Spoolinup AFPR issues

[NOSLO2PT0]

Anybody else have any experience with these? Not sure if this should go here or in the parts review, so mods, if necessary, please move to appropriate forum.

These haven't been made for quite a few years. They were popular back in the early 2000's when a bolt-on AFPR wasn't really available. They were probably the first to do so outside of Buschur's bulky bolt-on regulator.

I'm chasing down some widely ranging AFR's and this could be one of the culprit pieces. Had the base fuel pressure set at 45psi. Cruising around, the AFR was a steady 14.7:1. AFter doing a hard pull, the AFR's were bouncing around anywhere from 15.9 - 17.8!!! Car shouldn't even be running at 17.8:1, but it was cruising fine. Got home, checked fuel pressure, and it mysteriously dropped down to 41psi. Turned it back up to 45, but the AFR's still didn't line up like they did before.

I had one of these units years ago, and the guy that bought it off me was having the same problems. Couldn't keep the fuel pressure at a constant level. Kept having to increase it to get it where he wanted it. He said the internal spring was giving out. He eventually just sold it.

Has anyone had one of these units and had the same issues of fuel pressure falling off? Just looking for some input on this unit and people's experience.

 

[steve]

Mine is in my tool chest because it didn't look like it was tracking manifold pressure 1:1.
I don't know if they were build to work with E-85 either. Ethanol at E85 levels can impact various metals like aluminum, plastics and rubber.

 

[logic]

I'm with Steve on this one; I'd try disassembling it and check for any corrosion or build-up, and make sure the seals and diaphragm look right; I'd expect a bit of swelling on any seals, at the very least. If memory serves, those things were just bare aluminum assemblies, right?

 

[jrohner]

Some of those AFPRs are junk. Get a new one or get a stock FPR. 17.8:1 AFR is still driveable. My car can even idle at a leaner ratio than that, even with the 272 cams.

 

[pneumo]

I've experienced the same thing. I think that's why they changed the design. The newer style uses a longer spring which should be more durable.
I had one of the original designs and it eventually got so bad it wouldn't hold 35 psi without the adjusting screw bottoming out against the diaphragm. I'm still using the newer style, no problems yet. If the spring goes soft again I might try cutting open a stock FPR and use the spring out of it.

 

[jrotten]

I bought one of these from the spoolinup jokers back in the day too. It worked well for awhile and then the car suddenly started to run like ass. I figured it was the diphragm or spring but I cant visually see a problem with either when I take it apart. Put the stock reg back on and boxed the AFPR. Id like to get this thing working again but I guess I'd have to pirate rebuild parts from another brand of regulator to fix this one. I am pretty certain that the spoolinup guys used a readily available diphragm and spring and just CNC'd an adjustable housing to fit, anybody know what diaphragm/spring they might have used to build their units? This may be a pointless post, but I have 150 bucks invested in a paper weight right now so its worth a shot I 'spose.

 

[steve]

It might help if people knew what it looked like. Here's mine disassembled.

The side of the diaphram facing up in this picture actually goes against the seat in the base shown above it.
The aluminum cap fits in/on top of the spring and the adjuster bolt seats into the depression (not shown) and the other end of the spring fits into the metal center of the diaphram.

 

[pneumo]

To add a little info, the pic in Steve's post is the first version. That's the one that tends to loose pressure and go bad.

 

[steve]

Not really the first version. It is one of the last revisions before they tried to make a 2G AFPR.

 

[Bohrn]

subscribing.

and adding that mine has suffered a loss of vacuum as well.

I was/have been chasing a driveability issue as well as a random knocksum issue for a while now.

I put a secondary vacuum hose on it, plugged the one that goes to the vacuum nipple on the regulator and applied vacuum to the secondary hose. The regulator would not hold vacuum, and it would show on the fuel pressure guage. It would loose all the vacuum in about 4-6 seconds.

I pulled it and took it apart, but there is nothing visibly wrong with it that I can see. I am a professional mechanic as well, so its frustrating.

