Category Archives: Fuel

New Fuel Pressure Regulator and Braided Lines

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On this 2023 July 4th weekend, bowtie6 got treated to a new fuel pressure regulator and braided lines.  The old setup consisted of a GM style non-adjustable pressure regulator and a set of E85 resistant rubber fuel lines – I wrote an article about that (click here).  I was never really pleased with the rubber hoses because the braided lines are much nicer and bullet proof.  So I pulled the trigger and ordered parts for the new setup.

This is what the old setup looked like:

The new regulator is a high pressure version from Aeromotive with a matching fluid filled gauge.  This is the setup after the first fitment.  However, with all this bling that bracket just did not look good…And this is what I mean…

We had to cut the old mount and in the process the aluminum mount got scratched up pretty bad.  I tried to sand this down but didn’t make much progress.  Instead, why not just use some carpet material?

Ah! Much better!  A keen eye will also notice the difference in pressure.  I checked what the E67 PCM expected, and that was 58 lbs/in, so I bumped that up a bit.

The photo above, shows the whole setup.

  • On the left the box with the silver lid holds the high pressure fuel pump
  • The line going up from the pump goes into the regulator and from there is a return line back to the pump container and to the left the line going to the engine.  That is a hard stainless line that goes under the body to the engine compartment.
  • And finally the lines that feed the pump container.

High pressure fuel pump inside this enclosure

I’ve written about this setup in a prior post Ecotec Fuel System and ECOTEC Fuel System – Part 2 in case you want to read more about that.

And this is what the front looks like.  This is another braided line going into the fuel rail.  The other side connects to the stainless tubing under the frame of the car…

Fuel Regulator Fittings

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The Ecotec engine uses a similar fuel delivery system as fitted in the LSx engines in that the fuel rail is “returnless”.  This means there is only one line feeding the fuel rail on the engine.  In order to make this work, a special fuel regulator with built in filter has to be plumbed not far from the fuel pump.  There are several fuel regulator fittings available and in today’s installment I’ll document my experiences.

In an earlier post, I wrote about bowtie6‘s Ecotec fuel system (click here) where I described the separate staging tank holding the fuel pump.  About two weeks ago, I noticed the insulation post around the fuel pump’s B+ terminal my cousin Jim had fabricated had deteriorated due to coming in contact with fuel from the tank.  In order to solve this problem, I had to take the small tank out which required disconnecting the fuel regulator fittings.  After putting all the bits back together I found the fuel regulator fittings were not exactly “clicking” correctly.  They held in place but I was not pleased with the fitment so I safety wired them in place as shown in the following picture:

We can all agree this is not exactly the most elegant way to do things.  So why the safety wire?  Well, turns out on the little plastic tabs that “click” the blue fitting in place are not exactly the best design in the world.  Sure, car manufacturers use them all the time and they work flawlessly.  However these are aftermarket units made by Russell (a division of Edelbrock) and they are not exactly OEM quality.  I found out this by experience and by reading the latest issue of Car & Craft’s engine swaps magazine.  So where is the problem?

The following photo shows one of the two pump-side lines going into the regulator.  I’ve removed the fitting so you can see the small ring around the metal tube (more on that later)…

The next photo shows the fitting and the small plastic clip that holds all this together:

The small white plastic clip is very cleverly made.  There are two sets of barbs on it.  The inner pair locks in place around the ring on the metal tube from the picture above this one.  That keeps the plastic piece from sliding out.  Then the barbs also lock in place on a shoulder inside the fitting.  However in order to make this work, the plastic spring loaded affair must be crisp and not in the least deformed.  Taking this apart deforms the plastic clip and this prevents a positive lock.

The last two pictures show the white plastic affair locked in place.  As mentioned previously, this assembly is then pushed on the tube in the regulator and if all goes well the two barbs on the plastic clip snap on the ring molded on the tube.  All this looks good on paper, but I noticed the plastic “clip” had lost some of its “spring” and this all did not really lock in place so well.  The kicker is that these fuel lines are holding 50+ psi pump pressure and if they decide to part ways, well… you end up having a real bad day.

Remember that magazine I mentioned above?  There was a very good article in that issue about fuel systems and they cautioned on using these fittings.  And, they also suggested an alternative.  Unfortunately, the alternative is also made by Russell.

I did call the Russell tech line and talked to a rather abrasive dude on the phone about my experiences.  Right of the bat, he was not very interested in my findings nor on making things right.  Basically he told me to buy the new fittings and took no ownership to the fact this was a bit on the “unsafe” side.  I even told him about the article in the magazine, but he dismissed that too.  At any rate why argue with someone unwilling to stand by their product so I ordered new fittings.  While not exactly “cheap” (they are about $16 each) quite frankly I rather spend the money and have the peace of mind this is not going to come apart and sling fuel all over the place.

The solution is to use these fittings:

These fittings have a much safer design.  Instead of the spring-loaded plastic affair, they have a threaded cap that holds the fitting in place.  The threaded cap has a “U” shape that slides over the tube on the regulator and when tightened grips the ring (look at the very first picture on this post) keeping everything securely in place.  With this together, there is no slippage and no danger of this ever coming apart.

