2K4 STI Posted August 22, 2007 Share Posted August 22, 2007 My 87 RX with the EA82T runs fine at part throttle,but when im in boost"when the boost light comes on" it kinda hesitates. Any idea on what to check? TIA Quote Link to comment Share on other sites More sharing options...
rllywgn Posted August 22, 2007 Share Posted August 22, 2007 Hey if you havent got the tune-up done yet.. you can swing by and ill help you do it. I'm sure we can get the sputtering sorted out. May be a possible vacuum leak or fuel delivery problem. I would also suspect the o2 sensor. I'll be at the meet thursday if you can make it.. btw.. no one stocks ea82 fuel filters here in town.. usually have to be ordered.. let me know if i can help Quote Link to comment Share on other sites More sharing options...
TheSubaruJunkie Posted August 22, 2007 Share Posted August 22, 2007 Possible culprits: Fuel filters MAF Knock Sensor Coolant Temp Sensor Bad spark plugs Bad plug wires. Ive had all of those malfunction when i owned my RX. They all caused hesitation and sputtering when under boost. -Brian Quote Link to comment Share on other sites More sharing options...
2K4 STI Posted August 22, 2007 Author Share Posted August 22, 2007 Thanks guys and yeah Rllywgn Ill be out at the meet thursday night.Ill talk with you and see what all i need to buy and maybe we can get it done this weekend. Quote Link to comment Share on other sites More sharing options...
calebz Posted August 22, 2007 Share Posted August 22, 2007 Quick note - If the problem only manifests itself under boost, it shouldn't be the O2 sensor. The stock ECU ignores the O2 sensor when under boost. +1 on a complete tune up. Are you getting any ECU codes? Quote Link to comment Share on other sites More sharing options...
2K4 STI Posted August 23, 2007 Author Share Posted August 23, 2007 Its not thowing any codes at all,just the hesitation in boost. Ill do the tune up this weekend and see if that cures it.If not ill be back on monday Quote Link to comment Share on other sites More sharing options...
calebz Posted August 23, 2007 Share Posted August 23, 2007 Boost leak is one of the first things I would look into. If theres still a problem after the tune up of course Quote Link to comment Share on other sites More sharing options...
TheSubaruJunkie Posted August 23, 2007 Share Posted August 23, 2007 Boost leak maybe... but your boost gauge should indicate that (you DO have a boost gauge, dont you?) -Brian Quote Link to comment Share on other sites More sharing options...
2K4 STI Posted August 23, 2007 Author Share Posted August 23, 2007 I just bought the car about 3 weeks ago,so no boost gauge yet It does have the wonder Boost light,which im convinced is just a light that comes on at a certain throttle position Quote Link to comment Share on other sites More sharing options...
85T-REX Posted August 23, 2007 Share Posted August 23, 2007 There's a pressure switch in front of the passenger side strut mount. That's what turns the light on. Does the hesitation clear up at high RPMs? I've had my RX for a while and it's always done that up to about 3-4K RPMs. Then it smooths out and pulls hard to 6K. Sometimes the surge was more noticable but even with new heads, different turbo, and no code problems, it still remains. Not a boost leak, just the nature of the beast. Quote Link to comment Share on other sites More sharing options...
2K4 STI Posted August 23, 2007 Author Share Posted August 23, 2007 It does it at any rpm when the boost light comes on.I notice it more on the highway when accelerating. Quote Link to comment Share on other sites More sharing options...
85T-REX Posted August 23, 2007 Share Posted August 23, 2007 I would imagine your RX has a disty with a vac advance. The boost could be retarding the ignition timing. If you take the disty cap off and put air pressure on the diaphragm, you will probably be able to see the advance mechanism moving backwards. I modified mine with a tee and check valve to vent that boost pressure and it made a big difference in the amount of surge. It didn't eliminate it completely but it made it a lot more bearable. Quote Link to comment Share on other sites More sharing options...
2K4 STI Posted August 23, 2007 Author Share Posted August 23, 2007 Do you happen to have a pic of how you installed the check valve? Quote Link to comment Share on other sites More sharing options...
85T-REX Posted August 23, 2007 Share Posted August 23, 2007 I can get pics this weekend but it's simple: 1. Just cut or add a piece to the vacuum line going to the diaphragm. I put mine close to the diaphragm. 2. Put your two hoses onto the straight through portion of the tee. 3. On the third leg, put on a short piece of hose. 4. Install the check valve with the flow direction going away from the tee. (The end you can blow through would be the end you attach to the hose.) 5. If you want, you can vent the other end of the check valve back to the air box where the filter is. I tied mine into a line from the canister that's attached to the air box vent line. You should notice a big difference. Keep us posted. Quote Link to comment Share on other sites More sharing options...
