02 yukon 5.3 flex Vin "z" no fuel pressure.
05-16-2016, 06:26 PM
#1
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02 yukon 5.3 flex Vin "z" no fuel pressure. Hello gents, I have a problem that I simply cannot figure out.
Here's my setup. 2002 gmc yukon xl 5.3 liter flex fuel vin code "z".
The problem is I'm only getting 48 lbs of fuel pressure at the test port. Key on engine off. When running I show 42lbs. By unplugging the fuel regulator, the pressure Climbs to around 47lbs. To my understanding the fuel pressure needs to be around 55-60. The motor runs terribly if you can imagine.
Here's what I replaced so far trying to identify the problem.
Swapped out fuel pumps, (total of 4 times, using different brands) replaced plug on harness, new fuel filter on frame, replaced regulator, checked fuse, changed relays, and have even reground the plug itself to the frame. To all of which yields the same results. 42lbs pressure. Getting 12.4 volts to the gray wire on plug.
What am I missing? This is a headache and my only vehicle! Please help!
Here's my setup. 2002 gmc yukon xl 5.3 liter flex fuel vin code "z".
The problem is I'm only getting 48 lbs of fuel pressure at the test port. Key on engine off. When running I show 42lbs. By unplugging the fuel regulator, the pressure Climbs to around 47lbs. To my understanding the fuel pressure needs to be around 55-60. The motor runs terribly if you can imagine.
Here's what I replaced so far trying to identify the problem.
Swapped out fuel pumps, (total of 4 times, using different brands) replaced plug on harness, new fuel filter on frame, replaced regulator, checked fuse, changed relays, and have even reground the plug itself to the frame. To all of which yields the same results. 42lbs pressure. Getting 12.4 volts to the gray wire on plug.
What am I missing? This is a headache and my only vehicle! Please help!
05-19-2016, 12:16 PM
#6
Restricted User
The early flex regulators were set for 48-54 PSI. If you're running 47 PSI, then you are only 2% off from 48 PSI, which is within the trim ranges for the stock ECU, so it would correct it from there.
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05-19-2016, 11:59 PM
#8
Restricted User
If you really think its fuel pressure, swap in a non-flex 55-58 PSI regulator.
It sounds to me like you noticed the fuel pressure was low and decided to blame all of your problems on it, and then began replacing parts to fix it, while completely ignoring the actual problem.
It sounds to me like you noticed the fuel pressure was low and decided to blame all of your problems on it, and then began replacing parts to fix it, while completely ignoring the actual problem.
