Fuel Pressure Regulator?
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Instructor
Joined: Dec 2024
Posts: 216
Likes: 85
From: Phoenix, Arizona
Fuel Pressure Regulator?
1989, 4speed auto. Fuel pump is 4 years old. RapidFire #5s @.045 torqued to spec. Running 91.
Unknowns:
-Fuel filter is in a PITA location to swap, I have one waiting. Welcome to tips here.
-Unsure on age of fuel injectors.
Fuel Pressure:
- Vacuum line off
- Primes to ~25psi (low?)..and slowly drop off. Maybe losing 1-2 PSI/min
- Cranks and runs @ 43 psi
Symptoms:
Cold Start (sitting multiple hours):
- Extended crank. 6-7 seconds on a single crank or multiple shorter cranks. Sputters for a second and then catches.
- Slow to accelerate after transitioning to 2nd/3rd gear.
----Once i've been driving for ~5+ min, this sluggishness goes away...which makes me think fuel vs. spark.
Warm Start (Coolant @ 195+)
- Typically a 2-3 second crank, sputters for a second and then catches.
- No acceleration issues.
Intermittent
- Rough idle. Will surge between 500/900 rpms.
----Hit or miss on this happening when the AC/Heat is on or off....seems to happen occasionally in both scenarios.
Unknowns:
-Fuel filter is in a PITA location to swap, I have one waiting. Welcome to tips here.
-Unsure on age of fuel injectors.
Fuel Pressure:
- Vacuum line off
- Primes to ~25psi (low?)..and slowly drop off. Maybe losing 1-2 PSI/min
- Cranks and runs @ 43 psi
Symptoms:
Cold Start (sitting multiple hours):
- Extended crank. 6-7 seconds on a single crank or multiple shorter cranks. Sputters for a second and then catches.
- Slow to accelerate after transitioning to 2nd/3rd gear.
----Once i've been driving for ~5+ min, this sluggishness goes away...which makes me think fuel vs. spark.
Warm Start (Coolant @ 195+)
- Typically a 2-3 second crank, sputters for a second and then catches.
- No acceleration issues.
Intermittent
- Rough idle. Will surge between 500/900 rpms.
----Hit or miss on this happening when the AC/Heat is on or off....seems to happen occasionally in both scenarios.
Last edited by ramahon; Dec 16, 2024 at 04:48 PM.
Thread Starter
Instructor
Joined: Dec 2024
Posts: 216
Likes: 85
From: Phoenix, Arizona
