HELP from the fuel Gods...
Thread Starter
Teching In
Joined: Aug 2016
Posts: 26
Likes: 1
HELP from the fuel Gods... 2001 Camaro ss
Put the car on the dyno yesterday and woudn't pull passed 4500. Car was last dynoed at 466 rwhp.
Fuel pressure guage would drop from 60 psi to 20 psi under load. No brainer...weak pump.
Pulled the two year old Racetronix pump out and replaced it with a new AEM 50-1000 pump that I had on the shelf. Didn't have time to put it back on the dyno but car pulls hard under steet driving.
Problem is, is that in now starts hard. Several seconds of cranking before it fires. It's a little better if I crank, stop, and crank again. I touched nothing else. Just replaced the pump. I have a steady 60 psi to fuel rails prior to startup, during startup, and running. Also replaced the fuel filter during pump swap. Thoughts?????
Also, the car has the hot wire Racetronix fuel harness. I pulled the fuse at the battery because I don't know how the new pump would act with the hot wire addition if that makes sense... Do I leave it unplugged?
Appreciate any help on this...I'm stumped and really frustrated.
Put the car on the dyno yesterday and woudn't pull passed 4500. Car was last dynoed at 466 rwhp.
Fuel pressure guage would drop from 60 psi to 20 psi under load. No brainer...weak pump.
Pulled the two year old Racetronix pump out and replaced it with a new AEM 50-1000 pump that I had on the shelf. Didn't have time to put it back on the dyno but car pulls hard under steet driving.
Problem is, is that in now starts hard. Several seconds of cranking before it fires. It's a little better if I crank, stop, and crank again. I touched nothing else. Just replaced the pump. I have a steady 60 psi to fuel rails prior to startup, during startup, and running. Also replaced the fuel filter during pump swap. Thoughts?????
Also, the car has the hot wire Racetronix fuel harness. I pulled the fuse at the battery because I don't know how the new pump would act with the hot wire addition if that makes sense... Do I leave it unplugged?
Appreciate any help on this...I'm stumped and really frustrated.
The return hose or pressure hose on the pump cam fail in tank. Usually the generic bulk fuel hose isn't up to the pressure before the regulator and it pops the cheap clamp holing the hose.
Most aftermarket pumps will not hold pressure when not energized. Turn off the key and pressure rapidly drops to zero. Aeromotive makes a very clear statement about that on their FAQ page; I don't know if AEM does.
If you turn the key, count to 4-5, and then start and it fires right up, that's the issue.
You can install a one way valve in the in the line to hold pressure when the pump is off. Or energize the pump for a few second before starting.
If you turn the key, count to 4-5, and then start and it fires right up, that's the issue.
You can install a one way valve in the in the line to hold pressure when the pump is off. Or energize the pump for a few second before starting.
Thread Starter
Teching In
Joined: Aug 2016
Posts: 26
Likes: 1
Well, it always started just fine with the Racetronix pump even when it was weak. Both the Racetronix and AEM pump have one way valve inside the nipple for leak down, or at least that is what I assume the purpose is.
TECH Addict
Joined: Oct 2016
Posts: 2,513
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From: PDX-OR-USA
Some of the check valves require some flow and pressure to close, they are just so the fuel can't flow back though the second pump if its a standby/spare pump.. They don't close just under the pressure from the static fuel when turned off. Also when you order the pumps, there are often options for check valve or not in the part numbers, they can be check and bleed or check and hold as well.
