Engine swap electrical questions

[Legacy777]

I started looking into the electrical stuff a little more closely today.

I know that the cam & crank sensor positive leads need to be switched. I played around with some spare ECU connectors and figured out how to get the wires out, so that should be a pretty easy thing.

I need to wire up the pressure sensor, wastegate, and pressure exchange solenoid. One question I had was regarding the pressure sensor. In stock form, it has shielding around it. How important is that? I've got the turbo legacy harness, so I could pull the wiring and shielding out.

A few other things......I would assume the altitude sensor pin has a wire in it on the n/a cars. They show it not to have a wire on the turbo cars. I would assume it goes to the TCU, but I haven't looked yet. Does anyone know any different?

The idle air control valve, the open & close end circuits seem to be wired backwards from the n/a model. I can easily swap the pins, but I'll probably do some testing, just to verify that's the case.

I noticed in the 92 FSM, there is additional shielding wires for the airflow meter & TPS. It's probably not a big deal. I thought it was weird though that the pin they list for it is 1*9. Anyone have any ideas about why they did that?

That's the only differences I noticed in the ECU I/O diagrams between models.

[vrg3]

You'll probably be fine without the pressure sensor shielding as long as you don't route the harness right along the spark plug wires or anything. And even if they did occur, little fluctuations on that signal line wouldn't have much effect on anything.

If you do decide to shield the wire, though, you might have an easier time using some microphone cable, or even shielded cat 5, instead of trying to tear the relevant parts out of a stock harness. Matt (legacy92ej22t) is using an oxygen sensor harness made out of shielded POTS cable.

Yes, the barometric pressure signal goes from pre-93 NA ECUs to the TCU. For you this is a non-issue.

The IAC pins are not wired in reverse. I think the difference in specified voltage in that chart is just because the ECUs operate the valve differently.

The "1*9" is a typo. The MAF sensor shield goes to pin 19 on that connector.

[Legacy777]

So pretty much the pressure sensor is the only thing I should worry about. The other stuff shouldn't be issues.

I'll think about what to do regarding the shielded wire. Cat 5 wiring is a little small, but I'm sure I could find something else.

[vrg3]

I wouldn't say you even need to worry about that.

Cat 5 is thin, yes, but there's, like, no current flowing through those wires. Use a couple of the pairs in parallel if you're worried though.

[Legacy777]

Thanks Vikash

[Manarius]

I wouldn't say you even need to worry about that.

Cat 5 is thin, yes, but there's, like, no current flowing through those wires. Use a couple of the pairs in parallel if you're worried though.

Could go to Cat6 if he needs high flow

[Legacy777]

I pulled the wiring I needed from the harness today. It didn't take too long. I've got the pressure sensor shielded wire from the sensor connector all the way to the ECU pins. I should be able to just plug the pins into the empty spots on my ECU connectors.

The other two I'll have to solder some spare pins on because those sets of wires went through one of the SMJ connections.

[Psychoreo]

just covering my back for when i start running the wires.
ok, when you say pressure sensor you're talking about the MAP sensor right? (don't slap me please), if you are, can that be plugged into the stock NA harness MAF plug without bad things happening?
Then the Wastegate solenoid, black to ground, red to ecu power?
pressure exchange solenoid is ....? Recirc valve? if not where is it? this being my first time doing an engine swap, as well as my first time dealing with a turbo car, and first subaru, the questions are endless. thanks!!!!!

[vrg3]

ok, when you say pressure sensor you're talking about the MAP sensor right? (don't slap me please),

Yes. It's just that, strictly speaking, it measures atmospheric and manifold pressure both, so it's not just a MAP sensor.

if you are, can that be plugged into the stock NA harness MAF plug without bad things happening?

No.

Then the Wastegate solenoid, black to ground, red to ecu power?

I believe it's red to ignition-switched power and black to to the ECU's boost control pin.

pressure exchange solenoid is ....?

The little brown cylindrical doohickey above the pressure sensor and wastegate control solenoid.

Look at the picture at the top of this page:

http://www.graphics.cornell.edu/~v/chrysler_map/

[Psychoreo]

if you are, can that be plugged into the stock NA harness MAF plug without bad things happening?


No.

sweet, i got one thing kinda right...then again, i should unplug it from the stock harness... and many thanks for the pic. that cleared it up instantly.

[Psychoreo]

oh, so with the pressure sensor, the concensus (sp?) is to run shielded wire right? I was thinking from the sensor, under the intake tube, along the fender, attach it to the plastic shielding along the fire wall and into the ecu. any forseen problems?

