TheGloriousTachikoma

So while Lucy's cooling system is apart I decided to take off the OMP and clean it. Very long story short it hasn't been pumping oil for awhile and I decided to try and find out why. So following the steps of the FSM, the motor itself is within spec (22.5 ohms all four ways). Next step is to test the harness voltage. Okay, battery charged and hooked back-up. Key on, and I test the two indicated terminals on the harness plug for voltage back to the battery. 0.11v for both of them. What does the FSM say to do in this case? "Repair Harness". ...Okay...

Before I start cutting off the harness wrap, where can I expect this to end-up? The FSM and Haynes manual don't show the OMP on any wiring diagrams (that I could find), and unfortunately I allowed my wiring diagram book to...be destroyed by the weather. Or am I doing something horribly wrong?

I don't mind premixing. But I wouldn't mind not premixing even more. If this turns out to be a fruitless endeavor, the engine just has to last another year and premixing for that period isn't daunting.

Thanks for the time.

dwb87

iTrader: (22)

I'm going to assume you're referring to a series five N/A.

You can expect the electric MOP wiring to end at the ECU. Pins 2I (BR/W), 2A (G/B), and 3D (BR/B) to be exact. If you're looking to replace the wiring... You can depin these wires at the ECU and replace them with new wires that run all the way to the MOP, and replace the female harness pin connectors at the ECU plug. (If you're able to find them.) - If not, you can thoroughly splice the new wire onto about two inches of the old wire coming from the harness plug.

1989 FSM: Lubrication System <- Notice the electric MOP plug with each wire color, wire position, and pin on page D-18 near the bottom.

Also, after you replace the wiring and reinstall the MOP, you may want to premix for a couple hundred miles. This is to ensure that you're getting the much needed lubrication that may not be there right away from removing the MOP and associated lines temporarily. It takes a bit to rebuild the oil pressure through the MOP lines.

TheGloriousTachikoma

-The FSM doesn't indicate if/where the 12v comes from for the OMP. Both 12v wires are equally dropped at the connector. The harness is a little knarly, so I cut the wires down at where they emerge from the harness and still @ .7v. I suspect I'm going to find continuity between the ECU pins and SM1/2/3/4, so my question is where the 12v source comes from.

-I'm dissecting the harness (mainly because I have to integrate the signal wire for my new coolant temp gauge and easiest way is to run it into the cabin via the harness). Does the 12v for +B on the OMP connector originate @ 2I, 2A, and 3D? or does the 12v source from somewhere else?

-The FSM mentions that the ECU must be replaced if the 3S/T/U/V are not 12v when key on...how likely is this?

TheGloriousTachikoma

Well I tried running a resistance check from 3S to SM1/2/3/4 and on all of them it was OL. I'm not ready to try replacing that many wires, I think that I'll just keep premixing for now. I discovered something interesting as well. Whoever had pulled the ECU from it's original car has spray-painted a stripe across the connector end, meaning the pins have a layer of glossy paint on them and tiny streaks where it's been scraped away by the connectors.

Don't ever buy a RX7 for $1000


Well, the other thing is that, I think the pins are the ones I'm looking for, but I'm not sure. The wires that correspond to 3S/T/U/V are not the same color as SM1/2/3/4. I'm hesitant to cut and splice new wires since this is two engine harnesses cut and spliced together by Mexicans working out of a lean-to. (I promise I'm not joking, I saw it with my own two eyes. Neither did I buy this car. It was a gift...or a curse, depending on what angle you see it). 3S is the fourth pin to the right, top row, from the left side of the leftmost connector plugged into the ECU, correct?

satch

iTrader: (1)

There are two B/W wires that should have 12 volts w/key to on and this comes from the Main Relay. There's a three wire Green check connector near the Pressure Sensor that has a Blue/Red, Blue/Yellow and a B/W wire. The B/W wire is the same two B/W wires at the OMP plug.

EDIT: Connector X-11 which is one of the two large connectors above the ECU mates the Front harness w/the Emission harness. X-11 has a B/Y wire at the end of both rows of wires and the two B/W wires are next to the B/Y wires. If the Front side has 12 w/key to on then the B/W wires on the Emission side of the plug should read the same.

TheGloriousTachikoma

The yellow/orange plugs clipped together?

satch

iTrader: (1)

I know what color the S4's are and not the S5's. It's one of the two large main plugs that many of the ECU wires run to. You could also tell by the wire colors in each, which I already mentioned. The Green check connector I mentioned earlier is part of the Emission harness. If this B/W wire has voltage w/key to on then X-11 must be good to go w/respect to the B/W wires because X-11 takes the voltage off of the Front harness and passes it onto the Emission harness. If you have battery voltage w/key to on at the Green check connector but not at the OMP then the splicing on that B/W wire is suspect.

TheGloriousTachikoma

Turns out I was probing the connectors wrong. From the OMP connector to the ECU connector, I'm getting .1 ohms, so the control wires are good! XD I just need to run a new 12v line!

I'll check the position sensor in the morning, see if that's still good. If the sensor is disconnected, does the ECU throw a code/limp mode, or just the motor?

SirCygnus

iTrader: (1)

dont black/yellow wires have 12v during ign?

