Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: maracus on 09 August 2010, 21:19:20
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hi peeps bit of a puzzler for ya...
I recently changed from a td saloon GLS to a CDX estate, both on a manual. i used to get a calculated 36 mpg on a regular basis and occasionally nearer 40 for driving like Gramps. The car didn't exactly feel slow after being used to a 1.8 astra sport. Now i'm in my estate i'm barely getting more than about 30/32 mpg and it feels flat below 2,300 rpm. I had the car 3 up the other week and to accelerate from 50 i had to find 4th, then 3rd to make any sort of effort to overtake. The old saloon could pull a bus behind it like it was empty (not literally but the point is there).
One night i was heading home with my foot to the floor in 5th, could barely muster 115 then when i backed off, a load of red hot embers flew out from the exhaust. For the next day or2 it had its low down pull and was great on fuel, but progressively got worse again.
I assumed it was the cat blocked so changed that. No difference. Then i changed the rest of the exhaust. No difference. I noticed the thermostat seemed to be stuck open as the engine wasn't getting hot properly. Changed that, temp now spot on, all else, no change. I've poured a tub of redex derv into 20 ltrs of fuel and thrashed it, no change. and again by the reccomended dilution, still nothing. Also swapped the egr valve, little solenoid things attached to the vacum pipe from it, and the MAP sensor off the other car, also no difference.
The turbo sounds like it boosts fine and it doesn't smoke more than i can expect. i cant see any obvious hose splits or damage to the intercooler, but, that said, i haven't removed the hoses to thoroughly inspect. Also, it seems spot on as it should when its hot and sunny, but as soon as it starts to think about getting cooler it all goes out the window. 30ish MPG cant be normal even for the heavier estate, surely???
Sorry about the waffle i hope someone can shed light on this, much thanks in anticipation. I desperately want to chip the car :y but want it running right first lol so kinda wanna get it sorted; 450 miles to a tank is starting to get to me
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450 to a tank? I should be so lucky - I get 350 around town out of mine (granted it is an automatic).
Anyway, moving on..
I'd check if the MAF is hooked up to the correct manifold reference line; if it isn't you'll get a general lack of power but no fault codes (been there, done that)
Also that the EGR isn't stuck open and/or the EGR solenoid isn't continually open - then you'll get a lack of power off boost (plus plume of black smoke) and power on-boost albeit less than you should have as you blow boost out of the exhaust. In my case that was solved by disconnecting the vac line to the EGR valve on the manifold, otherwise you'll have a slightly more complicated test (or blank off the connection to the exhaust manifold with a bit of tin can - it'll last long enough to test it, at least!).
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Where are you Maracus?
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i'm in the Huntingdon area, Cambs.
disconnecting the vac line- do i need to blank it off or doesn't it matter? i'll give that a go tomorrow see what that does. not got an airflow meter on this one so doubt its that..
in fact, thinking abut it, i bet it is that solenoid because i didn't swap that one :D (couldnt figure if it just pulls out or what so just left it) Does it undo or just slide off or anything like that?
will blank off the EGR valve anyway i gather this gains a bit more power anyway but want it running right first lol
Will post on here again tomorro to inform of progress...
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Suggest you check the small diameter tube which goes from the underside of the inlet manifold to a pressure sensor (a 1" cube) mounted on the bulkhead .... it's above the dipstick. This get blocked by oil & prevents the turbo from operating effectively thus causing poor acceleration.
Once you have the engine cover off it's a 5 minute job to check. Not sure it will effect your fuel economy though.
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Interesting one!! I would have said exhaust blocked too, did you only change the cat or the whole system?
should be almost full boost at around 2000rpm not as late as you say at 2300, wondering if you have a boost leak in the intercooler or something? if its been driven like mrs daisy for a few years it could be the ecu has to learn, when i swap ecu around as im want to do occasionally it always goes very well for the first few days then gradually the performance settles down as up here on the mountasin roads you cannot boot it,
if the boost sensor is not blocked with crap or its pipe split, and your positive the leak off pipes including the one back to the pump are ok, then try removing the ecu for a few hours, let us know how you get on!!
