Skip to content
View in the app

A better way to browse. Learn more.

Ultimate Subaru Message Board

A full-screen app on your home screen with push notifications, badges and more.

To install this app on iOS and iPadOS
  1. Tap the Share icon in Safari
  2. Scroll the menu and tap Add to Home Screen.
  3. Tap Add in the top-right corner.
To install this app on Android
  1. Tap the 3-dot menu (⋮) in the top-right corner of the browser.
  2. Tap Add to Home screen or Install app.
  3. Confirm by tapping Install.

Crazy revving on startup

Featured Replies

Adventure - if you want the ECU out of that car, I can pull it easy enough, throw it in a box and send it your way if you will cover shipping costs.

yupper - pm being sent with info - please let me know if you dont get...

 

(still never recieved that last pm from you)

  • Author

pm and payment sent. Thanks again!

 

I'm going over the whole thing with a mag light just in case any critters got to nibbling on the wires. Maybe I'll just swap in the wiring off the old engine to eliminate another possibility while I'm waiting for the ECU.

  • Author

Can't find any nibbled wires. Hopefully this ECU does it. if not, I'm thinking I'll swap the whole intake manifold etc. over and hope it gets cleared up somehow. it's weird.

Heres to hoping. The only time I e ever had an engine redline all on its own was when the TPS went bad and at that I had to move the throttle before it would do it. If I let it idle it was fine, but the slightest touch on the gas pedal was enough to make it redline. Swapped TPS and it was cured, but any electronic component which fails properly (or unproperly) could cause the same reaction.

  • 2 weeks later...
  • Author

Well, put the "new" ECU in this morning. And we're still revving. Back to the drawing board. I have the old engine and all it's components, and a full EJ18 setup (same in a number of parts) Anyone have any other ideas on what I can try?

 

I have to think that a Vac leak, even a large one wouldn't just put me at redline right away would it? Even so, there's no good way to check while it's running with a spray can or something because the engine would run dangerously high.

 

Could I have missed something in swapping the injectors over? Also considering swapping the whole intake manifold over to see if that clears it up... I have to think this is a simple fix though.... if only I could figure out what it is.

Edited by AdventureSubaru

Yep.

 

NO

 

not in 90,91

 

Manual has a 2 pin, single coil

 

Auto, and 92+ have the 3 pin, 2 coil type.

Well, put the "new" ECU in this morning. And we're still revving. Back to the drawing board. I have the old engine and all it's components, and a full EJ18 setup (same in a number of parts) Anyone have any other ideas on what I can try?

 

Uhh....you did check that the throttle cable is not too tight?

 

Otheriwise, I'd say you have a leak at the intake manifold.

Stumper for sure.

 

What about fuel pressure? I'm not sure if a stuck/ clogged pressure regulator would make it do that but if you have one to swap it only takes a few minutes.

 

Maybe that combined with a massive intake manifold leak? I would think it would have to be the manifold base gaskets or the fuel rail O-rings if that were the case. At this point it wouldn't hurt to pull the manifold and check the gaskets.

 

Still wondering if you ever got the TPS adjusted. The procedure for this style sensor looks much simpler than the later versions.

  • Author
Stumper for sure.

 

What about fuel pressure? I'm not sure if a stuck/ clogged pressure regulator would make it do that but if you have one to swap it only takes a few minutes.

 

Maybe that combined with a massive intake manifold leak? I would think it would have to be the manifold base gaskets or the fuel rail O-rings if that were the case. At this point it wouldn't hurt to pull the manifold and check the gaskets.

 

Still wondering if you ever got the TPS adjusted. The procedure for this style sensor looks much simpler than the later versions.

 

Fuel rail O-rings! I pulled one of the rails - no O-rings between the injectors and the engine. Swapping the rings from the old engine now. This should do it!:banana:

 

Also... I feel pretty silly for missing that when I swapped them over.:o

  • Author

yep. It's off and running. Feels like it could use a tune up. (sitting 3 years would do that.) So I'm going to give it some better plugs. Otherwise is running as it should.

 

Would the plugs from an EJ18 swap over to an EJ22? I got some good ones in my spare motor.

If you change plugs, you want to run NGK-BKR5EGP or BKR6E11. Great plugs, decent price. EJ18 plugs might be the same length, but don't quote me on that. As long as they are the same length from the nut, down to the electrode, you are good. Don't want to put a hole in your pistons now that the motor runs good.

 

Amazing how a little o-ring can cause such an issue, eh?

Fuel rail O-rings! I pulled one of the rails - no O-rings between the injectors and the engine. Swapping the rings from the old engine now. This should do it!:banana:

 

Also... I feel pretty silly for missing that when I swapped them over.:o

 

:lol: It was just a guess, I was still convinced it was the TPS!

Glad you found the source of the problem!

 

For plugs I run the NGK BKR6E11. NGK part# 2756. <-- The parts store will list this number. Too difficult for the average parts jockey to figure out the long part numbers I guess. :confused: But the other number is what's printed on the side of the plug.

Yay!!! :banana: it runs right!!

 

 

+20 on the BKR6E11/2756 plugs - what has been used in pretty much all our Subarus, never had any issues with them

 

REALLY glad to hear you got the ol girl running properly! :banana:

  • Author

Thanks Joanne! About as good as could be hoped for. I'm going to dial up the throttle a little bit because it's idling low and give it new plugs and this car should be ready for the next 100k.

hold off on messing with the idle until after you get some new plugs in her - probably wouldnt hurt to do new wires as well.

 

Glad to hear that it is finally running closer to right tho - good luck with her!

New wires already done. The blown motor had a nice set of NGKs on it.

 

Thats what I like to hear!

 

I was coming back from South Beloit, I should have stopped and checked out ur swap and such!

Don't mess with the theottle screw because that will mess up the TPS reading. Put some new plugs in it, run some Seafoam and some strong fuel system cleaner and drive it for a few days. The idle should adjust up on it's own as the ECU learns optimal fuel and spark curves.

Please sign in to comment

You will be able to leave a comment after signing in

Sign In Now

Account

Navigation

Search

Search

Configure browser push notifications

Chrome (Android)
  1. Tap the lock icon next to the address bar.
  2. Tap Permissions → Notifications.
  3. Adjust your preference.
Chrome (Desktop)
  1. Click the padlock icon in the address bar.
  2. Select Site settings.
  3. Find Notifications and adjust your preference.