850 Fuel Injectors

I recently put a fuel cleaner in a full tank of fuel (this is the same
additive my dealer routinely puts in Volvos coming through.) This is a 1993
850 with 120,000 miles on it. It has developed a vibration and appears the
engine is running rough, especially with torque on it. My question is,
would this be an appropriate time to replace the fuel injectors? If so, how
difficult are they to replace? I do most of my own work, but have never
done this job.

I'm concerned I cut some dirt loose and it has clogged an injector.
Otherwise, the engine runs like a champ. Thanks for the help

Randy in frigid Pittsburgh

 

Randy, I have been reading up on injectors today and it seems that they
should be cleaned/checked at 50,000 miles and replaced at 100,000 miles. It
is possible that the cleaner has shifted a minute speck of dirt into the
nozzle area of the injector. Take them to your nearest Bosch dealer who
should be able to clean and test them for you and tell you if they are
approaching replacement time. The usual result of them getting close to
"lifex" (life expiry is that performance and fuel consumption start to
suffer.

Here in South Wales we just have some drizzle at the moment with expected
highs of 8 - 9 degrees and dry for the next couple of days.

All the best, Peter.

700/900/90 Register Keeper,
Volvo Owners Club (UK).

 

I had similar symptoms on my '96 850. Turns out it was a bad wire boot
(had an obvious burn through). I suggest you pull off your wire boots
and check each one very carefully for cracks or signs of damage. You
will usually get a CE light, but perhaps it's not as bad yet on your
car.

 

Thanks guys for the info. I'm going to pursue both leads. Several months
ago, I changed my normal procedure of filling up with 93 octane. I have
since been putting mid-grade (89 octane) and today I filled up my nearly
empty tank with 93 again and put in one more can of fuel additive. It seems
like already there is an improvement. In the meantime I will take Peter's
advice and get the injectors checked and also check my wire boots. Last
summer I replaced the plugs, but did not put in a new set of leads... this
has potential.

Thanks again for the prompt replies. I am also going to check the motor
mounts as I have replaced several on my Volvos over the years.

Cheers,
Randy

18 degrees F / -8 degrees C