Hey guys,
I'd like to share my fuel system nightmare that finally came to an end.

To make long story short I had the following problems:
-Long engine start
-Instant zero fuel pressure after engine shut off
-Injector tuning issues with ECMLink
-knock at low boost 18-20psi with retarded timing

My fuel issues started happening after the following upgrades:
-WALBRO 255 rewired
-Aeromotive AFPR
-Modified GM Rochester 17113744 injectors
-New OEM fuel filter
-Upgraded fuel line from filter to rail

Since all of the above were installed at once I was not sure what to blame and where to start. So after many month I decided to pinch my return line (rubber line after AFPR) to see if I can hold pressure and instantly got positive results (pressure does not drop).
Basically it meant oring on the fuel pump was not cause of the problem.

Next step I decided to open AFPR and look inside.



After I removed 4 allen bolts the red housing just popped open and spring and two metal plates fell on my desk.



Inside I was hoping to find something similar to what I saw on this post but it appeared my AFPR was build using different design. I was disappointed because everything looked normal with my AFPR at first.

Now if you look closely at orange gasket with round metal plate you can see an alignment issue there. Because everything just popped open i had no visual proof of how things were working together before. My guess is that metal ball was not sitting directly on top of the return outlet.

So after I reassembled AFPR (making sure little metal ball sits directly on the outlet center) I reinstalled AFPR back into my talon.



Now my fuel system continues to be pressurized (apprx 1 hour) after engine is turned off. After fixing AFPR my tune now is where it should be with fuel settings set to what is recommended on ECM Wiki page. (before i had to lower my global to compensate for rich fuel mixture at WOT)

I hopes this helps someone having similar issues after installing AFPR. Share your story with Aeromotive FPR here.

Is the line still pinched at your return line?

You didn't mention if you left it or after you fixed your AFPR returned it to its previous state.

Edit: Glad to see you sorted things out

yes returned line was only pinched for brief few seconds to test pressure. I used adjustable pliers together with my ecmlink to perform this test. Engine did not need to be started.

This is great news.

I remember a thread not long ago with everyone chiming in about how it was normal for those symptoms.

Guess it isn't afterall.

alex, check your pm

replied

I had a problem with my Aeromotive years ago,when my boost would rise I would get bucking like it was running out of fuel.I took it apart and the spring inside was brocken in about 5 pieces.I phoned Buschur who I bought it from and he told me Aeromotive had a batch of bad springs.I was going down to the shootout the next week and picked one up from him,put it in and car ran great.

Yeah, I was in on that thread about the aeromotive afpr's, but never had the right allan wrench at the time to pop it open...now I do, and since Alex has laid out the way, I'm going to see if I'm victim to the same issue, otherwise I'm saying frack it and going with an RCI fuel filter, rail, and afpr.

Now that I think of it ,it was Tym Switzer I was talking to that's how long ago that was

Popped mine open and I have the same design Alex. I looked at the ball and the seat and there were no burrs that I can see and when I removed it carefully, it seemed to have been seated correctly. I flung it back together and crossing my fingers when I finally start it up.

As I said though, if it doesn't work, I'm going to get a package deal from RCI and say goodbye to two troublesome parts.

Thanks for posting! I was waiting for this!

Let us know how it goes Andrew

yeah Bryan and I have been talking about this issue for some time in pm as both of us are having a new unit put in I have a Fuel lab unit so I dont think I have anything to worry about but fuel issues cost me an engine so I think I will be worring either way LOL

Yeah I am going to open up my aeromotive one tonight and then throw it back in and see how it goes. Hoping it will hold pressure like Alex's does now. I am still on stock pump so I know oring is not my issue.

There's a way to cheat a bit instead of opening it up. If you've got a gauge somewhere in the loop, check the pressure while the engine's running (or else the pump on without the engine running). Then shut off the engine (or pump) and watch the gauge. See how long it takes for the pressure to drop. If it takes an hour or so to drop to zero, the seal in the FPR is probably as good as it's going to get. If it drops much quicker (under 5 mins) there's probably something wrong. 'Course there's no substitute for opening it up since all is revealed, but the pressure test will tell alot.

guess both my AFPRs are no good, neither hold for 5 mins.

I will add, that is the test that Alex did, but when you pinch the return line it checks whether or not the oring on the pump is still good or not.

so just opened mine up and found this. If you can't see it there seems to be some nicks taken out of the metal, what would I use to smooth this out?

