Solved: Subaru Diagnostic help required

Discussion in 'Modified Shizzle' started by pgtips, Jul 24, 2019.

  1. Hi,

    I had a horrible knocking noise in my camper for ages, I went round tightening every hose, cable tying up etc but it was a sod to find until eventually, 3rd time up on stands I noticed a 'longer' shock absorber bolt. Tightened it up and great, ready to go.

    So I added coolant and bit of oil etc (funnel slipped so created bit of a mess) got it back on the floor for yet another test drive but now its running really 'lumpy' and conks out at idle after couple of minutes or so.

    It starts on the button, no red engine light. I know i said it conked out at idle but initially it ticks over fine, you wouldn't know any problem until pull away. Its like its cold and reluctant to go.

    And that's the problem I need help diagnosing, wtf have I done, have I knocked something or is this coincidental.

    I'm thinking :
    coil pack - but it starts on the button.
    vacuum I haven't found any pipe obvious/loose but maybe need to check more thoroughly)
    Fuel, I can rule that out, filters & injectors etc because I also have LPG installed and its as bad on both fuels, in fact less tolerant on LPG it cuts out much sooner.
    MAS - ? Mine was new when i put the engine in but maybe

    I'm lost where to start, could be none of above. I am sure I must have knocked something off, a cable, or connector but I don't know what. Like I say starts on the button and no red engine light.

    Has anyone else had anything similar or point me in the (or a) right direction, coil packs, MAF etc could work out expensive 'tests'.

    Thanks, PG
  2. Matt at @pkrboo might be able to help :thumbsup:
  3. Think I've fixed it, air intake filter too close to rear hatch was restricting air (so was air related but not the AFM)

    Need to properly check but can't drive for couple days. Pics below but I can't upload from my device for some reason so have to do it when I'm next at a pc
    Last edited: Jul 25, 2019
  4. I expect you knocked something electrical like a temperature sensor that was loose while fiddling. I bet the fault is still there. So as it warms up it is still being fed rich mixture whìch makes it run rough.

    An idling engine needs relatively little air.
  5. Hi,
    I wanted to finish up/close this thread as solved and hopefully will help someone else out.

    My problem was air. Air filter to be exact. Mine looked immaculate, lovely and clean but I removed it (in desperation really) to run down to the local spares shop to get some brake cleaner to clean up the AFM probe.

    bingo, Night and day difference, it ran just fine.

    I put my 'immaculate looking' filter back on and it ran rubbish again. So it was def air.

    A trip to halfords and fitted up (after spraying the AFM probe with brake cleaner) and it ran lovely. 500 miles lovely for our hols the next day (so no stress ;-/

    I was massively relieved so its something to bear in mind even if your filter looks great. I went away with a spare AFM and filter but not needed. I've now got 2 spares so shout me if anyone needs one :)

    My temps are a bit high , upper 80s as high as 94 when the fans kicked in back to 88 so thats my next job to figure out how to get the temp down a bit as the fans kicked in a few times on this trip.
    Merlin Cat likes this.
  6. what air filter are you running now? what were you running before?

    your temps sound fine to me. should sit happily at 88-90. fans kick in at 96 and will stay on til 88 liek you have seen so thats normal. (well it does a depend a bit on when the fans are kicking in? after a long motorway run etc?)
  7. air filter is back to front in these photos mate.
  8. yeah your right i read around the forum most are up in the high 80s but at one point I read 96 and I was sweating. The rads always get it back to 88 but I'd be happier if it ran in the 70s/low 80s somehow.

    I was reading about the liquid additives you can add to coolants but think its a bit of a myth so the plan to deflect or divert exhaust heat is what I'm thinking.

    But maybe it just is what it is. What is a safe temp for the engine?
    Last edited: Aug 22, 2019
  9. what temp is your stat and it will normally be a bit around that. BUT engines like to run at about 90. if it climbs to 96 and the fans kick in and do their job then all is good, don't sweat it. low 870/low 80s would be bad, its not the optimal operating temp.
    Poptop2 and pgtips like this.
  10. ah ok, I need to keep that in mind.

    I (mistakenly) spent the whole trip with the thought thought that getting close to (or hitting) 100 was pull over time, bit nervy lol !

    i.e 100 = boiling = car about to go kaput/burst pipes and carnage !

    now I know it was ok all along... :)

    looking on the net it seems that 110 would be ok but my fans kick in at 94 and gets back down to 88 so that contradicts this and tells me it wants it lower (between 94 and 88).

    So what is my panic pull over temp? 110, 120 ?
  11. As the system is under pressure the boiling point is higher so 110 is fine, that’s why you should never undo to radiator cap when hot.
    pgtips, Valveandy and Dubs like this.
  12. mines been as high as 107 degrees and is fine, that was last summer in the mega heat, towing and going up the steep hills near manchester on the motorway, it got back down going downhill!!
    Dubs likes this.
  13. 107 ..I think I'd pass out ...:burp:
    Valveandy likes this.
  14. Dubs

    Dubs Sponsor


    I managed to cook mine when I was facking about with under dash heaters and got an air lock, so can confirm that 120 is about when it all goes wrong!

    When modern car gauges sit bang on 90, the coolant will actually be anywhere between 80 and 100, they are just designed to not worry you if they go a bit over 90.
    pgtips and pkrboo like this.
  15. Thermostats are usually 92c opening temp so as said anything between 90-110c is normal :thumbsup:
  16. Don't forget it will warm up quicker on the lpg. Looks a tidy install getting all that to fit. :thumbsup:
  17. Subaru stats are either 78 or 82 (plus a couple of other temps) definitely not 92
  18. Mine usually sits around 90/91

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