Fuel Delivery Issues RTH (1 Viewer)

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strictlyRUM

strictlyRUM

Joined
Apr 5, 2015
Threads
10
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150
Location
Redmond Oregon
Sorry Guys but I have used up all my Google Foo and have no answer to my quandry. I have done a complete heart and brain transplant and cannot get it going again. I had a 97 that was rolled and a 92 with a bad motor so I combined the two and am trying to get fuel to it at this point. I rebuilt the motor and alot of other crap. I have gone through and tested all the componants as per the FSM. All seem to check out. Fuel relay, fuel resistor as good as I can check with a cheapo DMM. I did jump it to see what I could do but no dice. I am getting 5.7-5.9 volts at the pump when it it cranking. I have tested the fuel pump and can get it to run on a 9 volt battery.

My question is what volts should I be seeing at the pump? Have I missed something?

Thanks guys. I have read through so many helpful threads on this site. Without it I dont think I would have gotten this far for sure.

I just thought of something to add. I am not getting any fuel gauge movement when I am in the on position either. I tested the sending unit at the pump and get variable resistance when it moved but the gauge doesnt move when its all hooked up?

Jason
 
Should be 12 volts I believe, I know that once it's running the voltage will drop and jump back up under load. I had fuel issue and ran with a multimeter hooked up monitoring fuel voltage for about a month trying to catch what was happening when my fuel problem would occur. Good luck
 
strictlyRUM said:
Sorry Guys but I have used up all my Google Foo and have no answer to my quandry. I have done a complete heart and brain transplant and cannot get it going again. I had a 97 that was rolled and a 92 with a bad motor so I combined the two and am trying to get fuel to it at this point. I rebuilt the motor and alot of other crap. I have gone through and tested all the componants as per the FSM. All seem to check out. Fuel relay, fuel resistor as good as I can check with a cheapo DMM. I did jump it to see what I could do but no dice. I am getting 5.7-5.9 volts at the pump when it it cranking. I have tested the fuel pump and can get it to run on a 9 volt battery.

My question is what volts should I be seeing at the pump? Have I missed something?

Thanks guys. I have read through so many helpful threads on this site. Without it I dont think I would have gotten this far for sure.

I just thought of something to add. I am not getting any fuel gauge movement when I am in the on position either. I tested the sending unit at the pump and get variable resistance when it moved but the gauge doesnt move when its all hooked up?

Jason
Click to expand...
I'm guessing you have the newer driveline and ECU in the older rig? Early FSM should tell you what voltage the early pump is looking for. The later FSM should tell you what voltage, and when, the later ECU will send out.
 
Yes all the 97 except the body basically. I couldn't find a voltage reading. It has resistance reading and a process for testing it with a direct jump from power but nothing as far as voltage that I could find. There is one place it tells how to test the output on the ecu to body ground. It says 9v there.
 
Yes. Everything is from the 97 except for the shell. It has to be or it no worky.
 
I would make certain the FP wiring/connections are good first.
You can bypass all FP logic by jumping the circuit opening relay pins 2-4 and jumping the FP relay pins 3-5.
This will cause the FP to run continuously at high speed when the key is in the ON position and should only be used for diagnostics. If the FP runs correctly then the issue is with the logic circuit. If it doesn't run correctly, then the issue is with the +12 getting to the FP itself.
 
The pump works fine as tested per fsm it's just not getting enough volts. My scangauge/torque light says fuel system- open loop. My next step is to test at each connection starting tank side and working my way forward. Does anyone know if the resistor and relay need to be mounted for ground? Right now they are laying on fender wells. Still tying things up. I would like to get it running before I completely it as there is an oil leak between engine and transmission that has me cautious. Everything is new just hoping I haven't pulled enough vacuum to make the pcv system work yet.
 
I jumped the resistor and didn't get any change. I tested the relay as per fsm. The fuel pump was tested from plug so those connections should be fine. I'll try jumping relay and resistor at the same time to see what happens but it won't be till this evening.

Thanks for your help.

Wish me luck.
 
Well No dice there........ I still get 5.9ish when in the on position and it actually drops to 4.9 ish when cranking? I cant start testing then wires until later in the week as I have a couple midterms to study for still, as well as the Kids Karate tomorrow and I still have a rototiller to take back tomorrow and a pickup full of lawn crap to take to the dump tomorrow. Uggh? Any other thoughts between now and then are appreciated.
 
There will be a voltage drop with the load of the motor applied. Does the FP run with the jumpers in place? Are you getting fuel to the rail?

If not, then since the logic is bypassed, we have to look at the +12 path.
EFI relay / pin 2 of the COR / pin 5 of the FP relay / connector ID2 / connector BO1 / FP.
Ground path is supplied by connector BO1.
 
It doesn't run with everything jumped. It doesn't run at 5 v but it runs if it put 9v or 12v to it directly. No fuel has made it into the lines yet. So rail is dry. I will now start engine side with logic in place and find my voltage drop. Does that sound reasonable? With the scan gauge saying open loop it makes me think there may be a bad wire somewhere. No gauge movement also makes me think that. I am pretty new to this depth of electrical so I greatly appreciate the help.
 
Oh and I forgot..... the CE light is on when the key is on, so that tells us efi fuse is good right?

Again thank you
 
strictlyRUM said:
Oh and I forgot..... the CE light is on when the key is on, so that tells us efi fuse is good right?

Again thank you
Click to expand...
It tells you that the EFI fuse is good, the EFI relay is closed, and the EFI system is in a ready state.
You need to verify that you're getting +12 to pin 2 of the COR and that +12 is making it's way down the path.
 
I PMed @jonheld but if anyone else has any ideas I would appreciate the input. I am an engineering student and have a little bit of a breather today before I start studying for finals. I am able to get out there today and I am instantly irritated. Please help.

I am still not able to figure it out. I can get 14 volts at the pump and it doesnt come on. I have the pump out and jumpers run into the connector where I can get a reading of 14 volts at the end of the jumper wires. Still no love. I go back to the 9 volt battery and connect it directly via jumper wires and the pump runs? Is this an amp issue? I put the battery charger on it and turn in up to start which says 200 amp so it should get enough but I have no way of measuring amps at the jumper? Any thoughts?

Jason
 
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