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have you tried the paper clip test. :y
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Not sure if you are due for a fuel filter, but try the Diesel Magic trick. ::) It will make sure your injectors are clean (Better than just Redex in then tank). :y
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disconnecting the vac line- do i need to blank it off or doesn't it matter? i'll give that a go tomorrow see what that does. not got an airflow meter on this one so doubt its that..
It doesn't matter - the vac feed on a diesel is from a vac pump rather than the engine, so unlike a petrol you're not introducing an unmetered air leak when you unplug it.
And .. you do have an airflow meter ;) Early TDs (like mine) have a MAP sensor only, later models have a MAF sensor just after the airbox.
Here's some pictures from an earlier thread of mine:
Here's the EGR valve - I've unhooked the vac feed from mine since this photo was taken (everything was plumbed in wrong after the previous owners engine swap!):
(http://i45.tinypic.com/9jonld.jpg)
This is the EGR solenoid - yours should be attached to the bracket on the inner wing, not dangling down here like mine was:
(http://i49.tinypic.com/a0waap.jpg)
(Depending on year you may have three hoses on the solenoid with one running to a little filter cartridge)
This is the MAP sensor - it should be attached to the hose going directly to the underside of the inlet manifold:
(http://i49.tinypic.com/w8ars0.jpg)
Like this one:
(http://i45.tinypic.com/2ymaet2.jpg)
HTH!
Oh and yes, I forgot to say - obviously do a new air filter/fuel filter/diesel magic in the fuel filter if it's not all been done recently :)
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cool cool... just a quick point to add (gotta dash- mrs's house for dinner by 5, oven is on!!!) while i got chance...
Based on what my tired mind could take in during the early hours this morning, today i unplugged the two little black boxes, one in turn. The first one i unplugged, the car performance was completely shot, so plugged back in and removed the other plug.
Its abit hit and miss i know but on the way from work, the instant cons gauge seemed to be giving a much better reading than it did. I will not know for sure til i've driven it abit more but will update soon..
..and yes it has had new filters oil and redex in the fuel filter too but i'll try that D magic stuff it seems highly rated on here :)
I'll reply abit better later when i got time to think abit easier and will check the further points suggested.
Not paperclipped it yet, surely nothing will be flagged if the management light aint coming on????
Changed whole exhaust eventually, and as for the turbo, you can hear it spooling up it just seems slow doing so, but the car doesn't open up and pull until the 2300 mark
I'll let ya know a bit more shortly... ta :y
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cool cool... just a quick point to add (gotta dash- mrs's house for dinner by 5, oven is on!!!) while i got chance...
Based on what my tired mind could take in during the early hours this morning, today i unplugged the two little black boxes, one in turn. The first one i unplugged, the car performance was completely shot, so plugged back in and removed the other plug.
Its abit hit and miss i know but on the way from work, the instant cons gauge seemed to be giving a much better reading than it did. I will not know for sure til i've driven it abit more but will update soon..
..and yes it has had new filters oil and redex in the fuel filter too but i'll try that D magic stuff it seems highly rated on here :)
I'll reply abit better later when i got time to think abit easier and will check the further points suggested.
Not paperclipped it yet, surely nothing will be flagged if the management light aint coming on????
Changed whole exhaust eventually, and as for the turbo, you can hear it spooling up it just seems slow doing so, but the car doesn't open up and pull until the 2300 mark
I'll let ya know a bit more shortly... ta :y
this shows codes stored and won't always display the eml light.
try pulling he vac pipe off the egr valve and see how it runs :y
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Changed whole exhaust eventually, and as for the turbo, you can hear it spooling up it just seems slow doing so, but the car doesn't open up and pull until the 2300 mark
That sounds exactly like mine was when the EGR was stuck open - what I presumed (but haven't proven yet) is that my EGR solenoid is stuck in the 'open' position, always supplying vacuum to the EGR valve rather than only supply vacuum during steady cruise states.
Incidentally you don't really gain power by disabling the EGR as the valve should only be open when you are cruising at a steady speed and/or very low throttle angles (er.. not that there's a throttle plate on a diesel, but you know what I mean!) - what it does is pass a certain amount of inert (exhaust) gas into the intake to be re-burnt, thus reducing the effective cylinder capacity and increasing steady-state economy and decreasing NOx emissions.
