5MT swap causes electrical weirdness

Flywheel, Clutch, Transmission, Axles, etc...

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5MT swap causes electrical weirdness

Post by AWD_addict »

So I finally got my 98 GT 5MT into my 90, but there are a couple little problems I think are electrical.
1) First time starting it things went good, a little cranking, then it ran. Starting the engine the 2nd and 3rd times it will turn over, but doesn't stay running unless I give it some throttle. After a few seconds of throttle, it idles ok by itself. What could cause this?

2) Another more alarming problem is that the engine dies while driving, apparently at random. The last time this happened, the check engine light went on for a second, then the engine died. I checked the ECU codes, but it has none. Is this related to problem 1?

3) And the speedo doesn't work. I unscrewed the base part from the '9? 4EAT and screwed it into the '98 5MT. It was a bit of a stretch, but the cable just reached. Using the old base part with the newer transmission should work, right?

Big thanks to Matt for answering questions and helping me drop the 4EAT without injury. :-D Posts from Josh, Vikash, Nick and others were helpful for random useful info. And of course, Josh's excellent swap guide was great.
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Legacy777
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Post by Legacy777 »

So you put a 98 5MT into your 90 legacy which was 4EAT....correct?

What ECU are you running? Did you keep the same ECU? If so, did you snip the AT/MT ident pin? Did you snip that lead going up to the old shift indicator in the dash?

Any more details as to what you exactly did with the wiring would be great.
Josh

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1990 Legacy (AWD, 6MT, & EJ22T Swap)
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206er
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Post by 206er »

are you sure you got the tab of the speedo cable correctly installed into the transmission's slot? was the cable so tight as to cause binding anwhere? they do have to spin with little resistance.
1994 Touring Wagon: ruby mica, 5mt swapped
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Post by AWD_addict »

Yes, my 90 Legacy was a 4WD 4EAT. I'm not sure exactly what year the 4EAT was, as the previous owner replaced it because it had lower mileage. The final drive was 4.111 though, so it was an early one.

I'm running the same ECU. I snipped the AT/MT ident pin, making triple sure it was pin 20 before cutting anything. I also snipped pin 18 of the B36 for the combination meter/neutral switch.

Wiring wise I cut off the B15 connector from the 4EAT and used it to plug into the car's harness as before. I crimped on connectors to the B15's wires for neutral (2), reverse (2) and the 11 and 12 wires jumpered together for the starter interlock relay. I bought a new clutch relay, it's hooked up so the clutch has to be pushed in to start. The clutch relay is also wired to the clutch switch and starter motor, as in the Subaru manual wiring diagram.

I don't know if the tab reached. It might be caught. Could the tab not reach deep enough even when screwed tight into the threads?
After tightening the base part onto the trans and driving around a little, it became noticeably looser. I tightened it again but still no speedo. Could it be unscrewing itself? There isn't every any speedo needle movement.
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Post by Legacy777 »

Take the cable out, spin it, and see if the speedo works. (I believe the ign needs to be on). If there's any way to jack the car up off of all four wheels remove the cable, and look down at the gear while the trans is moving....that will tell you whether the gear is good/working.

As for your wiring....I'm not sure....it sounds like you followed what I did...but it's not working.
Josh

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Post by AWD_addict »

I'll try spinning the cable. I won't able to check the trans part for a while, I'm really hoping this problem isn't from the little plastic gear in there. Before the swap my speedo would sometimes be jerky or slow to respond to changes.

I'm pretty sure I did the wiring correctly. Maybe the electrical issues are due to something getting knocked around while I was working on the car? It doesn't show codes for anything, but maybe a sensor is dying?

Thankfully the engine hasn't died while driving since I took a 90 mile highway trip and put some city miles on too.
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Post by AWD_addict »

I figured out the speedometer problem, the tab broke off the bottom piece! I think the tightness due to the short AT bottom piece stopped the cable from turning. The slot in the trans turned, breaking the tab.
MT style vs. busted AT style
Image
Image

I don't think this washer was like this before. I must have overtightened it.
Image

There was a bunch of debris in the trans slot hole. I removed it using a magnetic grabber, screwdriver, and a dustbuster. Straw mod to dustbuster worked first try. 8)
Image

Yes, the ign needs to be set to ON for speedo to function. Spinning the cable by hand (counter clockwise) got the needle to move.
I put the MT style part in, now the speedo cable isn't in tension so that's good.

But the damn engine won't start. :( Now throttle adjustment doesn't get it to run. It sounds like it begins to run, but stops right away. Could the lack of speedo function for a while have done something to the ECU? It still doesn't throw any codes.
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Post by AWD_addict »

Starting problem solved! I'm a genius.:roll:
When I was connecting the intake hoses after the swap there was one that didn't have a clamp. I forgot to find one for it. The hose was loose, causing the crappy performance. I heard a noise while cranking it the other day, which must have been the hose completely coming off. Connecting and clamping it restored normal starting and performance.

So my wiring is correct.

Yay shifting!
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Post by kingston »

just got my ss swapped at a shop from 4EAT to 5 speed. picked up a 2001 RS drivetrain and ended having to use everything hubs, diff, tranny then had to find a legacy driveshaft to get it all finished. The speedo is not working, they said i needed to get a manual one but right now it will stall at stop lights. Is the lack of speedometer the problem behind that? Not sure how they hooked up electrical but when i'm in gear, the N on the gauge cluster is illuminated.

For some reason when they swapped out the hubs, the ABS isn't compatible so now my ABS warning light is on.

Also i have a constant CEL light flashing non stop.
2002 WRB WRX Sportwagon
1989 S13 White Coupe
1992 Winestone Red Legacy SS
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Post by AWD_addict »

That's weird that they used everything out to the hubs. The axles from your SS should match up to the 01 RS trans fine.
If the RS diff had female axle splines for male axles, that would be the only reason to use the RS stuff. I thought the 01 RS diff had male axle stubs like the trans? :?

Try getting the MT speedo hookup I installed above^^^ to see if the lack of speedometer signal is causing problems.
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Post by Legacy777 »

The shop didn't do a complete job at the swap. The light is illuminating and back feeding into the ECU.

I don't know what exactly they did, but did you read the part on my write-up about the neutral switch?
http://www.surrealmirage.com/subaru/swa ... ml#neutral

You need to snip that wire.
Josh

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1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT

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kingston
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Post by kingston »

ok got the speedo sensor hooked up and it's working fine and dandy now. No more stalls at stoplights i guess since now the ECU can sense speed from the speedometer.

Josh, is the neutral switch thing for the annoying flashing CEL? I haven't gotten around to that yet. Just wanted to know what that did.
2002 WRB WRX Sportwagon
1989 S13 White Coupe
1992 Winestone Red Legacy SS
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Post by Legacy777 »

The neutral switch does play into engine idle adjustment, mainly on the automatics.....I'm not sure how much of a role it plays on the manual transmission cars.
Josh

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1990 Legacy (AWD, 6MT, & EJ22T Swap)
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kingston
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Post by kingston »

what about the constant CEL i get now...how do i fix that?
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Post by Legacy777 »

what code is it?
Josh

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Post by kingston »

no particular code...just constant flash flash flash flash while the car is running.

plugs are not connected. Happened since the tranny was put in.
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Post by Legacy777 »

Hmm.....it shouldn't do that. I bet there's a wire hooked up incorrectly that's grounding the read memory pin on the ECU.
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT

If you need to get a hold of me please email me rather then pm
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