I just got a 90 d150 thought all it needed was a fuel pump. I have replaced the fuel pump and am getting pressure but it seems that the injectors are not firing? Any ideas?

 

More info would help. You are getting pressure where, at the throttle body or at the pump? Are the injectors not firing or are they not spraying or are you not sure? Are you getting spark at the plugs as some of these systems are interconnected? Is this a TBI or multi-port injection? What engine do you have? When was the fuel filter last changed? Has the truck run since you got it and if not how long since it ran?

 

I am getting pressure at the throttle body and I dont believe that the injectors are firing. I have replaced the injectors, filter, and fuel pump. I have the 318 5.2L engine in it. It fires if you put starting fluid in the throttle body and thats how I bought it. Guy I bought it from said it just needed the pump. He told me that the pump quit 2 weeks ago but there are a lot of things he said that are not so true.

 

Doesn't sound like the previous owner was right. Run your trucks onboard diagnostics and tell us what you get.

1. Cycle the ignition key ON-OFF-ON-OFF-ON within 5 seconds. To cycle the ignition key ON means to turn it only as far as it takes to get the radio to come on. It does not mean to turn the engine on.

2. Count the number of times the "check engine" lamp on the instrument panel flashes on and off. The number of flashes represents the code. There is a slight pause between the flashes representing the first and second digits of the code. Longer pauses separate individual codes. For example, flash-flash-flash [pause] flash-flash represents the code 32.

The only way I know to tell if the injectors aren't firing is to use a noid light.

 

I am getting the following codes, 12,27,37,55. Update as well, it looks like the new injectors are smoked. They seem to be getting power but not a strong ground? I have checked all of the wires and they seem to be fine could it be that I am not getting a good ground through the computer?

 

12 Direct battery input to PCM was disconnected within the last 50 key-on cycles (normal) 27 Injector control circuit
37 Torque converter clutch solenoid CKT or park/neutral switch failure
55 End of error messages
What trouble shooting have you done that makes you think the injectors are getting power? Why do you think the new injectors are smoked? The injector wiring and the ground go thru the engine wiring connector. Have you checked the terminals inside the connector for corrosion. As I stated before you will need a noid light to accurately check the injector pulse.

 

I put a volt meter to the power side of the connector and negative side and only got 4-5 volts, if I went directly to the ground I got 10-12 volts. I also tested this with a test light. I have checked all the terminals for corrosion and used dielectric grease on all the connectors. When I got the new injectors I checked the ohms reading and it was like .02 and now one of them is at 2.3 and the other was at .7. I also noticed that the inside of the injector holes are now filled with what looks like rust, but that is behind the screen?

 

Fuel injector resistance should be 2.0 ohms. I have always been told that you cannot get a test of the injector firing system with a volt meter and that a noid light is the only accurate way to test it. Maybe I will learn something new here.

 

Update, I swapped the computer and now it will stay running as long as I give the fuel pump direct power. Now I have to figure that one out.