1989 Chevrolet Celebrity Repair Question
You have to determine which function is dropping out whern this happens.
Here is the testing sequence.
All "crank, no start" conditions are approached in the same way. Every engine requires certain functions to be able to run. Some of these functions rely on specific components to work and some components are part of more than one function so it is important to see the whole picture to be able to conclude anything about what may have failed. Also, these functions can ONLY be tested during the failure. Any other time and they will simply test good because the problem isn't present at the moment.
If you approach this in any other way, you are merely guessing and that only serves to replace unnecessary parts and wastes money.
Every engine requires spark, fuel and compression to run. That's what we have to look for.
These are the basics that need to be tested and will give us the info required to isolate a cause.
1) Test for spark at the plug end of the wire using a spark tester. If none found, check for power supply on the + terminal of the coil with the key on.
2) Test for injector pulse using a small bulb called a noid light. If none found, check for power supply at one side of the injector with the key on.
3) Use a fuel pressure gauge to test for correct fuel pressure, also noticing if the pressure holds when key is shut off.
Once you have determined which of these functions has dropped out,
you will know which system is having the problem.
he checked the fuel pressure and it is reading right
OK, finish the rest of the testing and post what the results were including the pressure reading.
he changed the plugs , the plug wires the injectors are working changed the throttle poistion sensor and fuel pump is holding pressure it will start but when you hit the gas it dies and sometimes it will start back and sometimes it wont
when it shuts off and you crank it with the noid light it does not pulse
ok he put a noid light on and with it running it is workin and fuel pressure gauge hooked up it reads 40 and when he turns of pressure is reading 42
Of course it flashes when it's running, otherwise it wouldn't be running. We need testing at the moment it's refusing to start.
he said he tried that the other day and when it wouldnt start it didnt flash
Yes, and you didn't finish the rest of the testing at that time.
Did the injectors still have power supply when that happened?
Did it still have spark when that happened?
Did it still have fuel pressure when that happened?
it still has fuel pressure and it still has spark but no power to the injectors