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HELP' loss of power 15mpg....


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42 replies to this topic

#26 Caboobaroo

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Posted 28 March 2013 - 08:16 PM

If the regulator was the issue, you're fuel pump would be dead already. Seen it happen in a few miles of running on a Forester XT, bad regulator toasted a new pump.

How do the spark plugs look or have they even been out? If so, what is the gap that has been set on them? What kind of plugs were used?

A P0420 is a catalyst deficiency code and it is possible the cat could be clogging up the exhaust. Is the exhaust (manifold, up pipe, downpipe, catback) factory or is any of it aftermarket? also, it is much easier to remove the downpipe to check for shaft play, not the inlet as most of the time, the factory ones will come off but won't go back on.

Does it run rough at idle? Try a can of brake cleaner to check for vacuum leaks around intake piping form the air box to the turbo, the intercooler, the base of the intake manifold whereit bolts to the heads, and the vacuum lines that are behind the power steering pump. While its idling and you're spraying those areas, anytime you hear the idle come up, you're in the area of a vacuum leak. Does it have an aftermarket atmospheric blow off valve or does it recirculate back into the turbo inlet?

#27 legend01

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Posted 29 March 2013 - 08:00 AM

Hi guys thanks for your replies,the car has a turbo back decat exhaust,the front manifold & uppipe are factory which it had when i got the car,when i was checking the pcv i checked the hoses including the intercooler hoses i havent checked the inlet yet.it hs a forge d.v. on it again was on car from when i got it i have got a standard one i think il try swapping that. it idles fine the only thing i'l ad is when i got the car when i started it cold or hot it would idle around 750rpm even on really cold days now on cold start the idle starts at 1500rpm+ then slowly drops as the car warms up.the plugs have been changed the last time couple of months back while it had this prob they looked normal.oh & the vacum was steady.

i must say this forum is the best one ive been on ive nown about it since i got my car as ive used the diagrams in opposed forces,but im also a member of a couple of others & you beat them hands down.thanks again for all the replies.


Edited by legend01, 29 March 2013 - 08:06 AM.


#28 nipper

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Posted 29 March 2013 - 09:21 AM

awwww

 

shux

 

stop

 

don't

 

 

i mean really, dont stop :)



#29 ivans imports

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Posted 29 March 2013 - 09:45 AM

I blame plugs had a 2.0 give me hell becuse had to high of ohom plugs and was jumping spark down the side of plugs a low ohom plug with tight gap any misfires will make ecu pull back timing and boost try a ngk vpower bkr6e-11 with a 0.55 0.60 gap and carfull not to break coils



#30 hp_pants

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Posted 29 March 2013 - 09:49 AM

Hi guys thanks for your replies,the car has a turbo back decat exhaust,the front manifold & uppipe are factory which it had when i got the car,when i was checking the pcv i checked the hoses including the intercooler hoses i havent checked the inlet yet.it hs a forge d.v. on it again was on car from when i got it i have got a standard one i think il try swapping that. it idles fine the only thing i'l ad is when i got the car when i started it cold or hot it would idle around 750rpm even on really cold days now on cold start the idle starts at 1500rpm+ then slowly drops as the car warms up.the plugs have been changed the last time couple of months back while it had this prob they looked normal.oh & the vacum was steady.

i must say this forum is the best one ive been on ive nown about it since i got my car as ive used the diagrams in opposed forces,but im also a member of a couple of others & you beat them hands down.thanks again for all the replies.

Yeah, this forum seems more laid back-it's not filled with idiots calling each other N00B and demanding that someone search...



#31 legend01

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Posted 29 March 2013 - 02:02 PM

Good day to all,well had another look today,took d.v. off & apart gave it a good clean then the pressure sensor on top of throttle body,then used a can spraying the inlet & other hoses to see if i could find any air leaks,couldnt find any,but i took car down the road & it goes alot better dont no if it was something i down today or i did unplug the front o2 yesterday then did a ecu reset,but hey im getting somewhere car still hesitates havent been far in it so its probably still going through re-learning stages,still have low vacum,so i think its on the way to getting it back to how it should be,going to give it a few runs & see what happens,strange hey, will report back soon.Thanks to all.



#32 nipper

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Posted 29 March 2013 - 03:56 PM

NOOB!!!!!!!!!!!!!!!

 

 

Ok got that out of my system :)

 

I am stil wondering if the timing belt jumped. Did this start all of a sudden, like the car was running fine, then the next start it started running poorly?



#33 hp_pants

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Posted 29 March 2013 - 05:02 PM

NOOB!!!!!!!!!!!!!!!

 

 

Ok got that out of my system :)

 

I am stil wondering if the timing belt jumped. Did this start all of a sudden, like the car was running fine, then the next start it started running poorly?

Man, n00b is spelled with zeros, not os. DO A SEARCH!!!!!



