98 DOHC 104000 MILES. CRANKS BUT WON'T START. CAN HEAR THE FUEL PUMP ,GOT 50 PSI AT FUEL RAIL, CHECKED ALL RELAYS
(FUEL PUMP.AUTO SHUT OFF). CHANGED FUEL FILTER/REGULATOR 15000 MILES AGO. OHMED OUT COIL PRIMARY/ SECONDARY, CHECKED FOR SPARK AND CHK SPARK PLUGS. CHK TIMING BELT.

COULD IT BE CRANKSHAFT SENSOR OR CAMSHAFT SENSOR OR PCM? ALSO NO ERROR CODES IN COMPUTER.

DAUGHTERS CAR AND SPENT HRS TROUBLE SHOOTING. (GARAGE MECHANIC)

THANKS FOR ANY ADVICE

 

get a stethoscope and turn key to on position and then listen for a high pitched whine...if you hear it it isnt the PCM ...crank sensor would be a good guess ...but I am not willing to bet the farm on it...if it hiccups on start up perhaps your timing is off to a degree or missed a tooth...

 

What codes are you getting when you check them? You should get a 55 and probally a 12. If you are not getting any codes at all the pcm is probally bad. The crank sensor is another good guess.

 

The car will start without the cam sensor working, but that would throw a code. If the crank sensor isn't getting a signal after a rotation or two, it will kick off the ASD relay and not do anything. That should throw a code as well.

When you take the key to "on" (not to start), does the CEL come on for a second or so and then go out? Wondering if the bulb is burnt out. But if a scanner was used to pull codes and you aren't getting any, that's not an issue at this point...

If you are getting spark from the plugs, that rules out spark pretty much... Fuel pressure is good, that really only leaves the injectors (maybe a good cleaning, but mine are still pumping away at 240k miles). On the air side, might try cracking open the TB a smidge, although a faulty IAC should throw a code. From there, timing belt being off a tooth or bent valves would be on my list to check, maybe even a cracked camshaft or rocker assembly, but that should throw a code as well.

 

Check for compression and that the plugs are getting wet from fuel. It should flood and wet the plugs if fuel is spraying. Stethescope or screw driver and listen to the injectors. If OK then, Pull the cats and see if it runs. Had one in the shop two weeks ago and the cats were plugged. Once removed and then tried again and voila there it is. Nastiest Air filter I have seen was the cause of the failed cats.

If you are getting spark and such then you probably have good crank and cam signals.