E30M30: No Power at ECU pin 18

[AndrewGood]

I can't figure out how to post the photos, so I'll just post the links:

http://s614.photobucket.com/user/AndrewGood1/media/2015-07-27%2010.59.21_zpse24xc3to.jpg.html?sort=3&o=0

http://s614.photobucket.com/user/AndrewGood1/media/2015-07-27%2010.58.28_zpsof1hulus.jpg.html

I am definitely getting fuel while cranking, but only when the bundled-red wire splice is connected to the battery junction. I have a new FPR coming in the mail now.

[EatsHondas]

Looks like you're missing at least one cable at the junction. You need everything in this picture except the random red one.

[AndrewGood]

Ok, so in your photo I see the main battery cable and the fusible link wire coming from the left-hand side of the picture. I have those already hooked up. I also have the fusebox power cable hooked up to the battery junction (it splits off into two connectors, which I have connected to the same terminal). I count four wires connecting to the junction in your attached photo other than the main battery cable and fusible link wire. Is that right?
Also, I do have all four wires connected to the starter motor.

The FPR is actually ok-- the ring clamps were just loose and fuel was seeping out from the hose.

I'm trying to figure out where the bundled red-wire connector goes to. It certainly needs to be powered, and it is definitely related to the main relay pin 87, but when I hooked it up to unswitched power from the battery earlier, I just burnt off some insulation on the wire running to pin 87. But there's nothing else nearby that it seems like it could be going to. It certainly seems like it's supposed to go to the battery junction block. I've tried to search for what this connector is, but surprisingly I couldn't find anything. I can post a photo of the connector I'm referring too if needed.

Another thing I thought I should mention: I'm turning the car over via the ignition switch itself. My key broke off in the tumbler, so I'm just directly turning the ignition switch. I'm not sure if this changes anything, but I thought I should mention it.

[EatsHondas]

Yes that's right. You also have a dedicated ground strap for the engine right?

Good news with the FPR, glad it wasn't bad. Now you have a spare.

Yeah can you post a picture of the connector you're talking about? I don't recall having to reposition anything like that.

I don't think the ignition situation would cause you any wiring problems.

[AndrewGood]

Yes, I do have a dedicated ground strap for the engine-- I have it going from the oil pan to the frame rail on the driver's side. It isn't the factory ground strap though, so there's a possibility it isn't functioning properly. I'll post photos of the connection I was talking about in just a second.

[AndrewGood]

Here's a photo of the connection I'm referring to.

In case the photo doesn't work again, here's the link:
http://s614.photobucket.com/user/And...kkgo6.jpg.html

[AndrewGood]

Might be on to something here. I finally decided to cut off every last bit of shrink-wrapping on the harness so I could follow all wires. I am pretty sure that the red-wire connector that has been in question is the power supply for the main relay. However, when I hooked up this connector, I short-circuited and burnt the insulation of a wire to the main relay. This wire was red/yellow and went to pin 87 on the main relay. Now, when I looked at the wiring diagram EatsHonda posted, I saw that there is a red/yellow wire running from pin 87 on the main relay which goes to the ABS system. I am positive this is the same wire I fried. Now my E30 was used as a track car by the previous owner, so I think my ABS might be disabled in some shape or form. If this red/yellow wire is getting 12V, but isn't being put under load (because ABS is disconnected in some shape or form) then that could cause the short-circuit right? Because when I had the red-connector hooked up to the battery junction, I was getting fuel, so clearly this connector is powering the relays. I don't plan to have ABS anyways, so can I simply remove this red/yellow wire from the main relay and harness?

[AndrewGood]

Made some huuuge progress today!!!:D:p:D

I went ahead and cut and removed the red/yellow wire that runs from the main relay pin 87 to the ABS System (this is the wire that had been short-circuiting and burning). I then reconnected the relay power supply wire to the battery junction block. I tried turning the engine over again, but it still didn't start up. However, I am definitely getting fuel-- I'm positive of this.

I then decided to follow JLevie's diagnostic guide again and was astounded by the results!

-With the key on, I have 12V at pins 27, 18, and 37.

-I have confirmed continuity and 0V at DME ground pins 2,14,19, and 24.

-I have verified continuity from DME pin 1 to coil negative, and have verified that DME pin 1 to ground is an open circuit.

-This is the only area where I had an issue, but the previous time I followed JLevie's guide I got the correct values here At DME pins 47 & 48, I wasn't able to get 500-560 Ohms, I tried different ways of hooking up the multimeter, but only was able to get "OL" (Overload on the multimeter).

-I confirmed continuity from DME pin 36 to Main Relay pin 85 and from DME pin 3 to Fuel Pump Relay pin 85.

-With the key off, I confirmed 12V at DME pin 18 and Main Relay pins 86 and 30.

-With the key on, I confirmed 12V at DME pin 27 and pin 18.

-Again, no voltage at DME pins 2, 14, 19, 24.

-12V at coil positive and 12V at fuel pump relay 30.



If you follow along with JLevie's diagnostic guide, you will see that I have the correct values for EVERY SINGLE STEP except the correct amount of resistance at DME pins 47 & 48.

Is my issue now related to the CPS? I literally installed a brand-new CPS yesterday (bought on ebay), so I doubt the CPS itself is faulty. I tried starting the car twice and switched the plugs between the CPS and spark sensor as I know this is a common mistake, so I'm now trying to think of other possibilities. I am definitely close-- I made it through the entire diagnostic guide besides the step referring to DME pins 47 & 48. Also, I am getting fuel now, so I hopefully am a short step away from starting her up!!!

[EatsHondas]

Yes 47 and 48 are for crank position. What brand of part did you buy? Non-OEM can cause problems. You need to be able to see that specific resistance.

[AndrewGood]

No I bought it on eBay, I'm gonna install the old one and try again

[AndrewGood]

I swapped the old CPS back in, and am still getting infinite resistance at pins 47 & 48. Am I testing it correctly? I just have been plugging the positive cable of the multimeter into the pin, as JLevie's guide says neither pins need to be grounded. Could I possibly have two bad CPS's? That seems unlikely...

[AndrewGood]

I tested the CPS directly at its plug and got 540 ohms, which was within the acceptable range, so I must have an issue with the harness side of things. I followed the black wire running from the CPS plug and saw it led straight to the DME, and the wire looked to be in good condition. I bought this harness recently, and it is in very good condition. I followed the wire until it was actually going into the dme connector.... any ideas for what to check for? I was thinking about trying to open up the dme connector to see if there's an issue with the pins themselves, but I wanted to check online before getting into that.

[AndrewGood]

Ok, so I went ahead and pulled the dme connector apart so I could look at the wiring for pins 47 & 48. The pins looked a little loose so I just pressed the wires in a little tighter and bam! getting 560 ohms on the multimeter.

I decided to follow the full JLevie guide one more time before trying to start her. I got the correct values for every single part and yet... still no start. Any ideas for what to check next? I'm getting fuel, and I'm going to check spark in just a second.

[EatsHondas]

Are you getting spark?