hello forum,

I have recently purchased my first volvo. I have owned several mercedes and still do, but never a volvo.
I see alot of similarities in design and durability. The volvo i purchased is a 1989 240 DL. the problem i am having is coming up as a bad MAF sensor. I am getting code 121. I done a little searching online and saw that you can verify the MAF is INOP by unplugging the MAF while its idleing and if idle improves, the MAF is bad. do you all agree?

 

Welcome to the forum. Better to ask model specific questions in that forum.

 

If the idling improves with the MAF sensor unplugged then it is bad.If the idling gets worse when unplugged then the MAF sensor is OK. Code 121 suggests this sensor is bad however..You can try cleaning the plug connections with an electronis cleaning oil spray and see if it helps.

 

IIRC, you never EVER unplug the MAF while the engine is running, or you stand a good chance of frying either the MAF or the ECU.

you shut things off, wait a minute, THEN unplug it, and the engine should run in 'limp mode' where its running rich, and with degraded power, but at least its running.

 

i apologize. i thought i was in the proper forum for my question. what forum should i be in for a 89 240 dl? thanks.

 

thanks for your advice. here is what i noticed. when i first got the car it was running so bad i could hardly get it loaded on the trailer. no idle what so ever. I started working on it etc. got it running while i was under the hood and sprayed carb cleaner in the intake pipe while doing hard revs. after about a minute of that, it started idleing somewhat ok. not at all perfect though.
I then did the unplug MAF thing and noticed huge idle improvement. however, while maf was unplugged and idle improved, i could not accelerate at all. it was just be sucking air and die unless i let off the throttle. then it would go back to idle. if MAF was plugged in. idle quality sucked, but at least it would rev up just fine. Ideas??

 

89 is a LH 2.4 system, I believe? yeah, if you have codes, you must have LH2.4 (our 1987 240 is LH2.2 and doesn't ahve the codes)

some common causes of bad idle:

• vacuum leaks
• dirty throttle body
• clogged up idle control valve
• bad/flakey engine temp sensor
• bad/flakey crank position sensor
• bad wiring to any of the above

while this FAQ is written for 700/900, it 99% applies to your late model 240 (same B230F engines, same fuel injection, only major difference is, the 240 doesn't have the 'radio suppression relay', so you can ignore anything that mentions that).
Engine Tune and Performance:

following the troubleshooting there will get you a long ways...


p.s. yeah, no MAF == no power. there's no throttle position sensor on these engines, the MAF is how the ECU knows how much air its using, so it knows how much fuel to inject. dead MAF == idle only in limp mode.

pps. clean the flame trap (or replace it if its totally trashed), its likely been neglected. this is under the intake manifold and provides crankcase ventilation. http://www.swedishbricks.net/faq/flametrap.html