My 427 SOHC Build..... Finally the time has come!

[cobracammer]

OK ordered a new MDS starter (High torque) replacement.  Since the headers were built around it, I just figured replace it with the same one.

Been doing a lot of reading, and no where can I find that you can contaminate a 12 V switched power source.  almost everywhere I read, hooking up a EZ EFI system by fast, people "Tap" in to another 12 V switched power source.  I may be wrong, but I don't see how the 12 V signal wire feeding the MSD box can interfere with the FAST EFI computer.  Its basically just a switch to tell the box (s) to power on?

Anyway, since I cant tinker any further due to the broken starter....  Chris from the shop called me this morning.  I explained to him what had happened.  I told him that the engine was running for about 2 minutes, and etc.  I am basically sending it back to his shop to get it in running order.  I need to check back on Wednesday to make sure he has room inside the shop to put the Saleen, as well as his EFI guy to take a look at my wiring, setting (even though its plug and play) and install the new starter and gas pedal.  Basically I just want to drive this car for a bit and then sell it  LOL 

Possibly a side oiler cobra replica next.....

Or a cammer cobra if I play my cards right.  This part sucks, but building the engine was a blast (even with the stress of doing it for the first time).

Ill keep you all posted.  Starter shipped out today

[jayb]

For what its worth, I think you should listen to the FAST guy.  On my EFI setups I run power and ground directly from the battery to main power and ground connections of the EFI box, and I also put one of those bypass capacitors right next to the EFI box, for noise filtering purposes.  Then I run a dedicated 12V switched supply to the EFI box's switched power input, to key it on and off with the ignition key.  And as you have already discovered, the 12V must remain on when you have turned the key to start, not just when it is in the run position.

I don't know if your EFI system can be hooked up like this or not, but the FAST XFI system I use on my Galaxie works fine this way.

[cobracammer]

Hey Jay.  I agree. The MSD box and the FAST EFI box both have power and ground running directly to each side of the battery (as per each set of instructions).  The part that the FAST EFI tech said was the problem is the switched power source.  When I told him that I had the EFI computer twisted to the MSD box signal wire and had them "tapped" into one fuse location, he said that's a biggie.

 I am going to have the shop leave the transmission lock out solenoid left connected to the kick panel fuse location.  I'll ask them to run fresh stand alone lines for both the MSD box as well as the EFI computer right off of the ignition wiring in the dash?  At this point, I would settle for 2 toggle switches on the dash for these.

Ill let you all know as soon as I have any news  :0) 

[cobracammer]

Just wanted to throw some thoughts out there......

After speaking with the EFI Tech, and he explained about the vacuum ports on the throttle bodies, it got me thinking.  There are a few vacuum ports on each throttle body.  I had my fuel pressure regulator reference hose running to a "Manifold vacuum port", when it should have been referenced to a "Ported vacuum port"......

Just this alone sounds like my issue?  I would assume there would be a lot more vacuum in the manifold which was then telling my fuel pressure regulator run richer?/ Leaner? (not sure).

I am still not clear on how this affected it, but since it started and ran, but then dies......  The first time I got it running (where it ran for like 2 minutes), as soon as I touched the throttle it died.  This was either it flooded it or starved it of fuel possibly?

Also of note, when I removed the sparkplugs to roll the engine over, some of the plugs were sooted/fouled up.... and some were so clean it looked like I just installed them.

I have this speaking suspicion that something small and stupid (like the vacuum reference line) is what is causing this headache!

[jayb]

Jason, if you aren't running a supercharger or turbocharger, you should not reference the fuel pressure regulator to the manifold; the port on the regulator should be left open to atmospheric pressure.  This way you will always get your 43 psi or 50 psi, whatever, in the fuel rails.  If you reference it to the manifold the vacuum in the manifold will subtract from the fuel pressure that the regulator is set at.

For a supercharged application, you need a manifold vacuum reference (not ported vacuum), because as the intake runners are pressurized, the fuel pressure must be increased to deliver the same amount of fuel.

If it ran for a couple minutes, then quit when you opened the throttle, I'd agree that it is probably a fuel issue.  On the plugs, if they don't all look the same, or close at least, that would also be a clue for a fuel issue.  Maybe one bank of injectors isn't working right or something like that?

[cobracammer]

Hey Jay,

OK I just got off the phone again with FAST EFI tech support.  Here is what this person said.....

