i have a 91 240 b230f engine with 180,000 miles.

it was originally having issues with low idle on cold starts- when it warmed up, the idle was fine. so, we replaced the idle control valve, cleaned the flame trap, cleaned the throttle body. it idles much better when cold now, but as soon as the car warms up (about half way up the temp gauge) the check engine light comes on - code 113, fault in injector- and white smoke starts to come out of the tailpipe.

we've tested the injector leads and all are good. is a clogged injector the only other cause-- or could a bad coolant temp sensor cause this code?

anyone have any ideas?

 

code 1-1-3 is 'fuel trim' (lambda control) too rich or too lean. general cause is a bad O2 sensor or wiring fault related to it.

white smoke usually means coolant is getting into the engine. is there any oil slick on the coolant in the overflow bottle ?

 

thanks for the reply!
nope, no oil in the overflow bottle.
volvo service manual says code 113 is a fault in the injector....am i not reading that right?

 

presumably, your 1991 240 is "LH 2.4" injection. 'fault in injector' is a Motronic 1.8 code used on 960's with the straight 6-cyl 'white block' engines

Engine and OBD Diagnostic Codes

 

thanks for the clarification!
where is the 02 sensor, and is there an easy way to check it?

 

the O2 sensor is screwed into the exhaust downpipe just forward of the catalytic converter, under the car, about where the passenger front seat is.

its connectors are clipped to the firewall under the hood, there's two of them, a square 2-pin connector (power for the O2 sensor heater circuit), and a round 1-pin connector, they are near the wiper motor on a 240 (near the top of the right side of the firewall). unplug the round one, take a couple inch long thin strand of copper wire (like, a single strand from a lamp cord), and wrap one end a turn or two around the connector pin, then reconnect it. use a digital volt meter on a low DC volts setting, start the car, wait for it to warm up and put the red probe on that little wire (I wrap the wire around the probe so I don't have to hold it) and the black ground probe on engine ground (fuel injection rail where the brown ground wires go). once the car is warmed up, the voltage should go from less than 0.5V to more than 0.5 V back and forth every 5-10 seconds. like, 0.1 to 0.3 low and 0.7V to 0.9V high, then back. the exact voltages don't matter, its that they are swinging back and forth. if it is, then the engine is running in 'lambda balance'. if its stuck high or stuck low, then the engine is too rich or too lean, or your O2 sensor is toast. if its too slow going back and forth, the o2 sensor is old and should be replaced.

 

this is so helpful! thank you so much.
I'll give it try asap!

 

seems to be stuck low-- doesn't swing at all.
i guess it's time to replace the o2 sensor.
thanks again for your help!!

 

low means too lean. there *are* other causes for too lean, like air leaks in the intake plumbing between the MAF and engine, or in the exhaust manifold. but an O2 sensor is a pretty easy thing to replace, and they typically need renewing every 100k miles or so.

 

if i clear the CEL, unplug both connectors to the 02 sensor, start the engine and the car still throws the same 1-1-3 code, would the 02 sensor still be the cause?

 

in that case, the code is being thrown because its not seeing ANY o2 sensor at all.

per your volt meter test, the o2 sensor isn't working (or your mixture is way lean).

 

I'd worry more about the white smoke! The OBD1 codes in these cars are hit and miss-- many faulty, confusing readings as a result. Start by taking a compression test; white smoke is indication of a bad head gasket and if you have that you'll get all kinds of code head scratchers. A bad O2 sensor won't cause white smoke.

 

it's not a lot of white smoke-- just a little and only when the temp goes to half way. like clockwork, every time. i start the car and there's no white smoke, no CEL, then as soon as the gauge hits half way, the CEL comes on and i can see a bit of white smoke coming from the tailpipe. does that sound like head gasket? the car does not overheat and does not have oil in the coolant.

 

how about coolant in the oil? creamy yellow-white goo under the oil cap is the first sign.

 

Hard to say-HG problems can be tricky, as oil, coolant, and compression can get mixed every which way. Better take a compression test before going further.

 

just wanted to give an update on this...
I redid the test on the 02 sensor (was not confident with my first results) and it checked out fine. So, I removed the injectors and cleaned them which got rid of the check engine light and no more code 1-1-3 (yay!).
I still have a little white smoke coming from the tailpipe and I do have creamy goo on the oil cap. Scary. I don't have a compression gauge, so i can't test the compression right now--but, signs are pointing to a leaky head gasket right?

 

yup, they are.

good thing is, this is one of the easiest cars ever to do a head gasket on.