Symptoms of a bad fuel pump?

[WayneM3]

My car has about 104,000 miles, of which about 65,000 have had the Evolve Supercharger system. A few months ago while accelerating on the highway (in Mexico) at about 7,000 RPM I got an engine malfunction error with fuel pump error codes. I cleared the codes and it never came back. What I have noticed though is that the car hesitates above 7,000 RPM in higher gears (1st and 2nd go too fast to tell) and feels like it doesn't want to spin faster. I even noticed it as low as about 5,500 RPM today on the highway. It never used to do this. I changed the spark plugs a while ago (they could probably use another change) and everything on the intake side seems to be in correct working order. The other strange issue is that sometimes on initial throttle tip in from a stop there is a slight hesitation - just for an instant but it didn't used to do that either. I swapped engine software so that is not the issue as both issues happened with either software.

I originally thought it could be the fuel filter but discovered that it is a "lifetime" one built into the fuel pump. I will probably replace it but I would rather have some educated guesses before I spend $500 on the replacement pump/filter.

Thank you for any input on this.

[Green-Eggs]

Originally Posted by WayneM3

My car has about 104,000 miles, of which about 65,000 have had the Evolve Supercharger system. A few months ago while accelerating on the highway (in Mexico) at about 7,000 RPM I got an engine malfunction error with fuel pump error codes. I cleared the codes and it never came back. What I have noticed though is that the car hesitates above 7,000 RPM in higher gears (1st and 2nd go too fast to tell) and feels like it doesn't want to spin faster. I even noticed it as low as about 5,500 RPM today on the highway. It never used to do this. I changed the spark plugs a while ago (they could probably use another change) and everything on the intake side seems to be in correct working order. The other strange issue is that sometimes on initial throttle tip in from a stop there is a slight hesitation - just for an instant but it didn't used to do that either. I swapped engine software so that is not the issue as both issues happened with either software.

I originally thought it could be the fuel filter but discovered that it is a "lifetime" one built into the fuel pump. I will probably replace it but I would rather have some educated guesses before I spend $500 on the replacement pump/filter.

Thank you for any input on this.

It sounds like you're running out of fuel pressure. These are the same symptoms you will see for people making 600+ whp. If you're in the 600+ whp category, then you need to upgrade your fuel system. If you're well below 600 whp, then you should be fine.

To diagnose, data log fuel pressure, RPM, AFR, and spark. When the problem happens, look at the spark, AFR, and fuel pressure logs. The symptoms of needing an upgraded fuel system, you will see spark and AFR go crazy on the logs...and the fuel pressure will dip well below 5-bar (down to 3-3.5 bar).

EDIT:
There is also a connection to density altitude with the 600+ whp needing a fuel system upgrade. The lower the density altitude, the more likely you will get fuel-induced cut-outs. Colder nights, lower elevations, you will see this more. The one thing throwing me away from this for you, is that you're reporting this happening in the summer.

[WayneM3]

Originally Posted by Green-Eggs

It sounds like you're running out of fuel pressure. These are the same symptoms you will see for people making 600+ whp. If you're in the 600+ whp category, then you need to upgrade your fuel system. If you're well below 600 whp, then you should be fine.

Thank you for the ideas - I will try the datalogging. I am nowhere near 600 WHP so I don't think that is an issue - I would guess I am somewhere in the 500-520 range.