A stocker works fine, but pressure is too high due to the Wally pump. Keydiver chip is tuned for 44psi base, so its not cosher right now, but even like this its way better than the on again, off again adjustable one.

If anyone figures out a definitive solution post it up. I like the small size, look and easy of use of this FTaS one, but it doesn't work consistantly.

 

[pneumo]

and adding that mine has suffered a loss of vacuum as well.

I was/have been chasing a driveability issue as well as a random knocksum issue for a while now.

I put a secondary vacuum hose on it, plugged the one that goes to the vacuum nipple on the regulator and applied vacuum to the secondary hose. The regulator would not hold vacuum, and it would show on the fuel pressure guage. It would loose all the vacuum in about 4-6 seconds.

I pulled it and took it apart, but there is nothing visibly wrong with it that I can see. I am a professional mechanic as well, so its frustrating.

It's easier to find a leak by doing a pressurized boost leak test through the vac line. Just use some soapy water and watch for bubbles. Usually the leak occurs at the adjuster screw. A little teflon paste should seal the threads.

A stocker works fine, but pressure is too high due to the Wally pump. Keydiver chip is tuned for 44psi base, so its not cosher right now, but even like this its way better than the on again, off again adjustable one.

If anyone figures out a definitive solution post it up. I like the small size, look and easy of use of this FTaS one, but it doesn't work consistantly.

If the stocker is working, don't fight it.
My AFPR is still working so I haven't looked for a solution. One idea try is to cut the hat off a stock fpr and see if the spring is the same size as the spoolinup afpr spring.

 

[Bohrn]

its not leaking out there, its bypassing vacuum out the vacuum port.

And as for the "working fine" bit, its not working fine, its just working better than the faulty aftermarket one. And it has the same problem that every other big pump stock regulator 1g car has. The pressure regulator is being over run. Stock pressure is 38 psi. Stock auto pressure is 42 or 44, I forget. This is 58 psi at idle with the vacuum line off. Its not OK, but its also not leaking like the aftermarket one is.

And its not a matter of how strong the spring is, the internal return passages of the stock regulators are too small to bypass enough fuel volume at idle and cruise to properly control fuel pressure.

As well, even if this regulator could work correctly, 58 psi is too high as I am running 27+ psi on my turbo. the math on that is not good. 85psi at the pump. RRE's tables show that as much to high for sustained fuel volume.

 

[NOSLO2PT0]

And it has the same problem that every other big pump stock regulator 1g car has. The pressure regulator is being over run. Stock pressure is 38 psi. Stock auto pressure is 42 or 44, I forget. This is 58 psi at idle with the vacuum line off. Its not OK, but its also not leaking like the aftermarket one is.


As well, even if this regulator could work correctly, 58 psi is too high as I am running 27+ psi on my turbo. the math on that is not good. 85psi at the pump. RRE's tables show that as much to high for sustained fuel volume.

What kinda pump you running to push your base up to 58psi? A Walbro 255 rewired with an A/T regulator (43psi base) should only push it up to about 51psi at idle. Unless you got something bigger than a 255 back there. 85psi at the pump, and the Walbro gonna take a dump real fast. Actually, the relieve valve starts kickin in around 78-80psi.

 

[this_tsi_8urV8]

Relieve valve?
Could mine be semi-closed or blocking the return path?
It's reading about 75psi and I already turned the screw out (lessen pressure) and it's reading the same. I disconnected the fuel pressure return line and read normal. What should I do? Take off the return line to tank and clean it and see if anything comes out? Just replace the return line?
I have a fuelab afpr and have feed line from filter to rail, return line to fpr. I'm thinking about replacing both feed and return lines all the way from the tank.

 

[NOSLO2PT0]

Just to follow up on this. The regulator wasn't the issue for the car running dead lean at times. The MAF-T settings were wrong. It was by no fault of the AFPR.

 

[steve]

Imagine that, MAFT problems. That never happens....

 

[NOSLO2PT0]

Stupid MAF-T! I know how much you love those things Steve!

