Fuel pump not kick on

[mkiiitnr]

so heres the back story, car started to hesitate then completely die. Got it towed home and I pulled code 11, so got that fixed then a code 14 popped up turns out i had a bad igniter, got that replaced. she fired up right away then it died a few minutes later. No codes were present. i jumped the fp b+ and heard the fuel going so i started it back up, ran then died. tried the fp and b+ again and nothing. i then tried the fp straight to 12v and the fuel pump relay on the passenger side fender starts buzzin. Whats going on????

thanks for your help i advance

 

[grimreaper]

pull the relay and check it to make sure its within specs http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=FI&P=114

do you have a fp gauge? aftermarket regulator? which fuel pump?

 

[mkiiitnr]

stock pump, fuel system is stock

 

[BlackMKIII]

Check the relay. A buzzing sound means it's turning on and off very rapidly, when (IIRC) it should just click on when the key is on and off when the key is off.

 

[mkiiitnr]

using the tsrm.....b+ to fp has continuity, b+ to FPR has NO continuity, b+ to PR has no continuity. My multimeter has a function where it buzzes if there is continuity.....so with that said looks like i need a new relay thanks abunch for your help guys, always reliable as usual!

 

[mkiiitnr]

is there anyway to bypass the relay? just wondering cause i need to get to work! haha if not oh well ill bum a ride

 

[jdub]

That is not a good idea
The ECU controls the FP...without Fp & +B jumped, it only operates when the motor is started or the motor is running. Bypassing the relay can defeat the way it's intended to function.

 

[mkiiitnr]

well ordered a new relay, thanks for the help, guess the only way to get rid of the relay is by doing the 12volt mod but thats a no no for a stock pump.....again thanks for the help

 

[jdub]

The 12 volt mod does not get rid of the relay, it just moves a larger version to the back of the car. You do bypass the relay under the hood, but the new relay in the rear takes over it's function...it's switched on (under ECU control) using the stock wiring.

 

[jetjock]

Let us know how the new relay works out. I hope it wasn't expensive...

 

[grimreaper]

am i reading into that to much or is that sarcasm i sense from jj?

 

[mkiiitnr]

Hey so i got a used fuel pump relay and it still doesn't work. i checked for continuity and came up with the same readings as i did before there was continuity between b+ and Fp and then there was 77ohms between b+ and fpr and no continuity between b+ and Pr. these were the same measurements i got for the old relay. did i just get swindled into a blown relay???? can some body measure their fuel pump relay to confirm this?? oh and the car did start up ran for not even a minute then just died. and im still not throwing any codes

 

[jdub]

am i reading into that to much or is that sarcasm i sense from jj?

You're not reading too much into it

 

[Supra87T]

http://cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=FI&P=70

This should help you....

 

[grimreaper]

your results from the test are as they should be on a WORKING relay, lol.

You're not reading too much into it

:biglaugh:
it didnt cross my mind to "grade" the results with the tsrm
Read

 

[mkiiitnr]

lol yeah i realized that, im learning a lot about electrical through this ordeal, are there any common problems with the efi system that you guys are aware of that my cause my problem, just asking because between going to school full time and working full time its just taking me time to trace the problem. again thanks a lot for everyone who s inputting

your results from the test are as they should be on a WORKING relay, lol.


:biglaugh:
it didnt cross my mind to "grade" the results with the tsrm
Read

 

[grimreaper]

http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=FI&P=11

start here

 

[mkiiitnr]

Ok so i wanted to update with the situation and see if you guys had any input. I finally got fed up and took it to a shop that specializes in auto electrical, after diagnosis they have narrowed it down to being the CPS.....they said they would let me know in the morning after more tests if this is true. Do you guys think this is the wrong assumption made by the shop?. I don't know much about the electrical system on our car but I didn't think the CPS would cause the fuel pump to not turn on. Excuse my ignorance! thanks a lot everyone has been a great help

 

[Poodles]

No signal from the CPS = no cranking of the motor = no fuel

CPS wiring issues are VERY common on these cars...

 

[jetjock]

^ Well, you need to define cranking. The CPS isn't involved with the starter turning the engine over.

OP: On a GTE the fuel pump runs when the key is held to start. That function is completely independent of the CPS. However for the pump to continue operating after engine start/key release the CPS needs to be working. Course, if the CPS is dead there'll be no spark and no injection, therefore no start. I assume that's what Poodles is referring to but my point is fuel pump operation should occur during cranking even if the CPS is dead.

i then tried the fp straight to 12v and the fuel pump relay on the passenger side fender starts buzzin. Whats going on?

The relay *should* buzz when FP is jumped directly to +12. At least it should with the key off. Have the shop look at the schematic and ask them to explain why. If they can't, find another shop....