427 engine (part 2) - RHS block

[Rich Z]

Well, apparently I can get a disk brake hardware kit with these clips. I checked Advance Auto first, and they want $34.00 for the kit. What?!? That didn't sound right, so I checked a couple of other sources, and prices were from $7 to around $14. That's more like it. I would rather have bought them local, for time constraint reasons, but when I contacted Advance Auto through their chat system, I must have gotten the bottom of the barrel for their customer service staff. She kept on insisting I was asking for a price match, and no, I'm asking to see if your pricing is in error. Finally I just gave up and ordered the kit from RockAuto. I got a kit for the front as well, since I'll probably be pulling those calipers off to clean up the brake stuff and also check for anything broken or missing. I just don't trust that ANYTHING was done right at this point.

[Gannet]

Heya Rich. My car finally came home today. Between the drive home and a little cruise we did about 80 miles. So far so good. There are a few little things I want to work through, but hopefully nothing like the recurring nightmares you are having. My sincere sympathies!

Oh and thanks for the feedback on the lift. I ended up with the same model and am well-pleased with it.

[Rich Z]

Originally Posted by Gannet

Heya Rich. My car finally came home today. Between the drive home and a little cruise we did about 80 miles. So far so good. There are a few little things I want to work through, but hopefully nothing like the recurring nightmares you are having. My sincere sympathies!

Oh and thanks for the feedback on the lift. I ended up with the same model and am well-pleased with it.

Hey Dave,

Man, great to hear you have your car back finally! I was wondering how that was going for you. If you have any videos, post 'em up, please. I sure would like to see and hear a project that went RIGHT for someone.

Did you get the shorter front arms for your lift? They made a world of difference on mine.

Hope your car runs flawlessly, or at least with minimal problems.

[Gannet]

I didn't do anything special about the lift arms. I read what you posted, but decided to take the unit as it came and then see about. As it turns out it looks like the arms are fine.

No videos yet other than the one I think I posted up a while back:


It's certainly not flawless, but it's pretty good. It starts, cold or hot. It idles. It cruises pretty smooth at 1200 rpm. Not bad for 16 degrees of overlap. I had it in some stop-and-go yesterday and the coolant never got over about 226 at worst. That whole area will need some rework for summer, but I knew that.

There are two issues I need to address soon: I'm not happy with the open breather catch can and the way it puts oil smell into the cockpit. The design was my choice, it just isn't working out. It still has a slight surge/roughness at very light throttle. I'm also not sure about throttle transitions and performance when getting on it, something seems not quite right there. Oh, and it also seems to drink a LOT of gas, but no documented numbers yet, So, breather rework and more tuning. If that's all I end up with, I will count myself lucky.

[Rich Z]

Yeah man. If most of your issues are just tuning related, it's just a matter of expertise (or trial and error) to get the correct tables that have to be adjusted and figuring out what your engine needs between the input values and output values to smooth things out. I'm hoping that all my driveability issues are strictly programming misjudgments. Having to change any hardware to straighten out those deficiencies would be a rather bitter pill to have to swallow.

I'm surprised that the standard arms work with your car. When I had the fronts extended perpendicular, there was only about an inch of tolerance between them working or not working. Perhaps they are just providing them with the shorter arms as standard now?

[Rich Z]

Today a friend of mine (Kenny Blankenship) came over to help me figure out the fuel system on my car. What I wanted to know was how much of the stock electrical was remaining in the car, and what it would take for me to put everything back to a stock configuration so I would have a launching point from which I could move forward to get a fuel system that could supply the engine with the fuel it needed but in a SAFE manner with all the failsafes that are inherent in a stock system.

So, here's what we found.

The stock electrical system is intact to the stock fuel pump, which is still in the tank. Although the connector at the pump had had a couple of wires cut, they appeared to have been simply reconnected as they were, and then taped. Power is applied to the stock pump, and it shuts down after running for two seconds when the ignition key is first turned on.

Matter of fact, the stock pump IS still running when power is applied, which we discovered by disconnecting the power wire running from the fuse box to the Aeromotive pump, and simply putting the 20 amp fuse for the stock fuel pump back into the fuse box. So the stock fuel pump electrical was not disconnected at all.

Then looking at the fuel lines themselves, they are run in this manner:

Stock fuel pump -> (-6AN) -> Aeromotive pump -> (-8AN) -> passenger side fuel rail -> (-6AN) -> driver side fuel rail -> (-6AN) -> fuel pressure regulator -> (-6AN) -> stock fuel pump. *note: The fuel line splits at the driver side to go to the fuel rail and also branch off to the fuel pressure regulator.

And here's the conclusions and observations we came to.

• The stock fuel pump and the Aeromotive fuel pump are BOTH running in tandem with the stock fuel pump being used to feed fuel to the Aeromotive pump.
• There are NO fuel filters in the fuel line at all.
• The fuel pressure regulator is on the RETURN side of the fuel system and not on the feed side going into the fuel rails.

Commentary on this arrangement.

Seems rather odd to have a large Aeromotive fuel pump on the car that is dependent upon the fuel supply from the stock fuel pump. If the reason for putting that larger pump in place is because the stock fuel pump cannot provide enough fuel for the higher horsepower demands of the engine, then how can the stock fuel pump be expected to provide enough fuel to the Aeromotive pump to accomplish that goal? Secondly, the -6AN between the stock pump and the Aeromotive is too small for the fuel flow demands anyway. Thirdly, how did this engine develop 692 horsepower on the dyno at Aaron's shop without just flat out running out of fuel? Perhaps just not running long enough at that power level? I'm surprised that there wouldn't have been a noticeable fuel pressure drop showing on the fuel pressure gauge while running at WOT. My guess is that had the engine been run long enough, it would have gone into a dangerously lean condition because of fuel starvation.

