1990 740 GL shuts off while cruising, hard restart

Ron Richison · Post by **Ron Richison** » 29 Jun 2008, 09:30

170,000 miles, 1990 740GL non turbo.
Car shuts off while cruising along. Does not sputter or stall, just quietly turns off. I can restart it only by unplugging the MAF sensor, starting and then replugging before taking off again.
No codes from the #2 socket in the diagnostic and a 4-4-1 code in the #6 socket. Only problem is that my Chilton's doesn't list a 4-4-1 code.
New (factory Bosch) MAF sensor installed 2 months ago.
Why would it restart only by unplugging that sensor??

wojeepster · Post by **wojeepster** » 29 Jun 2008, 10:57

by unplugging maf sensor you are setting computer to 'limp home mode' where it doesn't use engine sensors to run. When problem occurs check for spark, check for gas and go on from there.

Ron Richison · Post by **Ron Richison** » 29 Jun 2008, 11:18

So, what does it tell me when it won't start until it is unplugged? Does this eliminate gas?? what else might it eliminate.
I also just read that there is a thermostat that can go bad in your air cleaner box, this will quickly effect your AMM.?? This car has been through some hard problems and 2 AMM's.
ever heard of this?

Ron Richison · Post by **Ron Richison** » 30 Jun 2008, 18:21

still looking for a reply on my stalling problem. I have spark and gas.
How about the crank position sensor. My daughter's Buick did the exact same thing and it turned out to be that sensor. Would it have the same effect for a Volvo? What would the symptoms be for a bad crank position sensor?

fasttaxi · Post by **fasttaxi** » 09 Jul 2008, 18:20

The engine would cut just out at sometimes after hot, sometimes cold.
After plugs, wires, gas filter, and numerous times to the shop, trying to solve the problem. I decided to change the Ignition control module, problem solved. BTW found out the hard way, after ruining a nearly new tire, the rims for the 740&940 are a different offset. Mounting another model volvo wheel on the front will not have clearence enother to the strut. However the wheels will working on the rear.