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My FAST EFI / fuel injection mod thread

The choke power wire does NOT have 12v while cranking. Need to find a new keyed on/ cranking wire for the FAST. I got my water neck figured out and filled the system with distilled water. If the water neck leaks, at least it wont be messy. I found another FAST fuel hose fitting that is leaking. I will be removing the last hose and replacing with something better made. That makes 2 fittings that have leaked. Even if I fix them, will the others leak right after....or down the road? Screw that stuff, I can't deal with it.

I tried to fire it up, but I just got backfires. I get a loud, quick pop of a backfire through the carb. I'm fairly certain the timing is correct, I only took out the dizzy to install the engine. When I got it, it had already been broken in on the dyno. Unless my marks are wrong, then I guess it's the timing. Dunno, gave up tonight to watch a movie.

What normally causes it to backfire through the carb? I crank it for several seconds, it pops, and I stop. It never thinks about starting. :(
 
Do you have the rotor 180 off? I think it's impossible for it to backfire through the carb now! :waytogo: If it's really backfiring through the intake it may be firing the cylinders when the intake valve is open.
 
Yeah, I hope to try the dizzy today. Being a PITA, I hope it's the problem after checking it.

I can't hear the injectors clicking when the ignition is turned on, or even while cranking. How do I know I'm getting fuel? (other than when it starts or backfires haha)
 
I do hear the injectors click on key-on. To check for fuel open the butterflies and look down the bores when you key it on. Just don't crank it, you dont want it to backfire when you are looking down there!
 
Thanks, I'll have to look down the throat. Need to find a neighbor to turn the key for me, I got one :) but he's hit or miss. I hear the fuel pump come on, but it doesn't do anything after the initial prime. It never comes back on until I turn the ignition off, wait a few seconds, and turn it back on. I still need to fix that leak though too. :angry1:

Not a fan of things blowing up in my face, been there, done that, don't likey. :)
 
I should warn you, if you open the butterflies past 80% or something it will go into flood clear mode and it won't squirt any fuel. You may be able to tell just by putting your hand on one of the injectors at key-on so you can feel/hear the click, it's pretty audible. Also, when you are cranking, you should see the RPM go up on the handheld unit, that tells you the ECM is getting an RPM signal. Without that, it won't supply any fuel during cranking. Not 100% sure,it may fuel on keyon no matter what. But the floor clear mode will stop fuel delivery during cranking.

What blew up before?
 
The injector click is pretty audible you will hear it. At first I thought it was the fuel regulator chattering but its the injectors. It only fires the injectors at key on once. It won't fire them again until the engine is cranked. It will still run the fuel pump again after the ignition has been off for a few seconds.

For the key on/crank power, I couldn't find any wires either so I called EzWiring (manufacturer of my chassis harness) and they said the only wire that has power in both key on and crank is the distributor. They said its a clean signal and can also be used for a fuel injection system. So to be sure I called FAST and they said it would be fine.
 
The injector click is pretty audible you will hear it. At first I thought it was the fuel regulator chattering but its the injectors. It only fires the injectors at key on once. It won't fire them again until the engine is cranked. It will still run the fuel pump again after the ignition has been off for a few seconds.

For the key on/crank power, I couldn't find any wires either so I called EzWiring (manufacturer of my chassis harness) and they said the only wire that has power in both key on and crank is the distributor. They said its a clean signal and can also be used for a fuel injection system. So to be sure I called FAST and they said it would be fine.
 
I'm guessing it's your timing, if it is backfiring it must have fuel or there would be nothing to backfire.

Also, I read in the manual that it disables key on fueling until the engine starts. It will supply more fuel during cranking, but it won't supply more fuel at keyon until it has ran. So that means keyon may not happen unless you disconnect the battery completely to reset the ECM.

Also, make sure the handheld unit has power during cranking too, if it loses power you will lose your new settings before the engine has ran the first time.
 
Okay, got all new fuel lines installed. Turned key on and pump ran for the normal few seconds. It came up to the adjusted 50 psi and held for a few minutes, then held 40 psi for 10 minutes or so. It finally came down to zero.

Couple hours later, while trying to start the truck, I noticed my fuel pressure would only get up to 50 psi, then drop within 10 seconds to zero. I have no external leakage, all lines are holding and I don't smell any gas. The intake manifold is dry under the TB.

Also, I'm not hearing any injector firing. I heard them once, a long time ago when I first screwed around with the system. But never again. I've disconnected the unit from the battery for a minute, then wired it back up. I've also gone through the basic tune and setup wizard again.

I'm also getting a sort of back fire through the TB. It's a very quick blast of air, popping if you will, and there are black marks on the throat leading upwards. I'm 99% sure my timing is right. The engine was dynoed and distributor was left on. I marked the rotor position on the dizzy, and the body position on the intake before removal. After it backfires, it smells bad. Not of gas or burnt gas, just a strange bad smell.

Also, I am getting an rpm reading on the handheld, so that's good.

I would pay someone to get it running in a heartbeat. $1000 for someone to fire it up and make sure everything is good.
 
it's really hard to get a distributor back in exactly as you pulled it out. I'm guessing you've got it way retarded, try advancing it till it does something else, like being hard to crank? Also the fuel pressure is only supposed to be 43 psi. If you don't start it, it won't maintain the pressure. I think the fuel circuit will quit telling the pump to run? Also if you don't start it, the injectors won't fire each time, as it's not supposed to flood the engine. I bought my system from a local speed shop and my dealer was very helpful in helping me sort problems out. Who did you buy your system from? Call them for help.
 
I'm going to call FAST on Tuesday. I bought the system from Atlantic Speed. The fuel pressure is adjustable. I set the regulator to 50 psi and the computer to match. It seemed most people ran it a tad higher than factory adjusted 43.

How do I get the damn injectors to go again? It's been months since it last pulsed. How the hell am I supposed to get it running if it wont pulse again? Ugg. Tuesday is so far away.
 
I never hear the ticking of the injectors. Key on, cranking, nothing. I heard them about 2 or 3 months ago when I was messing around with the system. I am still working on the truck and it is going slooooow. I still have not fired it, so therefore, I guess, the injectors will not spray until it's running. Sounds like a problem to me.
 
with the key on, pump the pedal and see if you hear the injectors pulse.
 
It still sounds like there is something wrong with your timing to me. And yeah, if you give it half throttle it should inject more fuel when you crank it, but it still won't fire if the timing is off. Once it injects on key-on, it won't do it again until it is fired, but it will still inject fuel during cranking.

For your engine I would leave it at 43 psi. No reason to run 50 psi unless you are close to or over 550 hp, all its going to do is give you less fuel resolution down low.
 
Low battery caused that symptom on a customers car. Had enough voltage to crank but not enough for the efi I guess. I also had mine stop pulsing after it set when I was doing the trans swap. Just had to reset the tune. All I know is that the engine won't run if you don't hear the pulse at key on.
 
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