Please help!
#1
![Default](/forum/images/icons/icon1.gif)
To start with the car is a 1990 740 GL non turbo. I bought it 2 days ago and i have been in the garage messing with it since i brought it home. So the car drives fine when the engine is cold, but when it gets warmed up it chokes and loses power above 2000 rpm. The rpm gauge goes erratic and the whole car surges. It is very difficult to decipher if it is air, spark, or fuel. I absolutely cannot figure it out. I ran the codes and it appears its popping for faulty signal to/from air mass meter, and RPM sensor signal absent intermittently. Do the symptoms i described sound like it could be this? i replaced the plugs and wires but i haven't touched the ignition coil, distributor or rotor yet. Thanks in advance for the help.
#2
![Default](/forum/images/icons/icon1.gif)
crank position sensors have been known to get erratic when hot, but I'd reset the codes and see if they come back, those could be old codes. I've never heard of a MAF thats thermally sensitive, anyways, they are in the path of fresh air, so they don't tend to get hot.
the ECU (fuel injection control unit) relies on a 'coolant temp sensor' aka CTS to tell it how warm the engine is so it can adjust the mixture accordingly. See here for how to diagnose it.
http://www.swedishbricks.net/700900F...eSensors1.html
the ECU (fuel injection control unit) relies on a 'coolant temp sensor' aka CTS to tell it how warm the engine is so it can adjust the mixture accordingly. See here for how to diagnose it.
http://www.swedishbricks.net/700900F...eSensors1.html
#4
![Default](/forum/images/icons/icon1.gif)
Ive been reading through the forums all day looking for people with similar problems, i don't want you to have to repeat things you probably have a hundred times lol. I am going to try to wiggle the cable around and see if i can tighten it up or anything. Is it tricky to get out and can it be done without removing anything? Have you ever heard of air mass meter, wiring, problems ever effect the way a car drives like that though? I would very much not like to have to spend the money on i new one if i don't have to.
#6
![Default](/forum/images/icons/icon1.gif)
the crank position sensor is on the back of the engine, near the transmission bell housing, and has nothing to do with the MAF/AMM other than that they are both connected to the ECU (actually, the CPS is connected to the ICU, which passes the signal onto the ECU).
the CPS is an inexpensive part, and not /too/ hard to replace, although its kind of awkward reaching it.
the CPS is an inexpensive part, and not /too/ hard to replace, although its kind of awkward reaching it.
#7
#8
#10
#13
Thread
Thread Starter
Forum
Replies
Last Post
MNWILD
Volvo 240, 740 & 940
21
09-10-2020 11:29 AM
Sanel30
General Volvo Chat
1
02-18-2010 09:16 PM