Reader Question I have a 1989 volvo 240DL wagon. It starts fine, as soon as I drive a couple miles it starts to run rough,idles rough puts out black smoke,you can smell gas fumes when it’s running like this, it also has a dead spot in the throddle when i accelerate. Then it will smooth out and run fine for awhile. I’ve tried fuel injecter cleaner, that makes no difference.
I should tell you it has 260,000 miles. Could injecters need replaced? it there a test we can try to check them?
Thank you for any help you might have.
Wow that is a LOT of miles. Have you tried the basic stuff, spark plugs, spark plug wires, distributor cap, ignition rotor etc. etc. if not, have your mechanic take a look at those items and replace them as needed.
Black exhaust smoke means, too much unburned fuel. Common causes,
1. faulty oxygen sensor
2. ignition timing issue, ignition is “out of time” – faulty timing belt installation can also cause that
3. worn out items I listed above
4. fuel pressure regulator leaking or faulty
5. Computer system problem
6. Throttle position sensor bad
7. internal engine problems – worn out valves, weak compression etc. etc.
Rarely are the injectors the issue, try to eliminate the other items first
Austin C. Davis