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Discussion Starter #1
car has been running good other then a few small snags here and there. most recent was i had a bosch fuel pump die due to debris. i cleaned the tank, and all the lines properly, installed a walbro 255 and was back in business.

now over the weekend i was tuning the car without any issues. parked it for the night. next morning it was cold so normal hard starting issues, let it warmup for 10 min and fuel pump dies. no power to pump, no power at EFI relay under hood at any of the 4 prongs, no power at B+ at the diagnosis port.

i can jump a 12+ source from the battery to the FP port at the diagnosis port and make the fuel pump turn on. normal key on and crank has no power to fuel pump. is there a common source that the EFI relay and the diagnosis port get power from?

and i do have a small parasitic drain on the battery but its not enough to even luminate a test light. dont know if this is a common issue or not, just trying to give all the info i can.

summery:
no power at pump
no power at diagnosis port
no power at any of the 4 prongs for the EFI relay (underhood fuse box)
i can jump 12+ to FP (in diagnosis port) and make pump come on.

no other known issues as the car has been running well. also tried replacing the EFI and MAIN relay under hood with new ones just for shits and giggles, with no luck.
 

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check the circuit-opening relay down by your left foot. Jumper pins 1 and 2.
 

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When I went with the SDS engine management, I tossed the circuit opening relay and put in a Bosch style relay there that became my defacto fuel pump relay. I know it's tight quarters there so maybe you want to pull that relay and bench test it rather than trying to jumper across pins 1 and 2 in place. Check resistance across pins 1 and 2 should be open circuit. Then apply and hold 12v and ground across pins 4 and 5 and check resistance across 1 and 2 again - if it shows a short circuit now the relay is good and next step would be to check 12v coming to pin 5 from 7.5A ignition fuse.
 

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Also, I would highly suggest replacing the fuel pump wiring if you have not done so yet. I burnt out my first Carter pump since it needed more juice than the OEM wire could deliver.
 

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Discussion Starter #6
that seems to be a better solution. although i dont like not knowing what exactly happend and wiring up my own circuit with a realy would sove this. im also going to check the 3 wire sub harness for power as that supplies the diagnosis port with voltage. (which has none at this point)
 

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Discussion Starter #7
looking for the location and or wire color of the factory power source to the fuel pump. where is it located in the engine bay?

i have already wired up a relay and im going to utilize the factory wire to send the new 12v from the relay to the fuel pump. just need to find it quick.
 

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IIRC it is the blue wire with the black stripe coming from the fuse block in the engine bay. When I rewired mine, I just ran all new 12g wire.
 

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Discussion Starter #9
im going to test the factory wire and if it has high resistance or too much voltage drop across it then ill run a new one. i just dont like adding anymore wires to the car.
 

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Discussion Starter #10
update.

i used a 30amp bosch relay (standard SAO relay) and wired my own circut for the walbro 255. i tapped into a 12v key on source- this wire was in a 3 wire sub harness that junkie made for me for the 7mgte swap. its an approved source by the man himself. the power wire off the battery to the realy has a 20amp fuse inline. then i ran a 12 gauge wire from the relay all the way to the fuel pump and utilized the oem plug. then grounded the fuel pump to a good chassis ground in the rear.

this circuit is working properly but now there are new issues.

car has a no start condition which is new. the engine has been getting harder and harder to cold start and even start at opp. temp. now it will fire breifly then die or not fire at all.

fuel- AFPR gauge is reading 48 psi when key on and only droppes a few psi when cranking.

spark- i have spark at all 6 plugs could be considered weak but i wouldnt think this would cause a no start. when i pulled the plugs they were black with fuel so i cleanded/dryed and reinstalled with the same results. NGKs btw

timing- has not been changed at all and the car was running and i was doing street tuning with no issues a week ago.

air- no restrictions or issues there

battery was charged up and i even had a jumper pack (400amp) just too aid in a faster crank and see if that was it. nope


overview as i know online diagnosis is hard.

-car ran great
-fuel pump had no power one day
-wired a relay to control fuel pump
-car started with some difficulty, and if u touched the throttle it would die
-A/Fs were all over, real lean like 16s then real rich like 10s on different start up idels.
-now no start with fouled pluggs
 

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You may just have weak spark plugs. Or you do have a leaking CSI. Remove power to the pump relay and clean the plugs. If it starts up and idles ok and than slowly dies when the Fuel pressure drops its the injector. If it starts and dies before the pressure drops its the plugs.
 

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Discussion Starter #13
It can also be low compression. ie.. Melted pistons from a bad tune last week.

A/Fs were steady 11.2s under boost + the Ross pistons are tuff. deff could be but i highly doubt i hurt the engine. im leaning torwards wiring issues... idk??? bad CPS??

ill deff check out that cold start injector and see whats up
 

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Discussion Starter #14
pulled the CSI out and turned the key on to build fuel pressure and there was no leaking fuel, so im going to get another set of plugs as the NGKs in there now are just too black and fould out. ill keep this updated when i get those in. thanks for ur guys help
 

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Discussion Starter #15
new set of NGKs installed and weak spark turned into no spark, so im going to swap out the igniter and see if that does it. coils all have the same resistance, i have 12v at the igniter, both igniter and coil packs are grounded to tested good grounds. am i taking the correct steps here with my diagnosis?
 

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Discussion Starter #17
You sure you did not unplug something when you pulled the CSI out.
i only unbolted the 2 10mm bolts from the underside of the manifold to take the CSI out. didnt even unplug it. is there a way to test the igniter?
 

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Discussion Starter #19
spark plugs new, coils good, have power to igniter so ecu ign is sending. cross fingers on that igniter as from there it will be real guess work or worse....

thank you for your help.
 

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The Ignitor power runs off the coil power wire from the EFI relay #2 the ecu trigger wires from the ignitor are green and green/white.
 
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