1990 Toyota Camry.4cyl Starts normally drives about 50 or so miles and dies. It will not immediately restart. Turn off the ignition key for a few minutes and it starts back up and may travel 1 mile or 10 miles before it dies again. It appears after the first failure the interval between stalls gets shorter and shorter untill the car is left alone over night. the next day i get 40-50 miles and it stalls. I loosened the fuel line at the filter under the hood and during the period it wont start there doesnt appear to be any fuel pressure. Is there a more acurate way to test if the fuel pump is failing or the sensors that control it are?
It does sound like a fuel pressure problem. I don’t think there is a pressure tap on your Camary unless one has already been added. There is a replacement banjo bolt for the fuel filter that allows interfaces with standard fuel injection pressure gauges. Your filter is over on the left side of the engine compartment in tight quarters.
The only other tests are to make sure that power is getting to the fuel pump. There is a fuel pump relay that could be going bad. Check that power is available at the B+ side of the relay coil. Also the Power Control Module has to turn that relay ‘ON’ by grounding the armature coil. The PCM should turn the pump on for a few seconds when the ignition key is turned “ON”; while cranking; and keep it “ON” as long as the Crank Position Sensor is sending a signel.
Hope this helps.
Check for spark the next time the engine won’t start.
If the computer loses the ignition reference signal the computer see’s no reason to run the fuel pump.
Tester
Is the CEL on? I’m assuming when it fails, it will still crank, but just not start and run.
It’s almost certainly either a spark or fuel problem, but hard to tell which one without further diagnostics. If you can get the car to fail at a shop, ask them to check for spark during a period of time when it still won’t run. If the the spark is ok, it is likely a fuel problem. Which they can test using a fuel pressure measurement.
If you’re behind on your routine maintenance schedule, now might be a good time to get caught up on that too. It might just be a clogged fuel filter for example. If you are past due on changing your fuel filter, consider that a suspect. Sometimes the restriction will overheat the pump or the pump relay, and cause this kind of symptom.
Could be some kind of temperature sensitive exhaust restriction too I guess. That could be diagnosed with an intake manifold vacuum test. Before going on a parts replacement spree, at least ask your mechanic to do the testing to decide whether the problem is ignition, fuel, or exhaust. Best of luck.
@Researcher you’re right. Toyota has NEVER had fuel pressure test ports on their engines.