Bobbo63 Posted August 19, 2015 Share Posted August 19, 2015 Been dealing with a cyl 4 misfire for 8 months. no bad sensors, no other codes. it does it randomly. Ive swapped injectors, new sensors, new coil pack. I always get a cyl 4 misfire. i can pull over, shut it off for a few minutes and its fine. When climbing a steep hill, the engine will start losing power till the cyl quits. Please help me with anything i can check. Link to comment Share on other sites More sharing options...
700watts Posted August 19, 2015 Share Posted August 19, 2015 Compression test Link to comment Share on other sites More sharing options...
Bobbo63 Posted August 19, 2015 Author Share Posted August 19, 2015 Compression isnt the issue either. Forgot to mention that. It comes and goes. If it was compression it would go bad and stay that way. Are there any actual subaru mechanics on this forum or all we all just glorified highschool mechanics? Link to comment Share on other sites More sharing options...
whitetiger Posted August 19, 2015 Share Posted August 19, 2015 clearly you need to verify cylinder integrity. something is happening as temps go up, since when you should it down(let it cool down) the problem goes away. compression and leak down tests are needed. unless you have done them, dont dismiss them. if they all do check out good, you may have a valvetrain problem, like a sticky intake valve when temps go up. -glorified highschool mechanic. Link to comment Share on other sites More sharing options...
Bobbo63 Posted August 19, 2015 Author Share Posted August 19, 2015 It comes and goes. Its gotta be electrical. It will come and go without shutting the motor off sometimes. If it were compression, wouldnt it be dead and not comeback? Its a phantom electrical gremlin. Link to comment Share on other sites More sharing options...
Jdubgt530 Posted August 19, 2015 Share Posted August 19, 2015 I have the same problem with my 97 lgt but I don't lose any power. I've taken the same steps so all that there is left is to replace the computer which comes today, found out that there is a new computer for my year and model. Mine has a 22611 ac990 and the replacement part is a 22611 ac991. I talked to my buddy who is a mechanic and said since I have replaced everything and I don't lose power when the misfire happens then he said the only thing it can be at this point is a too sensitive computer Link to comment Share on other sites More sharing options...
Bobbo63 Posted August 19, 2015 Author Share Posted August 19, 2015 I lose power bigtime if it decides to happen. Its much worse in the winter than it is in the summer. I thought it mighta been egr... and with how dirty it was i thought it might have had a bit to do with the problem, since it is on cyl 4. that wasnt the issue either. Link to comment Share on other sites More sharing options...
twisty Posted August 20, 2015 Share Posted August 20, 2015 Please help me with anything i can check. Compression test Compression isnt the issue if you dont want advice, dont ask. youve replaced the whole electrical system for the engine so far and think its still an electrical issue. how about you check the compression and timing components to make sure they are legit before dismissing them? even if it is just to tell us we were wrong. - industrial programmer that works evenings and weekends at a real mechanic shop as a hobby. Link to comment Share on other sites More sharing options...
Bobbo63 Posted August 21, 2015 Author Share Posted August 21, 2015 I dont have a compression tester. If it was compression, would this problem have the ability to come and go? If it was compression wouldnt it be eating oil? If it was compression, wouldnt there be blue smoke coming out of the tailpipe? If it was compression and i had a compression tester how would i go about doing this test? Climb a hill, shut the car off, pop the hood, pull the all plugs, crank it, check the levels while the problem may fix itself cause? Sometimes it clears up when i shut it off for a few minutes? Cause sometimes i can drive through the misfire, and it will clear up. This issue comes and goes, with the engine hot and or cold. The plugs i pulled out, and the plugs that are in...are clean as they should be. This is how i have ruled out compression. Link to comment Share on other sites More sharing options...
Bobbo63 Posted August 21, 2015 Author Share Posted August 21, 2015 Lets pretend its not the compression... whats the next step? Link to comment Share on other sites More sharing options...
whitetiger Posted August 21, 2015 Share Posted August 21, 2015 I dont have a compression tester. get one. If it was compression, would this problem have the ability to come and go? yes, if is related to how hot things get under load, or a sticky/leaky valve. If it was compression wouldnt it be eating oil? no, not always. If it was compression, wouldnt there be blue smoke coming out of the tailpipe? no, not all compression issues are piston ring/blow by related. it could be valve train related too. If it was compression and i had a compression tester how would i go about doing this test?Climb a hill, shut the car off, pop the hood, pull the all plugs, crank it, check the levels while the problem may fix itself cause? Sometimes it clears up when i shut it off for a few minutes? Cause sometimes i can drive through the misfire, and it will clear up. This issue comes and goes, with the engine hot and or cold. The plugs i pulled out, and the plugs that are in...are clean as they should be. This is how i have ruled out compression. just because the problem is only evident sometimes during driving does not mean that you wont see anything when you do the test. the bad cylinder may still be evident in the test results. you need a compression and a leak down test in the suspected cylinder. the last thing you want to do is start worrying about intermittent electrical gremlins without first verifying cylinder integrity. No one is saying that it is the cylinder for sure, but you must eliminate it as a problem before you start tracking down bad electronics, having already replaced the easy parts. Link to comment Share on other sites More sharing options...
