Jump to content


Welcome to Ultimate Subaru Message Board, my lurker friend!

Welcome to Ultimate Subaru Message Board, an unparalleled Subaru community full of the greatest Subaru gurus and modders on the planet! We offer technical information and discussion about all things Subaru, the best and most popular all wheel drive vehicles ever created.

We offer all this information for free to everyone, even lurkers like you! All we ask in return is that you sign up and give back some of what you get out - without our awesome registered users none of this would be possible! Plus, you get way more great stuff as a member! Lurk to lose, participate to WIN*!
  • Say hello and join the conversation
  • Subscribe to topics and forums to get automatic updates
  • Get your own profile and make new friends
  • Classifieds with all sorts of Subaru goodies
  • Photo hosting in our gallery
  • Meet other cool people with cool cars
Seriously, what are you waiting for? Make your life more fulfilling and join today! You and your Subaru won't regret it, we guarantee** it.

* The joy of participation and being generally awesome constitutes winning
** Not an actual guarantee, but seriously, you probably won't regret it!

Serving the Subaru Community since May 18th, 1998!

Guest Message by DevFuse
 

Photo
- - - - -

engine popping under load


  • Please log in to reply
9 replies to this topic

#1 danzick

danzick

    USMB Regular

  • Members
  • PipPipPip
  • 97 posts
  • Livingston

Posted 24 April 2012 - 07:32 PM

So my 88 gl 1.8 spfi is popping and backfiring really bad under a load. It runs fine if you can maintain under 1/4 throttle but as soon as you get in a load situation it just backfires and has hardly any power new maf sensor new o2 sensor pretty new engine coolant temp. Tried swapping distributors and didn't help. Any thoughts?

#2 MilesFox

MilesFox

    Catch this Fox!

  • Members
  • 10,501 posts
  • Madison/Milwaukee, WI

Posted 24 April 2012 - 07:37 PM

have the timing belts been done? how long has it bee doing this. sounds timing related. nmay be the timing belt is a tooth off.

#3 danzick

danzick

    USMB Regular

  • Members
  • PipPipPip
  • 97 posts
  • Livingston

Posted 24 April 2012 - 07:40 PM

Well when its on the interstate it will run ok but just kinda miss every once in awhile. That's kinda why I didn't think it was timing.

#4 danzick

danzick

    USMB Regular

  • Members
  • PipPipPip
  • 97 posts
  • Livingston

Posted 24 April 2012 - 11:46 PM

Well I drove it home tonight (commute 60 miles a day) and on the way home it was running soo bad. Zero part throttle. It would sorta run at wot and I limped it home that way never letting off the throttle. Did a compression check and all cylinders are 150 and one is at 130. All the plugs were a good brown accept one and it was pretty black? Took all the spark plugs off while it was running and found that its firing on all cylinders. Timing belts? I wouldn't think it would run at all if they failed? Car used to run just fine when I got it.

And might I add that's it tearing out the center of the air filters? Did it to my original and I figured it was a fluke and just old and I put a brand new one in and it was tore out aswell? Im guessing it has something to do with the fierce back fires?

Edited by danzick, 24 April 2012 - 11:49 PM.


#5 skingry

skingry

    New User

  • Members
  • PipPip
  • 22 posts
  • San Francisco, CA

Posted 25 April 2012 - 12:57 AM

I'd check the wires with a meter, just because you are seeing spark when the plug is out of the head doesn't mean it's giving spark when the piston is up and compression is barreling down on the plug (it's a whole different world under compression).

I pulled these values from the "How to Keep Your Subaru Alive" book that tboned linked me to:

OHC models: The resistance for the coil and spark plug wires should be within the following values:

SPFI
Coil Wire - 2.43k-5.67k
Wire #1 - 8.38k-19.56k
Wire #2 - 2.99k-6.97k
Wire #3 -7.90k-18.44k
Wire #4 - 2.41k-5.62k

#6 czny

czny

    USMB is life!

  • Silver Subscribers
  • 338 posts
  • Azusa, California

Posted 25 April 2012 - 09:18 AM

Sounds like you've got a cracked distributor cap & it's cross-firing some cylinders. Check the inside of the cap & rotor for tracks.

#7 danzick

danzick

    USMB Regular

  • Members
  • PipPipPip
  • 97 posts
  • Livingston

Posted 25 April 2012 - 05:59 PM

Brand new cap and rotor too. Forgot to add that to the list.

#8 TomRhere

TomRhere

    Certified BRAT nut!!!

  • Members
  • 3,977 posts
  • Hillsdale, Mi. USA

Posted 26 April 2012 - 04:18 AM

Just a thought here,

A worn cam lobe, or worn cam follower for an exhaust valve can cause an above idle backfire thru the intake.

Burnt gases can't escape the cylinder if the exhaust valve isn't opening properly. Higher engine RPM's will leave those gases in the cylinder when the intake valve opens, causing a backfire.

Have repaired a few OHC engines with that problem. Haven't done a Subaru yet, but it is possible on these engines also.

Like I said, just a thought...

#9 LPGsuperchargedBrumby

LPGsuperchargedBrumby

    Fully retarded and low on compression

  • Members
  • 656 posts
  • Dunedin, NZ

Posted 26 April 2012 - 04:59 AM

i had my carby'd EJ22 do a similar thing to me a couple of years ago....turned out it was the plug leads breaking down under load...it would run fine until i got to around 10" manifold vac... any lower than that sounded like a battle was happening up front.

it drove me nuts trying to find what was wrong as the cap rotor coil leads and plugs where all only about 3 months old at the time....'newish' bum leads aren't the kind of thing i had struck before

#10 ivans imports

ivans imports

    1000+ Super USER!

  • Members
  • 2,938 posts
  • lumby bc canada

Posted 26 April 2012 - 10:26 AM

lean misfire lean misfire check feul preshure and volume bad pump or slight intake leak or hydrolic lifter seat has creeped up and not alowing lifter to work properly do's it pop out the exhaust or just intake ?




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users