Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: TheBoy on 19 September 2012, 20:40:56
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Whilst fresh in my mind...
When he turned up, O2 BLMs:
Integrators, around 100 (low)
Idle (B1 - 190, B2 - 160) (high)
Partial Load, around 130 (good)
Air/fuel ratio (Rich/Lean) seemed sluggish at idle, flipped at about 1Hz at 2000rpm, lazy lamdas, both banks.
Reset BLMs, took for drive, all around the 130 mark, except at idle, when integrators crept to 150ish, with Air/Fuel showing lean until then, then flipped at 0.33 - 1Hz
Seemed slightly down on power to me, although Webby said otherwise. MID readings for instantaneous consumption seemed quite low - I'd expect mid to high 30s average when cruising 50-60mph, reality was mid/high 20s. MID has correct 035 config, and readings seem to match Webby's experience of it using more fuel recently. This leads me to suspect that the engine is really using that amount of fuel, rather than leaks (which I couldn't detect, or smell).
After test run, brakes still cold. EGR can get to about 55% before the thing really splutters. Injector cut-off exactly as expected.
MAF, at idle, with A/C off, 9kg/hr.
Any views/ideas?
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Exhaust wadding breaking up and strangling the engine? (That's what I'm starting to suspect on mine, but must check the other things too)
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Was also thinking blocked exhaust. Although I don't understand all that flipping stuff.
Awaits reply from Kevin Wood. :)
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Exhaust wadding breaking up and strangling the engine? (That's what I'm starting to suspect on mine, but must check the other things too)
Thats a valid point :y, although Webby reckons its not down on power.
Any way to check, didn't notice it needing a haircut
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Any way to check, didn't notice it needing a haircut
Sadly I can't think of one - short of cutting the boxes open or just replacing it on the off chance.. I can imagine it's possible for the centre sections to get bunged up if they lose their wadding and, for whatever reason, it doesn't make it all the way to the back.
Could easily bypass the rear box but not so easily bypass the centres :(
Could the timing belt have jumped a tooth? I can't remember if it's been done recently or not on that car.
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Exhaust wadding breaking up and strangling the engine? (That's what I'm starting to suspect on mine, but must check the other things too)
Thats a valid point :y, although Webby reckons its not down on power.
Any way to check
Cable tie a rubber glove on the tailpipe and start it up. If healthy it should pop the glove after a couple of seconds idling. I've seen them so bad (and not leaking) that the glove hardly inflates!
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thanks very much for the readings and time spent on the car. Its very much appreciated. I have no real understanding of those figures but as we discussed I'll give it a full service with new fuel filter and air filter. Do you reckon if i replaced the o2 sensors that would be the next logical step? Cheers :-)
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sorry James only just seen your post. That certainly sounds like a plan. I presume cable tie it up tight ?
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Could the timing belt have jumped a tooth? I can't remember if it's been done recently or not on that car.
That crossed my mind as well. I think its nearly due.
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thanks very much for the readings and time spent on the car. Its very much appreciated. I have no real understanding of those figures but as we discussed I'll give it a full service with new fuel filter and air filter. Do you reckon if i replaced the o2 sensors that would be the next logical step? Cheers :-)
Try JamesV6CDX's suggestion above as a test as well..
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sorry James only just seen your post. That certainly sounds like a plan. I presume cable tie it up tight ?
No need to cable tie, just hold it on.
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Remove lambda, fit length of pipe to a pressure gauge through open window to cabin. Need to rig something up.
Although in all cases it blew the pipe off the lambda boss if blocked before a reading cold be taken. ;D
The slightest gas escape will fill a glove btw. It's a lot if volume.
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Is it getting up to temperature?
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Is it getting up to temperature?
Yes - both gauge and ecu CTS
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Is it getting up to temperature?
Yes - both gauge and ecu CTS
:y
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More I think about it, I keep coming back to MAF. Be nice if any other 2.5 owners can get a MAF kg/hr reading at idle, AC off. I always thought a 2.5 should be around 11-12kg/hr with A/C off.
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More I think about it, I keep coming back to MAF. Be nice if any other 2.5 owners can get a MAF kg/hr reading at idle, AC off. I always thought a 2.5 should be around 11-12kg/hr with A/C off.