#34 legend01

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Posted 29 March 2013 - 07:35 PM

it did start all of a sudden but it was one day it was running great then out of the blue it ran crap then it would be ok for a week or so but it gradualy got worse were it ran worse nearly all the time,i do see your point if had jump a tooth but it would run good now & again,i do have my new kevlar belt & tensioners ready to put on it was just that it got the point were i couldnt see me getting the car to run right again without spending a fortune which i dont have at the moment,so il see how it goes over the next couple of days.

im not that new old timers lol ive had my beast for couple of years now just havent put many post up,as up until few months ago had only done things to car if i wanted ie:put coilovers/ new alloy rad/ fuel pump/3port solenoid/rebuilt front calipers/sti blue seats/have kept the oil changers regular also got new antifree to go in when i do belt,i always wanted one but i thought when i got it it would be not as good as it is its been fantastic car i love it apart from second gear went just before christmas had gearbox rebuilt new clutch then this mystery prob ive done 30 odd thousand miles in it already its just great to drive.anyway things are looking up a bit,would like to find out why vacum is so low,il keep you informed.many thanks



#35 ivans imports

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Posted 30 March 2013 - 09:49 AM

the jdm turbo i worked on other day pulled 17 in/hg vacume was 2.0 turbo a 2.51 na pulls 22 in/hg at idle think its the turbo cams that do it and low comp ratio



#36 legend01

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Posted 30 March 2013 - 03:14 PM

Hi everyone,well its been snowing & freezing today so havent done any more work on car,i did take it for a little drive & it does still feel better,ive also noticed that the dump valve is going off more so maybe it was stuck shut/open hopefully its just going to get better,havent been able to put that many miles on it yet so dont no what mpg is like but i have got a good 6hour drive coming up next weekend & thats going to give me alot more info on how its going.in the meen time il keep you updated on how it goes.cheers



#37 Caboobaroo

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Posted 30 March 2013 - 03:56 PM

The dump valve can stick, especially when they are a cheaper, aftermarket one. Seen a few cause vacuum issues due to being stuck open.

#38 legend01

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Posted 31 March 2013 - 05:00 PM

well its a forge d.v. havent heard of many probs with these,i might try the factory one on & see how that goes,but at the moment its running alot better thank god its was realy getting me down & killing my wallet as i was down to 15 ish mpg & when you are use to 30mpg thats a big loss.

well if all goes ok il be doing my cambelt next,ive had it for ages so must get it on.

then i might have a go at a record set by another wrx same spec as mine tuned by the same tuner Racedynamix who mapped mine,when he done mine i didnt want every last drop of power out of it was looking for more yes but within reason & better mpg which i got both,when he did the last tweak he said it was an easy 290bhp with alot left or big safety margin,anyway this other wrx set this record at 298bhp & i think i could get to that if not beat it,i dropped dynamix a message yesterday & the reply was no probs so seams confident.well we'l see.

what sort of bhp are you seeing from 2L over there which are pretty standard?



#39 86 Wonder Wedge

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Posted 04 April 2013 - 10:04 AM

How's the intercooler? Fins all look good, no impact/rock/crap from scoop damage? Not wondering if intake gasket could be bad as well..

 

You can take a can of brake cleaner (I prefer a can of propane, like a torch of some sort, unignited of course) and lightly spray around hose connections, metal to metal connections, welds on the intercooler, ect and see it the idle picks up. If so, there's your vacuum leak. You could also try limiting the vacuum lines off the manifold by unplugging them and capping the manifold ports (go one by one) and watching the vac gauge.

 

Also, you could have jumped a tooth on the belt and the belt stay in the new position on the cam. I've seen them do that several times (when people drive 2x the miles on an interval) and run like crap until they change the belt.



#40 legend01

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Posted 04 April 2013 - 05:18 PM

Hi all,yes intercooler looks all ok i do clean any crap out of it regularly,all seems to be going well at the moment so its looking like it was d.v. still havent been on a long drive yet but seems so much better.thanks for all the help hope i can give the same in return.cheers



#41 legend01

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Posted 23 April 2013 - 06:54 PM

  1. Hi all,well so far so good,still seems to be ok ish alot better than was,going to look at t/belt tomorrow,only thing i have noticed is i changed the rad cap today & after a drive checked it was ok only to find that there were a few bubbles in the overflow tank & top hose wasnt pressurized like it normally is but then went out again & it was ok so dont no if that is start of HG going i just hope not...but we'l see... 


#42 wtdash

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Posted 23 April 2013 - 10:20 PM

Hi,

I'd do a compression and leak down test on your engine....just to check its 'health'. The EJ2xx engines are known for breaking ringlands w/higher miles.

 

If you want info on HP/Torque, I'd go over to NASIOC.com to see what Yanks are getting out of their EJ205/207 engines. Some are putting BIG turbos and injectors on their cars and making impressive #'s. The US uses Wheel HP/Torque, not Crank...so don't be surprised to see lower numbers in comparison to the UK.

 

GL,

TD



#43 legend01

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Posted 03 June 2013 - 06:46 PM

HI all well ive done a few mile & ive put the oem dv back on & at first didnt make a huge difference but now im hearing the turbo spool up & it going alot better so im thinking cat is blocked & putting the recirculating dv back on is helping turbo spool,so do i now get the up-pipe out & have a look to see if it is blocked or what do you reckon any other ideas im still not losing any oil at all it not smoking,let me no your thoughts please.cheers






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