wallyblackburn Posted November 19, 2016 Share Posted November 19, 2016 Finally got my '06 Forester running after putting the correct crank sprocket on (Thanks, montana tom). Repeat of back story: car has sat disassembled for almost 4 years. Complete engine rebuild. Once I got it started, there was a terrible high-pitched squeal that would come and go. I finally got it isolated to the fuel pulsation damper on the driver's side fuel rail. To be honest, I never even noticed these little buggers before. It is running rough and I am getting misfire and lean condition on that side also. At first I figured it was just 4 year old gas causing it to run rough, but now everything points to this pulse damper. So, my question is: anybody know anything about these things? Is it something I'm likely to get past by filling up with good fuel, injector cleaner, etc. and running the old gas through? Or are these things usually failed/not failed period? Nobody but Subaru seems to have one so I'm guessing failures are rare. Subaru has them for about $70 - I have no problem buying one, just wish I had some clue what it even did. Thanks, Wally Link to comment Share on other sites More sharing options...
Fairtax4me Posted November 20, 2016 Share Posted November 20, 2016 Think of it like a shock absorber for the fuel line. Gas comes up under high pressure, and every time an injector opens that pressure drops a little then bounces back. Somehow they figure that eventually causes things to wear out, and it can create a clicking/rattling sound coming from the fuel lines or fuel rail. If you think thats the problem, remove it and run a straight section of high pressure injection hose as a temporary fix. Link to comment Share on other sites More sharing options...
lmdew Posted November 20, 2016 Share Posted November 20, 2016 I have one I could send you. Don't fail often. Is your's bolted to the fuel rail? $15 shipped. Link to comment Share on other sites More sharing options...
wallyblackburn Posted November 20, 2016 Author Share Posted November 20, 2016 I have one I could send you. Don't fail often. Is your's bolted to the fuel rail? $15 shipped. Darn, already ordered one. Thanks though. BTW, this one does screw on to the rail - it hangs down in the middle between where the injectors connect. Link to comment Share on other sites More sharing options...
wallyblackburn Posted November 20, 2016 Author Share Posted November 20, 2016 Think of it like a shock absorber for the fuel line. Gas comes up under high pressure, and every time an injector opens that pressure drops a little then bounces back. Somehow they figure that eventually causes things to wear out, and it can create a clicking/rattling sound coming from the fuel lines or fuel rail. If you think thats the problem, remove it and run a straight section of high pressure injection hose as a temporary fix. Given that this one won't stop squealing (and I mean squealing, loud - it's crazy), I went ahead and ordered a new one. Hopefully it fixes the rough running issue too. Thanks, Wally Link to comment Share on other sites More sharing options...
wallyblackburn Posted November 22, 2016 Author Share Posted November 22, 2016 Think of it like a shock absorber for the fuel line. Gas comes up under high pressure, and every time an injector opens that pressure drops a little then bounces back. Somehow they figure that eventually causes things to wear out, and it can create a clicking/rattling sound coming from the fuel lines or fuel rail. If you think thats the problem, remove it and run a straight section of high pressure injection hose as a temporary fix. Ordered one, but no word on when it's coming in. Given how obscure this thing seems to be, figure it might take a while. In the meantime, I'd really like to at least know if this i the problem. The way this one screws right into the rail, I can't really bypass it with a piece of hose - at not without cutting the rail! Wonder if I took this one out, cut a round piece of gasket to block the opening, and screwed it back in if that would at least let me tell if it is problem? Thanks, Wally Link to comment Share on other sites More sharing options...
Fairtax4me Posted November 22, 2016 Share Posted November 22, 2016 I was thinking this would be one of the type that sits up on the strut tower where the fuel lines run up before they go to the engine. If it just threads onto the rail maybe you can find a plug or a bolt with the same thread and screw that in place of the damper. If that engine sat for several years you may need to have the injectors cleaned to get the varnish out of them. Link to comment Share on other sites More sharing options...
idosubaru Posted November 23, 2016 Share Posted November 23, 2016 If those things ever fail it's rare. Has anyone else ever heard of these doing this? I've never seen it before. I would guess its compromised from sitting. Any chance bugs/ rodents can in the lines? Link to comment Share on other sites More sharing options...
wallyblackburn Posted November 23, 2016 Author Share Posted November 23, 2016 Failures are indeed rare, but they do happen. This post and the article it refers to are insightful: http://www.subaruforester.org/vbulletin/f66/if-u-having-misfire-codes-idling-problems-read-104693/ But, to be honest, I would never have even thought to look at this thing if it weren't for the fact that it squeals like a banshee. The loud squealing is something I have not been able to find anything else about. Ahh, the adventures... Link to comment Share on other sites More sharing options...
wallyblackburn Posted November 23, 2016 Author Share Posted November 23, 2016 Well...put the new dampener on and...IT SQUEALS! Going to start looking at injectors next... Link to comment Share on other sites More sharing options...
Crazyeights Posted November 23, 2016 Share Posted November 23, 2016 (edited) By chance are the fuel pressure and return lines swapped around the wrong direction at the engine? Is the fuel pressure regulator good, and the fuel pump pressure within spec? Edited November 23, 2016 by Crazyeights Link to comment Share on other sites More sharing options...
Fairtax4me Posted November 24, 2016 Share Posted November 24, 2016 In not sure it would run at all with the lines swapped, but it's worth checking. I'm wondering if the regulator is plugged with varnish or something. Might be a good idea to check the fuel pressure like crazy said. 1 Link to comment Share on other sites More sharing options...
wallyblackburn Posted November 24, 2016 Author Share Posted November 24, 2016 In not sure it would run at all with the lines swapped, but it's worth checking. I'm wondering if the regulator is plugged with varnish or something. Might be a good idea to check the fuel pressure like crazy said. I'm gonna do that tomorrow. Take regulator off and blast it with carb cleaner, etc. When it throws code, it is always misfire on #2...will give that one good cleaning and swap with #4 if previous steps don't help. The squeal of the dampener is bizarre though... Thanks all, Wally Link to comment Share on other sites More sharing options...
Recommended Posts
Please sign in to comment
You will be able to leave a comment after signing in
Sign In Now