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Discussion Starter · #1 ·
I have a 93 volvo 240 which has been running great since about a month ago.
Im a 22 year old volvo tech out of SAFE but all I know are the new volvo's. I have no experience with the 240 systems, nor any tech at work to help me. Here was I have going on. The 240 will idle great but as soon as you off idle it, it will start bucking and misfiring bad. Under a load or just sitting there in park.
fuel pressure within specs, maf with in specs, i've changed the ecm and had no luck. ect, knock and tps all within specs. I was wondering if the ignition module might be bad? When it starts misfiring, it's running rich, you can smell it. I can't figure it out and it is kicking my butt. I've already put both fuel pumps, cap rotor coil plugs maf and a flame trap. I hate throwing parts at it but theres senior volvo tech here. The other volvo tech is a toyota master who/s been woking on volvo's for as long as i have 1yr. Any input would be a great help.
 

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Also I would look at the TPS.
Has anything else been done to the car lately?
You didn't replace the rear main seal did you?
 

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Discussion Starter · #4 ·
Never changed the rear main seal. O2 sensor is swinging good. tps is reading idle and wot perfectly. also the cat glows red during the misfire/bucking ordeal.
have ya'll ever seen the ex 116k module go bad or act up?
 

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If the cat is glowing then most likely the cat is bad.
Dop the exhaust all the way and crank it up and see if it does the same thing.
 

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Discussion Starter · #6 ·
i dropped the exhaust from the mainfold and made no difference. im telling, its a weird problem. but i appreciate the input. anybody see a ez 116k module go bad or cause a similar problem?
 

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I have seen them go bad but very rare!!!
Was it like that when you bought it?

The reason I ask is because if someone else did the rear main seal and installed the flywheel wrong it would act like you are explaining.

The flywheel has to be on a proper way.The speed sensor reads and times off the flywheel.

How does the engine harness look?
 

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Discussion Starter · #9 ·
I've had the car for about a year now. This problem just started to occur about a month ago. I changed the rpm sensor, but the was about
4 month ago and never had a problem. Didnt take the tranny out or nothing like that. It idles fine but as soo as you give it gas it starts sputtering, backfiring ocassionally, and bucking. It will finally get to about 4000rpm and hold it but its the getting there. After awhile with theengine running the way it is, it won't even rev. It's like it loses a cyl. or something, but all of them are firing.
 

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Yes it is very weird!!!
I will see if I can remember anything else.
Other that that I am out of ideas for now but I will see if I can come up with anything else.

One other thing have you checked the timing belt to make sure it didn't jump?
Set up the timing marks and check it.
Don't do it by the crank pulley because it might have spun on you.
 

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The power stage is part of the ignition system.
Most of the time it is located on the Left side inner part of the fender.
It is a sensor mounted on a peice of aluminum.
 
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