Morning:

I have a 1998 DI 4.0L (HSE) that exhibit the following readings at the fuel rail:

Cold (key on) 24psi
Cold (start/idle) 31psi
Cold (2000 rpm) 29psi

RAVE Specs call for 34-37psi

Seems low, and would explain some extended crank times when cold and power issues when pulling a 2000 pound load up hills.

Plan of attack to increase power and improve drivability...

Replace fule pump with E3047 FP (rated at 55-70psi)
Replace fuel pressure regulator (ERR6185)

*Induction service, throttle body clean-out, new plugs & wires - done

Additionally, been looking at:

1) Reworking air box to remove restriction and increase cool airflow into intake plenum
2) Replacing camshaft with a 4.6L unit (or Crower RV/Torquer)
3) Hedders with high-flow cats and flowmaster muffler (2.5" exhaust)
4) ECU chip with performance enhancing fuel management and ignition profile to compliment engine breathing ability

My research has indicated a 15-20% in engine performance, and given the 4.0L is rated around 180 BHP, this should get Rover up to around 215-220 BHP?

Interested in thoughts!!!

Ron

 

Id say go for it. I wouldnt mind gettin a few more horses out of my truck also. Sounds like you have a good plan of attack.

 

Might start with the basics and change your fuel filter!!!
If you are not throwing any codes, chances are your engine is happy where it is at and God only knows you don't need 70 pounds of fuel pressure.

 

not to highjack the thread but what type of gauge do you use to measure the feul rail pressure, it is like a tire air stem can you use a tire pressure guage?

 

I have a round dial tire pressure gauge, works perfect. I've heard the pop out stick type dont work as good. But yes, it's a regular shrader valve

 

If you're gonna tear the engine apart, throw the pistons and crank from a 4.6 and build a stroker

 

OZ, I installed an air-tex 3270 pump for the same reason.(similiar pressures)

Runs much better.

I don't know that I'd change the reg until I confirmed it was bad.

I agree, change the fuel filter (cut the crimps off the steel-to-rubber connections & install a different filter w/clamps)

luck,greg

 

Thanks Mike...it was changed about 4 weeks ago with the 60K major tune using a unit from AB.

Typo issues...sorry, it is an LSE.

As for fuel pressure...I really have not been able to find a fuel pump in the 40 psi range??? They are either in the 35 psi range, or the 50+ psi range...if anyone had other alternatives - that would be way cool!!!

An adjustable fuel pressure regulator for the DI would be nice...that way you could set the fuel system up at 40 psi and be done with it.

Bottom line, here is my major problem. The engine runs like a clock, no noise, no smoke, no codes...perfect!!!

I have a 100 acre farm located about 15 minutes from the closest paved road (by design...God's country, I tell ya) with a couple of horses and a Kubota 42hp tractor. By the time I get any of these loaded (including trailor) I need to be able to safely pull 5000-6000 lbs.

The electric brake installation works perfect! I just have problems pulling a 1000 lb. trailor in the ozark mountains...never mind the heavier ones???

The Rover is a perfect vehicle...4WD, rugged, kids love roaming the property with it...stereo thumps, it's awesome...just need a little more power......HELP!!!

 

The regulator will bring the pressure down, my airtex is rated @ 70psi, it runs 37psi

luck,greg

 

Thanks Greg!!!

That was my rational...you could have unlimited pressure from the fuel pump, the regulator will hold the fuel system to factory specs...it would just be nice to bump it another 2-3psi to help the bosch injectors???

Another thing that I notice when pulling 2-3 mile grades is from around 2200-3400 rpm's the engine seems flat (like driving into a hard wind)...then it seems to pull out of it from around 3500 rpm's and higher...according to articles I've read, this seems to be a well-known problem with the stock 4.0L Rover engines???

My thought was the camshaft from a 4.6L (or crower replacement from D&D Fabrications) would help provided I opened up the exhaust side a little bit...again, still looking for 30 horses, or so..thanks!