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Changed whole exhaust eventually, and as for the turbo, you can hear it spooling up it just seems slow doing so, but the car doesn't open up and pull until the 2300 mark
That sounds exactly like mine was when the EGR was stuck open - what I presumed (but haven't proven yet) is that my EGR solenoid is stuck in the 'open' position, always supplying vacuum to the EGR valve rather than only supply vacuum during steady cruise states.
Incidentally you don't really gain power by disabling the EGR as the valve should only be open when you are cruising at a steady speed and/or very low throttle angles (er.. not that there's a throttle plate on a diesel, but you know what I mean!) - what it does is pass a certain amount of inert (exhaust) gas into the intake to be re-burnt, thus reducing the effective cylinder capacity and increasing steady-state economy and decreasing NOx emissions.
often wondered the ins and outs of the whole EGR thing :y
also, 'steady cruise states' is when fuel consumption really suffered, why stuck open?? maybe not opening at all?? Which makes me wonder, would blanking off the EGR not cause such symptoms?
Any hows, yeah... i unplugged the wiring to the EGR solenoid and it goes loads better now, it has throttle response and a desire to accelerate again too. Also, for the first time ever, i managed to maintain an average consumption reading of 37mpg heading into cambridge ;D
also, the turbo spools by the time its around the 2k mark :D
I would think that this 'cure' would indicate that there is a problem, as you suguest, with the EGR. Altough i did change the valve for one i can assume was good, I would think maybe there is a problem along where the other vac pipe goes from the solenoid off under the manifold, or maybe the wiring/some sort of eleccy control unit hidden somewhere in the dash/etc. - any ideas???
will be getting some diesel magic, tried to earlier but the local halfrauds only had petrol magic >:(
I did try previously disconnecting the EGR vac pipe from the valve but it seemed to make no difference.
:y a MASSIVE thank you to all involved so far... you have saved me some serious annoyance!! :y
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Suggest you check the small diameter tube which goes from the underside of the inlet manifold to a pressure sensor (a 1" cube) mounted on the bulkhead .... it's above the dipstick. This get blocked by oil & prevents the turbo from operating effectively thus causing poor acceleration.
Sorry i should of followed this up :D will look tomorrow :y i think thats what im getting at (???the solenoid??)
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glad you found it, first thing now is to thoroughly clean the egr, (unbolt the whole throtle plate housing)you should be able to suck the tube and see the egr moving in and out when its clean,
if this dont cure it then it must be the solenoid
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Suggest you check the small diameter tube which goes from the underside of the inlet manifold to a pressure sensor (a 1" cube) mounted on the bulkhead .... it's above the dipstick. This get blocked by oil & prevents the turbo from operating effectively thus causing poor acceleration.
Sorry i should of followed this up :D will look tomorrow :y i think thats what im getting at (???the solenoid??)
Well Evo was talking about the MAP sensor hose, there, rather than the EGR solenoid; the MAP sensor hose is connected to the inlet manifold so gets full of all the oil & crap & crud that's in there, while the EGR solenoid is hooked up to the vacuum pump which is clean..
But yeah - worth cleaning out that hose and the EGR valve itself in the inlet manifold.
Which reminds me - Omegatoy; is there a gasket between the EGR and manifold that'll need replacing? I haven't had mine off yet to check :)
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Suggest you check the small diameter tube which goes from the underside of the inlet manifold to a pressure sensor (a 1" cube) mounted on the bulkhead .... it's above the dipstick. This get blocked by oil & prevents the turbo from operating effectively thus causing poor acceleration.
Sorry i should of followed this up :D will look tomorrow :y i think thats what im getting at (???the solenoid??)
Well Evo was talking about the MAP sensor hose, there, rather than the EGR solenoid; the MAP sensor hose is connected to the inlet manifold so gets full of all the oil & crap & crud that's in there, while the EGR solenoid is hooked up to the vacuum pump which is clean..
But yeah - worth cleaning out that hose and the EGR valve itself in the inlet manifold.
Which reminds me - Omegatoy; is there a gasket between the EGR and manifold that'll need replacing? I haven't had mine off yet to check :)
nope!! no gasket in there on either end!!!
