My 1994 Volvo 940 (non turbo) wagon has been having a specific problem. Two mechanics haven’t been able to figure it out. The problem happens when it’s raining, about to rain, just after rain, and when the air is damp. When the weather is not like this, it starts and runs like a dream. If the weather is like this, it will do one of two things:

1) It will crank but not start, even after numerous attempts.

2) It will sputter and start (unwillingly). It will idle (reluctantly) and I’ll warm up the car. After warm, I can drive for about 1 mile. At this point, it will stall out as I stop for a stop sign or red light. Then, it will crank but not start. If I wait about 15 minutes (with intermittent failed attempts to try starting it), it will start and I can then drive without it stalling out.

My mechanic friend says it's a Regina system. He replaced the crankshaft sensor, distributor cap, Idle Air Control valve (IAC valve) and manifold absolute pressure sensor (MAP sensor). A different mechanic replaced the coil, only. Unsure if there’s a module that goes with this coil.

If you have any ideas, I’d appreciate hearing them. I love my car and want to fix this problem. Could this be something with the fuse box? Thanks!

 

Was the rotor button replaced?

Has anyone made it rain on the engine? Mist the engine ignition system with a spray bottle while running - and see what happens. Perhaps finding where it's arcing to ground.

 

Many thanks for your reply! I'm pretty sure the rotor button was not replaced. Also pretty sure no one made it "rain" on the ignition system while the car was running.. What does one look for/see when doing this? Also, do you know if the coil for my car (Regina system) has a module? Many thanks!

 

1. Arcing - where the moisture is causing the spark to go somewhere other than the spark plug/s. Most visible in an inside location, with dimmer lighting.

2. Yes, the coil is bolted to the ignition control unit - and is usually sold as one part. I may have only ever seen one bad one. So they are not a common replacement item.

 

also look at your wires - there should be a date code stamped on them - if they are over 5 years, time to replace. In fact I'd probably replace the cap/rotor/wires/plugs just to baseline if you don't know when they were last replaced. +1 on hoonk's advise - I've actually done the misting/dark garage trick to find an arcing wire...

 

Great! Thanks so much for your helpful reply! Much appreciated! I'll try that out.

 

Many thanks for your helpful reply! I'll try these things out. I can't wait to resolve this issue with my car.