How do you test/diagnose fuel injectors ?
10-07-2015, 09:49 PM
#11
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No OEM marine ever offered a 502 in 2005 from their production lines. Most 454 and 502 big blocks for the marine end was gone in 2001 as they were replaced with the 496 - 375 hp and the 425 hp and that basically was across aboard.
Volvo did offer the 454 up till 2002.5 because they bought a ton to keep that package going when the marine version 496 was in place. Volvo really started to push the 496 in 2002 as Merc pushed it in 2001. Just saying.
was this a older app 502 (2001 and back ) repower or reman thrown into a 2005 boat ? Or is this a Volvo 496 - 8.1 L ?
Volvo did offer the 454 up till 2002.5 because they bought a ton to keep that package going when the marine version 496 was in place. Volvo really started to push the 496 in 2002 as Merc pushed it in 2001. Just saying.
was this a older app 502 (2001 and back ) repower or reman thrown into a 2005 boat ? Or is this a Volvo 496 - 8.1 L ?
10-08-2015, 07:10 AM
#12
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You can get a general idea of the health of the injectors with an ohm meter, a pressure gauge and an Injector tester - hook the tester one at a time to each injector, pressurize the system, and then pulse the injector and record the pressure drop. Do this for each injector. If the pressure drop is for each injector is not close in value, there is a problem with what ever injector is the abnormal number. Check the resistance of each injector coil with the ohm meter. Generally the value is in the 12-14 ohm range unless you are running high flow injectors. If the meter reads infinite resistance (open circuit), the injector coil is bad, or if a value for one of the injectors is way off from the others.
However, since you stated it is intermittent, I would be willing to say the windings in the injector are shorting out when the injector gets warm. Had this issue before - runs great while cold and for a while when you start to get on it, then the motor starts to fall on it's face... The issue will occur in shorter periods of time if left uncorrected. The field tests I described above may not catch that problem. It may show up if the injectors are dynamically cleaned and tested. I found the issue by eliminating every other variable over time and finally bit the bullet and replaced the injectors - Problem solved.
However, since you stated it is intermittent, I would be willing to say the windings in the injector are shorting out when the injector gets warm. Had this issue before - runs great while cold and for a while when you start to get on it, then the motor starts to fall on it's face... The issue will occur in shorter periods of time if left uncorrected. The field tests I described above may not catch that problem. It may show up if the injectors are dynamically cleaned and tested. I found the issue by eliminating every other variable over time and finally bit the bullet and replaced the injectors - Problem solved.