[vrg3]

then again, i should unplug it from the stock harness...

Unplug what from the stock harness?

You need both the MAF sensor and the pressure sensor.

oh, so with the pressure sensor, the concensus (sp?) is to run shielded wire right?

If Josh alone can form a consensus.

I was thinking from the sensor, under the intake tube, along the fender, attach it to the plastic shielding along the fire wall and into the ecu. any forseen problems?

I'm not sure I follow... Which intake tube? And which fender? What plastic shielding?

The way I would probably do it, just because it seems like the most obvious way, would be to run the wires around the passenger side strut tower and then along the back of the firewall, and then around the brake booster to the little grommet underneath.

[Legacy777]

I just did the wiring today. I ran the wires along the back of the fire wall and in through the grommet.

Getting the wires through the grommet was the hardest part because I already have my light levelers going through there.

[Psychoreo]

Unplug what from the stock harness?

You need both the MAF sensor and the pressure sensor

ok, i'm confused again. the MAF sensor attaches to the airbox on an NA correct? But on a turbo it's called a MAP sensor and it's a different sensor but in the same place?

I'm not sure I follow... Which intake tube? And which fender? What plastic shielding?

What you said was what i was trying to say, but i was thinking about the sensor that attaches to the airbox. under the airbox, along passenger side fender/strut tower area, across the firewall(mine has some wires with the plastic makes wires not look so crappy stuff around them following the firewall), and then through the grommet.

Josh: any recomendations between the shielded and non shielded?

[vrg3]

ok, i'm confused again. the MAF sensor attaches to the airbox on an NA correct? But on a turbo it's called a MAP sensor and it's a different sensor but in the same place?

Both turbos and atmos use MAF sensors attached to the airbox.

Turbos also use pressure sensors connected to the manifold through vacuum hoses and the pressure exchange solenoid.

What you said was what i was trying to say, but i was thinking about the sensor that attaches to the airbox.

Ah. Okay. You just use the factory wiring for the MAF sensor.

(mine has some wires with the plastic makes wires not look so crappy stuff around them following the firewall)

Ahhh... I follow now... like that corrugated tubing.

[Psychoreo]

Both turbos and atmos use MAF sensors attached to the airbox.

but they are different right? my old one was plastc, the new one's metal. they also had different insides. i'd assume they'd be different because of the "wrong sensor" CEL code that pops up if you use the NA one.

Turbos also use pressure sensors connected to the manifold through vacuum hoses and the pressure exchange solenoid.

and that's on the cluster of stuff by the passenger side strut tower right?

Thanks

[vrg3]

but they are different right?

Yes, you're correct. Most atmos use that plastic-housing sensor, but the turbos use the metal-housing sensor.

and that's on the cluster of stuff by the passenger side strut tower right?

Right.

[Psychoreo]

sweet thanks for the info!!!

[Legacy777]

Josh: any recomendations between the shielded and non shielded?

I ended up using the stock wiring since I had it available. If you really want to use shielded wire, cat 6 is probably your best bet. I looked around and couldn't find anything else that was readily available and inexepensive.

As for recommending shielded or non-shielded.....I can't say....?

[Psychoreo]

back from the almost dead,
In the top picture, http://www.graphics.cornell.edu/~v/chrysler_map/ the wires from the red clip goes where?
and as for the pressure sensor, there's three wires right? one red one yellow(could be white) and green. those wires went where? i couldn't find the info. Thanks

[vrg3]

That info's in the wiring diagrams and on my web pages.

By "red clip" you mean the connector on the pressure exchange solenoid? The yellow-with-red-stripe wire goes to the ignition relay (which powers the solenoid). The green-with-yellow-stripe wire goes to the ECU's "pressure exchange solenoid" pin.

All three pressure sensor wires go to the ECU. There's a connector a couple of centimeters away from the sensor, and all three wires connect to differently-colored wires on the other side. The red wire becomes a white wire and goes to the ECU's "MAP sensor power supply" pin. The white wire becomes a black wire and goes to the ECU's "MAP sensor signal" pin. The green wire becomes a red wire and goes to the ECU's "MAP sensor ground" pin.

[Psychoreo]

i'm just trying to make sure i do everything right so i don't light my car on fire...

so yellow/stripe would go to the ignition relay, is that in the fuse box or the ECU pin b58.12(ignition switch)? and green/stripe goes to F47.20

the others are very self explainatory. Thanks for the plethera of information and assistance.

Jon

[vrg3]

The ignition relay is mounted next to the fuel pump relay under the dash.

Look at the wiring diagrams. The "ignition switch" wire does not come from the ignition relay.