Bobbo63 Posted August 22, 2015 Author Share Posted August 22, 2015 How do i test the signal to the injector? i have a test light, and 2 different multimeters? I will be buying a compression testor on monday. Im 99.9 % sure its not compression, but since its my cash i guess its no big deal. Wouldnt the plug be showing nastyness if it was valve train related? When my car starts acting up it sounds just like this... Luckilly the obdII still works in mine. @.22 sec. Link to comment Share on other sites More sharing options...
meier motor sports Posted August 22, 2015 Share Posted August 22, 2015 this thread makes me giggle like a glorified highschool mechanic. Link to comment Share on other sites More sharing options...
Bobbo63 Posted August 22, 2015 Author Share Posted August 22, 2015 How does a glorified highschool mechanic laugh? The part of this thread that is pissing me off is, im not asking how to test my phucking compression. Ive had a few of cars in my past with a bad cyl either being valvetrain related or ring related... or a combo of both, and they have all responded the same way. Usually making some sort of mess on the plug after a month and being a constant issue. not a random failure. What in the hell specifically sends the signal to the injector? Compression? Link to comment Share on other sites More sharing options...
meier motor sports Posted August 22, 2015 Share Posted August 22, 2015 cam signal sends the signal to ecm as to engine position and the ecm determines precise timing based on load and other info for fuel and spark ignition. if the cam signal fails you will probably get a cel and if the engine stays running it is based off aprox timing via crank signal. engine will not re start at this point until cam sensor works again. the best way to check injector signal is with a lab scope, but you can simply use a noid light set. it is provided 12v via the ecm. usually constant 12v from switched fuse source and the ecm will supply ground on the other wire to make the injector fire. to check the coil is a bit more technical. easy money is switch the coil to another cyl and see if your misfire follows. if yes then replace, if not keep looking Link to comment Share on other sites More sharing options...
Bobbo63 Posted August 22, 2015 Author Share Posted August 22, 2015 so if just one cyl is acting up.. its either an ecu, or compression? So 12 v flows through the injector, and it merely grounds out in the ecu making the signal? Link to comment Share on other sites More sharing options...
meier motor sports Posted August 22, 2015 Share Posted August 22, 2015 or a coil or an injector or maybe a vacuum leak. but since you have already thrown a bunch of parts at it, try a compression check Link to comment Share on other sites More sharing options...
Bobbo63 Posted August 22, 2015 Author Share Posted August 22, 2015 Secondly thank you guys for all the info. Link to comment Share on other sites More sharing options...
Bobbo63 Posted August 23, 2015 Author Share Posted August 23, 2015 Already swapped injectors.. front to back, side to side. no dice... I will be doing a compression check on monday and will be posting results. What p.s.i. neighborhood should they read? If compression comes back fairly even across the cyl...whats the next step? ecu? Link to comment Share on other sites More sharing options...
Bobbo63 Posted August 26, 2015 Author Share Posted August 26, 2015 got busy with work this week. Been working 3 1/2 weeks, no days off, on call so i cant really find a proper window to do this. I almost pulled it off in 30 minutes. I had run a compression test on the pass side with around 150 psi- per cyl. As i was getting ready to do the drivers side my phone rings... it was work. I then proceeded to drive 400 miles this afternoon. So... heres the latest.... Last night i installed a vac guage. My vac reads about 5 on the freeway, and i cant get it over 20 at an idle. when i rev the moter the vac drops and then climbs higher than when its at an idle. At this point... im thinking the drivers cam may have jumped a tooth. So ill finish the compression test in the morning. Link to comment Share on other sites More sharing options...
