Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: tigers_gonads on 22 February 2011, 23:48:19
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bit of a long one so please stay with me on this ::)
my mig started out as a short plenum 2.5 v6 :y
the car run great until one day the bottom end went bang :'( ............... so, i bought a 3ltr lump and dropped it in :y ( kept the 2.5 plenum / ecu / maf / ect )
the engine seemed to run ok but sometimes when you slammed the throttle open, it would seam to bog down abit where as if you fed the power in, it pulled like a train :y :y
tonight, i decieded to go the hole hog and fit it with the 3ltr long nose plenum / throttle body and 3 ltr ecu.
car starts ok ............. but idle's a little high ( about 1200 rpm ) :(
if you slam the throttle open, the engine seams to bog down to the point that is nearly stalls :'( :'(
have checked for air leaks and found non.
have clamped off the icv and it stalls.
the only thing left from the old 2.5 system is the airbox / maf
if you managed to get to the bottom of this without falling asleep then your help / advice would be appriecated :y
cheers steve
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bit of a long one so please stay with me on this ::)
my mig started out as a short plenum 2.5 v6 :y
the car run great until one day the bottom end went bang :'( ............... so, i bought a 3ltr lump and dropped it in :y ( kept the 2.5 plenum / ecu / maf / ect )
the engine seemed to run ok but sometimes when you slammed the throttle open, it would seam to bog down abit where as if you fed the power in, it pulled like a train :y :y
tonight, i decieded to go the hole hog and fit it with the 3ltr long nose plenum / throttle body and 3 ltr ecu.
car starts ok ............. but idle's a little high ( about 1200 rpm ) :(
if you slam the throttle open, the engine seams to bog down to the point that is nearly stalls :'( :'(
have checked for air leaks and found non.
have clamped off the icv and it stalls.
the only thing left from the old 2.5 system is the airbox / maf
if you managed to get to the bottom of this without falling asleep then your help / advice would be appriecated :y
cheers steve
EGR sticking or blocked ?
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egr valve was swapped from the old plenum.
it didn't need a clean but it got one anyway :y
no eml light on reciently and no codes stored :-/
are the 2.5 and 3 ltr Maf's the same ?
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MAF sensor? Worth trying a different one. ::)
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are the 2.5 and 3 ltr maf's the same ?
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Did you keep the old throttle body or swap it for the one on the long plenum?
I would try swapping it, either way. Maybe the throttle pot is different. (it it this which gives you enrichment as the throttle is opened rapidly).
Kevin
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imo disconnect the maf and try with ecu defaults..
also I would check throttle position sensor..
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are the 2.5 and 3 ltr maf's the same ?
I've sold a 3.0 maf via this site, I also have a 2.5 maf currently for sale.
I'll check to see if the part numbers are listed in my ad's...
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are the 2.5 and 3 ltr maf's the same ?
I've sold a 3.0 maf via this site, I also have a 2.5 maf currently for sale.
I'll check to see if the part numbers are listed in my ad's...
Pretty sure they are the same. :-/
Kevin
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2.5 MAF sensor. Bosch 0 280 217 519. http://www.omegaowners.com/forum/YaBB.pl?num=1297614167
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If you didnt use the throttle body off the 3.0 plenum then they are different...one pulls from the top the other from the bottom...
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throttle body and plenum are from a 3lt engine .
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No part number listed unfortunately! I'm sure I made a note of it when I sold the item though, I'll check my p.m.'s later when my Daughter has finished on the p.c. if you need me to...
www.omegaowners.com/forum/YaBB.pl?num=1286275283
I think I still have the throttle body from the 3.0, if you are interested?
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If you didnt use the throttle body off the 3.0 plenum then they are different...one pulls from the top the other from the bottom...
Yes, indeed. What I am wondering is if the connector on the throttle pot is wired the "other way round" on a 2.5 loom since the pot will turn the opposite way. Worth trying it with the 2.5 throttle body on the long plenum IMHO. Granted the cable might not reach, but a few manual blips of the throttle should indicate if matters have improved or not.