 

[Car Cannibal]

I have that AFPR on our 2nd Talon and it's been fine for years, if you read the pressure from a liquid filled gauge you can only be 100% sure on the readings while the engine bay is cool.

Full Throttle Speed started selling that regulator later on so Mike would have some info on possible replacement parts.

 

[DSMopar]

Anyone know where I can pick up one of these? I need an AFPR that I can pass off as stock (CA smog) and there doesn't seem to be anything on the market currently...

 

[logic]

The spoolinup unit definitely doesn't look stock, even if it attaches directly to the fuel rail. I don't believe anyone is actually selling these anymore; as Car Cannibal mentioned, Full Throttle used to sell them, but I don't see them in their inventory anymore.

If all you want is "bolt-on" (and visual inspection be damned), Buschur still has their modified SX regulator that bolts directly to the fuel rail. I have one of these, it exhibits some "oddities", but nothing a rebuild wouldn't likely resolve.

Another option might be to hollow out the stock FPR, and install a proper AFPR elsewhere in the return line out of sight. Or do what the Evos do: underdrive the fuel pump under low load, and eliminate half the reason you probably need an AFPR in the first place. Implementation details are left as an exercise to the reader.

 

[steve]

Or do what the Evos do: underdrive the fuel pump under low load, and eliminate half the reason you probably need an AFPR in the first place. Implementation details are left as an exercise to the reader.

Mitsubishi has been underdriving the fuel pump for a while on different cars to work around the problem. On the 3000GT they switch the voltage control via the ECU http://www.dsmtuners.com/forums/newbie-forum/340938-modify-stock-fpr-2.html#post152070993

 

[DSMopar]

Ya I've seen the SX, i'll pass. Way too pricey and doesn't look anywhere near stock. The spoolinup will work with a coat of black paint, trust me.

 

[Car Cannibal]

I haven't been paying attention to the fuel reg offerings for us but is no one making a bolt on reg similar to the Charged Air (original designer)?

 

[HighPSI TSi Guy]

its not leaking out there, its bypassing vacuum out the vacuum port.

And as for the "working fine" bit, its not working fine, its just working better than the faulty aftermarket one. And it has the same problem that every other big pump stock regulator 1g car has. The pressure regulator is being over run. Stock pressure is 38 psi. Stock auto pressure is 42 or 44, I forget. This is 58 psi at idle with the vacuum line off. Its not OK, but its also not leaking like the aftermarket one is.

And its not a matter of how strong the spring is, the internal return passages of the stock regulators are too small to bypass enough fuel volume at idle and cruise to properly control fuel pressure.

As well, even if this regulator could work correctly, 58 psi is too high as I am running 27+ psi on my turbo. the math on that is not good. 85psi at the pump. RRE's tables show that as much to high for sustained fuel volume.

if you're truly experiencing FPR overrun, then your base pressure is still stock. It is not the 58 you see. Your base pressure is still 37.5 and at 27 PSI you'll see 64.5 PSI of fuel pressure. If it is truly overrun, you'll just see 58 PSI at idle and as boost goes up it won't be a 1:1 relation until ~58ish PSI. It may even go down before it goes back up as the duty cycles go up and you are putting more fuel into the motor and less out the fuel return. Tune the car properly and you'll be fine.

 

[pneumo]

Something I Learned Today

I had a chance to disassemble a stock FPR today and compared the spring to the Charged Air/Spoolinup AFPR spring. They're nearly the same! The stock spring fits in the AFPR! The only difference is the stock spring is a little stiffer with thicker wire, 1.5mm diameter vs 1.1mm, so swapping springs might not let you lower pressure as much. Then again, the stock fpr that I took apart is from a NT which has higher base pressure anyway, so maybe the spring from a turbo fpr might be softer.
<a href="http://s442.photobucket.com/albums/qq145/DRW-4G63/?action=view&current=FPRsprings.jpg" target="_blank"><img src="http://i442.photobucket.com/albums/qq145/DRW-4G63/FPRsprings.jpg" border="0" alt="FPR spring"></a>