F.A.S.T. XFI sequential and speed density mode problems

[CorvetteDave01]

I'm getting the car tuned (427 sbc, FAST xfi, solid roller cam, FAST dual sync distr) and dynoed tomorrow in Alpha N mode, bank to bank because there seems to be a signal interference with my dual sync distributor, ignition box or computer somehow. Things just aren't running properly in speed density or load speed density mode, but fine in Alpha N.

Here is what we have done so far.
Checked the ground to battery - fine
Checked the power to battery - fine
Ran an extra ground strap from the motor back to the negative chassis ground

Things I am thinking about working on when I get it back.
New plug wires
Coil change or ign box change (have a MSD 6A with a Blaster 2 coil)
alternator wire disconnect to check for interference
Running a new 'points' wire to the computer
Running several other ground straps to the chassis from the motor ('76 vette)

Any thoughts????

[Fuelie Fan]

what happens in speed-density mode that makes you think you are getting interference exactly? What kind of vacuum does this engine make at idle?

[CorvetteDave01]

Well there is an ignition interference error. Also, now that I have it home and have driven it the below things concern me.

1. 41 degrees total timing is too much, I think the timing is way off
2. The car is cutting out at about 4500-5000 rpm now that it is in sequential mode.
3. It doesn't have near the power a 427 should have. More like a 350. Had the engine builder drive it with me and he agrees that it seems to be a timing/ignition issue. Just not sure where to start. I went through the dual/sync distributor timing procedure 3 times to asure that it was correct, guess I'll do it again.
4. The first, Snapon timing light we used was very erratic as it was too sensitive, think the dual spark box was the problem. Put a cheaper light on it and it was fine. If the dual spark can mess up the timing light, it makes sense that it would mess up the computer as well.
5. Might rewire the ignition box/coil away from the main engine harness.

Anything else? I'm really starting to get frustrated, because this motor just isn't running right.

[Hammered]

I would do the easy things first. The XFI and most other systems are designed to be used with a spark box so I would program your timing and fuel first. Somebody (your builder) should be able to give you a starting map for the timing. Also, replace the plugs once you get the VE close because they typically get fouled in the early stages of programing an EFI system.

I would also double check your rev control settings and other initial settings.

[laguna4efi]

CorvetteDaveo1, have you made anymore progress? I happen to be employed by FAST and just joined this site yesterday. If there's anything I can do to help please let me know.

[efituner]

I have the FAST XFI on a Jet boat with a 468 chevy built to the max. This fuel injection has been nothing but a complete Nightmare from day 1 3years and still does not run right! I have had every problem someone could possibly have. After fixing every issue I have come across and there have been MANY!

Here I am with this. My motor will not start until I advance the timing in the xfi to 36 degrees advance! For a big block Chevy? Yea took me almost a year to figure out why this thing such a finicky SOB to start. Combine learning that this wanted 36 degrees advance and the fact that I am running a MSD 7al3 ignition box that will not F ing run if you fall below 12.5 volts for whatever reason! So combine the fact I had a faulty alternator that wasn't charging my batteries and I had to melt my starter and rip hair out of my head while playing with cranking fuel maps and base fuel maps and so on. This thing has made me look like an IDIOT many times. I would get this thing to start and run awesome. Drag it 100 yrds back it in the water and then it would not start for nobody! Why? 3 things. 1. Bad alternator. 2. MSD needs 12.5 volts or you need a paddle. 3. Fast XFI wants 36 degrees advance.

So here we are now. I can get it to start. It runs decent till about 5000 Rpms then almost completely shuts off till you back off the throttle. Has about 450hp im guessing out of 750 it had in a room on a dyno before nitrous. By the way before you ask I had a faulty distributor module in my FAST duel sync distributor. This caused the ECU to kick out my expensive dyno tune out of the computer. They never saved it or gave me a copy. I got to deal with making my own. I was up to the task since I have tuned other engines on other EFI systems. This thing would not stay connected to a laptop for more than 10 or 15 seconds. The motor would start then immediately shut off while disconnecting itself from a laptop. Sometimes would completely crash the laptop in the process. Oh the fun times. So if your reading this and your having the same problem its your distibutor module. I sent them the ECM twice and they said nothing was wrong with it.

So anyway if your exhausted reading this I am exhausted f ing with this so any help would greatly be appreciated. I am thinking if I advance my timing a bit more across the board I will be able to hit the rev limiter at 7500 rpm and get the power I want. But am afraid to start tuning for 300 shot of dry nitrous with the timing this far off. I really dont want to blow this thing up. I can post pictures of this engine and boat and have at least 40k plus invested in little boat. Ridiculous yes but its my brothers baby so hey.

How do I get this thing timed right? Do I play with the crank Ref angle? Its set at 50. Or do I pull the distributor and reset it? What is the procedure?

[LSx_88_Ciera]

http://www.fuelairspark.com/Base/Dow...p/Chapter6.htm

[MrForce]

What distributor are you currently running? If it is the XFI, are the plates inside the set to the 50 degree angle or the 1 degree?

http://www.fuelairspark.com/Instruct.../FAST4-113.pdf.


Rob

[efituner]

Took me all day to figure it out. ****ing with instructions pulled off 5 different sites and forums. Funny how FAST gives you precise directions on how to use every damn distributor but the one designed to work there OWN dual sync! Stupid! Yea so remember how I said I had a bad distributor module from the get go sent it back to fast. They sent it back to me. Had the engine builder drop it at Speed O Motive for me. Was cursing his name ever since last weekend for putting the distributor in retarded. Sorry Rick. It was 180 off and he just rewired the cap to work but it was still almost 1 cylinder off that's why I had to put 36 degrees advance to get it to fire. Turned out to be a blessing in disguise. I never would have figured out FAST installed the distributor module in the WRONG DAMN PLACE! And by that I mean, they put the damn thing, not on 0 degrees, not on 50 degrees, but to the left of 0 degrees which places every crank signal in between the actual terminals on the cap. Yes the holes line up this way. This ****ed off an entire summer infact a whole damn year I couldn't run this boat to run! Were these guys just ****ing with me or what? I seriously want to kick someone square in the nuts right now at FAST! I was playing with it for hours and was dumb founded on why the crank light would come on when the rotor was in between terminals on the cap. Moved the module to the one of the 2 correct positions 0 degrees, amazing the crank lights line up with the terminals on the cap. Tonight reading your instructions which I could not find anywhere the FAST4-113pdf i realize is not the right position for me so I will switch to the last possible 50 degree tomorrow and fire it up again. It fired up on the 0 degree but revved up and shut off quick. Error code 16 came up so I stopped there.

So this begs the last question for me. I cant get a cam sensor light to go on no matter what. So I think my second module is JUNK right? The crank sensor lights up but that's it. It needs to be be replaced right. Other wise I am just guessing a 1 out of eight chance its right. I think the led is just burned out cause the motor runs. I will check that yellow wire for volts or ohms or something and see if i can get it. At least I finally have this expensive nightmare of fuel infection figured out.

Thank you guys so much for the great and vital information. It really helps out big time. John.

[TurboNova]

hey John,

sounds like you need to take two deep breaths.

I can help you get some of this set and working correctly.
First off your distributor needs to be set to the 50 degree mark.
Second, if you can get it to run then you need to sync the distributor to the engine timing. With a timing light and looking in the spark table on the laptop.

Have you looked through the setup info in the help menu?

You might also be interested in taking this class that I will be teaching this summer.

FAST™ XFI™ fuel injection Training Course Open For Enrollment

Let me know what questions you have.