Looks like those nicks are right at the top? At least the one around 4 oclock seems to be. Can't see the one around 12 oclock very well. If it is a ball sealing on that taper, it would seal further down. If the nick is only at the top, I would not touch it.

The 12 oclock one stops about a mil before the hole, but the one at four is raised a little so I think that's why it won't seal.

I need to re-smooth it, if I don't this thing will just sit in the garage being useless.

Here is close look of what mine looked like.





ALSO
The adjustment bolt sits much taller after reassembly. (set to hold 43.5psi)
Before

After

Yeah where your ball seals it's clean there, that's perfect!

Pressure after engine shut off video sample

Before
http://www.youtube.com/watch?v=IRb0LuPqeCs&feature=relmfu

After
http://www.youtube.com/watch?v=43TeaFTDuU4&feature=youtu.be

So i goofed around with my fuel lab and it slowly looses pressure which is better than the fast drop that the aeromotive is still doing after I screwed around with it. I am going to talk with Aeromotive and see if I can get a new housing.

Unless I can find somekind of christmas tree shaped sandpaper thing, than I make give that a try and see how it goes.

huh... Very interesting. My car seems to have the same symptoms as yours did Alex. I should look into this aswell. Aeromotive AFPR, but a different model (13301 I believe)

Held pressure at about 20psi right after shutdown, bled down to 0 after 5 minutes.

This is too common with Aeromotive FPRs and they never want to admit it is improperly machined/assembled units. I'm going to grab an RCI one and give it a shot for the next season.

i wish i would have read this earlier... i just ordered an Aeromotive to replace my Fuellab unit. The Fuellab is leaking gasoline into the vac lines and line for the boost guage, also causes the car to run 43psi all the time. If i remember correctly the car should be at 33psi idle and 42psi WOT? I hope this Aeromotive works out and holds pressure, because the fuellab sure doesnt lol.

The Aeromotive PN is 13109, not sure if its the same as the one you have Alex?

Sounds like your diaphragm is ripped and from what I can quickly see, doesn't look like you can buy just the diaphragm.

43.5psi with the vac line disconnected, which is around 37psi on an "average idle" when the line is connected. It will rise 1psi for every 1psi of boost above the base 43.5psi (since it was set at 0psi of boost)

The ripped diaphragm was what i was thinking after doing some reading, otherwise no reason for fuel to be entering the vac lines. I do have a "Hot Start" issue, after driving the car for a bit and shutting it off it has a hard time starting again, and when it does it runs terrible for a few min, then back to normal. Im hoping the broken FPR is the reason for this issue..
Thanks for the reply Andrew.

Yeah, could possibly explain it.

I'm sure that low pressure on startup makes the engine that much more difficult to crank, when I get to the farm this weekend, I'm going to finally wire in a switch to the fuel pump to manually turn it on before I start cranking to finally give a conclusion to my theory.

In your case, the extra gas that is being sucked in by the vacuum is probably just enough to throw off the ratio into hard start territory, then if it is continued to leak, it is unaccounted fuel that is probably being slowly adjusted by the short term fuel trim.

Once you get it fixed, any other issue related to this should be fairly to diagnosis if there is still an issue with the FPR out of the way.

Ziggy do you think you could make up something like this for the compact model?

Drill the hole bigger to the outside of the yellow circle 1/4-3/8" deep and install a tapered rubber bushing where the yellow is that extends up 1/6-1/8" above the hole so it will seat against the valve.



I don't have any tools in my tiny work shop to do this.

Sure you can:
Link

Tyler, I amsure I could drill that out for you, but not sure where to source the rubber bushing?

Heh, didn't even think of checking RTM, I knew you had the aeromotive rebuild kit and I thought that was all. I took a look at the Fuel Lab website and couldn't find anything, nor did a quick google search bring anything up.

That's good news to know for Troy to know that he would either be able to sell it as is, knowing somebody could rebuild it, or rebuild it and sell it.

That is the FIRST place you are supposed to look for ANY DSM part

It is!!

In my defence, it wasn't a pure DSM part - it was a universal thus, I thought manufacturer would have a rebuilt kit listed on their site, little did I know...

Just teasing, Andrew....
But if our site is getting to be more comprehensive than the manufacturers', that is good to know

I made the mistake of NOT hearing about RTM before.. used to order most of my stuff from DSMgraveyard, made a $2200 order and they fecked it up.. i honestly did not think that there was a local supplier of DSM parts lol.
As for the fuellab i guess i.can just rebuild it and sell it