First, the fuel pressure regulator does need a vacuum port reference (even though its not supercharged).  He said that since its a free flowing return system, it uses the vacuum to bring the fuel pressure down....  not increase it.

second, I asked him about the 12 V signal wire being shared....  he said no big deal (in his experience hasn't caused an issue)

3rd, we went over fuel pressure again.  Interestingly enough, the tech yesterday said I should bump it up to 50 PSI with the 8 injectors (instead of the 43 PSI the instructions say).  This guy laughed and could not believe someone from their company would have said that.  He said this......  With 482 cubes and 8 injectors, assuming 600-650 horsepower, you want to set the fuel pressure regulator to 32 PSI (with the car off).  When you do initial setup on the handheld computer, you want to leave the 42 PSI (the default PSI the computer has input).  He said, "I bet you were drowning the engine the first few times you cranked it", at which point I explained that the 1 time I got it running, I touched the throttle and it immediately died.  Then when I pulled all the spark plugs, some of them were BLACK and wet. 

He had picked up during our talk that I was using the MSD 6A box, at which point he asked how I had it wired.  I explained that the instructions for the MSD ignition box are the same as the EFI computer as far as the red(+) power wire goes to the (+) terminal on the battery, and the Black (-) ground wire goes to the (-) terminal on the battery......  That was his Ah-Ha moment!  He said So you have the FAST box wired to the battery (like the instructions say) and the MSD Box (like the instructions say)?  I say.....  why yes!  He said , the biggest problem they find with people calling in is "noise" on the ground side of things.  He told me to take the (-) black wire off the battery for the MSD box and ground that to Chassis.  He would almost guarantee that was one of my biggest issues.

So I was flooding the engine with the 43 PSI (when it really should be 32PSI) and there is supposedly a ton of "Noise" from the MSD box being grounded to the battery (infact the wire looks that go to the MSD box and the FAST efi are literally stacked on top of one another and tightened town on the (-) side of the battery.

LOL  I may try and somehow replace the starter by myself when it arrives on Thursday and with these changes, give it another shot.

[jayb]

What he told you is completely different from the EFI systems that I've run, including a FAST XFI.  These tune themselves systems must be a whole 'nother animal...

[cobracammer]

I am going to go home tonight and adjust the fuel pressure down to 32 PSI, and also remove the (-) battery wire from the MSD box and ground it to the frame.  I re-read over their (MSD) instructions and it says that you can ground it to the negative side of the battery or ground it to a good chassis ground.

I am going to try these changes out with a new starter before I have the car flat bedded over to the shop and spend who knows how much more $$   

In regards to the vacuum reference line to the regulator, I explained to the gentleman that this will not be a supercharged application.  And I wasn't sure why the vacuum reference would be needed on a naturally aspirated engine.  He explained that unlike other applications where the vacuum reference line adds more fuel pressure with increased vacuum, the FAST EFI (Self learning) one decreases fuel with increased vacuum.  So far I have spoken to 3 different techs, and all 3 say the reference is needed......  but who knows at this point, the next person I call could end up saying "Geeze, you know your car wont run because you have a vacuum reference line hooked up?  "LOL

The only thing that's keeping me going right now is that I heard this engine run!  It ran for a few minutes and there were no oil leaks (YET) LOL

really hoping that these few items are all I did incorrectly and the car fires right up next time.

[cjshaker]

Don't you just love when you call for tech support and you get two TOTALLY different answers from two different people?!! That would have been enough for me to ask "Then is there anyone there who actually knows what the hell they're doing??"

I'd say that that is about enough for me to never want to deal with them, but unfortunately that kind of crap happens with ALMOST all the companies. Tech supporters are usually anything but...

[WConley]

Jason -

The older factory Ford EFI systems use a pressure regulator that's ported to the intake manifold.  I started my career at Ford in the Fuel Metering group.  The reason for the vacuum signal is that these old-style systems don't adjust the injector pulsewidth to the manifold vacuum.  The "adjustment" is done mechanically with the regulator. 

A fixed pulswidth would push too much fuel at idle, since the manifold vacuum is high and is "sucking" fuel out of the injector.  The regulator drops fuel pressure to keep the same "delta" pressure between the fuel and the manifold, so they can run the same pulsewidth.

I'm thinking the self-learning aspect of the FAST EFI system becomes a lot easier if you're not electronically jiggering the pulswidth with manifold vacuum.  The system probably only needs to tweak one master pulsewidth to get the engine running well at all throttle positions.

