I have an 87 tpi 305 and just installed the engine and the injectors are not pulsing where do I start troubleshooting? It gets fire but no fuel, it has a new fuel pump in it also. The car sat for six years so I do not know the history behind it, but the tpi is off of an 86. Thanks

 

Check the grounds that attach to rear of cylinder heads & then go to your ECM & PROM, try to scan, etc..

 

check fuse buy the battery.

 

Couple things to look at here

First, make sure that the ignition module is good. Usually, if you have spark, it is fine. But get it tested at autozone or something to make sure it is sending a proper reference signal to the ECM, as the ECM turns the fuel pump on and off based on if your dizzy is sending reference pulses or not.

Second, check your fuel filter. If it is plugged, your pump will not be able to get enough fuel up to the injectors.

Check your fuel pressure, make sure that it is building at least 40 some PSI when you prime the fuel system by turning the key on and off a couple times. Also watch that the pressure isn't falling excessively after the fuel pump turns off.

Check your injector wiring. Make sure that neither of the fuses for the injectors are blown, and that they have 12 volts of power on one pole of the injector plugs when the key is set to on. The ECM provides ground for the injectors, not 12 volts

Final thing is to check that your injectors are working properly, check their resistance (most are around 16 - 17 ohms or so, if I remember correct, and they should all be pretty close in their resistances), and use a noid light to make sure that the ECM is pulsing them.

 

An update. I am getting plenty of fuel pressure and the spark is fine. I get voltage at the injectors but no pulse. Now the one thing is I may have a tbi distributor will that make a dif? I also tried another cpu still the same. thanks

 

Shouldn't, make any difference at all. I've got a TBI dizzy in my truck with the TPI too, and it works dandy, gonna put a big cap back in though, that remote coil is a pain in the butt.

I originally swapped them out to test if the big cap HEI was having problems or not, cause I couldn't get the truck to run. Big cap HEI has been great in my TBI truck, but since it is designed for the remote coil, while my TPI truck isn't, I'll swap them back out

Can you do us a favour, and go rent a noid light and install it on one of the injector plugs? (unplug the rest)

You should see it pulsing when you crank your engine, if you don't then there is something wrong with the injector wiring (wrong pin or something) if there is, then something must be up with the injectors.

 

maybe the oil preasure switch is shot . Could be why all the injectors are shut down . Just a thought.

 

I had this problem after installing my 395. The dizzy has an electronic modual which tells the injectors to fire once per each turn of the crank. It was this electronic modual which went bad simply sitting on the shelf,,, go figure.

As I understand it, the injectors always have the positive side powered, the injector is grounded to make it open and flow fuel.

Buy a node injector test light (cost a few bucks at your parts store). Pull one injector connector off and plug in the node light. then have someone turn the key and watch to see if the node light flickers,, if it flickers, then the injector should be getting power to open. If the node light does not flicker, then of course the injector is not getting grounded out, so it will not flow any fuel.

 

If your ecm is toast they wont pulse. my .002, also if you have a couple bad injectors it can cause a similar type scenario check the resistance on the injectors.

 

Make sure the plugs on the ignition module are on tight and seated properly, the four wire connector controls the injector pulse while the two wire is the spark. If every thing is connected, then swap in a different module and see what happens.

 

I found the problem! Some body had added and extra wire to the fuse box for some reason. I removed it and we have pulse, thanks for all the help guys!!

 

Well, I bet that one isn't in the service manual. Good that you found it.