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No Fuel

PostPosted: Fri Jul 05, 2019 1:03 am
by fvkagi
I cannot get my car started but it will run on ether, so it is not getting its own fuel. I have been looking through the system and I am pretty certain there is no voltage going to the fuel pump relay. Is there a fuse or something that I am missing that is before the relay? Any advice would be appreciated!

PS. There is a hardline that is blocked off, it looks like there are 4 fuel lines or something...can somebody explain that? haha

Re: No Fuel

PostPosted: Fri Jul 05, 2019 2:52 pm
by underscore
This thread has the schematic for the fuel pump wiring, you can use the check connectors in the diagnostic plug to bypass the COR and fuel pump relay/resistor. If the pump comes on then check the COR and FPR and go from there.

Re: No Fuel

PostPosted: Fri Jul 05, 2019 8:23 pm
by 93celicaconv
The top left of the attachment shows the fuel pump wiring & control. Note there is also a fuel pump resistor in the schematic. The ECU plays a major part in the fuel pump control also. As underscore stated, best to use your check connector to bypass the Circuit Opening Relay and the Fuel Pump Relay to see if the pump comes on. If not, would either be a problem in the wiring to/from the fuel pump, or the fuel pump itself.

Re: No Fuel

PostPosted: Fri Jul 05, 2019 8:32 pm
by fvkagi
I bypassed the relay using the diagnostic port and the pump came on! So that is good I don't have to drop the tank lol. I just bought alligator clips so I can test the fuel pump relay and the circuit opening relay.

Also, when I had the pins shorted on the diagnostic port I was seeing 10V where the fuel pump relay is...does that point to the COR? Thanks for the help everybody!

Re: No Fuel

PostPosted: Fri Jul 05, 2019 8:40 pm
by 93celicaconv
fvkagi wrote:I bypassed the relay using the diagnostic port and the pump came on! So that is good I don't have to drop the tank lol. I just bought alligator clips so I can test the fuel pump relay and the circuit opening relay.

Also, when I had the pins shorted on the diagnostic port I was seeing 10V where the fuel pump relay is...does that point to the COR? Thanks for the help everybody!

I believe 10V at the pump for the way you tested is good. I believe the circuit is still going through the fuel pump resistor. The ECU switches to full 12V when the ECU sees the intake manifold vacuum/pressure getting at/above a certain level after the ECU determines the engine is running.

If I were you, I would next check if your COR is getting switched 12V with the ignition key on (0V with ignition key off). If yes, check the COR is outputting 12V while cranking the engine (the ECU keeps the COR off until the ignition key is turned to START).

Re: No Fuel

PostPosted: Fri Jul 05, 2019 10:08 pm
by fvkagi
Ok... it seems that both the COR and the fuel pump relay are working. I just powered them with the car battery and they both clicked shut.

I also measured the voltage on the COR plug and there was 10V on one of the outer pins and 12V on the middle pin. Could this be a grounding issue? I was hoping one of the relays were just dead haha.

Thanks everybody for the help!

Re: No Fuel

PostPosted: Fri Jul 05, 2019 10:41 pm
by underscore
Whoops, I didn't post the link to the thread, my bad: viewtopic.php?f=10&t=51893&mobile=desktop

Using the diagnostic port still uses the EFI main relay but bypasses the circuit opening relay, fuel pump relay, and fuel pump resistor. I'd leave the jumper in and start it with the COR in and the FPR out and see if you have 12V on pins 3 of the FPR plug and go from there.

Re: No Fuel

PostPosted: Fri Jul 05, 2019 11:46 pm
by fvkagi
Ok, I am starting to think it might not be an electrical issue. I bypassed the relays using the diagnostic port to get the fuel pump going (I hear it running) and disconnected the return fuel line and nothing was coming out. I wanted to get the fuel feed line off but it has some kind of wonky clamp I didn't want to mess with.

I have pictures of all of the hardlines coming in from under the car and labeled what they where connected to. I bought it like this and have no idea if it hooked up correctly. Thanks!

