Harness Adapter, and tried wiring a bit, but couldn't even get the ignition to say ON, so I went back to my setup. I believe I have everything I need to get this engine running, I just can't figure out the electrical. I was considering just putting the three power wires directly to 12V, but I didn't want to blow anything up.
 
Discussion starter · #38 · (Edited)
It's very odd, when I try to click the datalogging it gives me an error (something about calibration, forgot at this moment, will capture and get back) then the timer will start. When I press the starter button to crank, the timer turns off and I get a snapshot I believe of the engine pictured here: Hondata 4.4.7. I just go to file > new > [RSX (type-S) - PRB) > TSX-04-05 stock.kal. Am I missing any steps?

104535
104536
104537

104538

104539
 
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