TheGloriousTachikoma

Yes, and the power wires for my OMP are as much as may as well be dead. Hoping to find a convenient place under the dash to power the new gauge as well as source volts for the pump.

satch

iTrader: (1)

That's the job of the B/W wires as it taps into the B/W wire which runs to all of the engine solenoids. If the B/W wire at the check connector has 12 volts w/key to on then the spot where the B/W is tapped into to which runs to the OMP must be bad if they don't have voltage at the OMP. Understand?

TheGloriousTachikoma

Yes. But I'm not disassembling my entire harness looking for one corroded splice. Due to an instance of negligence on my part I no longer have the book of wiring diagrams and do not know where the splice for the OMP is. Following the bundle of wires from the ECU, the two left connectors together go straight up to the grommet at the firewall. The right most connector heads off to the left to the IP. The closest thing you mention is a pair of yellow and orange connectors roughly above the ECU, but it seems neither directly connects to the engine harness. And which check connector? there must be ten of them on this car. :/

satch

iTrader: (1)

First off it would make sense to tap into the same wire that is supposed to provide voltage to the OMP. Does this make sense? Say yes. Secondly, I never suggested trying to locate the crimps as I was just pointing out what is the likely cause. Thirdly, did I not already state where the Green check connector was located (post #5) and what the color of the three wires are? The answer is a resounding yes. And the closest thing I mentioned was actually the Green check connector located near the Pressure Sensor and not X-11. The only reason I mentioned X-11 was that it a conduit for passing the voltage onto the B/W which you said was dead at the OMP.

TheGloriousTachikoma

okay, my bad. I know of that check connector. I'll investigate it today.

TheGloriousTachikoma

Tested the indicated wire at the indicated connector. That pin to the - battery post: .6v
I'm dropping 11.2v somewhere between that connector and the battery.

Where under the dash can I draw a new 12v power source from, enough for a gauge, the gauge's light, and the power for the OMP motor?
[EDIT] Actually, I need to fix that. W/O that wire getting 12v, I can't adjust my TPS, can I?

TheGloriousTachikoma

Dammit.

I cut a little but of insulation off the big 14ga black/white wire coming from the firewall to the engine (before the splice into all the solenoids and OMP wires).

.62v difference between the wire and ground.

So I crawl under the dash and manage to probe the X11 connector on the body side.

.62v

AAAAAAAAAUUUUUUUUUUUUGGGGGGGGGGGGHHHHHHHHH!

If I solder in a jumper from the ignition tumbler to the body side of the X11 connector, will I blow anything up?

Yes or no. This **** ends tomorrow with either my OMP and aux ports working again or...

[takes a deep breath...meditates for a few minutes...]

I cannot delve further under the dashboard or into the harness. I simply do not have the emotional strength, and Lucy needs to be back on the road. In all seriousness, if I run a jumper from a new source of 12v+ to the body side of the X11 connector, will I damage anything? And what is a good place under the dash that will support the emissions controls' need for 12v+?

satch

iTrader: (1)

The connector X-11 has two sides where one side is the Emission side while the other is the Front side. If you measured the Front side w/key to on and had little if any voltage then that suggests chances are very likely that your Main Relay is not functioning properly. Does it click w/key to on? If it did then the voltage would find itself to the Green Check connector by the leading coil that has a B/W wire and two Yellow based wires as already mentioned. So w/key to on simply measure for voltage on this B/W wire. If it is not present then the focus lies on the Main Relay. It is integral that this wire have 12 volts w/key to on. If it does not then your ECU will not be powered up nor will a majority of your solenoids. In other words, the car won't be going anywhere soon until you diagnose what the root of the problem is as opposed to jumpering a new source for voltage.

TheGloriousTachikoma

Nice positive click from the relay. Also, prior to this the car was running fine. Permanently in open-loop, but fairly well. Nothing happened since then, and when I began dissecting the harness. (so far only wires cut were to the OMP)

satch

iTrader: (1)

You still need to verify whether or not there is voltage on the B/W wire in the Green check connector near the leading coil w/key to on. Use the negative battery terminal as your ground for the multimeter.

TheGloriousTachikoma

.64v, at the black/white wire. Also at both yellow wires and the orange wire in the single connector next to that one.

Next step is to check output @ the main relay? I just find it...coincidental that the main relay would fail in this way st this time.

satch

iTrader: (1)

I hope you have the key to on when measuring the B/W wire. If so then turn your Main Relay upside down and check for constant voltage on the White/Red wire and the White/Blue wire (no key necessary for this check) in the four wire plug. Share w/us your findings.

If neither of these two wires have voltage then the EGI fuse is blown

TheGloriousTachikoma

...

...

As soon as I read those words 'EGI fuse is blown', I had a moment, that even a double-Picard facepalm could not convey.

I unplugged the EGI fuse because I had planned on changing the oil, and cranking the engine to get the stuff in the oil cooler out before filling with new.

Please...I am incredibly sorry about this wild goose chase. I mean it...oh my god...I really screwed the pooch on this one, didn't I?

I'll be back in a few minutes.

[EDIT] I have battery voltage at all indicated points.

And if my OMP tested within spec, then the reason that she wasn't pumping oil was because she was leaking, or the injectors are bad.

clokker

iTrader: (2)

Wow, a rarely seen Double Picard, thanks for sharing.
Should you really be practicing such a dangerous move so close to the Olympics?