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Excellent, that makes the job a bit easier ;)
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Well the car is REALLY doing my head in now!!! it seems back to its old ways again, i havent done any more investigating yet, been abit busy, but i have made another strange observation... [smiley=cheesy.gif]
it seems very random- one minute its behaving itself, the next its rubbish again; there is a long (metal?) pipe that runs along between the cam cover and the inlet, from the brake servo to top front of the engine. Im guessing from looking, thats a vacuum supply to the brake servo?? This also has a small cylindrical thing (some kind of one way valve??) with two small vacuum pipes running off it one of which goes to the EGR valve solenoid and cant remember for the other one right now, but anyhows the brakes are sometimes very sharp, and sometimes abit, sedate. I'm now going to try to establish any sort of relation between the brakes not working as well, and the running issues its having.
Could i be on to something here, or is just my clueless, adventurous mind just coming up with random rubbish?? [smiley=huh.gif]
just wondered if i've got a problem with whatever generates the vacuum, as this is not an area i have had much to do with to learn anything about.
:ycheers...
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If the vac pump your on about fails then the brake pedal will go very hard.
What your describing seems normal.
try replacing all the vac pipes leading off to the solinoid and the one to the egr
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Pretty sure the little white thing is a filter rather than a one way valve - on a petrol engine it'd be a one way valve, but there is permanent vacuum from the vac pump so I've always assumed it was there to prevent any crap being sucked into the vac pump and scoring the internals..
But yeah - I'd go with that, too.. replace all the vac hose, maybe leave the EGR valve blocked off from the exhaust and block the vac hose that would normally go to it somewhere along it's length and see if the problem stays away when you do that.. Could be a faulty EGR valve intermittently sticking, or even leaking past it's internal diaphragm?
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If the vac pump your on about fails then the brake pedal will go very hard.
What your describing seems normal.
try replacing all the vac pipes leading off to the solinoid and the one to the egr
my pedal hasn't gone permanently hard, but last night when i pulled up on the drive way and was shunting around, the pedal did go hard after a few uses in short succession but then returned back to normal, thats what made me pay attention to what the brakes were behaving like. I did wonder if this was normal. :-?
I'm going to go get them vac hose bits off the other car now so they're ready to go on when i get some spare time again, probably tomorrow (depending how long it takes).
will update asap... :y
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If the vac pump your on about fails then the brake pedal will go very hard.
What your describing seems normal.
try replacing all the vac pipes leading off to the solinoid and the one to the egr
my pedal hasn't gone permanently hard, but last night when i pulled up on the drive way and was shunting around, the pedal did go hard after a few uses in short succession but then returned back to normal, thats what made me pay attention to what the brakes were behaving like. I did wonder if this was normal. :-?
I'm going to go get them vac hose bits off the other car now so they're ready to go on when i get some spare time again, probably tomorrow (depending how long it takes).
will update asap... :y
yes the pedal will do that if the engine is idling just give it a gentle rev when shunting about this spins the vac pump faster.
the little white thing aaronjb is talking about is a filter for the egr system.I use a inline filter and change it regular. this will help the egr solinoid breath easier :y
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Yeah - I presume that's why on later models the EGR solenoid becomes a two-way valve with a small intake filter on it, as opposed to a sealed system..
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well peeps, i had a go at clearing down the pipe that goes to the MAP sensor, but the old throttle cable i used wasn't really wide enough do do a decent job, but resistance could be felt and it pulled a black slime of oily crap. the car just seems to have a mind of its own with what it does, when it does, regardless of what i unplug/remove/do.
:yThink i'll jot everything down on a piece of paper and systematicly go through it over the weekend and double check everything to try to figure it out. i'll let ya know how it goes...
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might be worth replacing the vac hoses to things like the MAP & EGR solenoid if you can.. I was planning on doing that to mine this weekend, actually, as I have a buttload of 4mm silicone hose lying around from the other car(s) :)
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car is a 2000 facelift - will the paper clip test
work on later models?
thanks
ken
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car is a 2000 facelift - will the paper clip test
work on later models?
thanks
ken
paperclip only works on the 2.5 the 2.2dti needs code reader :y
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ok i paperclipped it and all clear. I then done the diesel magic, no change. I have blanked off the EGR, again no change. Nowthen, i went to swap the ECU from the old 'tank' and i noticed the numbers on the label were slightly different and the one i took out said 'TV' and the other said.. something else, cant remember now but about to go look again. :D I swapped them over and the car refused to start and the light casme on, so i paperclipped the ECU and it came up with; 19, 64, 85, 92. Im now searching for the codes on here (had them the other night, now i cant find them)
:odid they put a different spec. ECU in estates or something?
