another fuel pressure dropping thread
Thread Starter
Pro
Joined: Sep 2006
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From: abingdon maryland
another fuel pressure dropping thread
ok, just got the car back. forged 346 ls6, ati d1sc, kenne bell boost a pump, racetronix pump, 60 lb motron injectors and mail order tune from ecs until i break the car in.
here is the problem. when i get on it, the pressure drops to low 30 psi and it idels at 45 psi. why the sudden drop. the aem gauge is reading high tens to low elevens...since i m breaking it in i m not going above 4k. the fuel pressure gauge is hooked up to the end of the fuel rail. it's a spa techniques gauge. could it be the heat soak on the sender unit b/c it is right there in teh engine bay? i m at a lost. i don't evn want to drive it till i figure out what's up. i just blew one motor and don't want to torch another one
any input is greatly appreciated. thanks.
here is the problem. when i get on it, the pressure drops to low 30 psi and it idels at 45 psi. why the sudden drop. the aem gauge is reading high tens to low elevens...since i m breaking it in i m not going above 4k. the fuel pressure gauge is hooked up to the end of the fuel rail. it's a spa techniques gauge. could it be the heat soak on the sender unit b/c it is right there in teh engine bay? i m at a lost. i don't evn want to drive it till i figure out what's up. i just blew one motor and don't want to torch another one
any input is greatly appreciated. thanks.
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Joined: Sep 2006
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From: abingdon maryland
Originally Posted by connecticut
you say heat soak, are you getting 58-60#'s on start up?
remove elec. sender off rail, install manual gage and ck pressure
remove elec. sender off rail, install manual gage and ck pressure
i just drove to work.....i will restart it once it cools down. i remember seeing 60 last night. if it is 58-60 at start up then i will pull the sender off the rail and check it with a manual gauge. k
Thread Starter
Pro
Joined: Sep 2006
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From: abingdon maryland
no luck. when i just turn the key it is at 52 psi but at start up the presssure is only 42-44psi with the hood open. i guess i have some things to figure out. 
Last edited by prochargedz; Oct 26, 2006 at 10:41 AM.
Le Mans Master
Joined: Aug 2002
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From: Houston TX
St. Jude Donor '11
I'm not sure I'd trust the fuel pressure gauge if the WB is still at 10-11:1 AFR in boost. It would be pretty hard to maintain that AFR with 30 PSI of fuel pressure, even with 60# injectors. It's not uncommon for returnless FI vettes to lose 8-10 PSI of pressure under boost, even with a Racetronix and BAP (although the latest theory is that the senders are getting heat soaked). It seems unlikely that you are actually dropping to 30 PSI especially since you have a Racetronix and KB BAP too.
Put a mechanical gauge on it.
Put a mechanical gauge on it.
