Can u guys please help point out my problem?

[mightywhitey_k5]

I was out wheelin and my rear bumper took a prety hard hit comming off a rock; directly after that my car was dead. when i go to turn it back on every thing works fine, the fule pump is wining like it should and the car is cranking over strong, but no gas, no go. latley i have noticed that my gas gaudge is not reading properly, i believe that this could be the fule sending unit doing this and that nasty hit i took could have killd my sending unit, i am not sure just a hunch. any type of info would be more than appreatiated. thankx. O ya this is an 87 k5 so it is F.I. the throtle body is not getting any fule when i try to crank the engine over.

 

[1-ton]

You could try calling your truck a "truck" instead of a car (just being a smart ass ) , but it sounds like the fuel pump died. You may have smashed the fuel tank into the fuel pump when you took a ride on that rock. You should check the fuel tank for damage, but this is just a guess.

 

[Hossbaby50]

I know on some FI cars and trucks they put in an impact switch so when a car got into an accident the switch would trigger and kill the system so it wouldn't keep pumping gas to the motor and possilby add to an engine fire. I don't know if K5's had this or not. I don't think they did but I don't know for sure.

If the pump is whining like it should be then you may have a sending unit problem like you think. Pull the sending unit out and check for a dropped pickup or clogged pickup. If that is not the case then I would say dead fuel pump.

Harley

 

[mightywhitey_k5]

ya good guess but the fuel pump is a week old and there is just a tiny dent on the tank nothing to get concerned about.

 

[Hossbaby50]

Get a mutlimeter and prob the fuel pump power wire and make sure it is getting 12 volts with the key on. If not then the problem is a fuel pump relay or in the wiring somewhere.

If it is disconnect the fuel line right outside the tank and have someone hit the key for a second or two and see if fuel comes squirting out of the lines. If so then you know your problem is upstream of the fuel pump and sending unit. If not then you know your problem is in the tank somewhere. Did you check to see if the pickup screen was clogged when you replaced the fuel pump?

If you do get fuel being pumped out of the tank then disconnect the fuel line at the TB and check to see if it is getting fuel there. If not then you know the problem is in the fuel lines between the tank and the TB. I am not sure where the fuel filter on an 87 is but have you checked it to see if it is clogged?

If you get fuel to the TB and the injectors are not firing then you have a problem in the wiring or the injectors themselves.

Get a noid light and connect it to one of the injector clips in the wiring harness. If the light flashes as the motor is being cranked then that is ok, if it doesn't then the problem is in the wiring or sensors somewhere.

Harley

 

[mightywhitey_k5]

ok cool all those checks should be helpfull. i want to try to avoid doping the tank if i can but if worst comes to worst then so be it. dont think it could be the pick up screan its as new as the pump, nor the injectors they are bouth new as well. not that i am not taking your advice into consideration and it is very help full but i have sort of a gut feeling about the sending unit thing so. is their any sort of check i can do to tackle that hunch.

 

[Hossbaby50]

Just narrow it down from the motor back. That is probably the easiest.

Disconnect the fuel line at the TB. If you get no fuel squirting out when you have some hit the key for a few seconds then you know it is farther down the fuel system. Then try and find the blockage.

Another good check to do is the noid light check. Go to Autozone or a local parts house and buy a NOID light for a TBI Chevy. Disconnect 1 of the injector leads from the wiring harness and plug that light in. Have someone crank the motor over. If it doesn't flash when cranking then there is a problem in the electrical system somewhere. If you are not getting the injectors to flash then check for spark in the motor. If the spark plug wires aren't firing either then I would bet that you have a bad ignition module. The ignition module can keep BOTH they injectors and the spark plugs from firing. They can also act independently bad depending on which curcuit in the module went bad.

Those are the 2 easiest checks to do since they are in the engine bay and can be accessed easily. Noid light are like $8-10, and well worth the cash. If it isn't that stuff then start working your way back down the fuel system. It is never a bad idea to change the fuel filter either, even if it isn't very old. It will rule out that problem.

Harley

 

[dyeager535]

Since you've replaced the fuel pump, you must understand that the fuel sending part and the gauge sending part are two seperate functions...the only reason it can be starving for fuel is if the pickup tube fell off or something broke loose and is blocking stuff.

Sounds like you may have broken the plastic baffle in the tank and either damaged or disturbed the float on the sending unit, which may also have affected the fuel pickup somehow. Doubt that is likely, since that in-tank sock would be nearly impossible to clog with the plastic baffle pieces, but you never know.

Ground the fuel gauge sending wire from the sending unit connector, if it pegs full, then goes to empty with no ground, everything outside the sender is fine.