I drive a 1990 Volvo 740 with a B230F engine. Ilsa is 148,200 miles young. Last Sunday the 15th Ilsa quit on me and I have not been able to get her to start until today but even now it has a lot of trouble.
It had been running rough at idle for quite a while and recently she had been getting harder to start. I would need to give her throttle and so forth. Then after taking a friend who had helped me replace the front brakes out for a burger she decided not run anymore. Right there in the Whataburger parking lot Midnight on sunday.

I have done the following trying to diagnose and make her run again.

-Throttle body removed, cleaned, and replaced.
-Idle Air Control Valve removed, cleaned, and replaced.
-Fuel Filter replaced.
-Flame Trap removed, cleaned and replaced.
-PCV Valve/Breather box removed, cleaned, and replaced.
-Fuel Pressure Regulator removed, cleaned, and replaced.
-Fuel Pressure Regulator replaced new.
-Added TL3 brand fuel injector cleaner gasoline additive to 2/3 tank.
-Air Filter replaced.

I know certainly or almost certainly that the following are not reasons for no start.

-Spark plugs produce good clean blue/white spark
-Intank pre-pump functional.
-Fuel Pump functional.
-Fuel System relay functional.
-Fuel pressure regulator functional.

These are the things that are on my list of possible problems to investigate.

-Fuel rail clogs.
-Fuel injectors.
-Recheck, & reclean, IAC valve. Rebuild if possible.
-Check Air Mass Meter.
-Check RPM sensor
-Check, clean EGR valve
-Check, clean Manifold Air Pressure Sensor

Now after replacing the O-ring on the old fuel pressure regulator after cleaning it I was able to start the car today. I immediately went to AutoZone. I picked up an R134 recharge can. I go outside to start Ilsa and she reverts to what she has been doing all week. Engine turns over but won't start. Its as if there is no fuel. I know that it does have fuel getting past the FPR. But my Dad wants to replace te fuel pressure regulator and we do. No luck. As AutoZone was about to close I buy a can of Ether starting spray and spray the air filter. Bam she starts again, but this time a clack clack clack sound accompanies right after she starts.

I then drive to Walmart looking for the air filter AutoZone was out of. No luck so I drive to the 24hr AutoZone about 15 miles away, replace the air filter and drive home.

Ten minutes go by I now leave to to pick up my girlfriend make the minute drive home and we eat dinner. We are about to go to the video rental and Ilsa won't start. I spray the new air filter with ether starting spray and she starts again albeit with a little extra throttle and makes the clacking sound. As we leave to go home she won't start again so I spray more ether on the air filter and it starts and clacks.

I told the gf that Ilsa was jealous and so I walked her home.

I am calling my favorite shop tommorow to set up an appointment but in the meantime I want to try more things on my list. I feel that I have done so much to repair this car and I don't want to involve myself with the fuel rail or injectors if they are difficult. What should I do. My gut is telling me to go back to the IAC valve.

Thanks for reading my incredibly long post.

-Poritz

PS will the ether starting spray mess up the air filter?