I have a 2000 RAM 4X4 with a 360 . I shut my truck off when I got to work , time to go home, truck cranks no start. checked for spark, got spark. ok must be fuel pump. So I get my wife to turn the key to the on position, cant hear it run so I check the relay, swaped it out with other relay checks out good. not shure if iI am checking the relay that I need to. (the one I am checking is the one that is for the fuel system) is thar one hidden son place els. I want to make shure power is getting to the pump so I pull the plug off the pump and check all for wires, (don't know what wire is for the fuel pump so I check all 4) no power. got any good ideas. this one is a brain stumper for me. I have ben a mechanic on the old stuff but this new stuff is hard to troubleshoot with the tools. I 'm thinking that you new guys would have the know.

thanks for the help that you have given so far. lets figgure it out so we can help others.

I am not yong any more, I try to pass the knolage I have gotten over the years. got ? on the old stuff, can help.


thanks

 

I would go with what bignbad said on the other thread. Try jumping directly to the starter. I think he was refering to a starter relay.

 

Where'd you check for spark at? The coil or the plugs? Cause if theres spark from the coil it doesn't mean theres spark at the plugs

 

If he's getting spark, then the motor is probably turning over. Here's a diagram of the fuel pump connector:

[IMG]local://upfiles/29576/1E371C9A9699450EB22EE36B0CA910E2.gif[/IMG]

If you want to check for voltage instead of pressure. Insert the probes of the meter into the connector then have your wife turn the key. Voltage does not just stay on the pump. There is a wire out of the computer, module c3 pin#19, that controls the fuel pump relay. When you first start, or try to start your truck, the PCM sends a signal to this relay for a couple/few seconds to pressurize the lines. After this, the PCM will not re-energize the relay until the fuel pressure sending unit tells it to. If your truck is not running. The pressure switch will not tell it to.

If you check for pressure and get it, you know that the pump is generating pressure, the lines are holding pressure, and that the pressure is getting up to the fuel rail. Then you can look elsewhere if need be.

Good luck, hope you get 'er started

 

what does the fuel pressure sending unit do and were is it i have a dodge ram 1500 1996 that wont start i have replaced every sensor fuel pump everythign but i have no power to the pump i have never heard of this fuel pressure sending unit

 

Because it doesn't exist. The PCM will turn the fuel pump on atkey-on for 1-3 seconds, then turn it off. However, the fuel pump relay is energized any time the engine is running or cranking.

The dark green/black wire is power for the FP. It should show power for the intervals described above. If not, go to the relay. See if you can feel it energizing. If not, swap it.If that doesn't work, the relay terminals need to be tested. The relay itself will have a diagram on it's housing, and the terminals will be labeled. Will have 4terminals; 30, 85, 86 & 87. 30 is full time battery voltage, 87 is the line to the FP, 86 is relay coil power and 85 is PCM controlled relay ground. If everything checks out there, you've got an open between the relay and pump. If the relay is lacking battery power or ground to the other terminals, you have to chase those circuits(Ground will only be present during the 1-3 second key-on or cranking). ground will come from PCM terminal 19. Fuse 9 in thefuse block is relay coil power. fuel pump power (terminal 30) comes from fuse 3 in the power dist. box.

Edit:

Almost forgot; make sure the fuel pump has a good ground, too. It's the Black wire. And inspect the terminals in the connectors for the pump. Not so much a Mopar thing, but GM's have had corrosion issues with FP connectors that are often misdiagnosed as bad pumps.