This all brings up some speculation on why I had the first Aeromotive fuel pump fail while at Aaron's shop. Obviously with the stock fuel pump in place on the stock circuitry, the stock pump would shut OFF after running for two seconds, as is normal. Meanwhile the Aeromotive pump is still running, trying to pull fuel from the stock pump which is now OFF. I'm not sure if the Aeromotive pump could do that (I doubt it), but in any event, it is running without ANY fuel coming through it, and quite probably would burn the pump up pretty quickly. My guess is that the cooling of that pump comes from the fuel passing through it. Much like you can burn up a stock pump if you run it while your gas tank is empty. Which, I believe, is why that first pump failed prematurely.

I haven't yet looked into Aeromotive's install instructions for the fuel pressure regulator, but it just doesn't seem logical for the pressure regulator to be providing constant pressure BACK to the fuel tank from the fuel rails instead of TO the fuel rails from the fuel pump. I'm presuming that the fuel pressure that is regulated is at the OUTPUT of the fuel pressure regulator, and does nothing at all about the pressure coming into it. So honestly, it just doesn't make sense to install a fuel pressure regulator in this manner. Basically, it appears that the fuel pressure going to the fuel rails was completely unregulated and was exactly whatever the fuel pump provided to it. Not sure how much that may fluctuate, but I would think that the fuel being provided by the fuel injectors was never really constant at all. I would guess trying to tune a car in this manner WOULD be quite a challenge.

So, here's what I THINK needs to be done to the fuel system.

• Disconnect the power and ground wire running to the Aeromotive pump and discard them.
• Drain the fuel from the gas tank(s). (I'm not sure that I have to drain the passenger side tank.)
• Remove the fuel lines from the Aeromotive pump and remove that pump from the vehicle.
• Relocate the fuel lines in the following manner:
  • fuel pump/tank -> (-8AN) -> fuel pressure regulator -> (-8AN) -> driver side fuel rail -> (-8AN) -> passenger side fuel rail.
  • fuel pressure regulator return line -> (-6AN) -> fuel pump/tank
  • Put one or more fuel filters in the feed side fuel line.

Of course, I need to figure out exactly what type of fittings, adaptors, etc. I need to be able to relocate those fuel lines. I'll certainly be doing some fuel line cutting and splicing, in any event. Hopefully getting the lines where I need them won't be too big of a headache.

But at least now I feel like I have game plan and the fuel system isn't just a foggy gray area that I didn't have a clue about what was there and needing to be done.

Of course, you DO have to wonder why someone would have installed the fuel system in this manner in the first place. And I will be quite honest about it, I am completely baffled about why Aaron wouldn't have looked this over and noticed these obvious (to someone who is supposed to KNOW this sort of stuff) problems and brought them to my attention. Seriously, running a fuel system with NO fuel filter in place? NO fuel pressure regulation at the fuel rails at all? I'm just hoping that this hasn't created any problems in my fuel injectors. They were NOT cheap.

Anyway, thanks, Kenny, for helping me out. I've still got my work cut out for me, but I do feel better about being able to DO what is needed now.

[navy2kcoupe]

ALRIGHT! Some serious and DOCUMENTED progress!
Andy

[Gannet]

That's a lot of digging. I'm not qualified to have an opinion on whether that lash-up is "correct" or not.

One question: why should the stock pump shut off after 2 seconds? I don't understand.

[Rich Z]

Originally Posted by Gannet

That's a lot of digging. I'm not qualified to have an opinion on whether that lash-up is "correct" or not.

One question: why should the stock pump shut off after 2 seconds? I don't understand.

I believe that the pump turn off after 2 seconds is a safety feature to keep the pump from running if the engine is not running. So if you stall the car, or perhaps have an accident and the engine is not running, the PCM detects that the engine is not running and shuts down the fuel flow.

A FYI, Kenny checked Aeromotive's website and it appears that putting the fuel pressure regulator on the return side may be acceptable practice. Sounds odd to me, but what do I know? I don't understand HOW it can regulate fuel pressure in that manner....

[Rich Z]

Well, apparently I am mistaken. The fuel pressure regulator (FPR) is in fact installed on the return line of the fuel system. I found a website that described this method of fuel regulation:

The fuel pressure regulator (FPR) maintains a constant pressure across the fuel injectors. That means the fuel line pressure (at the top or entrance of our injectors) minus the intake manifold pressure (at the bottom or exit of our injectors) is a constant, regardless of engine speed, or manifold vacuum or boost pressure. The FPR connects to the intake plenum using a vacuum hose. When there is vacuum in the plenum, the FPR lowers fuel line pressure 1 psi for every 1 psi of vacuum. When there is positive pressure in the plenum (turbo boost), the FPR increases fuel line pressure 1 psi for every 1 psi of boost. The FPR maintains fuel line pressure by controlling the amount of fuel that returns to the gasoline tank. To increase pressure, the FPR creates a restriction, reducing the amount of fuel that flows through it back to the tank. The factory FPR is not adjustable and has a limit to the maximum amount of fuel that can flow through it.

http://www.stealth316.com/2-fpr_upgrade.htm

However, I don't recall seeing that vacuum connection to the FPR that I see in all of the photos of installs and the FPR units I looked at online. I'll have to look more closely tomorrow and see what is going on there on mine.

But in any event, the good news is that apparently I will NOT have to relocate the fuel lines like I thought I was going to have to do. Well, at least not at the engine side, anyway. My plan is to simply move the AN-8 line from the Aeromotive over to the stock fuel pump, taking the Aeromotive pump out completely, and go from there.