Back fire at lower rpms
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Back fire at lower rpms
Hey my 88 bronco has an 89 5.0HO in it from a stang it's giving me a lot of backfiring at low rpms both warm and cold no clue what to start looking at. Could it be a fuel problem? Pleas help !!!
Fleet Owner
Joined: Oct 2005
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From: Kentucky
Check the fuel pressure, run the KOEO tests and stored code display. List any codes by number and when they were displayed.
Fuel pressure should be ~32-35 PSI at idle. Remove the vacuum line from the fuel pressure regulator then the pressure should go to ~40-45 PSI. Put the vacuum line back on, then blip the throttle. The fuel pressure should rise again to ~40-45 PSI.
Fuel pressure should be ~32-35 PSI at idle. Remove the vacuum line from the fuel pressure regulator then the pressure should go to ~40-45 PSI. Put the vacuum line back on, then blip the throttle. The fuel pressure should rise again to ~40-45 PSI.
Thread Starter
|
New User
Joined: Jan 2017
Posts: 4
Likes: 0
Check the fuel pressure, run the KOEO tests and stored code display. List any codes by number and when they were displayed.
Fuel pressure should be ~32-35 PSI at idle. Remove the vacuum line from the fuel pressure regulator then the pressure should go to ~40-45 PSI. Put the vacuum line back on, then blip the throttle. The fuel pressure should rise again to ~40-45 PSI.
Fuel pressure should be ~32-35 PSI at idle. Remove the vacuum line from the fuel pressure regulator then the pressure should go to ~40-45 PSI. Put the vacuum line back on, then blip the throttle. The fuel pressure should rise again to ~40-45 PSI.
ok so after I test that what will it tell me. That the regulator is bad or just that there could be a problem further down the fuel line ie pump or filter or heigh pressure pump
Fleet Owner
Joined: Oct 2005
Posts: 20,786
Likes: 1,751
From: Kentucky
If it's good start looking at vacuum leaks and spark quality.
If the pressure is out of spec. the first thing I would replace is the fuel filter, then the pressure regulator. If it's still low you most likely have a bad pump.
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