check engine
 

so im having trouble smogging my 93 240 wagon and i bought some **** to put in the tank that says it would make it pass smog. ive driven a 1/4 of a tank and now te check engine light is on. any ideas?

Nothing definitive, sometimes fuel additives produce strange running conditions that will trigger O2 sensor codes.

Define the smog color perhaps?

i dont know what you mean by define smog color plus im colorblind anyway. i was kinda thinking the same about the o2. im hoping itll turn off once its got a fresh tank?

You could always pull the codes from the obd reader underhood. That would also provide you w/ an opportunity to clear the cel.

I asked for the colour of the smog, to help further help. For example,

Generally speaking of course

Blue smoke = Oil. Either worn rings or thin oil from infrequent oil changes
Thick White = Burning antifreeze (These also stinks) Head gasket most likely.

I've also seen people put additives intended for coolant or oil into the fuel system, producing various smells and colours. Codes would help, however since it isnt OBD-II, I have little experience with that.

Vile, if you look at that link I pasted in my previous message, it shows how to read the codes, no code reader needed, and what all the possible codes are and likely causes.

All LH 2.4 volvos have this, pretty much everything from 89 to 95. In 1996, OBD-II was mandated, and it all changed.

thanks for your help guys i can always count on good answers from ya!

I say just replace the motor with a diesel from a Volvo big rig. Don't have to smog diesels ya know. ;)

im still not passing smog and i need to know what to clean and how to clean the egr valve etc. my nox is at like 650 which is apparently ridiculous and means its a dirty egr or a weak cat or something. what do you guys think? TnC

an EGR malfunction should show up as a OBD code, like 2-4-1 or something. which injection system does your 93 have? choices are Bosch LH2.4, LH3.something, Regina Rex, and you also might have a "Pulseair' system, the b230fd engine.

high NOX can happen from too lean of a burn, or from what you said. We had to replace the cat on our 87 at about 400K miles due to it not passing smog. we got a OEM cat, the after market ones are junk and won't last 2-3 years.

its the LH 2.4 system. whats a too lean of a burn? do you know where the egr valve is located?

too lean, means not enough gas for the amount of air (the opposite is too rich, which is too mcuh gas for the amount of air).

the EGR valve is under the intake manifold, its connected to a vacuum controller thing thats on the left wheel well, and looks vaguely like a ... oh shoot, do I have a pic?

ok, crummy pic, and its half cut off... the round thing on the top edge of this pic
https://lh6.googleusercontent.com/-1...0/IMG_8944.JPG

that vacuum modulator has two vacuum hoses, one goes to the vacuum spider on the manifold, and the other goes to the EGR valve under the manifold. the EGR valve in turn has a metal pipe that snakes around the back of the engine and goes to the exhaust header, and it has a pipe that goes to the intake manifold. the vacuum modulator also has an electrical connection on the bottom.... when the Ignition ECU tells it, the vacuum modulator opens and lets the vacuum 'suck' on the EGR valve control line, and this allows exhaust gas to be sent to the intake manifold to be used instead of air.

the OBD thing (the black box at the center of my picture) has a test mode where it will tell the EGR vacuum modulator to go ON, OFF, ON, OFF repeatedly so you can test it.... ignition off, put OBD jumper in #6 (ignition), key on to position II (without starting the car), and press the button 3 times for about 2 seconds each time with at least a second between presses, then you shoudl hear the vacuum modulator going klick-klack-klick-klack... disconnect both vacuum lines at the modulator, hook up a clean hose to the top fitting and suck gently on it, and if the moduator is working you'll feel your suction getting shut off, on, off, on.... key off to stop this test. Oh.... if any of the vacuum lines is remotely a little cracked, just replace it.

the other test of the EGR is to disconnect the lower line at the vacuum moduator, and start the car, then you need a little suction pump that you plug into that line and produce a vacuum, when you do this, the idle should stumble badly, if that happens, the EGR is probably working fine.

again, have you read your OBD codes? any sort of O2 sensor, EGR fault, etc should show up as a code. Engine and OBD Diagnostic Codes explains how to read them and what they all mean.

here's some tips on high NOx and other smog problems...
Engine Tune and Performance: