Recently my 1986 240 stopped running while driving. I have replaced the fuel pump relay and tank pump as I did not hear the relay click or both pumps running before this. After replacing, the car seems like it wants to start but simply will "catch" for a few seconds and then die out. Tried disconnecting the air mass sensor and the engine ran much better. Does this indicate a bad air mass sensor ( also called air mass meter)? Will the car run with it disconnected? Any help would be appreciated. Prior to this i did have trouble starting, would idle rough until warmed up, then ran good.

Tom

 

Sounds like the mass flow is bad.

Yes if it is bad the car will run better with it unplugged.

 

for an inexpensive one go to www.car-part.com go to the page with the asterisk. You should be able to find one for $25

 

Thanks for the tip on Car-parts.com. Could there be anything else wrong that I might be missing? Also, is it safe to drive with tha AMM isconnected?

 

I wouldn't drive far with it unplugged.

It only goes into a limp home mode.

 

Sounds like the MAF sensor to me. I just replaced one on my daughter's 1989 240. Couldn't find a used one so I bought one (remanufactured) at the local parts store for $170.00. Problem solved.

 

Have AMM on order. I saw in another forum that someone suggested replacing the air box t'stat too. I looked at mine this evening and didn't see anthing other than a spring loaded flapper door that diverts warm and cold air inside the box. It appears that warm air is off the exhaust via tha silver flex hose thatcomes in at the bottom of the box. Cold air enters the divers side of the box via a 2" plastic riser pipe in front of the radiator. This seems to work when pressure is applied to the spring manually, I assume when tie air reaches a certain temp the spring pressure changes and the flapper switches flow to the "cold side. Also, is there a test procedure to ensure the replacement AMM is not defective, I am trusting the word of seller. Sorry for the long winded post.

Thanks,
Tom

 

If the new one is bad the car will run like crap still.

Yes that valve goes bad sometimes. IMO it is a crappy design. When I had mine I pinned it open cutting off the hot air.