Warning - All Those Who Use An Aeromotive FP Regulator
 

Some of you may have followed my HTA3582R Twinscroll Project depicted here:
Ted B.'s HTA Twinscroll Project

There were only two issues preventing me from finishing my tuning and testing - a leaky TB shaft on my expensive Hypertune 75mm TB, and a fuel issue.

Mark Shead (Mark S) in the UK made a comment to the effect that he's had issues with Aeromotive fuel pressure regulators holding pressure at high boost. I know Mark just doesn't toss useless things out there, so I filed that in my mind. Coincidentally, at 27-28 psi with E85, I was well over 100% IDC at 6500rpm with FIC 1250s. I decided to connect a FP gauge to the rail and look at the gauge through the windshield as I drove the car.

Sure enough, the setup wouldn't hold more than 55 psi. Under boost, the FP would shoot quickly toward 70psi, then fall right back and settle around 55psi. I know that shouldn't be the case with those injectors and the dual in-tank Walbros with disabled pressure relief valves. I also noticed that the FP would drop to zero as soon as the key went to 'off', and that type of behavior indicates a leak. This is no good.

Walker (Drifto) is someone who is meticulous like myself, and I let him have a go at isolating the problem while I was away on travels. After making thorough checks of everything in the tank, he decided to disassemble the Aeromotive FP regulator. This is what he found:

Attachment 297737

This regulator uses a ball and seat arrangement to regulate pressure. As anyone can see, poor quality control on Aeromotive's part explains why the seat is irregular and mildly eccentric. It doesn't look like much to the inexperienced eye, but this is enough to create a serious pressure leak at the seat.

Walker exercised careful precision in reworking Aeromotive's sloppiness. The end result looks like this:

Attachment 297738

The end result? The fuel pressure is right where it should be. Walker then disassembled his own Aero regulator, and cleaned up that one as well. It seems it's hit or miss as far as what one gets from Aeromotive where this is concerned, but everyone who uses one of their regulators should be aware of it. Knowing what to look for and knowing how it must be addressed could save you in unnecessary headaches and wasted time.

Thanks again to:

Walker Morgan - www.mpfab.com
Mark Shead - www.madevelopments.com

I have a aeromotive regulator thats been sitting around for a while now. I should check it out and see if I happened upon a decent one.

That is some sloppy machine work! Good thing you got a "merticulous" guy to work on it. Is your car still at Walker's shop?

Is there any chance that regulator is a knock off and not an actual Aeromotive? The housing doesn't look like the quality I have seen from Aeromotive to be honest and I have not seen a problem from any of their products. I know there is a ton of stuff being ripped off by the Chinese now and labeled as actual products, that piece just doesn't look like what I've seen.

Glad you got it fixed.

I don't know, that's a good question. I haven't even considered that, although if this part has been knocked off, I can't that say I'd be surprised. I wouldn't think this would be a non-genuine part, but I can find out easily enough and will.

The anodizing does look a little sub-par with the Aeromotives I've had in the past.

One thing I have seen a lot on Aeromotives though is vacuum leaks all over the place on them. If you find your regulator doesn't raise a true 1:1, you probably have a leaky one. Pretty easy to fix with just a touch of Hondabond on every thread and a tiny bit on the diaphragm sealing surface.

I've also had an Aeromotive where the vacuum fitting was rubbing on the diaphragm spring, causing erratic fuel pressure. A few seconds with a disc sander had it sorted out.

Honestly, I've had to tweak every Aeromotive I've owned or installed on a friends car. Once you get them fine tuned, they work great though.

i have that regulator on my srt and my wife´s srt with no problems!!!

thanks for the heads up, ill be checking mine asap.

interesting find, that is a bit disturbing.

I have been assured that this regulator (which was purchased new) is a genuine Aeromotive item, so I have to accept that FWIW. This makes a case for why anyone venturing into high boost territory would be for the wiser to verify their fuel pressure under boost instead of assuming that it is what it should be.

I'm curious to see who else reports a similar situation.

What may be a tell tale sign for any of you who are using this FPR is fuel pressure that drops instantly after the key is turned off. Ted's car exhibited this. A FPR. with a proper seal will hold pressure or slowly bleed it off over a period of time. If it drops immediately you should look into this.
A car with less power/less demand for fuel volume at WOT may never see pressure drop off even with a damaged FPR like Ted's. Ted's car however uses every bit of the twin pumps and large injectors capacity on E-85 so pressure would drop above 5K. The symptoms mimicked insufficient fuel pump capacity, but after testing the pumps and finding them to be in good working order we opened up the regulator. The damaged seat was allowing enough fuel to bypass the FPR and go staight back to the tank, that the volume needed to feed the engine was comprimised. After the repair, the fuel pressure only slightly bleeds down (-2psi/10min.)after the key is turned off and pressure at WOT has been restored.
A point of interest for any of you who may own a shop-Listen to your customers. Mark Shead had advised Ted about Areomotives being poor at holding pressure and when Ted came to me about it being the possible cause I told Ted he was crazy:o. I've seen far too many of these things being used for many years and have never seen an issue like this. Well, we did an exhaustive search to find the cause of the pressure drop off before finally conceeding that Mark and Ted may be right, and after opening the regulator up we confirmed it. Oops! Maybe that saying about the customer always being right holds some truth.:lol:

I have this same issue on my other car with the aeromotive fpr, I dont monitor fp in the car but have a gauge on the fpr, I noticed if I turn the engine off the pressure drops to 0 quite fast.

So as a fix is it just a properly centered bevel or is it a circular profile?

Just curious if the regulator holds pressure now after the key is turned off.
BTW. Which model Aeromotive FPR was this one?

Ive heard of the Aeromotive issue before from some other guys who suffered with the same issue.

OOC - I have a Hypertune 75mm TB sat here I havent setup yet - how did you detect the leak and how did you fix it? New TB required?