Kevin
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I had a previous Omega that originally had a 2.5 engine but had a 3.0 put in it...needed the 2.5 throttle body to work properly :y
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If you didnt use the throttle body off the 3.0 plenum then they are different...one pulls from the top the other from the bottom...
Yes, indeed. What I am wondering is if the connector on the throttle pot is wired the "other way round" on a 2.5 loom since the pot will turn the opposite way. Worth trying it with the 2.5 throttle body on the long plenum IMHO. Granted the cable might not reach, but a few manual blips of the throttle should indicate if matters have improved or not.
Kevin
now thats a good point :y
anybody out there in oof land know if the looms for a 2.5 and 3.0 are the same ?
also i forgot to mention :-[ :-[
the throttle body on the car now ( 3 ltr one ) is a bit on the stiff side :-/
i have just taken it out for a blast and as long as you don't slam open the throttle under load, the car runs ok even though the revs at idle is still too high :(
around 2000 rpm when cold
around 1200 rpm when warmed through :(
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i have just taken it out for a blast and as long as you don't slam open the throttle under load, the car runs ok even though the revs at idle is still too high :(
Exactly what I would expect with a throttle pot problem. As you are opening the throttle it should enrich the mixture to avoid the engine bogging down. As you come off the throttle it will enlean it for the same reason.
With the throttle pot wired the wrong way, it's going to bog down as you open the throttle, unless you're teasing it open slowly enough for it not to matter.
As to the idle, the ECU has a closed loop idle algorithm that's activated by detecting the throttle is fully closed. (throttle pot again!)
If the ECU is not detecting a closed throttle correctly it will probably just open the ICV to a "safe" position that will prevent the engine stalling as it comes down to idle, hence the high and variable idle speed.
It all points to the problem with the throttle pot.
Kevin
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i have just taken it out for a blast and as long as you don't slam open the throttle under load, the car runs ok even though the revs at idle is still too high :(
Exactly what I would expect with a throttle pot problem. As you are opening the throttle it should enrich the mixture to avoid the engine bogging down. As you come off the throttle it will enlean it for the same reason.
With the throttle pot wired the wrong way, it's going to bog down as you open the throttle, unless you're teasing it open slowly enough for it not to matter.
As to the idle, the ECU has a closed loop idle algorithm that's activated by detecting the throttle is fully closed. (throttle pot again!)
If the ECU is not detecting a closed throttle correctly it will probably just open the ICV to a "safe" position that will prevent the engine stalling as it comes down to idle, hence the high and variable idle speed.
It all points to the problem with the throttle pot.Kevin
can the pot be removed and cleaned ? :-/
if so, carb cleaner ?? :-/ :-/
the plenum / throttle body has been sat in the shed for 18 months
i've been led to believe that the only difference between the looms ( plug wise ) is the shape of the LT coilpack plug and the MAF :-/
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can the pot be removed and cleaned ? :-/
if so, carb cleaner ?? :-/ :-/
the plenum / throttle body has been sat in the shed for 18 months
i've been led to believe that the only difference between the looms ( plug wise ) is the shape of the LT coilpack plug and the MAF :-/
The point I'm making is not that it's faulty, but that it's different between the 2 engines. Try running it with the 2.5 throttle body on and see what happens. :y
Kevin
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can the pot be removed and cleaned ? :-/
if so, carb cleaner ?? :-/ :-/
the plenum / throttle body has been sat in the shed for 18 months
i've been led to believe that the only difference between the looms ( plug wise ) is the shape of the LT coilpack plug and the MAF :-/
The point I'm making is not that it's faulty, but that it's different between the 2 engines. Try running it with the 2.5 throttle body on and see what happens. :yKevin
will do :y
when it stops chuffin raining ;D
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Putting the 2.5 throttle body back on the 3.0 engine certainly cured what sounds very similar in issue on mine mate :y
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Putting the 2.5 throttle body back on the 3.0 engine certainly cured what sounds very similar in issue on mine mate :y
swapped them round ( now running 3lt plenum / ecu ........... 2.5 throttle body )
runs great now :) :y :y
thanks for all the help / advise lads
cheers steve
now all i need to do is get it through a MOT :D :D
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Let me know how it gets on mate...have a spare car sat here atm for parts lol