Modern EFI systems vary the pulsewidth over the entire map in order to better control emissions.  It's much more precise that way, but a lot harder!

I think you're on the right track :-)

- Bill

[cobracammer]

Thank you   

While I am awaiting the Starter, I decided to get started on the gas pedal swap.  taking off the Saleen gas pedal was a snap.  There are just 3  nuts (10mm ) on studs.  After removing the nuts, just popped off the pigtail that controlled the electronic throttle.

To make this a little easier, I made a cardboard template of the mounting surface of the pedal flange.  this allowed me to mark out where holes should be drilled.  Then, after tracing out the holes in marker, I started surgery!  The Lokar pedal requires a 1 -3/4" hole (on a 60's mustang, this is already there with a plastic grommet in it.  I used a hole saw and slowly made my cut.  Then, now that I was able to lay the flange flat against the firewall, I noticed that there needed to be a little trimming done a the bottom of the flange to work with a funky contour in the sheet metal.  I made this cut with the angle grinder holding the flange in my vice.

Then its a matter of sandwiching the front and back of the flange together (one from the engine bay, and the other from the pedal area inside the car.  I had my wife hold the pedal itself against the flange while I tightened the bolts from the engine bay.  Finally, it came time to make sure that the pedal actuated the throttle bodies all the way to WOT.   After a little cutting, and a little finesse, the pedal holds the throttle open all the way when floored. 

This was not a huge item on the list, but it was definitely not something I was looking forward to in this heat.  All in all, I think the only thing missing is a throttle return spring (the FAST have little ones built in, but I think just for safety, I will add a light return spring to the rear throttle body to ensure it never sticks).

Also, I got a call yesterday from John in Texas (Yellow engine services) and he said that finally the rubber mold place finished his order and he has set(s) of the rubber spark plug tube dust caps available!!!  I ordered a set and they are on their way.  Once the car is running......I will trim the spark plug wires to fit and look pretty and these plugs will be added!

[cobracammer]

You know one thing I don't understand about my conversation with the FAST tech (the last one I spoke with)..... 

OK I have 8 injectors (4 on each throttle body).  And the FAST EFI system with one throttle body (4 injectors) is designed to handle up to 550 HP at 43 PSI.  The technician said because I have 8 injectors, I need to dial the fuel PSI down to 32 PSI.  This I understand, I was swamping the engine with way more fuel than it needed......  But what I don't understand is why he would have told me to make to tell the computer that the Fuel PSI is still 43?  The first question the handheld computer asks is do you have 1 throttle body or 2.....  So the computer, right off the bat knows I have 8 injectors.  I think after I have everything ready to turn the key again, I am going to call them 1 more time and ask. 

Question for Jay......  Even though you don't have this specific EFI set up (self learning), you still have 8 injectors.  What is your fuel pressure set at?  What injectors do you have?  This is what I found on the injectors based on 1 throttle body:

"Baseline for the EZ-EFI system is 43 psi, at which the four injectors and EZ-EFI throttle body will support 550 horsepower. The system will support higher horsepower with higher fuel pressure. The injectors are rated at 88-lbs/hr at 60 psi. "

[WConley]

It sounds to me that the baseline calibration on the FAST computer is assuming only four injectors.  Testing has probably shown that, with eight injectors, telling the computer 43 psi, but really setting fuel pressure lower, gets you into a nice fat sweet spot where the engine will run.  Then the self-tuning algorithm can go to work and optimize the pulsewidth and timing.

It may not make sense on the surface, but I've written plenty of this type of optimization software.  If you start the optimization in a bad place, it will fall off the rails and flood or starve the engine.  If you're in a solid sweet spot, the engine will still run while the controller is making its adjustments.  That will let the system figure out which direction to go with its adjustments.

Electronic engine controls are the devil's work.  At Ford we would tune areas of the spark/ fuel map that didn't seem to make sense.  It just worked better with that much fuel, so we left it there!

[jayb]

Jason, I'd listen to Bill on this one.  FWIW, my fuel pressure is always set at 45 psi - Jay

[cobracammer]

Thank you both. With all the knowledgeable people on here, I seriously feel like that kid on the bus with a helmet on.... finger in nose   

 I get the starter tonight so hopefully I can get it in this weekend and try it again :0)