my fuel pump primes for 2 sec then while cranking no spray at inj. inj fuse good, inj resistance good. this is an intermittent problem. fuel sprays she cranks right up, no spray and she cranks all day. sucks cause i cant trust to drive her. 1992 305 108,xxx had tune up at 80,xxx plugs wires fuel filter etc.. what sends the signal to the ecm to fire the injectors. intermittent problems suck, any suggestions would be great

 

The distributor sends a reference pulse (DRP) to the ECM. The ECM sync's to this pulse in order to fire the injectors. Likely suspects include the pickup coil, ignition module, and the 2 wire harness between the ignition coil and the ignition module (thanks to another TGO member for the last suspect).

RBob.

 

thats your ignition module going out, that just happened to me, same crap.. was like 40$ took 2 mins to install, just take off the distrib cap, and replace the lil black block!! peice of cake ez fix!

 

Im having the same problem, car wont start at all though, its wierd, got power to the injectors, swaped coil, swaped ign module and still no start anything else that could be a problem here? Runnin out of ideas and money thanks everyone-Rev

 

A no-start due to no spark/inj. pulse could be multiple items. Power to ECM,coil,ign. mod, to start with. Followed by reference in to ign module from pickup coil on distributor,and out to ECM. You can have spark but no inj pulse and that leans toward ECM.Without A scope your guessing but module is good guess.

 

Before you go swapping much else, put a timing light on it.
Is it sparking ?
Shine the timing light into the throttle bore.
Do you see fuel spray ?
If so, skip the next step.
OK, put the timing light inductive pickup on ONE ( and only one ) of the injector wires.
Does the light flash ?
If it does, start looking at fuel delivery. ( pump )
If not, then spark, but no injector is what VATS is supposed to do.

At the moment, more data is needed......

 

Still nothing, module is new, connected well as far as i can tell poured some gas into tbi to see if it might be a spark problem she fired up like a champ for a whole 2 sec before dieng of again, im thinking its the regulator for the fuel pressure or maybe the pump. Ill let you guys know thats for all the tips-Rev

 

Unfortunately, without a timing light that doesn't tell you that it's NOT a spark problem !
If there's no DRP, then it's working correctly based on what you've posted so far.
Or, could be VATS if your car has it.

 

I had a similar problem awhile back. I swapped to carb and then did a battery relocation. I later switched back to TBI. I could crank all day and it wouldnt start. But if I sprayed some gasoline down the tbi it would fire up and run great.

Turns out my battery voltage was getting pulled down too low from the battery relocation. During cranking the ECM wasnt getting enough voltage.

Check your battery, ground, and power wire

 

Ill check on the voltage and connections for the bat. Vats=vehical anti theft if so no dont got anti theft. Well i used a smiple bulb checker to check for power for the injectors, and they have power and the light pulses to what i can only hope is the Drp signal. I check power to the pump seeing as the injecters seem to working fine and i got 3 wires tan/wht pnk/wht and black i figured black was ground, the pink has power, but the tan is dead. Anyone know what these are for? Ill take a DVM to the pink to get a read and then to the tan but for now im out of ideas... Hopin it aint the pump though dont feel like droping the tank... thanks everyone for all your help so far. -Rev

 

MAP sensor?It controls fuel delivery and ignition timing.

 

Does tend to suggest the injectors are at least trying, though it's unlikely you'd see it with that kind of light, 'cause the pulses should be 1/100 second long or so.
You might just be seeing the voltage sag on compression strokes.
That's why I suggested a clam-on inductive timing light on one of those wires.
That will tell you that the injector actually got the fire signal from the ECM

I think you'll find that the black is ground, the pink is power from the pump relay to the pump, and the tan is the wire from the pump to the ECM to tell the ECM that the pump is actually running. If the ECM doesn't think the pump is running, no injector firing. Normally, it goes to battery when the pump is running, zero when it's not.
Turn the key off a while. 5 or 10 minutes. Crawl under, and paste your ear against the gas tank. Have someone turn the key on, but not crank.
You should hear the pump run for several seconds at least. That tan wire should go to battery voltage during that several seconds, and back to nothing when the pump stops. If not, pump relay, or bad pump. Based on what you've got so far, I'm afraid it's what you don't want to hear.