subytech1 Posted August 28, 2015 Share Posted August 28, 2015 Vacuum seems pretty normal, usually if you have a timing/valve issue, the vacuum gauge needle will jump around/vibrate a lot. I have seen knock sensors cause a lack of power up hills, also seen MAF sensors not post codes and still cause this issue, and (if equipped) I have seen intermittently faulty EGR vacuum solenoids allow exhaust to enter the intake at inopportune moments, I have seen low fuel pressure from a fuel pump going bad run fine around town, but as soon as you start driving up hill or go wide open throttle, the engine falls on its face/stalls. I have seen plugged fuel filters do this as well. I was a Subaru tech for a long time, and I would say truthfully that the compression test is probably the cheapest test because it only costs your time(other than the purchase of the tool) and least evasive, needing only to pull the spark plugs and to screw in the compression adapter hand tight, connect the gauge to the quick disconnect, disconnect the ignition coil, push the gas pedal to the floor, and crank the engine over so you can hear around 5 revs, you should be no less than 150psi but around 190psi depending on engine age. Harbor Freight has compression testers for cheap, and there are youtube videos on how to do this test. Even as a ASE Master certified tech, I would probably do this test because it's quick, easy, and allows you to check multiple systems at once. Even though most of the time I already know that the compression is already good, I'm just officially just ruling it out as a potential cause. I hope this info helps! Link to comment Share on other sites More sharing options...
Bobbo63 Posted August 28, 2015 Author Share Posted August 28, 2015 i had 150ish in the pass side, and 120ishon the drivers side. I think the crank has slipped a tooth. Steady vaccume. doesnt fluctuate.. Where are the solenoids and how do i test them? Link to comment Share on other sites More sharing options...
subytech1 Posted August 28, 2015 Share Posted August 28, 2015 150 is marginal at best, 120 is getting down there, you can also do what is called a "wet" compression test to see if your rings are worn out or not. Depending on which engine you have, SOHC or DOHC, the difficulty will very for this next step. You will want to put a few caps full of engine oil directly into the cylinder through the spark plug hole. The cap from a quart of oil will work, or what ever delivery device you may have that will work easiest. Then do the compression test again, only disregard the first readings and reset the gauge due to the first set of engine turnovers were to get the oil distributed to the rings. If your compression goes up/evens out, then your looking better and hopefully can rule out the timing as being off. I have never really encountered timing issues on a Subaru unless someone had messed with it, or if the belt was so overdue that it either skipped or broke completely. If your asking about the EGR solenoids I mentioned, I meant to type solenoid, no "s", sorry mistype... But the EGR solenoid is usually mounted on the drivers side of the engine near where the fuel lines go under the intake but in front of the intake. You will only have this solenoid if your vehicle is equipped with an EGR system. The EGR valve would be located in the same area only behind the intake. Front meaning radiator side and behind meaning firewall side. If you do see the EGR valve it will have a small black vacuum line going to the top of the valve. If you follow that line, it will take you to the solenoid. You would need to find something like a golf "T", disconnect the line at the EGR valve and plug the line with the "T" or equivalent. Then drive the vehicle to see if anything changes or gets better, If the car runs fine or better, then replace the solenoid that the line goes to. If you don't have any luck there, I would recommend going to any local parts store and have them check for history trouble codes that may be in the system, but not causing the check engine light to come on. This would hopefully lead you in the right direction. Link to comment Share on other sites More sharing options...
Bobbo63 Posted August 28, 2015 Author Share Posted August 28, 2015 i dont get any vacume through there what so ever. ive cleaned my egr port. It was caked shut. Now i can manually manipulate it... the idle goes a bit silly but it comes back. Egr aside... Sometimes the car runs smooth, sometimes it bucks n shudders goin down the freeway. Link to comment Share on other sites More sharing options...
subytech1 Posted August 28, 2015 Share Posted August 28, 2015 The solenoid will only allow vacuum at certain predetermined/calculated conditions, as in vehicle is warmed up to ops temp and your headed down the free way where sustained engine RPM at that range will cause the engine to get hotter and the exhaust will start to produce more NOx emissions, the EGR valve will crack open and allow exhaust gas from the exhaust port to enter the intake, slightly choking out combustion on a very small scale. It's just enough to lower combustion temps to prevent NOx emissions, but not enough to notice driveability issues. But if it was clogged up solid, then this isn't the issue. Have you pulled off your plug wires at the ignition coil? If you do, look at the metal post/socket the the wire connects to. See if there is any white/green corrosion, if found, the coil is almost dead. Also see what the engine does if you go WOT or Wide Open Throttle, if it stumbles then your fuel filter could be clogged, and/or your fuel pump may be getting tired. I have to get some sleep so I can get to work in the morning. I will check back tomorrow(today), hope you find the issue! Link to comment Share on other sites More sharing options...
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