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no fuel


jammer48
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Hi all, new to the forum... my son just bought a 1988 for 400 bucks and the previous owner told us it needed the fuel pump replaced. So I sprayed some started fluid in the carb to see if it would start and run and it did.... My son then took out the fuel pump while I was at work. When I returned home that evening he had placed it on the work bench so I thought what the heck I am going to put some power to it and see if the pump works. It fired right up and spit out gas all over the work bench. So then I assumed the pump was good and I checked the two fuel related fuses in the fuse box.. they were not burned out. I found a relay on the right engine compartment fender. I think my next step is to hook up the fuel pump again and see if I it will run or is getting power.

 

Anyone have any other ideas on what I should check next... I really don't want him to just be a "parts changer" I would like him to try and learn something and at the same time we can have a little father/son project.

 

Thanks in advance... Jamie.

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Hi Jamie! Welcome to the forums! Sounds like you have the right idea. :aok:

 

A father/son project of a Pathy, is, IMO, a fantastic idea! I have an '87 and LOVE it! It's still a 'work in progress', but working on it it's own reward! :wiggle:

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Thanks Rebel... we will see... I finally think I found something that he will stay interested in longer than 5 minutes... primarily because he can finally have his own wheels... :)

 

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Welcome!

 

Anyways to answer your question I'd first check the filter, my friend and I were heading up the coquihalla right after Merritt and we lost all power engine was struggling to stay alive, after 2 hours and 2 km later we unplugged the fuel filter and it started right up and we rushed to the closest crappy tire and bought a new one. (Truck was a b2200)

 

Otherwise check the lines make sure they aren't clogged, both sending and returning lines.

Edited by cvdloc
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UPDATE

 

checked the fuel line and I have good pressure.... and the return is working as well..... again, if I pour gas in the carb it starts and runs fine. I am now thinking it might be one of the injectors on the throttle body. but I am not sure how to check them... I see I have two wires going to each injector I am assuming one is ground and the other is positive.... any suggestions on what to do next?

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Well, follow the injector wires to the big plug where they meet the harness. The red wire is 12V+ see if it has power. If it doesnt, there's a safety relay in the passenger kick panel that if bad cuts power from the ECU to the injectors. Its orange. If you do get power, ohm the other injector wires (ground) to the ECU pins. I believe its pins 103 and 104 but I can't remember exactly its been so long. Best to check 101-106. If that's no good, find the fault in the harness. If its ok, I'd start by removing the injectors and having them tested/cleaned. To get them out you'll need to remove the TB to safely pop them out with a small socket. If you're lucky they'll slide out from pulling on the wires. Unlikely. You can bench test them by just powering them up and tapping the ground to ground. They may just be gelled up and you could soak them in solvent and if you have a jewelry cleaner even better. :shrug:

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Aaaand since I can't edit now, if no power from the safety relay to the injectors check the power coming in from the fusible links as well as the power from the ECU.

Edited by Kingman
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ok so I follow the injector wires back from the TB to its first connection... I disconnected the injectors and I do have power coming in at the adaptor plug.... but as soon as I plug the connection back together I still have power coming in before the adaptor but not across and to each injector... I noticed that tied into this adaptor are two looks like solenoids that are screwed into the side of the TB. now what??? do you have any diagrams of ecu and more information on the safety relay and where can I find pins 101-106???

 

 

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I'm No where near a computer. ECU pins are labeled on the plugs, they are green wire with colored striped. The ECU is under the passenger seat. Those two solenoids are the idle controls.

 

I doubt its an electrical issue really, probably stuck/clogged injectors.

Edited by Kingman
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Ah, misread what you said. So at each injector there's no power, but power at the main harness plug? How does the plug look? Any corrosion? Actually now that I'm thinking Bout it the power may be white and red or blue. Damn, its been a few years. And unfortunately I'm out on the road with no computer otherwise I'd send you the wiring diagrams. I think I got them from NicoClub for an '89 D21.

 

I do know the power wire from the ECU to the safety relay is red. Like I said, its in the passenger foot well kick panel. Pop it off and you'll see it right there and be able to see what color wires are coming from it.

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As you can see in the diagram, the injectors should always be powered up with the KOEO, or KOER, 12v from the ignition switch through a couple fuses, to the relay and to the injectors....If they don't have power in that circuit is your issue. The other wire pulses ground to the injectors directly from the computer.

 

Good Luck...NissanInjector_zps54fc50b6.jpg

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thank you adamzan.... the plug looks fine... no corrosion.... and I will check the safety relay.... the ecu is under the passenger seat and I have removed the seat and took the cover off the ecu... is this what you mean by "passenger foot well kick panel"?

 

vividkid... thank you for your response and the diagram... I do have power to the harness right at the TB.... their are 8 wires going into this harness and eight wires coming out of this harness.... I have power at the harness... however, going from the harness 4 wires go to the two injectors (2 wires to each injector) the other 4 wires go to each of the 2 solenoids that screw into TB. Each one of them has two wires feeding it....

 

I might be stupid but I keep getting stuck that this wire harness which is merely 6 inches from the injectors has power on one side of the 8 terminals but is not crossing over onto the other side to then power the injectors? The 4 wires that feed the two solenoids seem to be the issue.

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If you have power to the harness plug everything from that point back is a mute point as its obviously working correctly. Just be sure you have power going to the correct wires on the plug.

 

However having power on one end of a plug and not on the other doesn't really make sense unless the wires are broken inside.

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And by passenger foot well kick panel I mean the panel in the foot well, where your feet go when you're sitting, that you always kick with the top of your right foot. ;) Behind that is the safety relay.

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I agree... I am now printing out the part of manual that you gave me the link to.... I want to recheck everything I have already checked to be certain I am doing it correctly and then I will post back here what I find in the next day or two.....I will check the safety relay...thanks again and I will get back to you...

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  • 3 weeks later...

UPDATE

 

Ok got the correct wiring diagram in the mail... finally... and it took my all of 1o minutes to trace it to the fuel relay... a wire had broken off... I soldered it back on and it fired right up... changed the plugs but it still has a rough idle and won't stay running without assistance.... I am going to change the cap and rotor and see what that does...

 

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