So, When I did my engine swap it appears I have aplug with no where to plug in to My car is an '89 GXL, now with an S4 block swapped in.

I have looked all over and see nothing to connect to with this stupid plug!
So, any ideas where it goes?

 

My best guess is O2 sensor. How many terminals?

 

looks like it plugs to a S5 BAC

 

I could be wrong, but I do believe that plugs into a connector for an electric fan. I had a plug when I rebuilt mine that I didn't know where it went. It turned out it didn't go to anything cause I didn't have an electric fan. If I remember that plug is grouped with two other plugs.

I just took a better look at the pic. That plug is too far to the rear of the engine. I'm not quite sure what that is. I do know it is not the O2 sensor.

 

it does look like a thermoswitch connector similar to FDs, it is what triggers the fan to come on at a certain temp but on FCs it was used for the air conditioner fan.

i agree it doesn't look like an O2 sensor connector and also isn't for the BAC, it reaches to an area where there is nothing else to connect to so it likely isn't used.

 

I know it's not for the O2 or BAC, the O2 I have connected, and the BAC is a white plastic plug. The plug in question is a single terminal Grey plug, grouped on the branch with the Water-Thermo sensor (green plug) and the 2 primary injector plugs.

So it's some strange grey mystery plug. A Thermo-switch would make sense, since it would probably plug in near the Thermo-sensor, and on my FD the plugs for the Thermo-switch and Thermo Sensor are right next to each other.

It is an S5 harness I"m using too. The car has a mechanical fan and air conditioning. But the plug can't reach any part of the AC system. It could only reach the inatke and TB along with the water pump.

 

How's anyone supposed to know for sure if you don't tell us the wire colour?

 

the color is grey, as in the photo. pretty sure it has no connection now and is for a thermo-switch/e-fan

 

The outer cover is grey, just like half the wiring in the car. The wire inside is not. If it is for the e-fan thermoswitch the wire will be green/black.

 

Black with green stripe, so it must be the thermo-switch wire. Thanks again!

 

If I remember correctly, when I repalced the engine in my 90 GXL, there was an electrical plug under the upper intake manifold that didn't plug into anything. I believe that this is for EGR valve, which 89-91 n/a engines didn't have.

Hot_Dog
90 RX7 GXL

 

No, that plug was not for the EGR valve. Why would there be a plug for something not fitted to any model?

 

Just in case I decided to hook up an EGR into my S5 after swapping in an S4 block and somehow fit it under the UIM still. Notice the block off plate on the block in the pic with the mystery-solved wire. It would have been in the perfect spot!!

This S4 block swap is now running, but runs like crap still. Realized my ECU will not like running without the OMP hooked up, so today I strap the superficial OMP somewhere into my engine bay.

Then the vacuum lines..why couldn't there be another view given anywhere? so confusing. The solenoid rack is probably still connected wrong. And then all the lines by the LIM are hard to make out too.

 

The series four EGR valves do not, did not have an electrical plug on them. An EGR if installed will not make the engine run smoother/better. The blockoff plate in the picture I assume has a gasket under it to seperate the inlet/outlet passages that went to the EGR valve.

There was a photo of the vacuum rack installed mostly right just a few months ago.

It's not impossible to route the vacuum lines right by using the FSM and understanding what each solenoid does in life. Say your interested in the Relief solenoid for a series four turbo. You know from looking at the FSM that it has two hose. One hose is a source of air pressure from the aip pump via the ACV nipple. Then the other hose is the pressure signal coming from the solenoid to the ACV to make the relief diaphram work. That would be the nipple on the very bottom of the ACV. The one on that mushroom outfit on the bottom

Just take one solenoid at a time, figure out what it's for and work it out like that.

 

I wasn't serious about hooking up an EGR! I live in MN, so I have no need for any emmissions. I'm only keeping the vacuum rack so I can operate my ports and VDI still.

I've been able to make sense of the vacuum diagrams in the FSM, but it just gets confusing at times. I'll figure it out eventually though using the logic you spoke of.

 

i'm fairly sure the plug is for Jpec or Espec engines with an option the USpec engines did not use. i remember a plug that was dusty under the engine that was not used obviously due to it having never been plugged into anything on the last S5 engine i helped disassemble.

 

Non-US models have less plugs, not more. There's nothing on my engine that you don't have on yours. You guys got everything.

The e-fan temp switch is the only thing that some engines got and some didn't, so it's the only spare plug you're likely to find on the engine. I'm only talking about stuff actually on the engine.

 

well it does visually look identical to a thermo switch bung and i do recall an S5 we took apart with a bung similar to that under the UIM that was dirty so obviously it was not used for anything but really without a wire color we are just spinning our wheels about guessing at what this thing is.

 

I have so many random plugs in mine that I can tell haven't been plugged in for so long now. If it's running ok than I wouldn't spend too much energy onit bro.