fuel problem

[Rescuedad77]

I have an 87 tbi 5.7 liter engine , I just replaced my fuel pump, sending unit, fuel filter, and fuel relay but am still nit getting fuel to the throttle body. I rechecked the ground and it is fine does anyone have any ideas? thanks

 

[dyeager535]

This is a swapped engine, correct?

Not being condescending, how do you know you aren't getting fuel to the TB?

Please don't throw anymore parts at it.

 

[slyguy_22]

double check the plug back on the frame rail by the pump. use a volt meter to see if ur getting any power. also check ur fuel presure, you could just have a lot of air in ur line. that should help narrow down ur problem. could also be a bum fuel pump. good luck

 

[dyeager535]

Volt test is difficult since it won't get power unless it's cranking or on the initial 2 second prime.

 

[Rescuedad77]

I have narrowed it down to no power to the injectors but am again stuck as to where to go next? any sugestions

 

[Blue85]

Forgive my ignorance because I don't have a TBI truck. Is there a port to measure fuel pressure? I almost think I've seen an aftermarket add-on port for TBI, even though IMO all EFI systems should come with one.

When you say no power to the injectors, do you mean no 12V at the injectors with key on? If so, look at your injector fuse(s) and also follow that wiring.

Is this a new swap or did it run in this vehicle and then stop?

 

[83_Shortbed]

best way to check if you have power to the injectors is to use a noid light (should be able to find at Harbor Freight, maybe Sears or a tool truck if you can catch one) and that should tell you whether its a wiring problem to the injectors or some other problem. as far as a port to check fuel pressure for some reason Im thinking its possible but not a guarentee as some will but I dont think all do or it might be that EFI does in most cases not completely sure on TBI

 

[dyeager535]

No power at the injectors, or no ground? ECM grounds the injectors, you'd have to have the probe hooked to a ground to test voltage at the injectors with a multimeter.

 

[83_Shortbed]

No power at the injectors, or no ground? ECM grounds the injectors, you'd have to have the probe hooked to a ground to test voltage at the injectors with a multimeter.

thus the purpose of noid lights if it flickers your getting power and ground to the injector if you dont see any flickering you have a problem where the injector either isn't grounding or there is no power to ground

 

[Rescuedad77]

still no fuel

There is no scrider valve on this truck I don't know if there is an aftermarket one, but I did test it by removing the fuel filter and replacing it with fuel pressure gauge. I am getting 13 pounds of pressure. I then tested the injector wires with the tester grounded and found no power, so I bought a node tester the results were the same. I was told that maybe it could be a fuse wire that blew but I traced all of the wires and couldn't find anything all the wiring looks good. I went and had my ignition control module tested (someone told me that it could be the problem) but it came out good. The last thing to do is have my computer replaced, anyone have more ideas? I am willing to do just about anything to get her running again!

 

[dyeager535]

The computer is not your problem.

If you have no voltage at the injector connectors, you have a wiring issue. (I'd include ignition switch in this, or a dead battery)

I don't know EXACTLY how the injectors are wired up on TBI, but you either have two injectors on one fuse, or each injector on a separate fuse. Either way, the path for voltage to the injectors is: battery>ignition switch>fuse panel>injector(s) It's that simple. The ECM has nothing to do with voltage getting to the injectors, nor does the distributor.