From memory, that sounds about right... while since I had a baby V6 though :-[
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Cheers guys. Sorry what is wadding? And I'm presuming that if the exhaust is blocked then that could be why jaime got lazy o2 sensor readings?
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Cheers guys. Sorry what is wadding? And I'm presuming that if the exhaust is blocked then that could be why jaime got lazy o2 sensor readings?
Padding in the zorst to reduce noise :)
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Cheers guys. Sorry what is wadding? And I'm presuming that if the exhaust is blocked then that could be why jaime got lazy o2 sensor readings?
Lazy readings are due to lazy lamdas.
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Ime if the exhaust has been blocked by wadding you will know something is badly wrong.My car lost at least half its power when it happened. I struggled to get to 70mph up the M11 and daughter got to Stansted too late and missed her flight - which went down well. ::)
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ok thanks. So could the blocked exhaust contribute to fuel loss in addition to the lazy lambdas? sorry just trying to get my head around it :-) ps re the maf i could chuck Ralfs on and see if that improves things? :-)
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Exhaust blocked also saps power, so engine has to work harder = more fuel used
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ok thanks. So could the blocked exhaust contribute to fuel loss in addition to the lazy lambdas? sorry just trying to get my head around it :-) ps re the maf i could chuck Ralfs on and see if that improves things? :-)
Leave it a day or so before changing MAF, see if any 2.5 owners can get a reading first :y
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ok brilliant cheers for that. Almost forgot the one simple thing you asked me to do lol. The inst. Con readings were very iratic but stayed mostly at around 45 mpg
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Is it getting up to temperature?
Yes - both gauge and ecu CTS
What about intake air temp sensor readings?
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When I had my stainless exhaust fitted it was although I just broke free from towing a tractor or something....the exhaust must have been so blocked..
Maf was the original problem on my car. Convinced it then shafted my exhaust plus O2 sensors :(
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I'd regard that MAF reading as low on a 2.6. Not had much cause to worry about MAF readings on non DBW engines though. Different matter on 2.6s.
High idle trim might back up low MAF at idle, but trims look OK at partial load, which is where the economy will get hit. I take it there are no signs of an air leak?
High MID fuel consumption suggests injector duration is high, and, if backed up by real world consumption, the engine is either running rich, more heavily loaded or not running efficiently. That could be down to timing out, blocked exhaust, air leak into exhaust system or lambda sensors. Is it remaining closed loop at all times when it should? Excessive consumption while the trims stay normal favours blocked exhaust or timing out, IMHO.
The following might be useful:
Compare MAF at hot idle with another 2.5
Compare injector duration at hot idle with another 2.5
Try a CO meter in the exhaust and see if the emissions are to pot.
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Try running it with MAF disconnected for a while - just unplug it ;)
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Morning guys,
Once again thanks for all the input to this puzzler. Real awesome to see some real diagnosis especially for me wanting to go in to the field ;)
Ok, I'm in danger of being boggled by science here. So just to recap, I should be taking the following action:
- Awaiting the results of anybody else who can compare the 2.5 readings with theirs. Not really too sure if there's going to be many offers as presumably they'd need a TechII to get the readings? :-\
- Pop a marigold on to the end of the exhaust and test whether it fills up and blows off within a few seconds. This will indicate a blockage and I'll feed back the results tonight hopefully
- Swap out fuel filter and air filter and routine service (due anyway)
- Unplug MAF and run without to see if economy gets better
- Replace O2 sensors. I will do this but I'll have to get use the college ramps. Can i blowtorch these if plus gas not working? don't like the idea of burning residue from a chemical but you can tell me if ill kill myself or not ;D
Thanks guys, you're all stars! :)
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not sure but I have experienced , a small hole on exhaust pipes.. no remarkable noise but consumption changes..
and we hardly found it.. besides as said , air leaks also effect..
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My 2.5 used to have an idle MAF reading of around 11Kg/h with AC off.
Do check the breather pipes are not split and also check for any other airleaks. I have seen the larger breather split near its base and cause very similar running and operation without affecting idle.