Re: No Fuel

PostPosted: Sat Jul 06, 2019 2:53 am
by 93celicaconv
Do you have an ST185? I guess you never stated what you have actually. Hard to help if you have an ST165 or an ST205.

Below is a view of an ST185 fuel system on a USDM version. You need to verify your setup matches this if you have a USDM ST185. If not, that could be part of your problem.

Not sure how much rust you have on your system lines, but if you are very careful, you could remove the banjo bolt from the top of the fuel filter, then momentarily run your fuel pump to see if you get fuel coming out of the filter. If you don't, then you would have to trace the fuel line connected to the bottom of the fuel filter back to the top of your fuel tank to see if someone did something to this line. It's also possible the hose between your fuel pump and the fuel outlet from the tank came loose or broke, so the pump is just spraying fuel within the tank. If you can hear the pump, you should be able to tell from the sound if the pump is turning or if it has a locked rotor.

Re: No Fuel

PostPosted: Sat Jul 06, 2019 3:07 am
by fvkagi
93celicaconv wrote:Do you have an ST185? I guess you never stated what you have actually. Hard to help if you have an ST165 or an ST205.

Below is a view of an ST185 fuel system on a USDM version. You need to verify your setup matches this if you have a USDM ST185. If not, that could be part of your problem.

Not sure how much rust you have on your system lines, but if you are very careful, you could remove the banjo bolt from the top of the fuel filter, then momentarily run your fuel pump to see if you get fuel coming out of the filter. If you don't, then you would have to trace the fuel line connected to the bottom of the fuel filter back to the top of your fuel tank to see if someone did something to this line. It's also possible the hose between your fuel pump and the fuel outlet from the tank came loose or broke, so the pump is just spraying fuel within the tank. If you can hear the pump, you should be able to tell from the sound if the pump is turning or if it has a locked rotor.


It is a ST185, probably should have mentioned that haha. I will check all of this tomorrow once I have sunlight again.

Thanks for all the help! I would be so lost right now hah

Re: No Fuel

PostPosted: Sat Jul 06, 2019 5:16 am
by underscore
If you don't know how old the fuel filter is it's probably a good idea to replace it anyways. From memory if you take off the wheel you can get to the lower feed line and remove it, then put some hose over that to run to a jerry can or something and see if you at least get flow to that point.

Re: No Fuel

PostPosted: Sun Jul 07, 2019 11:48 pm
by fvkagi
Ok, I have figured out the issue! The hardline coming off of the fuel tank was facing the wrong way, so it was kinking the rubber line and not letting any fuel through. It runs (kinda) off its own fuel now, so thank you everybody for the assist!!

Now I just gotta figure out code 51 haha :doh:

Re: No Fuel

PostPosted: Mon Jul 08, 2019 2:23 am
by 93celicaconv
Code 51 on an ST185 is a Switch Signal error: No IDL signal or A/C signal to ECU, with check terminals TE1 & E1 shorted.

Re: No Fuel

PostPosted: Mon Jul 08, 2019 2:26 am
by fvkagi
93celicaconv wrote:Code 51 on an ST185 is a Switch Signal error: No IDL signal or A/C signal to ECU, with check terminals TE1 & E1 shorted.

Oh the PO deleted the AC thats probably what the code is for... it wont idle but that is probably because of a vacuum leak somewhere or something. I guess I will have to hunt for it hah

Re: No Fuel

PostPosted: Mon Jul 08, 2019 2:41 am
by 93celicaconv
If one deletes something that has I/O to the ECU, the proper way to delete that something is to ensure the ECU wiring is set so as to think everything is fine rather that throwing a code and having the check engine light on. Something to consider.

Now your engine doesn't idle? What does that mean? Exactly?

A vacuum leak typically causes a higher RPM at idle than normal, but should still have a smooth running engine when idling.

Perhaps start a new thread on this, or if you still have a restricted fuel supply between your fuel pump and your injector fuel rail, you should resolve that before touching anything that has to do with "your engine not idling".