Possible Fuel System Issue...HELP!!!

[TPhong]

Hello fellow Primers, I have a 1997 6-spd with approx 137K miles. I was driving yesterday, and after about 10-15 miles of driving, the car started sputtering. When I pressed the accelerator, it wanted to cut out, almost as if it was flooding. As I pulled into a parking lot the car shut off on it's own. I tried cranking it back up and it would start, but then immediately shut off.

So while waiting on the tow truck, I tried to do some troubleshooting. I was able to locate a paperclip, so I tried jumping the FP Resistor (which was extremely hot to the touch), and was unsuccessful. I had my wife pick up a new main relay, that was also unsuccessful. The fuel pump relay behind the driver seat was clicking also, but I couldn't hear the fuel pump priming. A mechanic friend of mine stopped by and suggested that it may be the fuel pump itself. He tapped on the gas tank while I tried to start the car and it fired right up. The car idled rough and was acting the same way it did before it shut off, but the odd thing is that if I could get the rpms above 4K, it idled fine. I tried to drive it, but as soon as it dropped under 4K rpms, it fell on it's face. Any suggestions or should I just order a fuel pump and replace it?

 

[GraemeD]

Do some troubleshooting before throwing a fuel pump at it. At least have the fuel pressure checked.
Changing the pump is kind of a big job.
The hot resistor is normal, that means it is doing its job. There is a reason it is mounted in the engine bay and has a large aluminum case!

 

[mr_goat]

Hi TPhong,

The fuel pump resistor adds resistance to the fuel pump when under 4k rpms in order to silence it a bit for normal driving. That is its purpose. The fuel pressure per se is controlled via the fuel pressure regulator. I had my engine suddenly sputtering below 4 k rpms but with the resistor bypass it went fine. However in my case it was the fuel pump starting to give up which was noticable first and foremost when running with the resistance. I replaced my fuel pump for a Walbro unit and removed my fuel pump resistor completely. No problemos now.

As GraemeD is saying though, if you want to really pinpoint the cause, a fuel pressure reading will point you in the right direction.

Good luck, I'm sure you'll find the issue and have it sorted quickly!

 

[TPhong]

Hi TPhong,

I replaced my fuel pump for a Walbro unit and removed my fuel pump resistor completely. No problemos now.

Did you have to rewire with the Walbro bc of a higher current draw?

 

[mr_goat]

I got this kit and it does not require any rewiring: https://www.scienceofspeed.com/inde...-high-pressure-fuel-pump-nsx-fitting-kit.html

 

[TPhong]

Just wanted to follow up and say, after replacing the fuel pump and fuel filter, my NSX is back up and running. I drove her around town for about 35 minutes last night with no issue. The throttle response with the new fuel pump is amazing! I ended up replacing it with a Walbro 255 and install kit that I ordered from Evasive Motorsports for approx $110 shipped. The install kit worked perfectly and the rewiring (2 wires, power and ground) was a piece of cake. Thanks for all the suggestions and comments guys!

 

[chudson1549]

great news Toyo

 

[JLCoolman]

Glad to hear you're back up and running Toyo!

How was the replacement process?