Post head gasket frustration

Heads, valves, pistons, rods, crankshaft, etc...

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Legacy777
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Re: Post head gasket frustration

Post by Legacy777 »

Regarding manuals and wiring diagrams, have you seen this post in the stuff you need to know forum?

viewtopic.php?f=12&t=14485

This is the wiring diagrams for the 90 Legacy which should be same for your 91
https://www.main.experiencetherave.com/ ... agrams.zip

If you're wiggling things around with the wiring and/or ECU and things change you need to look for possible frayed wires that are making contact and possibly loose connections/plugs.

I would recommend fixing/confirming you have addressed any loose wiring, plugs, or frayed wiring and then check sensors for the codes you have. Instructions are in the wiring diagram I posted.

For the coolant temp sensor, were you checking the two wire sensor or the single wire sensor?
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
mr.blub.blubs142
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Re: Post head gasket frustration

Post by mr.blub.blubs142 »

I figured out why I was getting a bunch of codes randomly. When I probed the ecu pins, they got slightly stretched and weren’t making good contact. I was able to re-tension them and haven’t had an issue with them again. The coolant temp sensor I was checking was the two wire one. I realize the one wire one only goes to the gauge in the car. I’ve had several mechanic friends come over and look at it and they’re all stumped too. I swapped my throttle position sensor with a good known one, no change. I swapped my idle air control valve with a cleaned and working one, no change. Just a few minutes ago I swapped in a brand new fuel pressure regulator, no change. I can’t find any wiring problems anywhere or any bad sensors. Currently stalls after a few seconds when I put it gear or if I let it idle and and warm up. The weirdest thing is that I was able to get it out of the shop and drive it down the road, and it drives fine as long as the rpms are up. When I slow down and the rpms drop to idle it immediately dies like the key is turned off. doesn’t idle rough, doesn’t buck, doesn’t try to stay running at all.
arse_sidewards
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Re: Post head gasket frustration

Post by arse_sidewards »

>When I slow down and the rpms drop to idle it immediately dies like the key is turned off

Check your VR sensors (crank and cam, prioritize crank though, it's the important one). Their signal quality increases with speed and the crank sensor absolutely will shut the car off if it's giving an intermittently garbage signal.

Also, don't spend stupid money on the OEM sensors that have the integrated pigtail. Buy a the sensors for a '95 (like $10ea) and the pigtails for a '95 (like $15ea) and cut the integrated pigtail and install the '95 pigtail.

You will almost certainly have to destroy the crank sensor to get it out. The top will come off, a 3/8 drill will get you access to the wire. Once you pull that out you can fold the outer casing into the now empty space to reduce the diameter and get it out. Sand the bore a tiny bit with some emory cloth and coat the new sensor with anti-sieze.
'93, '93 and '94 Legacy L, wagons, FWD and AWD, all are NA 2.2 w/ 4EAT.
mr.blub.blubs142
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Re: Post head gasket frustration

Post by mr.blub.blubs142 »

Wouldn’t the car throw a code if the crank sensor was getting an off reading? I still don’t get any codes when it shuts off. I did notice when I pulled everything apart that a little bit of one of the tabs on the back of the crank sprocket was cracked and not fully there. The main bulk of it was still there so I figured that wouldn’t affect it running. How likely is it that the damaged tab would cause this issue?

One more thing to mention, when the car dies when it gets warm, the only way to get it to start back up is with the throttle fully depressed.
arse_sidewards
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Re: Post head gasket frustration

Post by arse_sidewards »

If the car doesn't know something's wrong it's not gonna throw a code. If the car new something was wrong it likely wouldn't be taking the reading in good faith and wouldn't be running at all or would at least be be running well or running poorly consistently.

If the crank sprocket is symmetrical you can try and flip it to get a better part of the tooth under the sensor.

Generally it takes a really f-ed up tone ring to cause problems for a VR sensor. Failures of the sensor itself is far more common.

Post pics of the sprocket if you can.
'93, '93 and '94 Legacy L, wagons, FWD and AWD, all are NA 2.2 w/ 4EAT.
Legacy777
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Re: Post head gasket frustration

Post by Legacy777 »

Agreed, if you can post pictures of the broken tab of the crank sensor that would be helpful and may be a good starting point along with a replacement crank sensor as arse_sidewards suggested.
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
mr.blub.blubs142
First Gear
Posts: 83
Joined: Sat Oct 18, 2014 8:07 am
Location: Chehalis, WA

Re: Post head gasket frustration

Post by mr.blub.blubs142 »

I’ll post a pic of the sprocket when I get home. I’ll pick up a new crank sensor too. How would I wire the new one? My current one is a 3 wire sensor but the later model ones all appear to be a 2 wire sensor
mr.blub.blubs142
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Posts: 83
Joined: Sat Oct 18, 2014 8:07 am
Location: Chehalis, WA

Re: Post head gasket frustration

Post by mr.blub.blubs142 »

Here’s what the sprocket looks like. Hopefully the link works properly.

https://share.icloud.com/photos/0pnAtFF ... #Centralia
arse_sidewards
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Re: Post head gasket frustration

Post by arse_sidewards »

Yeah that's probably enough to matter. Distance from tooth to sensor matters a lot more than whether the tooth is a nice clean profile or evenly shaped, etc.

Not saying it's your problem but it's sure not helping.

Replacement sprockets are $25+ on eBay
'93, '93 and '94 Legacy L, wagons, FWD and AWD, all are NA 2.2 w/ 4EAT.
mr.blub.blubs142
First Gear
Posts: 83
Joined: Sat Oct 18, 2014 8:07 am
Location: Chehalis, WA

Re: Post head gasket frustration

Post by mr.blub.blubs142 »

Just replaced the crank sensor and it appears to be fixed. Idling smoothly at operating temp at 750 rpm. I’ll probably replace the sprocket at some point, but for now I’m just glad it’s working. If it breaks on me again I’ll let you guys know. Thanks for all the help!
Legacy777
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Re: Post head gasket frustration

Post by Legacy777 »

Glad to hear that the sensor worked. I'd be curious if it runs better with the new sprocket.
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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