Greetings,

I'm new here and I'm trying to help a friend diagnose a problem with her car but I'm not very familiar with Volvos.
The patient is a 1990 240, automatic with about 200k miles.
The problem is as follows; when staring from cold the car rubs fine for about 10 minutes or so and then gradually (a minute or so in duration) loses power until it shuts off. At the same time its losing power all of the dashboard warning lights come on. The car will not immediately restart but if you wait about 5 minutes or so it will restart and the problem will usually not replicate itself again during the rest of the trip. If the car is given a chance to completely cool off and is then driven again the symptoms will reoccur. These symptoms occur every time it's driven

In the beginning the alternator was suspect but I'm told by my friend that it was tested by an alternator shop and found to be OK. The shop that she uses suspected that the ignition switch was at fault and replaced it but that didn't solve the problem.

I tried to search for possible solutions but didn't have any success.
Any suggestions would be greatly appreciated.

 

all you need to test the alternator is a volt meter, when the car is running, the voltage should be 13.something across the battery, if it is, then its charging. if its 12.something or less you likely have a alternator or wiring problem (corroded grounds, etc).

hmmm. I'm feeling like a broken record, but I wonder if this isn't a ECT (engine coolant temperature) sensor problem (or related wiring). the ECT tells the ECU (fuel injection control unit) and ICT (injection control unit) how warm the engine is. its basically two temperature sensitive resistors, they are each about 2k ohms at room temp, and 200 ohms when the engine is hot. One resistor is wired to each of the ECU,ICU. the sensor is a plug screwed into the side of the engine under the intake manifold, and has two blue-red wires on its connector (probably covered by black tubing). its usually just behind the #2 intake port (but there's like 3-4 sensors in a row under there, and sometimes they are swapped around, depends on the year).

see http://www.swedishbricks.net/700900F...eSensors1.html for more info.

 

Thanks for the reply. I'm familiar with the alternator test procedure, but I neglected to mention that the car is in Massachusetts and I'm in Maryland otherwise I would have verified alternator performance myself.
What's really intriguing is your comments about the ECT sensors. I believe that theory is definitely worth further investigation.
Thanks again

 

the other thing is, a 1990 should be LH2.4, and should have the little diag block on the left strut tower. it would be well worth the minor bit of effort to read any codes from it. out of range ECT values will often throw a code. not all codes light the 'check engine' light. be sure to read codes from both pin 2 (EFI) and 6 (Ignition)

see Engine and OBD Diagnostic Codes

 

Bench testing the alternator is often useless. What is usually ignored is the CHARGE LIGHT on the dash. If that is not on when the car starts the alternator will not charge and the symptoms you describe may occur.

 

The traditional "no tools" test for an alternator is to shut the car off with the headlights on and watch them dim. As they go off with the key on volvos I'd look at the dome light instead.

Might be good to drive around with this plugged into your cigarette lighter in case the alt has flaky brushes or something that comes and goes.

 

indeed. as an electronics wonk, I go nowhere without my DVM ... its just too handy.

 

Thanks for the suggestions. I'm passing them on to my friend and we'll see what develops.