Hi John,

Pin 59 is power to the ECU when the air conditioning is on The affect of this is that the idle is bumped 200 rpm or so. You could wire this in when the cooling fans come on or you could ignore. All this power source does is tell the ECU that the air conditioning is on and that the idle needs to be bumped.

Sweet! I knackered the pin trying to get it out, only the wire came loose, so I can get another wire up there and use as you said, for cooling fan idle up.

99Super wrote:Sweet! I knackered the pin trying to get it out, only the wire came loose, so I can get another wire up there and use as you said, for cooling fan idle up.

I'm pretty sure the idle will correct itself via AIC and ignition timing if the only demand is the cooling fan. With A/C, the compressor and both fans can all come one at once creating a load spike on the engine. Worst case add the power steering pump and brake light load. (daily driving stuff)

I'm not rocking T5, but my setup I utilize the factory thermo switch on the radiator to to switch driving one relay to kick on fan 1. My ECU has a second output to drive relay/fan 2 when the engine coolant temp is at an even higher temperature. Dual stage if you will and no stumbling issue because there is not a large load spike, but a step load.

I won't sweat it then. I run a single fan off the radiator thermo switch and the second off a dash switch.

when i deal with c900s, i generally use the speed sender for the cruise control behind the dash, no idea where to pull from in a 99.

the last wire for the CPS goes to the middle pin of the 5.5 CPS plug, this is a the reference ground,

It appears that the sensor reference grounds just go to ground on the block. I tied the 5.2 CPS to the same ground bundle as the 5.5 and grounded pin 36 there as well. I have it all wired and have been checking all the connections today. I still need to hook up the fuel lines, but I think it's ready to turn over.

OK, So it's all wired and I tried turning it over w/ an un-modded 5.2 box. CEL is wired to a dash LED.
On first power-up, the CEL lit, the Fuel Pump came on for 3-5 secs, stopped and then the CEL went out.
Just like it's supposed to. No start (my battery is a bit low and wouldn't crank long).
I let the battery charge a while longer and tried to start but now the fuel pump doesn't come on.

I'm done for tonite.

John

If the fuel pump runs then your relays are working. The ECU will not ground the fuel pump relay after the initial prime unless it gets a signal from the CPS.

Can you plug your PC in and monitor while cranking? You will know immediately if you have CPS signal. Since I was running T5.2 I tested it before I installed the motor in the car.

I would verify power & ground to the CPS and signal to pin #40.

Also, if you moved any pins in your connector (which you should have), be sure you open the wings back up on terminal to lock it in place. Most faults I've seen are from loose terminals that push out when the connectors are plugged in.

I haven't had a chance to diagnose anything since last night. I suspect I have the reference ground wired wrong. Can I get a confirmation of where that is supposed to go?

MikeD sez: "the last wire for the CPS goes to the middle pin of the 5.5 CPS plug, this is a the reference ground"

Well that appears to just join the ground bundle and go to chassis. Where *exactly* does the reference ground tie into the system??

Just to confirm, you said you are using a stock ecu, all the stock US 5.2 cars had TCS, which did not use a normal throttle body or TPS. I think jordan said they will run, but barely as its not getting any input from the TPS... You need to reflash to a base map from a european 5.2 without TCS...

OK, I was hoping I would at least get a start. I guess I get to check and re-check wiring until I get my ECU.
Now, if Jordan needs to test his 5.2 bin file, I'd be happy to send him an ECU to flash!

You want my bin? it's running pretty good. Started with the non TCS 5.2 bin that's in T5 Suite. PM me your E-mail

Yeah, the car I fired on on the stock 5.2, started right up although it didn't idle or respond very well...it also ran very rich.

Either way, I'd flash you an ECU or try jskrebs tune if you can flash your own.

I thought it was possible to flash a 5.5 ECU with a 5.2 tune by concatenating two bins together , but I haven't done it before.

The reference ground is different depending on which harness you have I believe. Or at least I have seen a few variations. Sometimes they are bundled with the main ground wire, sometimes it is generated from the ECM and shared to all the sensors, which is the preferred method for clean signals.

In theory you want your power carrying wires, separated from your low voltage signal wires as they can crosstalk and effect readings. Most don't have a problem having them all to chassis ground though.