85 no start
01-24-2013, 11:29 PM
#2
Safety Car
Member Since: Mar 2005
Location: Fredonia WI
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You've verified you have spark?
Do you have a fuel pressure gauge to check the pressure in the runners?
Do you have a fuel pressure gauge to check the pressure in the runners?
01-25-2013, 12:11 AM
#3
Race Director
You need to check fuel pressure and make sure the injectors are firing.
Fuel pressure gauge and "noid" light. Or you can see the injectors firing with a digital voltmeter. The voltage will jump around with the injector pulses.
One wire is 12 volts, the other is the injector signal from the ECM. With the engine not running you should see 12 volts on both pins of the injector connectors. Check both banks, as there are two injector fuses, one for each bank. All 8 injectors fire at the same time so you only need to check one injector connector on each bank (to make sure the wiring is OK).
Fuel pressure gauge and "noid" light. Or you can see the injectors firing with a digital voltmeter. The voltage will jump around with the injector pulses.
One wire is 12 volts, the other is the injector signal from the ECM. With the engine not running you should see 12 volts on both pins of the injector connectors. Check both banks, as there are two injector fuses, one for each bank. All 8 injectors fire at the same time so you only need to check one injector connector on each bank (to make sure the wiring is OK).
01-25-2013, 02:24 PM
#5
Le Mans Master
Is the spark strong? Does the battery have a full 12 volts?
Need to check pressure at the fuel rail on the passenger side of the fuel rail.
Have you recently done any work on the car????? IF so, then what was done?
Need to check pressure at the fuel rail on the passenger side of the fuel rail.
Have you recently done any work on the car????? IF so, then what was done?
01-25-2013, 04:33 PM
#6
if you have spark and pressure (40 psi) in the rails...then that leaves the injectors. They must cycle for the engine to even burp.
you say the engine does turn over? rotates but will not fire and run?
if this is pre-VATS, then it has to be the inj circuit. Verify inj operation with a noid lite. If there is no inj cycling then trace that back to fuses, the power source at the battery jumper pole, and ECM grounds on the block.
as someo0ne stated, if there was recent work and it was ok prior, go thru that work and look for something damaged.
curious.....
why was the starter replaced if the engine would turn over? what told you to change fuel pump? was there no fuel pressure? what test did you do or was this diagnosis by checkbook?
you say the engine does turn over? rotates but will not fire and run?
if this is pre-VATS, then it has to be the inj circuit. Verify inj operation with a noid lite. If there is no inj cycling then trace that back to fuses, the power source at the battery jumper pole, and ECM grounds on the block.
as someo0ne stated, if there was recent work and it was ok prior, go thru that work and look for something damaged.
curious.....
why was the starter replaced if the engine would turn over? what told you to change fuel pump? was there no fuel pressure? what test did you do or was this diagnosis by checkbook?