2K4 STI Posted August 23, 2007 Author Share Posted August 23, 2007 Ok,ill give it a try this weekend along with the tune up. Quote Link to comment Share on other sites More sharing options...
2K4 STI Posted August 30, 2007 Author Share Posted August 30, 2007 Well i finally got all the tune up parts done.I did them in stages to see what was actually causing the sputtering. 1st stage Spark plugs Autolites #63 /cleaned Maf No change 2nd stage Spark plug wires No change 3rd stage Cap and rotor No more sputtering :grin: Turned out to be the cap and rotor causing it. Thanks for all the help guys :clap: Quote Link to comment Share on other sites More sharing options...
TheSubaruJunkie Posted August 31, 2007 Share Posted August 31, 2007 Your boost light is ran off of manifold pressure. There is a switch on the passenger fender, with a vaccum line running to it, and a couple wires leading away. When the manifold reaches positive pressure, the light comes on. So, it only comes on while making boost. Its a good spot to plumb a boost gauge into. This is where I mounted my gauge in my RX: Quote Link to comment Share on other sites More sharing options...
tizzle Posted August 31, 2007 Share Posted August 31, 2007 So, my RX is sort of doing the opposite. Runs great under full throttle, but sucks when not. I've had this problem over a year and can't figure it out. I'm going to start throwing old parts back at it and see what happens Quote Link to comment Share on other sites More sharing options...
Gloyale Posted August 31, 2007 Share Posted August 31, 2007 There's a pressure switch in front of the passenger side strut mount. That's what turns the light on. Yup. It's a pressure switch. But it comes on with virtually any amount of positive pressure(1 psi), but at least you know you are getting some boost. Does the hesitation clear up at high RPMs? I've had my RX for a while and it's always done that up to about 3-4K RPMs. Then it smooths out and pulls hard to 6K. Sometimes the surge was more noticable but even with new heads, different turbo, and no code problems, it still remains. Not a boost leak, just the nature of the beast. My 86 had the same problem. Still made power, but it would kinda pull and pause, pull and pause..... Only between 3000 and 3700 rpms. It would *catch* and pull hard from 3700 on up, like a switch, every time. I think it's from the Flapper MAF, because it's very common in the early style turbos. I believe the MAF signal is ignored above a certain RPM (perhaps 3700) The Hotwire style doesn't seem to have the same problem. Quote Link to comment Share on other sites More sharing options...
daeron Posted September 1, 2007 Share Posted September 1, 2007 Autolite??? Garbage!!! NGK BPR 6ES11!!!! Quote Link to comment Share on other sites More sharing options...
2K4 STI Posted September 2, 2007 Author Share Posted September 2, 2007 NGK BPR 6ES11 are these for a EA82T and gapped at what?? Quote Link to comment Share on other sites More sharing options...
daeron Posted September 2, 2007 Share Posted September 2, 2007 should be gapped right from factory, 0.036-.044 IIRC. http://www.ch601.org/engines.htm find subaru EA82 parts 1 and 2. Quote Link to comment Share on other sites More sharing options...
85T-REX Posted September 4, 2007 Share Posted September 4, 2007 I have the pics posted of the check valve setup I did. If your disty diaphragm isn't being pushed backwards, you wouldn't need to do this. If it is, I can explain the setup. Enjoy the RX. I would drive mine forever if I could. rex Quote Link to comment Share on other sites More sharing options...
carfreak85 Posted July 5, 2019 Share Posted July 5, 2019 (edited) On 8/31/2007 at 1:10 PM, Gloyale said: My 86 had the same problem. Still made power, but it would kinda pull and pause, pull and pause..... Only between 3000 and 3700 rpms. It would *catch* and pull hard from 3700 on up, like a switch, every time. I think it's from the Flapper MAF, because it's very common in the early style turbos. I believe the MAF signal is ignored above a certain RPM (perhaps 3700) The Hotwire style doesn't seem to have the same problem. @Gloyale It feels like my '87 RX is doing this, but I've only been able to drive it a few times and it's pretty subtle. Any suggestions? Edited July 5, 2019 by carfreak85 Quote Link to comment Share on other sites More sharing options...
el_freddo Posted July 5, 2019 Share Posted July 5, 2019 5 hours ago, carfreak85 said: @Gloyale It feels like my '87 RX is doing this, but I've only been able to drive it a few times and it's pretty subtle. Any suggestions? @FerGloyale Cheers Bennie Quote Link to comment Share on other sites More sharing options...
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