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[irratic]

97 2.5 estate.. was running perfect.. it stood for about a month..flat battery.. put new one on. starts first time sounds sweet.. as it starts to warm up it seems to miss. not all the time. ticks over perfect no missfire.. as it gets up to temperature as you're driving ,every time you accelerate it seems to miss. hold at a set speed it seems to be fine.. no oil anywhere near plug leads. sparkplug holes clean..  there does seem to be air sucking it at the top of the engine at the rear. ( but my car sounds the same and runs fine) now the vacuum diverter valve that is at the front of the engine, in between the two big air ducts moves on my car when i rev. on this one it doesn't, is it supposed to when you rev??? any other ideas would be appreciated as i've been trying sort this for a week.. and there is no EM light . it comes on when the ignition is first turned on, goes off and doesn't even flicker..thanks

[TheBoy]

My initial reaction is something HT...

[Bo Bo]

You might want to have read through this thread, I have a similar problem, it may give you some ideas.....

[STMO123]

97 2.5 estate.. was running perfect.. it stood for about a month..flat battery.. put new one on. starts first time sounds sweet.. as it starts to warm up it seems to miss. not all the time. ticks over perfect no missfire.. as it gets up to temperature as you're driving ,every time you accelerate it seems to miss. hold at a set speed it seems to be fine.. no oil anywhere near plug leads. sparkplug holes clean..  there does seem to be air sucking it at the top of the engine at the rear. ( but my car sounds the same and runs fine) now the vacuum diverter valve that is at the front of the engine, in between the two big air ducts moves on my car when i rev[/highlight]. on this one it doesn't, is it supposed to when you rev??? any other ideas would be appreciated as i've been trying sort this for a week.. and there is no EM light . it comes on when the ignition is first turned on, goes off and doesn't even flicker..thanks

Sounds like the font multiram is not working, but that should result in no pickup above 4000rpm, not a misfire. Maybe a vac pipe off at rear of engine?

Marks DTM is the expert.

[irratic]

the front multiram doesn't move... i'm still workiong on the car now..there is a vaccum to the solenoid at the back of the multiram. but disconnect it and rev the engine i get no vaccum that would go to the front multiram.. and yes it will rev abouve 4000 quite easily.. neither can i see the multi ram at the top rear of the engine (the one in the middle of the cam head) moving either . can someone confirm if they should be seen moving while revving the engine?? thanks

[STMO123]

Have a look here

http://www.omegaowners.com/forum/YaBB.pl?num=1153840176

[STMO123]

And here

http://www.omegaowners.com/forum/YaBB.pl?num=1152565204

[Bo Bo]

the front multiram doesn't move... i'm still workiong on the car now..there is a vaccum to the solenoid at the back of the multiram. but disconnect it and rev the engine i get no vaccum that would go to the front multiram.. and yes it will rev abouve 4000 quite easily.. neither can i see the multi ram at the top rear of the engine (the one in the middle of the cam head) moving either . can someone confirm if they should be seen moving while revving the engine?? thanks

This was the advice I got regarding this.

with a running warm engine ... blip the throttle, the rear multiram valve should move ... if you blip it again - but harder and further, the front one should move - but you do need to do it "fast and hard" (missus) ... alternatively, the valves can be manually activated using a tech2 tester ...

[irratic]

ok.. thanks folks.. so basically i should see some movement... which at the moment i'm not... so firstly would these not working for whatever reason give me the symtoms i'm getting or is it a different problem??? and as i seem to have vaccum to the solenoids and its controlled by the ecu ,does that mean the ecu is buggered? or something else??? ie , a fuse somewhere??? and if the ecu has gone down and put it in a form of lomp mode wouldn't the EM light come on??

[STMO123]

Dont be thinking ECU just yet. Try and check that all the vac pipes are connected and in the right place.

[TheBoy]

The multirams not working will make it seem a bit flatter at low revs, but won't cause a misfire...

[STMO123]

Not sure if he's decribing a misfire.... :-/

[irratic]

just rechecked and neither multiram is working.. but have vacuum up to the solenoids... it runs flat alright , don't suppose an ecu off a 3litre will fit just to try it??? just so happens ive got one lying around..

[TheBoy]

just rechecked and neither multiram is working.. but have vacuum up to the solenoids... it runs flat alright , don't suppose an ecu off a 3litre will fit just to try it??? just so happens ive got one lying around..

Unlikely to be ECU.  Won't work anyway unless you have matching immobiliser (or a tech2)

[irratic]

perhaps its not quite a missfire in the term... while driving it seems to miss, yes .. but perhaps more like the old carb cars used to if they were fuel starving when you were accelerating... i really just put it down to a missfire... non of the vaccum pipes have been touched since the car was running fine...

[irratic]

just rechecked and neither multiram is working.. but have vacuum up to the solenoids... it runs flat alright , don't suppose an ecu off a 3litre will fit just to try it??? just so happens ive got one lying around..

Unlikely to be ECU.  Won't work anyway unless you have matching immobiliser (or a tech2)

so if i could get hold of another 2.5 ecu to try it, it wouldn't work?

[STMO123]

Does the EML light up ok when you switch on? ie bulb hasn't gone?

[Bo Bo]

perhaps its not quite a missfire in the term... while driving it seems to miss, yes .. but perhaps more like the old carb cars used to if they were fuel starving when you were accelerating... i really just put it down to a missfire... non of the vaccum pipes have been touched since the car was running fine...

Sounds just like mine except my multirams are working.....

[TheBoy]

just rechecked and neither multiram is working.. but have vacuum up to the solenoids... it runs flat alright , don't suppose an ecu off a 3litre will fit just to try it??? just so happens ive got one lying around..

