Fuel Pump Trouble!!!!!!!!!!!

[86.5supraturbo]

I have an 86.5 supra (turbo), and when i put my key in my ignition and put it to accessories, my fuel pump won't turn on, it is a year old walbro 255, so i was being nosey and was gonna check for codes, i took a small wire and put it in the diagnosis box in the 2 slots farthest from the driver fender, the 2 outside ones nothing in the middle slot, and the fuel put turned on and my car ran perfect.... PLEASE help i need to get it figured out Thanx PM me please.

 

[radiod]

The fuel pump doesn't turn on until the engine is cranked. You can manually test the fuel pump with the car off by jumping two of the pins in that diagnostic port as well.

http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=FI&P=71

Did you try cranking the car and have it not start or did you just not hear the fuel pump when you put your key in the ACC position?

 

[86.5supraturbo]

yes i cranked the car and it started and ran for about 5 seconds and i lose fuel pressure, and no i did not hear the fuel pump running in acc position only when i plugged the wire in then the pump turns on and the car runs fine.

 

[mkiiichip]

Once again the pump WILL NOT RUN with the key in the "acc" mode ever. Or the "on" mode without cranking. The computer signals the pump relay only while it sees RPM signal. Its a safety feature.

 

[MarkIII4Me]

Any update on this? As my vehicle is doing the exact same thing. Starts and runs for 5 seconds. Fuel pressure drops to zero and the engine shuts-off.

 

[Mjcsupra]

Im not sure if they changed it on later models but i have a 90 and my fuel pump does come on with the car in the on position, i have a new walbro 255 and i can hear is seeing as their is no rear interior in the car. if it runs fine when you manualy turn on the pump through the diognostic port i would start with the fuel pump relay but thats just me. let me know what you find.

---------- Post added at 08:04 PM ---------- Previous post was at 08:01 PM ----------

Also make sure you dont have a vacume leak in the line going to the fuel pressure reg what ever one you may be running. i know they ran the line all the way under the intake and then back up and i replaced a crappy peice of hose that was probably leaking.

 

[kamikazemkiii]

Try jumping the fuel pump, May be the FP relay

 

[MarkIII4Me]

I have a 90T as well and at first I would build fuel pressure even without the engine cranking also. However, now it does nothing. I'll bypass the relay today and give the pump 12v from the diagnostic port just to make sure it still works. I'll be pissed if it doesn't since it's a brand new 285lph denso.

I know I must have some wiring issues since all of a sudden my turn signals, fogs, hazards, dome lights, lights on doors and the chime when you have the key in the ignition no longer work. Do they share a circuit or something? All fuses test good. Yesterday I dropped the fuse for the EFI btween the battery and fuse box. When I reached down to grab it, I must have pushed on something because I started hearing the key in the ignition chime come on. I went to the interior and found that the dome lights and door lights were working as well. But still no turn signals, fogs or hazards. I pulled the battery, went over my wiring and all looked good. However, when the battery was reinstalled,I once again lost what was just working.

 

[Mjcsupra]

sounds anoying, the issues you are having with the lights and chime and all that is all ran by the body ecu and not the engine or any other ecu, so if it were me i would look down the wireing from origin to that body ecu unit and make sure all the connectors are plugged in and working also i would go through with a DVOM if you have one and make sure you connectivity between all your lines. i have not had this issue and have never heard of the issue also, so this is where i would start, this body ecu also controls the fuel pump i beleive. so thats where i would start. let me know what you find.

 

[jetjock]

Body ecu huh? Where in the car is that located?

 

[Moy]

sounds anoying, the issues you are having with the lights and chime and all that is all ran by the body ecu and not the engine or any other ecu, so if it were me i would look down the wireing from origin to that body ecu unit and make sure all the connectors are plugged in and working also i would go through with a DVOM if you have one and make sure you connectivity between all your lines. i have not had this issue and have never heard of the issue also, so this is where i would start, this body ecu also controls the fuel pump i beleive. so thats where i would start. let me know what you find.

last time I checked, these cars don't have a BCM...

