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Omega Help Area => Omega General Help => Topic started by: branders on 15 May 2009, 13:39:50

Title: misfire at higher rpm's
Post by: branders on 15 May 2009, 13:39:50
just had a blow out on the coolant pipe to the heater cut off valve. Replaced that no problem but now i get i heavy misfire and backfire/partial cut out  on a cold engine about 3500 rpm.  Strange thing is that if i let the car idle for obout 15 to 20 mins the rpm where the misfire starts slowly climbs untill it reaches about 5500-6000 rpm. It idles very smooth and i thought that there was just obviously water ingress to one or several of the plugs, its just this misfire thats creapin up the rpm range that is confusin me. any suggestions out there?
Oh and if i leave the car for about an hour to cool down the whole thing just repeats.
dis pack and plugs replaced  about a year ago
ecu fault light flickers on if i maintain rpm at the misfire point, but clears when i back off.
Title: Re: misfire at higher rpm's
Post by: Elite Pete on 15 May 2009, 13:45:17
Have you done the paperclip test to see if there are any codes stored?
Title: Re: misfire at higher rpm's
Post by: cem_devecioglu on 15 May 2009, 14:02:30
Quote
just had a blow out on the coolant pipe to the heater cut off valve. Replaced that no problem but now i get i heavy misfire and backfire/partial cut out  on a cold engine about 3500 rpm.  Strange thing is that if i let the car idle for obout 15 to 20 mins the rpm where the misfire starts slowly climbs untill it reaches about 5500-6000 rpm. It idles very smooth and i thought that there was just obviously water ingress to one or several of the plugs, its just this misfire thats creapin up the rpm range that is confusin me. any suggestions out there?
Oh and if i leave the car for about an hour to cool down the whole thing just repeats.
dis pack and plugs replaced  about a year ago
ecu fault light flickers on if i maintain rpm at the misfire point, but clears when i back off.

increased pressure in coolant system and misfire sounds bad to me.. :-/

Title: Re: misfire at higher rpm's
Post by: branders on 15 May 2009, 14:20:54
no not done the test yet will get that out the way and get back to you.
i dont think the coolant is over pressure, the pipe was so perished from inside out! i think it was just a matter of time for that pipe. Just makes me wonder about the rest of the rubber pipework
No mayonaise in eitther system and did complete head gasket change bout six months ago.
Title: Re: misfire at higher rpm's
Post by: Ghost on 15 May 2009, 14:24:46
Sounds very similar to the probs I had. Paper clip test said cs sensor. but then again yours might be something simple.
Title: Re: misfire at higher rpm's
Post by: cem_devecioglu on 15 May 2009, 14:31:20
Quote
no not done the test yet will get that out the way and get back to you.
i dont think the coolant is over pressure, the pipe was so perished from inside out! i think it was just a matter of time for that pipe. Just makes me wonder about the rest of the rubber pipework
No mayonaise in eitther system and did complete head gasket change bout six months ago.

ok then :y

try the paper clip test..

Title: Re: misfire at higher rpm's
Post by: branders on 15 May 2009, 14:55:39
ok, done the test got code 19, which i believe is "no rpm signal"
is this sensor at the back next to the water hose for the heater cut off valve?
I had to disconnect a plug near there to gain access and i'm hopin that it's not connected again properly.