Unlikely to be ECU.  Won't work anyway unless you have matching immobiliser (or a tech2)

so if i could get hold of another 2.5 ecu to try it, it wouldn't work?

No, it wouldn't. You need ECU to be coded to immobiliser, and the key transponders to be programmed to immobiliser. If you can get ecu, immobiliser, and transponders from same car, that would be OK.

Though its extremely unlikely you have a ecu issue, that would be rare (unless you take it to a dealer, and thats because they are too stupid to use the diagnostic equipment)

[irratic]

EML lights up and goes off as normal when you first start .... me thinks over insure and burn it....its driving me mad...as the EML hasn't come on (during running) i'm assuming it wont have stored any codes??

[TheBoy]

Non working multirams are noticable, but shouldn't make it seem really bad, or significantly 'holding back', esp at high revs.

[irratic]

just rechecked and neither multiram is working.. but have vacuum up to the solenoids... it runs flat alright , don't suppose an ecu off a 3litre will fit just to try it??? just so happens ive got one lying around..

Unlikely to be ECU.  Won't work anyway unless you have matching immobiliser (or a tech2)

so if i could get hold of another 2.5 ecu to try it, it wouldn't work?

No, it wouldn't. You need ECU to be coded to immobiliser, and the key transponders to be programmed to immobiliser. If you can get ecu, immobiliser, and transponders from same car, that would be OK.

Though its extremely unlikely you have a ecu issue, that would be rare (unless you take it to a dealer, and thats because they are too stupid to use the diagnostic equipment)

if its unlikely to be ecu .. ... and i have vaccum to both solenoides , which are controlled by ecu. but no vaccum after them either both solenoids are buggered or i have an electrical issue going to both of them.. are there any fuses to them?? i accept the fact that the multirams not working may not be the problem i'm having , but never the less its the only thing ive found wrong ..LOL.. i think i need alcohol....lots of it..

[Marks DTM Calib]

Think we are all diving off down dark alleys here.....forget the ECU....the engines running isn't it....that should give a clue as to the condition of the ECU...remember, its only a small computer...

Multirams....are the vac lines connected to the correct bits on the solenoids.....is the vac feed to the nose of the solenoid and the output on the side.....if not, you get a vac leak and no multiram operation as when the valve is shut, the output is vented to atmosphere.....

This would also cause a vac leak and hesitation....plus a possible miss fire .

Its cases like this where I use two of the simplest and most effective diag tools you can get.....a vac gauge and a length of tube....

[sounds2k]

... have you tried the paperclip test, in case there are any stored fault codes that may help?

[irratic]

Think we are all diving off down dark alleys here.....forget the ECU....the engines running isn't it....that should give a clue as to the condition of the ECU...remember, its only a small computer...

Multirams....are the vac lines connected to the correct bits on the solenoids.....is the vac feed to the nose of the solenoid and the output on the side.....if not, you get a vac leak and no multiram operation as when the valve is shut, the output is vented to atmosphere.....

This would also cause a vac leak and hesitation....plus a possible miss fire .

Its cases like this where I use two of the simplest and most effective diag tools you can get.....a vac gauge and a length of tube....

ive checked positioning of the vac lines.. they are all ok and the vacuum is strong.. i do have a spare solenoid from behind the front multiram so i'll change that later see if it makes any difference.. perhaps both solenoids have gone down

[irratic]

... have you tried the paperclip test, in case there are any stored fault codes that may help?

not done the paper clip test as the EML hasn't been on so didnt think it would of stored any codes

[irratic]

DONE IT (I THINK) right lads.. cured the multiram prob.. powered up the solenoids and blew them threw .. must of had bits of dust in them... now the multirams work... it didn't cure the missfire... but now ive cured that for future reference.. when checking the leads it was cold and damp last night so didnt notice much. i.e no oil around the plugs.... been out today and did a reinspect... water in the rear n/s plug.. the worst one to get at and the one you cant look down.. sucked it out dried it with hair dryer and hey presto SORTED...i assume the engine ran fine untill the water turned into steam then caused a bad connection. as the plug lead is relatively sealed the steam could't go anywhere so condensed . so at cold it was fine.... the water runs around the plastic catch plate where the wipers are then soakes the soundproofing underneath which is right above that plug lead.....thanks for all your help

[STMO123]

Well done. Really glad you sorted it  

[irratic]

spoke to soon AAAAAHHHHHHHHHHHHHH. just done a load of miles up the motorway and this is the problem....it misses when you slightly accelerate... boot it with kickdown 6000 revs no problem , pulls your arms out. hold it at a steady 30,50,70 no problem.touch the accelerator slightly and hold it there it misses until its climbed speed wise to a coasting speed then misfire goes. stop at a juntion and pull off it missfires again untill you reach the speed where its not trying to accelerate. if while its missing you floor it. it'll drop down a gear and pull away no problem.... an ideas lads ?? anything..

[TheBoy]

Sorry, no real ideas. No more water has got in has it?

I've always had a feeling this is HT related, and said so earlier in post. I still think the same. Though usually shows up under heavy acceleration as well.

Are the plugs good? What about leads and DIS? Has water been dripping on DIS?

[irratic]

everything else seems dry and no contact with water...its a strange one...engine was too hot tonight to strip down to check the back plug and lead so i'll check tommorow..thing is when its stationary you cant get it to constantly missfire so even pulling the leads while running one by one wont help.....
question: if one of the lamda sensors had gone down the EML light would come on wouldn't it???
  i keep saying missfire.. not even sure its that anymore....i would of put it down to fuel starvation like blocked fuel filter but it responds so well with kickdown.....maybe time to put it on a rolling road...

[JamesV6CDX]

Still sounds HT related.. miss under load...