Unlikely to be MAF and the slow lambda readings hint more that its having to adjust across a wider range to go lean/rich (which is backed up by the learnt values)
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My 2.5 used to have an idle MAF reading of around 11Kg/h with AC off.
Do check the breather pipes are not split and also check for any other airleaks. I have seen the larger breather split near its base and cause very similar running and operation without affecting idle.
Unlikely to be MAF and the slow lambda readings hint more that its having to adjust across a wider range to go lean/rich (which is backed up by the learnt values)
hmmm. i did the breathers 1500 miles ago. and i remember thinking the breather pipes were split where they connect to the plenum (or breather bridge). 4500 miles ago i also changed the clamp on the big pipe to breather box for a jubilee clip. maybe rechecking of all of the above???
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ps, would a test for this air leak be to spray carb cleaner in the suspected pipes while running??
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I would take them off and physically examine them. At this stage we need to be 100% sure so we can tick them off the list of suspects.
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I would take them off and physically examine them. At this stage we need to be 100% sure so we can tick them off the list of suspects.
will do kevin thanks :) was just going to try and see if i could see a visible leak.
also it appears that my maf is down as mark got 11kg/h and i'm getting 9
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Indeed it is but that does not mean the MAF is at fault, its simply an observation that the measured air mass is lower.....e.g. a potential air leak is present.
In the case of the large breather (which it may well not be), air would be leaked in before the throttle and idle control valve hence idle is unaffected other than the upstream MAF reading is lower.
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Indeed it is but that does not mean the MAF is at fault, its simply an observation that the measured air mass is lower.....e.g. a potential air leak is present.
In the case of the large breather (which it may well not be), air would be leaked in before the throttle and idle control valve hence idle is unaffected other than the upstream MAF reading is lower.
ok thanks mark, i'm replacing fuel filter tonight and ill check the pipes prob at weekend. and ill also do the marigold test tonight too :)
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Indeed it is but that does not mean the MAF is at fault, its simply an observation that the measured air mass is lower.....e.g. a potential air leak is present.
In the case of the large breather (which it may well not be), air would be leaked in before the throttle and idle control valve hence idle is unaffected other than the upstream MAF reading is lower.
ok thanks mark, i'm replacing fuel filter tonight and ill check the pipes prob at weekend. and ill also do the marigold test tonight too :)
Quite robust those gloves ... ::)
MARIGOLD (http://www.youtube.com/watch?v=BNHVh9-tz_Y) ;D ;)
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ok chaps, evening was going well. marigold was instantly blown off on start up and i had it tied with a cable tie. Great. I then go to get the fuel filter off. Its off. But so is part of the fuel line :-( I'll post pictures later and i know it's fixable but could have done without this. Anyway anyone know how to fix this? Also to add insult to injury the other clip is very loose on the new filter. I've put the yellow cap on the one end but still have a fuel line free which I'm very nervous about. Please help :-( :-( :-(
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ok been reviewing how to repair this. Am i right in thinking that i get a thicker diameter fuel line and cut a short piece to go over broken fuel line to link broken fuel line to fuel filter and then jubilee clip both tight? If I've got that right then any idea what diameter fuel line to use? Sorry lads but just worried as i currently have an open line at the moment :-(
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Have replied by pm webby but basically yes :y
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cheers lazy, youre the best! :)
xxxxx
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cheers lazy, youre the best! :)
xxxxx
As I said, it's only a "temporary" repair and must be petrol rated line. But you would be better sourcing the right pipe and replacing it :y
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Hi Guy's. This sounds very similar to my problem see thread http://www.omegaowners.com/forum/index.php?topic=106685.0 (http://www.omegaowners.com/forum/index.php?topic=106685.0)
Thanks for the input on that one. Had a miraculous recovery with it. Put a coil pack from Steve at Omega Spares on, which didn't cure it. However, a couple of mornings later it started no problem but after this is when I noticed the MPG drastically dropping.
So, I too have high consumption if you watch the fuel gauge but the instant cons on the mid is telling me she's doing 38 at 30-40mph, when I release the throttle and free wheel it goes upto 999.9! Which may well be normal.
