ANSWERS: 2
  • "MAP signal," that's not what I expected. My '72 1800ES has MAP (Manifold Air Pressure) sensor, but my '92 240 and your '93 850 have MAF (Manifold Air Flow), or AMM (Air Mass Meter) sensors. At any rate, they perform the same function, and the literature I have at hand gives a similar interpretation for that code, but using the term "MAF sensor." The AMM (it's common name) measures the amount od air coming into the engine. It works in conjuntion with the O2 sensor which, essentially, measures the amount of unburned oxygen coming out of the engine. They report back to the engine computer, which adjusts the amount of time the fuel injectors spray on each squirt. The engine computer also adapts to your driving habits and the condition of the car for best fuel mixture and lowest emissions. If you pop the hood and find the air filter box, you'll find big, black tube coming out of it, going to the engine intake manifold. Halfway along that tube, you'll find that AMM. Start the car and the disconnect the AMM. If the car runs better without the AMM connected, then it probably needs to be replaced. If not, then work a little bit of fine sandpaper or an emory board into the connector to clean it. Do the same with the spade connectors that fit in. Slather it all up with dielectric grease (available at autoparts stores, keeps water and grunge out, avoids corrosion), and reconnect it. Now, recall that anything to do with the computer in this car needs to be taken with a grain of salt. What kind of computer did you have in 1993? Would you have trusted it to run an entire car? So, watching little flashing lights is not the bast diagnostic method. It just means thatone signal the computer in monitoring is out of whack with another. I got codes, for instance, that both my AMM and O2 seonsors were faulty. It turned out that both were fine. So, do other diagnostics, too. Note that the 1-2-1 code isn't telling you you have a bad AMM, it's telling you that something wrong with the signal from the AMM. When this happened to me, it turned out that there was a leak in the intake hose. You'll see vacuum hoses all over the place under your hood. Any of them could have developed leaks, as could the manifold itself. If you have a leak after the AMM, it will report to the computer on how much air is passing through it, and the computer will adjust the fuel amount accordingly to produce the best fuel-air mixture. Unfortunately, a bunch more air will be coming in that the AMM doesn't know about, so there will be too little fuel in the mix, and the car will run poorly, if at all. I would bet on this being your problem. So, first, do a visual check of the hoses under the hood. There should be a vacuum hose diagram ona label somewhere under the hood that shows how it should all look. Make sure they are all connected properly. Inspect the mail intake hose for leaks, both with your eyes and your fingers. It's probably best to remove this hose to inspect it. If you don't find any problems, another way to do it is to take a propane torch. Disconnect the radiator fan wiring at its relay, start the car (don't run it too long or it will overheat). Turn the torch on, but don't light it. Move it around near the hose connections and along the hoses. Don't forget to check near the fuel injectors, themselves, as the seals might be leaking. What you're looking for is this: if there is a vacuum leak, then propane will get sucked in instead of air, and the engine will race momentarily. If that happens, you've found your leak. If not, there still may be a leak, but it might be under the dash. You'll note that one little vacuum hose goes through the firewall, into the car. This actuates the vents. The easiest (but least conclusive) way to test for leaks here is just to try the vents. If they work well and quickly, it's probably okay. If you hear a whining noise coming from the middle of the dash when the engine is running, or if the vents don't work well, your leak is in there, and heaven help you, because then you're removing things like the glovebox, the stereo and the instrument pod. Not too bad on my car, and mybe not on yours either, but probably not much fun. So, given the symptoms, I'm betting you do have a vacuum leak, somewhere, but it might be a bad AMM. It could perhaps also be a bad O2 sensor, but I wouldn't start there. Good luck, and have fun. -EdM. '90 Volvo 240DL Wagon "Lola" '72 Volvo 1800ES "Galadriel"
  • My lambda light has been on for a while as well on my 93 2.0 20v 850 l car seems ok but its drinking stupid amounts of fuel and smells rich as hell!! ran the diog test thingy and got the 1-2-1 code any ideas

Copyright 2023, Wired Ivy, LLC

Answerbag | Terms of Service | Privacy Policy