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The ECU numbers that you're looking for usually end with '427' or '428'.
Lower 30s MPG is about the norm for a manual-boxed TD running locally - proven!
My previous TD Estate constantly achieved 33 mpg around here.
Performance was disappointing, though once chipped, it positively flew! :y
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I think there were four ecu types two for u2.5td and two for x2.5dts. one for manuals and one for autos hth :y
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I think there were four ecu types two for u2.5td and two for x2.5dts. one for manuals and one for autos hth :y
That could well be correct Chas ......
All the manual-boxed X25DT's that I've seen have '427' ECUs.
;)
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THe auto x2.5dt are428 and the u2.5 are 2?? :y
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The ECU numbers that you're looking for usually end with '427' or '428'.
Lower 30s MPG is about the norm for a manual-boxed TD running locally - proven!
My previous TD Estate constantly achieved 33 mpg around here.
Performance was disappointing, though once chipped, it positively flew! :y
well i was beginning to wonder it just seems abit extreme of a difference from the saloon before (37mpg regularly) ;D but i suppose i will just have to accept this as normal. also, i know there is more weight over the rear wheels but my old one would break traction in the wet in second quite happily, ;D it would even try in 3rd sometimes, this one wont no matter how savage you are with revs and clutch. >:( Dont know maybe my old one was chipped before i got it. but then why dont my turbo spool up as early on this one? (possibly down to the old one being chipped?) Plus if im not being gentle-ish with it it'll even droop down to high twenties mpg. think ill do well to get much over 400 miles from this tankfull and i do most of my driving on 60mph roads. So does an estate REALLY use an extra 100 miles worth of fuel per tank?? sure something aint right.
I have checked out the EGR and as far as i can tell, everything is fine there.
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ok i paperclipped it and all clear. I then done the diesel magic, no change. I have blanked off the EGR, again no change. Nowthen, i went to swap the ECU from the old 'tank' and i noticed the numbers on the label were slightly different and the one i took out said 'TV' and the other said.. something else, cant remember now but about to go look again. :D I swapped them over and the car refused to start and the light casme on, so i paperclipped the ECU and it came up with; 19, 64, 85, 92. Im now searching for the codes on here (had them the other night, now i cant find them)
:odid they put a different spec. ECU in estates or something?
19 incorrect rpm signal(crank sensor)
64 fuel qauntity out of range(diesel magic to fix)
85 immobiliser wrong singnal
92 cruise control(if you don't have it ignore this one)
Have you cleaned the swirl pot in the fuel tank yet
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no... but i will do next :y well i swapped the ECU back for the old one and it started fine no probs. No codes with this one back in, im guessing the immobiliser is in the ECU itself?? hence the code 85. As the codes are now gone i'll ignore what came up on that one and get the swirl pot cleaned- is this just a case of removing the big plastic screw cap and lifting out the pump? think i've seen a how to somewhere on here..
Neither of the numbers on mine end with '427' or '428' on both of mine.
could it be that it somehow has the wrong ECU on it??? :o
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the ecu is programed to the car imobiliser.
All fault codes are double digits on the t.d.
try this for swirl pot cleaning
http://www.omegaowners.com/forum/YaBB.pl?num=1251298222
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the ecu is programed to the car imobiliser.
All fault codes are double digits on the t.d.
try this for swirl pot cleaning
http://www.omegaowners.com/forum/YaBB.pl?num=1251298222
:ycheers will get onto that.. looks like i now know why my old one played up with low fuel... ::)
Erm, what should the turbo be boosting to?? :-?
I rigged up the boost gauge off the cavvy earlier to the MAP pipe to see what its doing. It behaves as follows..
My old omega used to take off between about 1750 and 2000 rpm whereas this one is only pushing about 11psi boost at this point. It progressively raises to about 19psi by about the 2250/2300 mark. It holds this until about 3000 rpm where it slowly starts to drop off until about 13/12psi by about 4000 rpm which it holds, pretty much to the limit.
