I need to know what trouble codes 121, 221, and 321 mean on a 1990 Volvo 740 with a B230F 8-valve single-overhead cam engine. thanks
1990 Volvo 740 base model B230F 8 valve S
121 is the air mass meter, 221 is fuel trim to lean at part load and 321 is no knock enrichment signak from the igntion computer. I would suggest replacing the air mass meter that is mounted to the air cleaner housing for the first 2 codes. the 3rd code I have seen this set by low voltage to computer at start up due to bad fuel pump relay. replace both of them. the relay is chaep.
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I replaced the fuel pump pick up screen and the fuel pump looked like it had been replaced. I just put another one in there but if the MAF sensor is bad it won't read air temp correctly and such, right? If I spray starting fluid in the snoot it will start and run on the fuel and then die. I also powered the fuel pump up independent of key position and tried to start it and it didn't fire. Also, this is the B230F with the Regina Ignition system. Does it have a MAF sensor or is that an ait temp sensor? thanks
no it doesnt have a air mass meter. and shouldnt have a 121 code. let me check the morning when I get back to work and will recheck the codes.
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ok 121 is map sensor signal faulty or missing. it is located on the left strut tower near the firewall, in a silver box. check to make sure the vacuum line is not plugged. the 221 is o2 sensor signal missing or faulty, the 321 is signal shorted to ground or missing. 02 sensors do go bad, have seen several of the map sensor vacuum lines plugged or have water at the low spot reducing signal to map sensor. I would suggest replacing o2 sensor, and if map sensor is pluged in and vacuum line is clear to replace it. check to make sure the cold start is plugged in, it is under the intake manifold on the side towards the engine.
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Would all this make it not start even when I spray starting fluid in it? It used to spark knock, fire and run on the fluid, but since I drove it a bit, the engine light came on, it hasn't run since it's weird.
Also, do I need a Regina Ignition system specific O 2 sensor? someone told me they operated differently than a normal one. thanks
yes you need a specific o2 sensor for the regina cars.
Why would it run for a while with the one I put in it when I replaced it? thanks
what o2 sensor did you put it in it? was it a(NNN) NNN-NNNN should be a ntk brand.
I got a replacement sensor from a local parts store that I have been dealing with for years and is very reputable. The part # XXXXX XXXXX STD SG36. $66.40 was the price. I had to solder the wires to the connector wires. This all was before I knew it had this Regina Ignition system which seems to change a number of small details in the operation of the engine. I did call them and ask them if it was for the Regina system and he looked it up and he said that it didn't say so chances are it's the wrong one, huh? Should I get a Regina-specific one? Let me know, thanks
Yes regina is a totally different beast from the bosch system. I'm not a fan of the cut and solder parts. I do know that a chevy pick up truck uses the same map sensor and is a whole lot cheaper than the volvo one. I would change the o2 and then go from there. have you cleared the computer yet? after readin gthe codes and replacing oxygen sensor. pull fuse #1 inthe fuse block behind the ash tray for a few seconds. this clears the memory(adaptations) from the computer.
ok I'll try that-thanks
If I helped please press the ACCEPT button. if you need to ask more questions feel free. Thanks Mike
20+ yrs volvo technician, Ase A1-A8, L1, A/C certified