I noticed the fuel pressure vacume pipe was disconnected n thought, wahey that's it! No chance lol. My injectors sound like they are really working hard, they are loud and can be heard in the car. Could the fuel pressure too high if the release valve doesn't work? I don't know how it works i.e. does the vacume increase or decrease the fuel pressure?
Had the plenum off the other day, really clean, breathers too. But I have a slight hissing sound coming from the rear of the plenum on the drivers side, hopefully I'll have the scuttle off today n get my head in as far as I can to find it. The hissing changes when I move the pipes around, so something ain't right. Other than the split breather mentioned here is there anything else I should look for?
When I disconnect the battery the rough startup happens every time I reconnect it, almost like the ECU has senile dementia lol. The EML doesn't light up and the fault codes (0170, 0173) are also gone then after about 8 miles they are all back. If I disconnect the MAF (thanks to a hint on here) when rough starting she rev's sweetly at 1500 no problem. Reconnect the MAF and idle drops to 500 revs. Does this indicate a knackered MAF.
Sorry Webby, didn't mean to hijack you're thread but thought you might recognise my car's problems.
Cheers in advance
Dave
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found a motor factors that has 10mm rubber fuel hose. i'm presuming thats about the right size to fit over the existing plastic line.
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I'd probably go for 8mm, but best to measure it. It will need to be a tight fit.
You can also get fuel line repair kits which have inserts to fit into the plastic fuel line to make it rigid so you can securely tighten up a pipe clip over it. Or just get someone breaking a car to send you the complete section of line. :y
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thanks Kevin. I tried to repair it but it didnt work. I went for ten mil. I tightened the clamp as much as possible but still it didnt work :-( I'm going to replace both hoses. I put a request for the part numbers in gen chat if anyone can help :-)
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thanks Kevin. I tried to repair it but it didnt work. I went for ten mil. I tightened the clamp as much as possible but still it didnt work :-( I'm going to replace both hoses. I put a request for the part numbers in gen chat if anyone can help :-)
Or PM one of the breakers, if you're lucky, one will have a car still, and whip it off for a reasonable charge :y
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Hi
I had this sort of problem on my 1998 25 v6, drinking petrol, the best mpg being was 20 mpg, change theromstate, it was reading but taking its time to climb, rad cleaned as well, major improvement, now mid 20's around town and high 30,s on a run and alot quicker, coolant sencer thought the car was still cold after a 10 mile drive so keep the ecu on enrichment. :)
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So Webby, did you get anywhere with your consumption issues?
Filled the Omega earlier today and got 18mpg on the last tank - granted that was mostly around town with a bit of short cruising work, but also mostly driving fairly sedately.. I really must look into it :-\
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So Webby, did you get anywhere with your consumption issues?
Filled the Omega earlier today and got 18mpg on the last tank - granted that was mostly around town with a bit of short cruising work, but also mostly driving fairly sedately.. I really must look into it :-\
Shit, I only got 17.0, and I'd been driving like Miss Daisy on my slippery tyres.
But who cares when its 74.9p per l
And I'm convinced I've got another gas leak. Fekking thing.
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thanks Kevin. I tried to repair it but it didnt work. I went for ten mil. I tightened the clamp as much as possible but still it didnt work :-( I'm going to replace both hoses. I put a request for the part numbers in gen chat if anyone can help :-)
Or PM one of the breakers, if you're lucky, one will have a car still, and whip it off for a reasonable charge :y
He was lucky. :)
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So Webby, did you get anywhere with your consumption issues?
Filled the Omega earlier today and got 18mpg on the last tank - granted that was mostly around town with a bit of short cruising work, but also mostly driving fairly sedately.. I really must look into it :-\
Shit, I only got 17.0, and I'd been driving like Miss Daisy on my slippery tyres.
But who cares when its 74.9p per l
And I'm convinced I've got another gas leak. Fekking thing.
I'm sure your "Miss Daisy" is probably my "Schumacher" ;D I used to get more like 22mpg doing this kind of driving, which more or less agreed with the GID saying 23.6mpg overall.. I'm fairly convinced something has changed, somewhere, in the car; I'm just not sure what yet.