Fuel Pump Questions

[79F1504X400]

I think I hijacked a thread...so I better just post my own. I have many questions. I need to make sure the truck is close to what it was before the PO started cuttin' and hackin'

1) Fuel supply and return lines. Is the supply line blue?
2) Does the return line exit from the FPR?
3) Are the relays on passenger side interchangeable? Ones black, ones gray but both have the same number of pins.
4) Why did the pump in the tank run when I pulled the connector on the high vol. pump?(key was off)
If anyone has some pics that would be great too. TIA

 

[Terry]

You are on the wright track. Yes the feed line is blue. Yes the return line comes off of the fpr. Yes you can swap the relays but one is the pump relay and the other one is for the ecm. If the truck wont run you will know why. As far as the pump issue, it sounds like the high volume pump could have a short and when you unhook it it supplies power to the circut so the rear pump will run. If you fry a dc motor which is what the pump basically is it will short to ground. Just my two cents.

 

[79F1504X400]

Thanks for confirming all of that. I just want to be sure before I start throwing parts at it. Next Im going to disconnect the battery and put 12v right to the pump and see what happens. Since I've heard the pump in the tank run, Im going to say its good.

 

[79F1504X400]

Appled 12v right to hi vol pump and it works. So then I jumpered the yellow to org/Lt blue on the FP relay and pump ran again. So would it be the FP relay?? or could the ECM relay be suspect? What wire on the ECM relay will there be 12v with key on?? Need to check TFI also. It will effect the fuel pumps too, right?

 

[IMenriched]

Appled 12v right to hi vol pump and it works. So then I jumpered the yellow to org/Lt blue on the FP relay and pump ran again. So would it be the FP relay?? or could the ECM relay be suspect? What wire on the ECM relay will there be 12v with key on?? Need to check TFI also. It will effect the fuel pumps too, right?

considering the relatively low price of the relay...and it would seem that is the issue, replace it.

 

[79F1504X400]

Replaced both FPR and ECM relays today......no luck. I'm not getting 12v at the inertia switch or a least I can't detect any voltage when you turn the key, but there is 12v on pin 1 of computer and there's 12v on both yellow wires going to the relays. How does the coil figure into all this?? What else should I check??

 

[IMenriched]

Replaced both FPR and ECM relays today......no luck. I'm not getting 12v at the inertia switch or a least I can't detect any voltage when you turn the key, but there is 12v on pin 1 of computer and there's 12v on both yellow wires going to the relays. How does the coil figure into all this?? What else should I check??

purhaps a bad wire.
not sure if found the Tech Library yet or not...but here is a few links that you might find helpful.
http://www.therangerstation.com/tec...es/Diagrams_ElectronciEngControls2_9_1of3.JPG
http://www.therangerstation.com/tec...es/Diagrams_ElectronciEngControls2_9_2of3.JPG
http://www.therangerstation.com/tec...es/Diagrams_ElectronciEngControls2_9_3of3.JPG

 

[79F1504X400]

Thanks....I've been using those schematics. Been looking for cut/broken wires as I've been going through the wires and relays and reading other posts about same or similar issues and checking my vehicle to see if condition exists. Next move would be to verify pump in tank will work with 12v applied right to it. I did hear it run when I pulled the connector on the front pump and it stopped when I plugged it in again. Thought that was strange.....or is it not??

 

[79F1504X400]

BINGO!!!! We have a winner!! (IMenriched) EEC relay wasn't getting ground. There's a plug right next to the battery, when I finally got it pulled apart the spade terminal inside was corroded to nothing. I removed it and spliced everything back together and the FP's prime. Now there seems to be a timing issue. When I'm cranking the motor, it acts like the timing is off a tooth. Ran out of daylight and warmth.....will do some more tinkering tomorrow.

 

[IMenriched]

BINGO!!!! We have a winner!! (IMenriched) EEC relay wasn't getting ground. There's a plug right next to the battery, when I finally got it pulled apart the spade terminal inside was corroded to nothing. I removed it and spliced everything back together and the FP's prime. Now there seems to be a timing issue. When I'm cranking the motor, it acts like the timing is off a tooth. Ran out of daylight and warmth.....will do some more tinkering tomorrow.

take it for a spin, 10 miles +, first. with proper connection the ECM might have a relearning curve. then recheck timing.
glad to see that you evicted that electrical gremlin.

 

[79F1504X400]

Would love to take it for a drive, but no start. She cranks, and tries real hard.

 

[IMenriched]

Would love to take it for a drive, but no start. She cranks, and tries real hard.

whats missing spark or fuel?

might be time for compression test

 

[79F1504X400]

Its getting both now. Before I got the pumps to prime it would crank and not give a hint as to trying...ie no fuel. Now that its getting fuel, its trying but acts like the timing might be off a tooth or two. Could also be mis-routed plug wires. Will be checking that this afternoon. I've done distributors before, but are these 2.9's any different than your basic V-8?? (Line up cyl 1, top of compression stroke....check that rotor is near cyl 1 ...... etc.) The TFI takes care of the rest, right??

 

[IMenriched]

Its getting both now. Before I got the pumps to prime it would crank and not give a hint as to trying...ie no fuel. Now that its getting fuel, its trying but acts like the timing might be off a tooth or two. Could also be mis-routed plug wires. Will be checking that this afternoon. I've done distributors before, but are these 2.9's any different than your basic V-8?? (Line up cyl 1, top of compression stroke....check that rotor is near cyl 1 ...... etc.) The TFI takes care of the rest, right??

yeah your on the right track.
http://www.therangerstation.com/tech_library/2_9_Page.html.....this shows plug wire routeing and other good info.

there is a schraider valve (like a tire valve stem), on the injector manifold...let the fuel pump prime a couple of times, then go and press it in. be ready with a rag...but it might have a air pocket. it shouldn't have air there, just fuel.

 

[79F1504X400]

Well I finally got it running last night. It was the plug wires. The PO had them installed wrong. Timing will have to be adjusted but it runs. Now need to sort out why blower motor only runs on high. Instrument lights need to be replaced as only one side of dash had lights, but thats an easy fix, I'm just glad its running now. Thanks to IMenriched for all your help.