Hello -

I have a '91 240 sedan that sat without driving it for a couple months and now I am having some issues...
The first thing that happened was the alternator stopped working. I replaced the voltage regulator and it started right up. I drove it for approximately 20 miles without incident. Before I left to drive home it started raining very hard with strong winds. I made it only 1/8 of a mile before I lost acceleration - I tried pulling out from the driveway and it just wouldn't respond. I crawled along for another 1/8 of a mile and turned off the road. I had a spare fuel pump relay (always keep a back-up) and put that one on and it seemed to fix the issue. I drove another 5 miles in heavy rain before the acceleration problem returned. I put the original relay back on and it started working again. I drove the rest of the way home in a heavy, heavy rain. The next morning the car started a little rough, and I had not gone more than 1/2 a mile before the problem returned...with vengeance. Now the car won't turn over unless I play with the accelerator pedal and crank it a number of times. Then it sounds terrible until I get it to a high RPM. Then it sounds more normal, but will stall out after a few seconds. I changed the plugs, wires, cap, and rotor. I cleaned the mass airflow sensor and throttle body. I cleaned all the grounds that I could find. I bought a new fuel pump relay. The crank position sensor wires look good. I am about to jump the fuel pumps to see if they are working. It just seems like it is electrical, what with the rain. Any advice would be much appreciated!

 

Replacing a voltage regulator will not make the car "start right up" ( the battery should be still weak) Yes you replaced the voltage regulator - is the alternator now charging? Do you have a voltmeter? What is the voltage when the car is running?

 

Yes, I had to recharge the battery. Once I did that, I checked it with my volt meter. It was reading over 12.6. After I started the car, the battery was reading 14.25 or so.

 

A 91 does have limited self diagnostics. Are you familiar with the rectangular black box with a wire plugged into the top of it under the hood on the drivers side? Plug the wire into port #2, press the button for one second (with the key on), and 3 digit codes will flash on the red bulb. Those codes can be very helpful for a diagnosis. I always used a book to translate them - but a quick check on google looking for "lh 3.1 codes" brought up many possibilities.

A maximum of 3 codes can be stored, and once you read them they can be cleared. A code of 1, 1, 1 - means no codes stored. Here's a partial list and instructions I found.

VCBC - Bosch LH 2.4 System Fault Codes - Volvo Club of BC

If you have no codes you can rule out most fuel injection components, except fuel pressure. (there is no fuel pressure sensor), fuel system relay, etc.

 

Thanks Hoonk.
I am familiar with reading codes. I ran diagnostics on both #2 and #6. I got 1-1-1 "no fault" on both. Good to know it isn't the related to the fuel injection. I'm getting ready to test whether the pumps are working by jumping them at the fuse holder.
D

 

if it sat for a couple of months without a full tank of fuel some water may be in the gas. you might try dumping a bottle of dry gas
into the tank see if that changes anything.

 

Thanks Silvermine! I'll head out and buy some HEAT.

 

um, my 1991 940 and 1992 740 both had check engine lights, which about half the OBD-I errors would light. I think on some 91's it was labeled Lambda (upside down Y) but its the same basic thing, connected to both pin 3 of the ICU and pin 22 of the ECU such taht either unit could light it.