Ross Posted January 23, 2005 Share Posted January 23, 2005 I have just replaced the vacuum advance diaphragm (it was stuffed), hoping it would stop this problem. It hasn't. The car will surge quite noticably when you are maintaining a constant speed, especially if im in a slightly too low gear (ie in 3rd at 60km/h). This goes away when more throttle is used, however at high revs (4500+) the surging returns, even at full throttle. It also feels as if it is lacking power at high revs. Seems to have plenty of power below 4000rpm. Any ideas? Thanks in advance. Link to comment Share on other sites More sharing options...
Ross Posted January 23, 2005 Author Share Posted January 23, 2005 Im thinking fuel injectors? does anyone know if these can be reconditioned? Link to comment Share on other sites More sharing options...
naru Posted January 23, 2005 Share Posted January 23, 2005 Im thinking fuel injectors? does anyone know if these can be reconditioned? Certainly,Larger towns will usually have a shop that specializes in diesel injector cleaning.They can do an ultrasonic cleaning and a flow/leak test. As for the surging, I`d be looking at other things first. Timing correct? Centrifugal advance sticky/stuck? High resistance throttle switch contacts?(mine were,easy to take apart and clean),throttle switch maladjusted?throttle stop screw maladjusted?(this will affect the ported vacuum signal to the disty vacuum advance),dead or lazy O2 sensor?(mine was),the proverbial vacuum leaks? Detonation?(you won`t necessarily hear it,knock sensor has a much more sensitive ear,you can monitor it by plugging a voltmeter into check connector #3 under the dash) If I was you,I would tap into the O2 sensor signal line w/a digital voltmeter to see what the O2 sensor says while the surge is occuring. Link to comment Share on other sites More sharing options...
Ross Posted January 24, 2005 Author Share Posted January 24, 2005 Thanks naru, ill look into those suggestions. How is the throttle stop correctly adjusted? My wrkshop manual says nothingg other than "don't adjust it", which isn't very helpful! Link to comment Share on other sites More sharing options...
naru Posted January 24, 2005 Share Posted January 24, 2005 Thanks naru, ill look into those suggestions. How is the throttle stop correctly adjusted? My wrkshop manual says nothingg other than "don't adjust it", which isn't very helpful! Good question.Nothing specific mentioned in the FSM,but reading between the lines of the throttle switch adjustment procedure suggests that the throttle will be at exactly 0 degrees when the stop screw is adjusted properly. Link to comment Share on other sites More sharing options...
Vanislru Posted January 24, 2005 Share Posted January 24, 2005 fuel pump Link to comment Share on other sites More sharing options...
85Sub4WD Posted January 24, 2005 Share Posted January 24, 2005 vacuum leak??? (after MAF, before turbo) - or fuel pressure regulator/filter Link to comment Share on other sites More sharing options...
Ross Posted January 24, 2005 Author Share Posted January 24, 2005 Found this afternoon that one of the springs for the centrifugal advance was disconnected (no idea how this would have happened?) and the stator magnet is broken in many places. I will fix these probs and see if it helps. Link to comment Share on other sites More sharing options...
Ross Posted February 11, 2005 Author Share Posted February 11, 2005 I fixed the centrifugal advance, and it has fixed the high rev problem nicely (engine also runs much smoother). However, the surging with low throttle remains. I would like to check the throttle stop screw adjustment before looking at the TPS etc, does anyone have any more info on how to check this other than what naru mentioned above? Thanks. Link to comment Share on other sites More sharing options...
tizzle Posted February 11, 2005 Share Posted February 11, 2005 I started a thread about the exact same problem a couple weeks ago. http://www.ultimatesubaru.org/forum/showthread.php?t=28929&highlight=rx+jerking I did several things. Turns out the timing was way off, and 2 of the spark plug wires on the distributor had the connections receded into the boot. I fixed that and it made a large difference, but the problem still persisted slightly. Then I ran 2 different fuel system cleaners as well. This also helped. I also replaced my fuel filter which was nearly brand new, problem still not solved entirely. ... I'm thinking that the fuel pump may solve the problem completely. Link to comment Share on other sites More sharing options...
Ross Posted February 11, 2005 Author Share Posted February 11, 2005 I read that thread, and i have checked/replaced all the things that you mentioned . I really want to get this stop screw thing sorted out before anything else, as i know it has been moved! Cheers Link to comment Share on other sites More sharing options...
tizzle Posted February 11, 2005 Share Posted February 11, 2005 Well, let me know what if you solve the riddle, and I will do the same for you Link to comment Share on other sites More sharing options...
Ross Posted February 11, 2005 Author Share Posted February 11, 2005 I think i may have solved it - at least partially. I have just replaced th stator magnet (which was broken in many places) and disassembled the bearings for the stator/module mounting plate (the one that the vacuum advance diaphragm turns - don't suppose youve got that on your engine?) and cleaned them. Seems to be running ok now, but the ignition problem has got worse, so its a little hard to tell! Link to comment Share on other sites More sharing options...
Ross Posted February 11, 2005 Author Share Posted February 11, 2005 I'd still like to check the throttle stop, does no one know how this is done? Link to comment Share on other sites More sharing options...
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