1989 Volvo 240, 245 low power, low mpg - need advice

"L.J. :)" wrote in news:1168980616.467571.24520 @q2g2000cwa.googlegroups.com:

Flame trap replace, check tubes connected to it as well (especially small one that goes to the intake manifold)...

Replace spark plugs, distributor cap, etc...

Throttle body clean, make sure the idle switch is working...

Constant idle speed motor is also easy to clean...

Use good gasoline...

You could always do a search on Volvo 240 forums for "Seafoam", or a Google search, and give that a try... I have yet to try it, so I don't know if it is as good as most people say it is.

I get 16-18 city and 24-26 highway, so mine is not that great either, but then again I drive like a maniac in NYC which requires some pedal to the medal so to speak.

Sounds to me like it's not getting enough fuel. Replace the fuel filter and see if that helps. Most common problem for an engine that idles great but won't drive well. Does the engine run really hot when you are putting it under a lot of load? If so, that's a pretty good indicator of a very lean fuel mixture caused by insufficient fuel pressure.

I was having the same problem with my 88 240... engine idled great, but was getting really poor mileage. The fuel filter was rusted to hell and the valve timing was off. Once the filter was replaced and the valve timing adjusted, my fuel consumption improved greatly and is now up near that 22 mpg mark. I also topped off my air pressure in my tires which was low.

Good luck, cton.

LJ :) here again to thank YourName and Zoltamat... and cton for responding. '89 Volvo 245, M47, 125K miles, B230F, non turbo. New Cat converter. O2 sensor.

The flame trap and 3 tubes were cleaned, it's just that i forgot to mention them. Spark plugs cleaned and gapped and distributor cap cleaned with a flat file tip until those 4 points were shiny. Center point clean and the spring seems about right.

The constant idle speed motor rebuild is a GOOD idea, and i think i will undertake that, next nice day weatherwise.

The fuel filter idea i overlooked under the impression that, if clogged, it might cause stalling, or misfiring on long uphills or something noticeable in an acute way. It has not occurred to me that too much fuel consumption could result from not enough fuel flowthrough. So, on the advice of volvo owners who might know more than me, i will undertake that, too, on the next nice weather day.

Timing was done. 'even went to the depth of the timing belt pulleys and their scribe marks, thinking that the rubber junction in the main pulley might have deteriorated causing the front cover timing marks to be inaccurate. 'Got 12 degrees(before tdc) (static) and all scribe marks and keys aligned with respect to one another at TDC. Plus there is no pinging, or overheat condition, nor are the spark plugs white or hot.

Thanks again for the ideas. Keep 'em coming LJ :)

I don't see air mass meter in that list, that's one of the most common causes of your symptom. You might also check the wiring to and the sensor that measures coolant temp for the ECU, it's separate from the one that goes to the guage.

In tank fuel pump mostly Fuel pressurer regulator maybe