Hey guys. Unfortunately our V70 met an untimely death on the highways of Mississippi. No injuries, just a nice car gone.

Anyhow, with the insurance check, we picked up a 740 wagon high mileage special. 274k miles on it's b230f motor. After getting her home, I performed a routine tune up. The dizzy cap and rotor were way burned, and the oil black and thick as coal. But what bothered me is the condition of the plugs - cylinder #1 was way lean and it got progressively richer as we got back to cyl 4. The car runs a LOT better with the ignition taken care of, but it has a definite lean condition off idle. Where should I next direct my investigation? My hunch is a fuel pressure regulator? Or is there possibly something wrong with the fuel pump? Or, should I just wait until I get the fuel filter replaced before I proceed?

 

Likely to be cruddy injectors. Techron is pretty inexpensive. If no improvement, you may need to replace injectors. Check compression, fuel pressure and timing also.
Ed

 

Been running nothing but chevron and texaco gas (with techron, naturally) since I picked it up and haven't seen an improvement. I should also mention I checked compression while replacing spark plugs and all cylinders were in the 150's which I find remarkable for that many miles. I'll hook up a timing light and check that, but I'll have to leave the fuel pressure check to a pro with all the unions and gauges. Thanks and keep the ideas coming!

 

Definitely get the rest of the stage 0 stuff out of the way...namely, the under car fuel filter. The intank pump sock is likely fouled too but that can wait a bit. When doing the filter, pull the fuel line coming from the tank, put a catch tray under it and turn the key on engine off...as long as there is a healthy gout of fuel you're ok there for now. There isn't enough Techron in gasoline to affect anything outside of a lab...buy a bottle of the stuff and dump it into the tank...try to burn the tank out in a day or two. Bosch injectors get replaced a bunch more than they fail...still, the n/a yellow tops are a dime a dozen but I'd recommend having them cleaned and flow tested first. Because the car is new to you, there are no doubt all sorts of issues to untangle. What makes you think you have a lean burn condition? What happens more frequently is unmetered fuel gets into the system causing a rich condition...usually a bad diaphragm in the fpr. I'd also plan on replacing the O2 sensor soon...I do that without even checking them when I get a new Volvo...they're always bad and they're really really important.