Adjustable Fuel Pressure Regulator

[Amacar]

Hi,

I would like to add an adjustable fuel pressure regulator to my XR. I have searched around and seen them mentioned. I've seen the Kirban name, but they don't make one for the 2.3 motor. Is it the same unit used on 5.0 Mustangs? I just want one that replaces the factory unit on the fuel rail. Any suggestions which one to get and where to go to get it?

[Stealth_xr]

You can get one for a 86- 93 5.0 mustang. It will bolt up. I am currently running a BBK 35-70 reglator. I got it from summit.

[DPDISXR4Ti]

I'll never use another Kirban. Mine failed within 24 hours of installation - could have holed a piston as a result.

I'll only use a stock modified CFI AFPR. I realize that probably sounds conflicting if you're not familiar - it means I modify a stock CFI FPR and modify it into a AFPR.

I'll have some for $50 at Carlisle if you're attending.

[Frag]

You can get one for a 86- 93 5.0 mustang. It will bolt up. I am currently running a BBK 35-70 reglator. I got it from summit.

+1 for the 5.0 unit.

[svosyco]

I have used Kirban FPR for going on 8-9 years without a failure on all my 2.3L Turbos.
Brad, you must have gotten the one originally meant for me.

[Stealth_xr]

Oddly enough i've heard of the aeromotive one failing as well.

[Amacar]

All helpful suggestions. My car is running rich across the spectrum. Can I use an adjustable regulator to lean it out from factory? If so, does that mean I will need one with a particular range? I am not sure what the factory regulator is set to, but I assume I will need one that activates at a lower pressure. Or am I just grasping at straws?

I've got an '89 with a fmic, gutted & ported intakes, forge bov, full 3" exhaust, big VAM and PE computer. It was rich before adding the VAM and PE and continues to run rich since they were added. I'm running fine and I know I should be a bit rich since I disconnected the knock sensor, but it is really rich across the RPM range. I was thinking that I might be able to use the fuel pressure regulator to lean it out.

[DPDISXR4Ti]

My car is running rich across the spectrum.

Then you should fix the cause of the problem rather than chase after a symptom. Let's step back first though.... How have you determined that you're running rich?

[shaydawg]

i have a kirban on my modded TC and my xr daily driver. they have never given me a problem.

[DPDISXR4Ti]

Brad, you must have gotten the one originally meant for me.

Sorry Lou, my bad.

It was a "perfect storm" sort of scenario, as I realized on my drive to the track that I was running a bit lean at maximum load (i.e. 120MPH going up a hill). Didn't have a means to soft-tune the fuel, but I did have a Kirban, so I swapped that in the evening before the track event and turned the FP up a bit. Worked fine for awhile, but on the last run of the day, I see my Fuel pressure DROPPING as load increases! WTF?!

I swap back to stock FPR the next morning and all is semi-fine for the rest of Day 2, save for the back straight where I'm into the 13:1 area at WOT.

A modified CFI AFPR goes on when I get home and has been fine ever since.

[Amacar]

Prior to putting on the big VAM and PE I put the car on a chassis dyno. At that time I did not pay to get the A/F sniffer, but the car seemed rich. To attempt to improve the situation I replaced all of the sensors (and the fuel pressure regulator) to assure the ecu was getting good information.

I then added the Walbro pump, big VAM, PE computer and disconnected the knock sensor. I went back to the dyno, this time paying up to measure the a/f as well. I was pleased with the hp increase, but the a/f ratio started below 10.0 at low rpm, stayed below 11.0 until about 4,000+ rpm, and only reached 12.5 at 6,000 rpm. I do not claim to be an expert (which is why I ask questions on this forum!), but this seems too rich.

What do you think?

[BeefFajitas]

Welcome to the EEC-IV.

[DPDISXR4Ti]

but the a/f ratio started below 10.0 at low rpm, stayed below 11.0 until about 4,000+ rpm, and only reached 12.5 at 6,000 rpm.

I'd need to know what was going when the 10:1 ratio was witnessed "at low RPM. If that was at steady throttle, you've got some sort of issue that needs to be addressed. If that was at WOT, it's normal.

Do you have an A/F gauge? If not, get one before proceeding any further. A simple cheapie narrow-band gauge that taps into the O2 sensor line will be fine for now.

[Amacar]

The readings I have were taken during a dyno pull, so the car was pulling through the rpm range in 4th gear up to 6,000 under load. The dyno operator was not familiar with our cars, and more used to new tech cars with newer tech ecus (EVO's for example). He commented on the jagged profile of my hp and torque lines as opposed to the smooth charts he was used to seeing. I am confident that some of the charactistics he was looking at are a function of the age and limitations of our ecu. This is why I initially just replaced sensors and assumed that was about all I could do.

If these figures are typical for the EEC-IV I guess I should stop worrying about it.

[aviatorpa23]

Amacar - If not a super secret - with your vehicle mods - what were the dyno reults? - looking to dyno the 87 soon and would like a base line - it has or will have similiar mods - tks Jim D.