This is what it looks like all completed:

As you can see, these fuel regulator fittings are much nicer and better designed.  If you are considering this for an engine swap, don’t waste your money on the fittings with the plastic spring-loaded clip.  Get the ones with the threaded cap.  You will be much happier and most important of all, safer.

 

ECOTEC Fuel System – Part 2

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Just a followup on yesterday’s post.  This time, a few pictures of the engine side of things.  Here is the fuel rail, on the extreme right is the fuel inlet and below the rail itself is the loom holding the wires for the injectors.

Here is the fuel supply side.  This one took some doing.  At the extreme lower side (close to the car’s body) you can see the end of the braided line.  That end has a crimped fitting that screws into the stainless steel line feeding fuel from the rear of the car.  That stainless line is held in place by these really cool brackets that unfortunately are not seen.  I’ll have to post about them in a later installment.  At any rate, on the other side of the braided line is another fitting that screws into the solid line shown below.

That line is basically a factory unit that has been modified bigtime.  Ther is a threaded fitting that was silver soldered that allows the braided line to be screwed on.  The reason why this had to start as a factory item is because of the special connector on the side of the fuel rail.  That one clicks into the tube sticking out of the fuel rail.  There is a special took that is used to take that out, by the way.

Finally, on the fuel rail itself you can see the Schrader valve (that black dot) on the right.  This is where you can tap a fuel pressure gauge into, for measuring fuel pressure.  This is all factory items.

Finally, this is what the injector underneath the fuel rail looks like. The rail looks rusted but that is only reflection from the red paint from the rest of the car.  In reality it is quite shiny.  This is number 2 injector going into the head.

And this keeps the engine alive and kicking!

ECOTEC Fuel System

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Supplying fuel to the Ecotec required a special delivery system.  Unlike the system we had in place for the V6, the Ecotec is a “returnless” design.  I’ll get back to that, but first let me describe what we had before with the V6.

The V6’s fuel rail required a “loop” for the fuel to flow in.  So a special made aluminium tank was made to fit the stock fuel tank location.  Since we wanted to extend the range, the tank was made larger.  This tank has two bungs, one is an output and the other a return.  The output was connected to an external high pressure fuel pump and plumbed to supply fuel to the fuel pressure regulator and ultimately the fuel rail up front on the engine.  A return line was also plumbed and this dumped unspent fuel back to the tank.  This is a “return” fuel system.

There are advantages to this design.  The pump can be easily serviced and replaced if needed.  However, these high pressure pumps are getting a little expensive these days.  Another advantage is that the fuel returns back to the tank and ensures a fresh supply of “cool” fuel – no vapour lock.  The big disadvantage and something that really screws up folks doing conversions is the tank must be modified (unless specifically designed like mine) to have a return line bung.

The Ecotec however, is part of the new design that does not use a return line.  With this system, there is a single line going to the fuel rail constantly supplying high pressure fuel to the injectors.  This posed some challenges for us.  Since we had made that nice alumimium tank, we did not feel like pulling it out and making a new one with only one output instead of the two used by the return system.

This is what it looks like now:

Whoa!  This looks busy.  Well, let me explain what is going on.  The fuel tank is covered with the black carpet.  At the very bottom, on the extreme right is the former “return” line input.  On the bottom of the tank you see another line feeding the small box on the left.  That is now the supply line into the small box holding the high pressure fuel pump (see picture below).  The fuel pump box above has two lines going up ending in blue fittings.  They supply high pressure fuel into the new fuel pressure regulator and combined fuel filter.  So you see, excess fuel goes back directly to the pump box.  The silver braided line coming out of the regulator feeds a stainless line that runs on the frame and feeds the fuel rail up front with high pressure fuel.  Very neat, and only one line goes forward.

This is what the fuel pump looks like.  The pump has a “sock” that mounts to the input side.  This is a pre-filter.  The rest of the bits are the rubber isolation tube on the left and the wiring adapter.  This is all GM as fitted to Corvettes.

OK – there is a reason for all this.  If you look closely at the tank you see a protrusion at the very bottom.  Even though the tank is baffled, when doing heavy cornering fuel has a tendency to starve the pump.  We solved that by making a special lower compartment that will not allow that.  Kinda like a windage tray on an oil pan.

The fuel pump tank (the small box) as described previously contains a submerged GM high pressure fuel pump.  The box has a “lid” held by several screws and machined to hold Vitrol “O” rings to keep fuel from leaking.  This is a tight seal.  The rubber line at the top of the fuel pump box allows air to escape, allowing the box to always be full of fuel.

The tank holds about 15 gallons and the small box holds about another gallon (give or take).  The beauty of all this is the fuel pump box always contains fuel.  When taking turns at high speed this all now ensured no fuel starvation.

Of course all this comes at a price.  All this has taken up precious space in the trunk but then again, I don’t carry a bunch of wrenches and spare parts like many other owners of “originally” restored cars do.  Furthermore, the extra fuel capacity offers a much more respectable driving range:  I have already been able to get 350 miles of city driving from a tankfull and still had some fuel left in the tank before filling it back.  I am hoping that once I get bowtie6 on a long trip on an interstate, I can reach the 400 mile mark.  Not too bad huh?

One more picture showing the custom made aluminium battery box housing an Optima Red Top battery.  Behind the battery box is the Triumph “bleed” tank that is plumbed to the fuel tank filler neck and allows fumes to be routed back to the intake side of the engine.