Does this sound like its behaving right?
Also why it so late boosting??
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the ecu is programed to the car imobiliser.
All fault codes are double digits on the t.d.
try this for swirl pot cleaning
http://www.omegaowners.com/forum/YaBB.pl?num=1251298222
:ycheers will get onto that.. looks like i now know why my old one played up with low fuel... ::)
Erm, what should the turbo be boosting to?? :-?
I rigged up the boost gauge off the cavvy earlier to the MAP pipe to see what its doing. It behaves as follows..
My old omega used to take off between about 1750 and 2000 rpm whereas this one is only pushing about 11psi boost at this point. It progressively raises to about 19psi by about the 2250/2300 mark. It holds this until about 3000 rpm where it slowly starts to drop off until about 13/12psi by about 4000 rpm which it holds, pretty much to the limit.
Does this sound like its behaving right?
Also why it so late boosting??
I altered my boost valve at the turbo it now kicks in at 1100 rpm :y
Just remember not to screw the nut up to far only adjust boost valve 1 revolution at a time then take for a run.
If you over do it the engine will self destruct
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[/quote]
I altered my boost valve at the turbo it now kicks in at 1100 rpm :y
Just remember not to screw the nut up to far only adjust boost valve 1 revolution at a time then take for a run.
If you over do it the engine will self destruct[/quote]
sounds scary lol but ill give it a go, just seems odd that its set like this given that TD's are known for low down torque. Plus it strikes me as loosing boost rather early.
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ok progress has been hampered :o pulled up this evening at home and it sounds like somethings fell apart in the rear wheel area (strange clunking going on) so will investigate tomorrow...
oh well back in the turbo at last... :D :y
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Hey peeps sorry to dig up an old post but i thought id give to those that have been following, some closure on the matter (i think...)
I figured my ERG gubbins were all working as they should through different playings about under the bonnet (including rigging up my boost gauge to the EGR pipe to monitor vacuum operation whilst driving) and that everything else sugguested wasn't shedding any light, then looked at the map pipe again...
I found that my MAP pipe was not actually blocked, but had a deteriorated area under the manifold that was starting to fatigue and split ::)so i changed the pipe.
After a good run and a weekend of use, fuel economy and performance seem better (better mileage on first half tank and a car load of people was killing it last time) so am expecting to get the 500+ miles from a tankful like i used to out the old one. So maybe this was my primary issue???
I'm also going to check my intercooler again just as elimination, because i want to remove it and closely inspect for damage as a lot of crud like a birds nest or something all came out when i pulled the rubber cowling off :o so just wanna be sure of that before i get it chipped up and start playing with the boost. :D :D ;D
anyhows, cheers peeps :y :y
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Hey peeps sorry to dig up an old post but i thought id give to those that have been following, some closure on the matter (i think...)
I figured my ERG gubbins were all working as they should through different playings about under the bonnet (including rigging up my boost gauge to the EGR pipe to monitor vacuum operation whilst driving) and that everything else sugguested wasn't shedding any light, then looked at the map pipe again...
I found that my MAP pipe was not actually blocked, but had a deteriorated area under the manifold that was starting to fatigue and split ::)so i changed the pipe.
After a good run and a weekend of use, fuel economy and performance seem better (better mileage on first half tank and a car load of people was killing it last time) so am expecting to get the 500+ miles from a tankful like i used to out the old one. So maybe this was my primary issue???
I'm also going to check my intercooler again just as elimination, because i want to remove it and closely inspect for damage as a lot of crud like a birds nest or something all came out when i pulled the rubber cowling off :o so just wanna be sure of that before i get it chipped up and start playing with the boost. :D :D ;D
anyhows, cheers peeps :y :y
well done mate!!! :y
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Good news indeed!
I fitted an eBay EGR removal kit (listed for the BMW - it's a plain tube replacement for the 'throttle body' type assembly that usually houses the EGR) at the weekend.. no difference, and it turns out my EGR was freely moving, anyway.
Still.. it can't hurt ;)
I best replace the MAP pipe next - I did blow through it, but I didn't actually pull it off from under the manifold (laziness!).. here's hoping replacing that lifts me out of single digit mpg!