You verified that the PCM is providing ground side switching/pulses for each injector but not the functionality of the whole injector circuit. You need to take the power/12V from the associated pink wire in the harness, not battery 12V. Then its best to use a noid light because that not only provides a visual indication that the circuit is working but it loads the circuit with a safe current level. Some circuit problems don't reveal themselves until they are fully loaded. A caution: be very careful loading ground side switching circuits with any load like an incandescent test light because those circuits are often unprotected and if you overload the driver in the ECM you can brick the ECM permanently. Always load with the expected load current or less. If you are not sure what your doing an LED test light is almost always safe. That said an old school test light is better in many cases as long as you know the currents involved

Testing the injector coil resistance is easy, with the harness plug removed, just measure the resistance between the two associated contacts in the top of the spider connector and look for 11 - 14 ohms (the correct pink and ground contact).

Fuel pressure. You say "running", do you mean engine running or just after key on, engine off and the 2 second priming cycle?


George

 

I meant pump running, the engine will not run but for a second or two and only after the 3rd or 4th try spraying fuel in it runs until the fuel is used up. I will get the noid tomorrow and try again tomorrow evening. Thanks for all your help, thanks very much.

 

Your pump pressures are in spec but your port pressures are not. This would likely be caused by a leaking injector or a bad regulator. That said I dont think they are low enough to completely prevent starting if this is the redesigned MFI spider.

Do you know the wattage in the test light bulb or can you measure the amperage?

George

 

I took a few days off from working on ole blue to catch up on house and yard work. I have noid injector tester on the way. Thinking about ordering a new delphi spider unit. Going to take the upper intake off and plug the harness back in and see if regulator is leaking and check injectors. I will run more electrical test at this time. Also looks like the hurricane may be heading our way. SE Ga. Doing maintenance on my generator too. Papajim

 

Checked the injectors with noid test and everything looks good. I just can't figure out why the injectors are not working while they are getting power to them. Could the IAC be causing any problems?

 

Did you put the noid light in the circuit between the connector pink power lines and the low side ground switching also at the connector? Did you test all six pink power wires at the connector?

George

 

I did as you said but still no spray at the injectors. I did find the fuel line not real tight at the firewall. Now it is not losing pressure at the port. It will start with fuel sprayed in the TB. I just don't know why the injector are not working. I'm going to keep on keeping on. Papajim

 

If fuel pressure holds at 55 psi after key on plus 15 min and all of the injectors are getting a firing signal then:

1) Measure all fuel injector coils and verify 11 - 14 ohms

2) Do an injector balance test where the fuel rail is charged and you fire each injector to see what the pressure drop is.


3) The security system. If you have a passlock problem it will disable the injectors and cause the truck to stall a few seconds after starting.

4) Another is could it be flooded, try peddle to the floor and flood start mode. Less likely due to running with ether but worth a try.

5) Do you have 1" of strong blue spark at the plugs that fire with a good cadence? Ether may overcome poor spark energy.


George

 

I believe I have found the problem. I removed the upper intake and hooked everything back up with the intake off. Turn the key and fuel went flying from the where the lines go into the injector assembly. After checking, the new assembly is not deep enough for the fuel lines to properly seal. The reason I checked this is, something told me to check the oil ....check the oil? I did and it was over full by about a quarter and had a hint of gas smell. So I'm waiting on new spider assembly. Will let you know if this fix the problem. Thanks for your help and patience. Papajim

 

I have finally received the new spider assembly and before installing the injectors I again checked for pulse and all was good. I plugged in the wiring harness and checked for spray at the injector. Again there were no spray. Checked the oms on the lowest setting on the meter, it showed none. I used a higher setting and it showed some but I did not write it down and can't recall what it was but will recheck. It did show correct volts. Again; power going to injector but they will not spray. papajim
update
just checked the ohms and they were all at 7.9