I'M NEW TO THE BRICKBOARD. I THINK I'VE STUMBLED ONTO A GOLDMINE AND WEALTH OF KNOWLEDGE.MY PROBLEM IS I BOUGHT THIS 1990 24O, 2 YRS AGO . IT'S BEEN GOOD TO ME, UNTIL 4 MONTHS AGO. THERE WAS A BUILD UP OF OIL ON THE REAR OF THE ENGINE-CLEANED FLAME TRAP!!! THEN WHILE DOING A FULL TUNE UP I NOTICED THE CENTER OF THE ROTOR BUTTON WAS COMPLETELY BURNT. NOW THE CAR WHILE ATTEMPTING TO START THE CAR IT SEEMS TO FLOOD AND BACKFIRE A LITTLE AND AFTER SEVERAL ATTEMPTS IT STARTS. IDLE IS ROUGH AND SOMETIMES IT STALLS WHEN I COME TO A LIGHT OR STOP. I HAVE TO KEEP MY FEET ON THE GAS AND BRAKES REVVING THE ENGINE SO IT WOULDN'T STALL. HERE'S A LIST OF THINGS I'VE EITHER DONE OR CHANGED.
-CHANGED PLUGS, WIRES, CAP& ROTOR ETC.
-REPLACED FUEL & AIR FILTERS-MAIN AND IN-TANK PUMPS-RELAY AND PRESSURE REGULATOR
-CHANGED COIL, POWER STAGE UNIT AND IDLE MOTOR.
- TESTED AMM, IDLE SWITCH, CLEANED THROTTLE BODY, INTAKE MANIFOLD (THESE SEEMED TO BE SUCKING OIL DUE TO THE FLAME TRAP BEING CLOGGED)?
-CHECKED AND CHANGED 25AMP FUSE CHECKED FOR VACUUM LEAKS, CHECKED FUEL INJECTORS (ALL SEEMED TO BE TICKING WHEN THE CAR WAS RUNNING.)
- IS THERE ANYTHING I LEFT OUT?
THERE'S NO PATTERN HAPPENS WHEN ITS HOT OR COLD.IT HAS GOTTEN PROGRESSIVELY WORSE, NOW THE CAR WILL JUST CRANK BUT NOT START. NOTE: MY OD SEEMS TO GET STUCK (OD RELAY MAYBE?) WHERE IS THIS LOCATED? HAVEN'T CHECKED FUEL PRESSURE BURT IT SEEMS TO BE GETTING FUEL TO THE RAILS JUST FINE. PLEEAASSEE HELP?

"THEN WHILE DOING A FULL TUNE UP I NOTICED THE CENTER OF THE ROTOR BUTTON WAS COMPLETELY BURNT. NOW THE CAR WHILE ATTEMPTING TO START THE CAR IT SEEMS TO FLOOD AND BACKFIRE A LITTLE AND AFTER SEVERAL ATTEMPTS IT STARTS."

How soon after your full tune up did things go bad? Right away? Since you changed the cap and rotor were they the correct replacements, and did you put them in properly? Are all the wires fully seated, especially the coil? That could certainly cause a world if done incorrectly.

Did you check for codes in the ECU? The crank sensor would throw a 2-1-4 code if it starts dropping pulses.

THE PROBLEM STARTED BEFORE THE TUNE-UP WAS DONE. THE WIRES CAP AND ROTOR ARE ALL FINE - SWAPPED THEM IN MY NEIGHBORS '90 240 RAN GREAT!!. THERE ARE NO CODES ONLY 1-1-1. I'M CONTINUALLY ELIMINATING EACH SENSOR AND DIAGNOSING COMPONENTS. I'LL TAKE A CRACK AT CHANGING OUT THE CRANK SENSOR TODAY, I HAVE A SPARE THAT I KNOW IS GOOD. THANKS FOR THE INFO AND INPUT. IF ANYTHING ELSE COMES TO MIND DROP ME A LINE. THANKS.

The AMM may still be bad...see the FAQs page on AMM. See if you have the pink-labeled ECU ending with Bosch number ending in 561. My 1990 ran similarly. After checking everything and replacing everything but the AMM it turned out to the ECU.

It does sound like a bad crank position sensor. Be careful not to break the mount for the sensor or you will have to remove the transmision to fix it. Kind of a PITA job getting the bolt started after removing the old one. Dan

OK! I PULLED THE CRANK SENSOR TODAY. IT WAS COVERED WITH OIL, THE TIP THAT GOES INTO THE BELLHOUSING WAS ALSO COVERED. IS THIS NORMAL? ( FOR THE TIP TO HAVE OIL ON IT). THE WIRE HARNESS WAS FINE, NOT CHAFFED OR BROKEN. I ALSO TOOK THE INTAKE MANIFOLD OFF TO CLEAN IT OUT ( I NOTICED IT HAD ALOT OF OIL BUILDUP,WHEN I REMOVED THE TB TO CLEAN IT OUT). I'VE CLEANED THE TB A FEW TIMES, AT LEAST AT EVERY 500 MILES, THERE ALWAYS SEEMS TO BE ALOT OF OIL IN THE TB AND THE AIR INTAKE HOSE. THE FLAME TRAP IS FINE(THE PREVIOUS OWNER PROBABLY NEVER KNEW IT EXISTED) IT WAS CLOGGED WHEN I BOUGHT IT AND OIL SEEMED TO BE BACKING UP INTO THE CRANK BREATHER BOX. I HAVE A FEELING I PROBABLY NEED NEW RINGS DUE TO THE AMOUNT OF BLOW-BY. IS THIS LOGICAL THINKING? I WILL HAVE TO DO A COMPRESSION TEST TO CONFIRM. I'M NEW TO VOLVOS SO I'M TAKING IT ONE STEP AT A TIME .
THANKS TO YOU VETERAN BRICKSTERS I WILL BE TAKING THE RIGHT STEPS.

Hi,

Seems like we're having the same problem. I just posted a message earlier today -- http://www.brickboard.com/RWD/index.htm?id=840633 -- take a look to see if any of the things I have tried so far might help. Seems like it might be an engine sensor issue -- a bad crank position sensor or engine coolant temperature sensor can give the problems you describe. I replaced both and it hasn't helped me, but it might be worth a shot. Also try replacing the thermostat. Hope this helps...

- Mark

Any chance it is your AMM (Air Mass Meter) that was failing, and now has failed?

AndrewinNC
87 240GL
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