I tried to start then engine I dropped in, and it cranks over, but I'm getting no fuel. Fuel pump is on, and there is fuel in the lines, but the injectors are not firing. I tested the leads, and I got a .26V reading with key on, and a -.6 reading while cranking. We tested my brothers Mustang, and it read 0 while on, -1 while cranking. (Wasn't sure which was positive lead or not, but I measured the same way.)
The new engine is a 351W with 24lbs injectors. I have a cobra computer (for a 5.0, but I thought it would just run lean) and a 96 cobra MAF (it calibrated for the 24, of thats what I read online.)
Does anyone think the computer is to blame, or something with the wiring?
The red wire side of the injectors should have 12v with the ignition in run.
This comes through the EEC power relay being picked. Since the fuel pump is running, the EEC power relay is picked.
The EEC pulses the ground on the other wire to the injector.
The red wire side of the injectors should have 12v with the ignition in run.
This comes through the EEC power relay being picked. Since the fuel pump is running, the EEC power relay is picked.
The EEC pulses the ground on the other wire to the injector.
Check for spark. If the computer doesn't see a pulse from the TFI module it won't fire the injectors (because it won't know when to fire the injectors).
I have spark. The first thing I checked. The TFI is new too.
Ran a voltmeter from the red wire to the neg battery post with the key in run, and it read 10.6. So did the other wire. The other wire is a ground, right? Is it always on, turning off when the injector fires, or the other way around?
The injectors should have a 12V feed any time the ignition is on. The computer switches the ground on and off to fire them. They will not have ground until the computer gives it to them. You're getting that voltage reading through the injector itself (power is going through the red wire, then through the injector, then into your volt meter). If the injector was "firing" your reading would be "0".
If you've only got 10.6 volts at that red wire you've got a problem.
If the injectors are used and have been setting for some time they may be stuck... Had this exact problem on a buddies F150 I gave him a set of 19lbers for... It would only fire one cylinder, the other seven were stuck... Wound up reinstalling his originals...
Had the problem again a couple weeks ago, on another set of used injectors with only 10K on them... I replaced the right bank injectors (chasing a interminent miss at idle) in the old Grand Marquis and it missed like Hell, till it ran about five minutes then cleared up...
You think all 8 would be stuck? I'm getting no firing at all. I soaked them in Seafoam before installing.
And I'm not sure how true that 10.6 is, cause I went out to recheck it, and the battery was pretty low. I don't see how it could be going through the injector, cause I pulled the wiring harness off of it to check...
Check and see if any local car parts stores have a "noid light".
It plugs into the injector cable and will blink if the EEC is firing the injector.
Ok, radio shorted out. I wanted to fix that first so I don't kill my battery.
I got a noid light, and it lights up. Dim at first, but then brighter. Can't really tell if it's blinking real fast, or alway on. Guess I might lift one side of the fuel rail up tomorrow, see if I'm getting anything. Any more ideas. I would think if they are getting signal, they would have to fire...
you can unplug the injector, jumper power and ground to each injector, listen for the click.
4 of the 8 i bought from tom were stuck (wouldnt click),, I gottem to free up by standing them upright inside a wood block with holes drilled.
filled them up with 3 in 1 oil and let them sit for a helava long time. Put power to them and they clicked.
A guy down here told me to boil some water, drop them in by a string one at at time in the water for about 1 min,
dry them off and put power to them. It works for him when they are stuck. He said it expands things inside and frees up the moving parts.
The noid light should defiantly blink... An injector pulse is similar to the spark from a single plug wire while cranking...
A open TPS circuit will put the EEC in dechoke mode and shut off the injectors...
Put the noid light on another vehicle so you can see what it's supposed to look like.
The light was pulsing, I got a better look at it when I had some help. Never totally went off, but definitely getting brighter.
I ran 12v to one of the injectors, and sure enough, it clicks.
If the EEC shut down the injectors, it wouldn't send a signal, right? I don't see how else it would stop it...
Have you checked your pressure at the fuel rail? Maybe your fuel reg got damaged in the install and is passing all the pressure back to the tank.
Does it run if you squirt some fuel into the intake?
-dz
Distributor stator? Mine was failing whenever the engine warmed up and then suddenly I'd stall. If the computer doesn't think the crankshaft is turning it cuts off the fuel, I believe.
There is always 12v applied to the injectors when the ign switch is on, the EEC only provides a pulsing ground signal to fire the injector, if noid light blinks pulse is there....
Applying direct 12V to an injector, is a good way to burn out its coil...
I'll try to test the pressure. 40 psi, right?
I rebuilt the distributor when I bought it, so unless I installed the it wrong, I wouldn't think it would be the stator. But is there any way to test that, just in case?
And we did try to use starter fluid, but it died when we stopped.
Sure sounds like no fuel pressure... 40 psi is correct, but if it will squirt fuel out the test port on the fuel rail, it should run(can you hear the pump when switch is first turned on?)... AGAIN If the light pulses, assuming they are not stuck or the coil open, then the injectors should be firing, forget the distributor...
i didnt see anything wrong with a momentary touch of power / ground to verify the injector clicked. If i were thinking , i would have said to:
loosend the dizzy lock down
turn on key
rotate dizzy left and right and listen.
you should hear a buch of clicking.
(with the dizzy cap of to the side, this is where you can see how the stator comes in to play. usually the dizzy case is locked down in one spot as you set the timing so the housing / stator is stationary. since the housing is moveable, we can rotate the housing left or right to pass the rotating part of the dizzy's fins through the stator assembly. This is what the eec uses to reference what cylinder you are on. I did not know till a few years ago that one fin is slightly narrow denoting it as cyl1.)
for fuel testing you can......
jumper the tan/light green wire to chassis ground up at the eec test connnector.
turn on the key only
fuel pump should run full time
turn off key
wait (pump will take double the time to shut off)
remove jumper
go to trunk relay (near trunk hinge pass side)
ground tan light green wire to chassis
turn on key
pump should run full time.
turn off key (pump will take double time to shut off)
remove jumper
If you do not hear the pump run for 2-3 seconds just by turning on the key(no jumper), your eec control circuit on the tan/light green wire (eec pin 23 iirc) is not managing the ground.
If you are able to start the car with a jumper on the tan/light green wire bonded to chassis, then the eec is faulty. (ie- someone in the past has been fiddling with thier fuel pump relay and did not know how the circuit worked, this caused a backfeed to the eec and probably blew a diode on the eec board).