cannot seem to get ECU to power on.

[washingtonracer]

Alright, I finally finished majority of my wiring. And over this past weekend I attempted to power on the ECU. But to no success. I Tried every com port option. Still nothing. These are the wires I have hooked up. battery +, 12v switched "running through relay, relay gound going to chassis groung, Relay positive going to 12v switched source. Analog/Digi Return, and 3 Pgnd wires are all grounded to Negative side battery. all sensors are connected. Only wires I have not attached to anything is Cam/Crank, Fuel - fan - , Am I missing something here? Is there anyone here in Washington that I could come visit, and have you guys test my ecu in your car?? I could provide a Case of beer if needed?

 

[Glen]

washingtonracer said
12v switched "running through relay, relay gound going to chassis groung, Relay positive going to 12v switched source.

Based on your discription of your relay wiring, I don't see where you went from relay to ECM, is this an omission? Any it should look like this.....

12V battery (+) constant
12V battery (-) constant
12V switch (+) to energize the relay
12V from relay to ECM

I don't know which relay U R using, but most have a diagram on them telling you which terminal is which. If you insist on running a relay on this circuit get an electronic relay.


You really don't need the ECM 'switched 12V +' to go thru a relay. Any switched source with run and cranking will work. The ECM fuse from the fuse panel is a good source for this.

 

[10SV6]

What kind of computer and operating system are you using ? I had a friend's car have a real tough time getting a Dell with XP to connect.

 

[washingtonracer]

The relay I am using is connected per instructions by Highpsi, anyways I cannot recall which pin on the relay is going to what, Perhaps I should go back and revisit this, or better yet, go get a wire tester, and make sure power is reaching everything. I have the 12v switched from ecu, chassis ground, 12v source from car and accessory wire which is going to the injector harness. those are all connected. "again I just don't recall which wires are going to which pins on the relay, but I am pretty sure it is correct. "I will double check after I write this. I have tried both the C-com software supplied with the ecu, "DOS based" and the windows based version. Both of which say Deminstration version. Now the C-com dos version does say sefi, I have bank to bank is this of any concern? I am also using windows 98.

 

[10SV6]

If you can get access to a DOS boot disk, boot the computer directly to DOS, then try running C-com from there. My friends car did the same thing you're describing. Only difference is that his car was running and I'd baselined it from my laptop, so we knew his computer was the problem.

You've tried the F2 key in the DOS version and the connect click from the Communication pull down on Win ?

 

[Craig Smith]

I don't think the problem here is that the ECU isn't being powered up, just that it's not communicating with the PC. I would check and make sure the com port you are trying to use is enabled and working correctly. You can check this in the device manager. Right click on the "My Computer" icon on your desktop, select properties, and then click the device manager tab from the window that pops up.

 

[washingtonracer]

well I did check the com port, it appears with no conlifcts in the Device Manager. I have not checked to make sure it is open through the Bios, however I would think that if it was disabled in the bios, it would not appear in windows. But then again this is Microsoft were dealing with here. I honestly think at the moment thats it's my relay going to the 12vswitched for the ecu and injector harness. Any pro's out there that know off hand which wire should connect to what pin on the relay, like ecu "L3 to pin 86 on relay, pin 87 to injector harness, pin 30 gnd and pin 85 to 12v switched source, something like that?? by the way that probabily is no way near what the wires are supposed to go to, I was just giving an example .

 

[Greg Kelley]

There are a lot of different ways to use (and mis-use) relays. I use this layout that I got from MSD's WEB site.

For powering a device (like a Fuel Pump)

87 -- 12v+ source (large gauge wire)
86 -- Ground
30 -- to your device (Fuel Pump)
85 -- to your switched 12v+ (Fuel Pump toggle)

 

[Roland Black]

hey Aaron;

Perhaps when we get together, we should do so at your house. I'll have my laptop we can try, and if no success there, then we can swap out ECU's for a test. Besides, I'd like a peek at the TT406 ;-)

Saturday is BOP @ Bremerton which I will be at (minus Syclone) but any other DRY day will work. Let me know,

 

[washingtonracer]

Thanks Roland, I actually have an autocross to go to up in Canada this weekend, So I will be out all weekend too.

Okay, So from what everyone is saying, there should be a constant 12v power going to the relay, along with a switched 12v power too?

If so then A: thats where I am wrong. Unless I have the idea of the 12v switched wire for the ECU backwards, Right now I figure that it's supposed to recieve 12v when a switch is turned.

for the relay as of Right now, I have Just a 12v switched source feeding power, A ground, and 3rd prong connected to the injectors, 4th prong connected to the ecu.

So how about this Senario. Should there be 1 constant 12v power going to 1 prong. 1 ground going to 2nd prong, 1 12v switched going to 3rd prong, and accessory "ECU" going to 4th prong. In the line to the ecu, I would splice in the injector power feed. It seems like thats the way it should be, I just now need to fina a schematic for the relay. or go take a peak at one in the store that has the schematic on the box still. Secondly Shouldn't the injecor line be fused with a lower amprage?

 

[washingtonracer]

Quick Confirmation, would this be correct?

87 -- 12v+ source (large gauge wire)
86 -- Ground
30 -- to your device (ECU/Injector harness)
85 -- to your switched 12v+ (Ignition Switch)

 

[Roland Black]

Yes, that is correct. Think of the relay as a two part system. Side one is when the ground sees 12v switched (as when key is turned on), it then energizes the relay which allows side two, the main 12 volt feed to go through the relay to your source, in this case the ECU. This allows you to have a small insignificant size switched 12 volts to the relay, and can run your #10 from battery to your relay and then out to your ECU. When the switched side is turned off, the relay is de-energized. A relay is only needed on the main power source. The bottom side of the relay should have the terminals marked as to which is what.

If things aren't better next week, give me a call..... 425 641 7648 and we'll see what we can set up.

 

[Glen]

No, that isn't right if your are using the Bosch SPDT 30A or 40A Relay.

30 -- Battery 12V (+)

86 -- Ground (-)

85 -- switched 12V (+)

87 -- ECU

This is straight from Bosch and as depicted on the relays. I am still cornfused as to why you want a relay in this circuit, and why you would not want an electronic relay if you insist on using a relay. Ford had a ton of problems doing this and using a Bosch relay similiar to this one. GM uses a BigFkin MAXI Fuse for this circuit.

 

[washingtonracer]

Alright, after a worrysome week, I screwed with the relay wiring for a bit, And FINALLY I got it to work. So problem solved. I was able to go in and to some inital configuration. it looks to be ready to go in the car and I will be able to start my engine up.


Some side questions though. I read earlier that Silicone will ruin a WB-O2 if it smells any of it . So will a standard 0-2 connect to the same connector in the meantime while I let the engine do an inital breakin? how does one go about breaking in a new engine when running this sort of injection.

 

[Glen]

No. Not where the wide band plugs into, but, you could use a standard O2 and use a dvom to read it. As for break-in, it is the same as a carb but you just have to get your tables set first. Run it in open loop and make adjustments based on the narrow O2. BTW, the majority of silicone sealant, quality stuff, is O2 sensor safe.