Need some help .I have a 91 240 with 128k.I pretty sure that I need to do a replacement on my fuel computerecr.When it get cold my idle goes up and down.With the car surging a little at times.I cleaned the throttle body.Put Tecron in the gas tank.Still it idles funny.The check engine lightis on .I know it's a fuel mix code.Every year this happens when it's cold.My mechanic told that it might be the problem.In my car now is a fuel computer # 280 000 556.Is there an upgrade # for this ecu?Or do I need to get the same one?Thanks

 

What code is the computer giving? It only does this when its cold out? Idles and runs completely normal in warm weather?

 

Thanks for the reply.I'm in Pa. it's 2% outside now .And 7 PM at night.Iwill get the code tomorrow.Yes it only happens in the cold every year.The first really cold day the check engine light light comes on.Then the car idles funny.I always run 92 Oct. in the car also.The mechanic said the last 5 yrs that it is a fuel mix code.Thanks for your time.

 

I will wait till tomorrow to see what the code is.

But to answer your first quiestion the computers need to be the same #'s

 

Jet Tech I'm getting 2 codes 232 and Diagnostic.I had the egrreplaced yrs ago.The good news is I went out this morning and recleaned the throttle body and Added some more Tecron in a new tank of gas.The car really had a good idle today with no surging.I was in a panic last night.What do you think is causing the 232 code every winter? Thanks

 

Jet I just read onyour older post that the 232 code is a vacuum leak.I'll try the WD-40 spray.On the hoses.So I'm guessing that I might not need a different ECU. ?Why does it happen when it is cold out?

 

Maybe because the air flow is different. Does your car still have the heat rise tube?

 

Tech.What is a heat rise tube?Where would it be?
Thanks
Jim

 

Here's a pic of the heat riser tube taken from the bottom of the car. This pic was taken right after I bought my 91 240 and before I replaced the steering rack along with a bunch ofother front end parts.

Oh yeah and sorry I didn't reply to your earlier post. Been wide open busy lately...I doubt you need anew ECU so let me do some digging on your 232 code and see what I can come up with.

 

Ok, I fondly remember code 232 now that I looked at the description. "Too lean or rich at idle". I had the same code for both of those instances at different times. The first time I had it there was a hole on the bottom side of my intake duct that I didn't see until I removed it. I cleaned the duct up, went around it about 20 times with some electrical tape and have never had another problem with it. I'm going to replace it soon but it really fell to the back burner of priorities because that darn electrical tape is holding like a champ, hech you can't even see it because the duct is black too.

The other time I had that code my fuel pressure regulator started leaking on me. My idle was fluctuating a little along with some part throttle stumbling. I pulled the vacuum line off the regulator and out came some fuel. I would start with the regulator first to see if it is leaking, heck if you can even smell fuel near it and not see it I would still change it.

The other thing is to completely remove the intake duct from the MAF sensor to the throttle body and look it over real closely while flexing it. The accordian style will hide small holes if you don't give it a little flex and look at it VERY closely. Let us know what you find and good luck!!

Dale

Oh yeah, one more thing. Actually I had that code show up 3 times not 2. After I repaired the hole in my intake duct, I forgot to hook up the vacuum line on the back side of it (firewall side) near the throttle body. That will for certain throw a 232....[:@]

 

Thanks Jet Tech.The heat rise tube is on the car.I'll follow your post to a tee over the weekend.Thanks for your help.You havealready saved me the cost ofa ECU.

Jim

 

Well Jet Tech.You gave me the right fix.I put the duct tape on the intake duct.I didn't take it off though. It was atight fit but I got it on good.It was just cold out.I'll do a good fix when the weather warms up a bit.Just by hearing the car idle now somethings different.The car has asmother idle.I cleared the codes in the computer.So far so good.
Thanks
Jim

 

Did you find a hole or tear in the duct? If so I found a new one pretty reasonable here http://catalog.eautopartscatalog.com...ir+Intake+Hose

I need one too, so rather then getting one out of a junkyard that is probably weak from weathering and heat, I'm going to get mine from the place I gave you the link to. For $33.04 I don't think you can beat it. They carry a scantech brand as well fora few bucks less but I can't find one person who speaks highly of anything scantech makes. By the way I've ordered tons of stuff from the place in the link, just be sure to order $75 or more and you get free shipping. It doesn't take long to spend $75 on an old Volvo, especially one like mine...

 

I never got a chance to look for a hole in the duct.I just did a quick fix with taping the whole duct.The weather has been bad in Pa.When it warms up I'll take off the duct and let you know.If I don't get a 232 code back.I'm going to just replace the duct anyway.Thanks for the link.
Jim

 

Hopefully after you remove the tape you'll see a tear or hole, then you'll know for sure what the problem was and rest easy knowing it won't return to haunt you....