 

[kamikazemkiii]

Any update on this? As my vehicle is doing the exact same thing. Starts and runs for 5 seconds. Fuel pressure drops to zero and the engine shuts-off.

How did you wire the denso? (use old wiring, new wires connect to old wires, or compete new wires to the clip)
May just be connection, I thought I had a friends wired good, turned out i just ran new wires all the way to the clip. connected the correct one to my 12v source, ground the other and vuala!

 

[lewis15498]

body ecu and not the engine or any other ecu.

Is there any other kind of ecu? could have sworn the "e" stood for engine.

Body ecu huh? Where in the car is that located?

Its under the flux capacitor, come on JJ, you should know this.

OP: I agree in stating it sounds like a bad fuel pump relay.

 

[Mjcsupra]

like i said i have never had this issue, although diffrent parts of the car are controled by different ecu, automatic trans has its own ecu, the TEMS has its own ecu, the engine had its own ecu the abs has its own ecu, so as far as i can tell from working at a lexus dealership most cars have a seperate body ecu that controls all the lights, windows, locks, etc. with the age of these cars in mind the body is controled by a set up of relays and switches, there are some realys on the passenger side kick panel, driverside kick panel, and under the hood, i would use the TSRM to track where the issue might be, its more than likely a intersection of all the stuff thats going wrong.

---------- Post added at 11:16 AM ---------- Previous post was at 11:12 AM ----------

And yes i use the term ECU loosly for any type of computer.

 

[jetjock]

There is no body ecu in these cars but using the TSRM (the TWED actually) to find the problem has been the best idea in the thread thus far. After all, we're talking about a very simple circuit.

Its under the flux capacitor, come on JJ, you should know this.

Funny you should say that because it's what I'm driving today. First time Ive had it out this year...

 

[Nick M]

Is there any other kind of ecu? could have sworn the "e" stood for engine.

ECM
ECU

Engine control unit, Engine control module
Electronic control unit, Electronic control module

It depends on whose book you are reading. Which is part of OBD phase II. Stop making up your own names.

---------- Post added at 03:01 PM ---------- Previous post was at 02:56 PM ----------

yes i cranked the car and it started and ran for about 5 seconds and i lose fuel pressure, and no i did not hear the fuel pump running in acc position only when i plugged the wire in then the pump turns on and the car runs fine.

That is nearly impossible with this car. The J-tube holds some residual pressure. The pressure regulator holds residual pressure. The pump holds residual pressure. If you shut the pump off while running, you will run out of gas. That is your only real option. If the car shuts off for another reason, pressure will not drop to zero. It can't. Unless....the j-tube is removed and the pressure regulator is gone for another and doesn't work right and the fuel pump has no check valve.

 

[3p141592654]

On the GE cars, all years, the fuel pump turns on only by the starter circuit being energized, or air flow in the AFM. No way it comes on with just ignition and a stopped motor.

For the GTE, the fuel pump turns on only by the starter circuit being energized, or when a minimum load is reached as calculated by the ECU, and that needs a spinning engine and air flow through the AFM.

 

[JStoked]

There is no body ecu in these cars but using the TSRM (the TWED actually) to find the problem has been the best idea in the thread thus far. After all, we're talking about a very simple circuit.



Funny you should say that because it's what I'm driving today. First time Ive had it out this year...

^NICE jj !!!

---------- Post added at 09:17 PM ---------- Previous post was at 09:12 PM ----------

^NICE jj !!!

This is to easy. Its the fp relay or bad wiring from the new fuel pump. Have you checked CODES??

 

[awsom-0]

Mine also does the same thing, I've check for codes and all are clear. I did the 12v mod on my walbro install too.

 

[Nick M]

Mine also does the same thing, I've check for codes and all are clear. I did the 12v mod on my walbro install too.

Does what?