Does any one make an adjustable fuel pressure regulator for the JK 3.8 motor? It is a common mod to increase the fuel pressure in motors for a few extra ponies. I have been doing it in my Chevy TPI, LT1, and LS1 motors for years with great results.

 

That's a different approach to push a few horses out of out minivan motor... I personally have not seen an application for the JK... Could you get a universal one from a similar size 6 cyl and fab it to work with your 3.8? This could be interesting...

 

You might want to find out how the motor is currently running, get a wide band o2 sensor on it. Not a great idea to just throw more fuel into a motor when you don't know the current air fuel ratio. You can lose horsepower easily by doing that, not to mention kill gas milage for no reason.

 

I have always tuned the Fuel Pressure by ear on my TPI cars. Stock was 36 psi and right now I have it set at 48 psi and get the best in peformance at that setting. However, right over 50 psi it starts to actually hurt performance. I am thinking I may have see if another applications adjustable regulator will work on the JK. I can't seem to find one for it.

Wide band for tuning is nice but pricey.

 

More fuel doesn't mean more power. How can you tell you have 48psi by ear?

The ECM will adjust engine control paramenters depending on what it sees from the O2. All you'll do is trigger an CEL. You'll need an ECM tune to take advantage of any kind of fuel supply change (if there is even any kind of gain from that kind of a mod). Besides, Fuel pressure is now regulated at the pump, there's no more external FPRs.

 

I use a fuel pressure guage. It's total rocket science.

 

Stock pressure is 58 psi +/- 2 psi. The fuel pressure regulator is located within the fuel pump module. It is serviced by replacing the fuel pump module assembly.

So it looks like I will have to change the pump and put in an external regulator inline to get it to work.

 

You should save your money bud, just being honest. I'd love to have more power in my jeep too, but not gonna happen with bolt ons for sure. Save up for a charger or a hemi swap.

 

Anyway, I don't see any benefit to this. You'll just be wasting more fuel. There will absolutely be no performance gains without being able to change the timing and amount of air going in the vehicle. You'll just burn rich and run the risk of triggering a CEL, fouling plugs and killing your cat.

 

I am building a crawler out of my 07 jk and have a question:
isn’t the regulator for the 3.8 in the battery box area? I am putting in a Motobilt Crawler fuel cell and have to use a inline fuel pump. I have chosen the Holley 12-170 and need to regulate it so I have a Fast regulator part # 307030 with the gauge. If the regulator is in the tank is the part that I am looking at strictly for the return line? If I eliminate that and return from the regulator what problems am I going to cause with the electrical that is plugged into the stock unit?