fuel pressure issue...Strange
fuel pressure issue...Strange Background: Bought my 98 TA WS6 3 mo ago. Took to track a week ago and couldn't get below 14.6 even when hooking. Got back from track and changed plugs, wires, fuel filter, cleaned K&N. Went back to track last night improved to a 14.1. Still too slow for this car. My 60's are decent at 2.15 but can't break into 13's or exceed 100mph.
So I decide it has to be a fueling issue (too lazy to do a compression check at this point). I check fuel pressure w/o engine running. It seems good at 54 lbs (very minimum for these cars). I start the engine, and the needle on the pressure guage starts vibrating really fast b/w 60 and 70 lbs constantly. Pressure is supposed to drop w/ engine running. What could this be?
So I decide it has to be a fueling issue (too lazy to do a compression check at this point). I check fuel pressure w/o engine running. It seems good at 54 lbs (very minimum for these cars). I start the engine, and the needle on the pressure guage starts vibrating really fast b/w 60 and 70 lbs constantly. Pressure is supposed to drop w/ engine running. What could this be?
Key on, engine off results in lower voltage to the pump. Engine running, the alt is now in the picture, and the voltage rises. [Hopefully, anyhow.]
Also, if the ecm does not see cranking rpm, the pump will time out, and may not get to full psi in the short time it's on.
Also, if the ecm does not see cranking rpm, the pump will time out, and may not get to full psi in the short time it's on.
fuel preesure Let me restate the issue:
I check fuel pressure w/o engine running and key on. It seems good at 54 lbs. I check again with the engine running, and the needle on the pressure guage starts vibrating really fast b/w 60 and 70 lbs constantly. Pressure is supposed to drop w/ engine running. What could this be?
I check fuel pressure w/o engine running and key on. It seems good at 54 lbs. I check again with the engine running, and the needle on the pressure guage starts vibrating really fast b/w 60 and 70 lbs constantly. Pressure is supposed to drop w/ engine running. What could this be?
How about..
Originally Posted by tee-boy
Let me restate the issue:
I check fuel pressure w/o engine running and key on. It seems good at 54 lbs. I check again with the engine running, and the needle on the pressure guage starts vibrating really fast b/w 60 and 70 lbs constantly. Pressure is supposed to drop w/ engine running. What could this be?
I check fuel pressure w/o engine running and key on. It seems good at 54 lbs. I check again with the engine running, and the needle on the pressure guage starts vibrating really fast b/w 60 and 70 lbs constantly. Pressure is supposed to drop w/ engine running. What could this be?
8 sec potential, 12 sec slip
iTrader: (50)
Joined: Apr 2002
Posts: 4,092
Likes: 2
From: Savannah, GA
Your stock fuel pressure is supposed to be 58psi. It will fluctuate a little with the engine running (between 58-60). So, your pressure is not "good" at 54, it is low. Why do you think the pressure would go down with the engine running??? It should stay the same, but it will go up as stated above because your pump is getting more voltage from the alternator.
Trending Topics
d
Originally Posted by ChevyChad
Your stock fuel pressure is supposed to be 58psi. It will fluctuate a little with the engine running (between 58-60). So, your pressure is not "good" at 54, it is low. Why do you think the pressure would go down with the engine running??? It should stay the same, but it will go up as stated above because your pump is getting more voltage from the alternator.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo 8 sec potential, 12 sec slip
iTrader: (50)
Joined: Apr 2002
Posts: 4,092
Likes: 2
From: Savannah, GA
stock pressure on mine was about 58 at idle, and 60 at part throttle...
something is definitely fishy tho if you are seeing 70 at idle. You sure your gauge is accurate???
something is definitely fishy tho if you are seeing 70 at idle. You sure your gauge is accurate???
follow up
Originally Posted by ChevyChad
stock pressure on mine was about 58 at idle, and 60 at part throttle...
something is definitely fishy tho if you are seeing 70 at idle. You sure your gauge is accurate???
something is definitely fishy tho if you are seeing 70 at idle. You sure your gauge is accurate???