LS400BOY

Ok when i get home im going to jumper it with the key on,yes i did find another fuel pump relay but still doing the same as the original relay whats chances of them both bad? I did get a cheap reader from radio shack, how do i check the relays? What do i set it on and work it on the relay?

LS400BOY

I just did the jumper fp and +b with the key on and i dont hear nothing still

sha4000

iTrader: (1)

You really need to check the fuel pressure like dicer suggested. Could this be a capacitor issue?? Are you jumping the terminals and listening yourself or do you have a helper?

LS400BOY

I had my wife and son sit in ther car while i was jumping it they both didnt hear nothing in the rear,i still havent cheched the fuel pressue yet hope to barrow one from a friend in the next few days,but i dont hear the pump come on and its a new pump,i found out the old one was still working so its not the fuel pump problem i know for sure

randal

You really need to start checking some points for voltage. Did you get that meter from your neighbor? Or better yet, just go buy one...they are very inexpensive these days and well worth having in the toolbox.

randal

There are still two more relays besides the fuel pump relay that could keep your fuel pump from running. The EFI main relay and the Circuit Opening Relay.

LS400BOY

I did get a multimeter from radio shack so i could check the fuel pump relay but how do i check it and where are those relays locates you mentioned?

dicer

I hope this helps. Maybe randal can tell you what terminals to check at, I don't have book handy now.

LS400BOY

Thanks ill look into this

randal

Take the meter and check for voltage between the +B pin and ground. It should be +12vdc when you first turn the key to "on".
Then check the voltage between the FP pin and ground. It should also go to +12vdc when you first turn the key on.
Then turn the ignition key to off and the voltage should go to 0.

If both those tests are good, then the upstream relays and fuses are all good as well. No need to locate and pull these other relays at this point. You can check their operation in place using the simple test above.

Report back with the results.

LS400BOY

Ok this is what i bought,what do i set it on??

dicer

When you do voltage checks you would twist it clock wise to DCV and point at the 20V, that will test for any voltages under 20 volts, you are looking for 12 ish plus volts. And you would use the red wire to the plus side and ground the black wire (test probe). There should be a manual of sorts with your meter to explain where to plug in the probes. How many plug points are there on it?

By the way.
DCV stands for Direct Current Voltage and that is what cars use, any battery system is DC.

ACV is what is in your house plug ins. And yes people use these meters all the time to check that as well.

Always make sure you have the correct thing selected on that dial before checking anything. You will probably never use the DCA and those mA selections, they are for milli Amps, one milli Amp is .001 of an Amp that is pretty small and is mainly for electronics work not for car systems.

The OHM selection is for resistance and I think that diode at about 7 oclock at the LH bottom is for continuity with a sound.

LS400BOY

Thanks thats helpfull,you know what there are instructions but its in spanish lol test prob is the red and black on the side in the pic

Gene01

The diode symbol marks the position for testing a diode (out of circuit). By checking both forward and reverse bias, you can check if the diode is generally good.
You would not likely use this function for automotive testing.
One more point - if you use the Ohms ranges (for checking continuity), make sure that the circuit is not energized.

dicer

So how is it all going now?