fuel system problems ka24de

So I'm making this post for josh. He has been having problems with his car this pass week. First the fuel pump and fuel pump relay went last week, we replaced both and it ran fine for 3 days. Then he was on the freeways and his car died on him. He got it towed to a shop, the next day we went to look at it before the mechanic. I had him try to start it and it started right up. We drove it around for ten minutes and turned it off. It wouldn't start up. We pulled the relay, bought a n lew again, and it ran for 5 mins Nd died. Any suggestions? I think its something related to fuel pressure. Any easy fixes or common problems?

pump go bad? does it sputter at all? rent a fuel pressure tester to see if it's got fuel pressure all the time.

jaybaum96 wrote:

We pulled the relay, bought a n lew again, and it ran for 5 mins Nd died. Any suggestions?

Does this mean you bought a new relay and it ran for 5 mins. after?? If so, (and the pump is new) it sounds like wiring...

Yeah he said it ran for five mins after the second new relay was installed. And then it died again. And yes the fuel pump is brand new.

Could it be flooding?

Check fuel injector o-rings. And when you put it back in, be sure to apply silicone grease on the o-rings so it doesn't get damaged when you're putting it back in.

600SX wrote:

jaybaum96 wrote:

We pulled the relay, bought a n lew again, and it ran for 5 mins Nd died. Any suggestions?

Does this mean you bought a new relay and it ran for 5 mins. after?? If so, (and the pump is new) it sounds like wiring...

this actually makes the most logical sense.

you bough a new relay and it died again....did the relay go out? or is the relay fine still?

Wiring

So have you actually been testing these relays or just throwing them at the car without testing? Have you also verified that when it doesn't start that it indeed is not getting fuel? Have you metered at the fuel pump with a multimeter also when it isn't starting to see if it is getting voltage?

yes, the fuel pump does not prime when the relays go out. Yes I checked for voltage, and its defiantly something with wiring that is causing the relays to go. At the fuel pump it will get voltage when a new relay is put in, and the car will start. Then he drives the car for 10 mins, turns it off and the car wont restart, something in the wiring is blowing out the relays and the question is what could do that?

pancho y onions wrote:

you bough a new relay and it died again....did the relay go out? or is the relay fine still?

the oem relay blew out, the second one was a p.o.s. as it was and it blew out, and Josh says he bought another one, put it in, the car drove for 5 mins and then died on him. I havent looked at the car since he put the new one in, so i couldnt tell you if that one blew out as well im just assuming from what he has told me.

Is everything more or less factory on the car?

yep, 100% factory for the most part, has a 3 inch exhaust and thats it. lol.

s13 or s14? s-chassis' are notorious for having way too small of wires (wire size) going to the fuel pump. If you can, pull the harness plug to the pump, check to see if you have power to it with a known good relay in. Also check the ground because it sounds like you have a short in the system thats tripping the relay. All else fails run new wires back to the pump and releave your headache. If you dont want to run new stuff then start tracing wires looking for a break or rubbed through area.

O-rings wont trip a relay. You have an electrical problem. You get me a year on the car and ill get you a wiring diagram to figure out the issue.

Its a 93 Vert. How would you go about wiring in a switch for the fuel pump?

I wouldnt wire in a switch for the pump unless its going to be driven on the track only. The pump runs on a swtiched 12v power (key on=power) and a ground. Once i get home i can post wiring diagrams. I cant rite now since im at work.

If you dont want to listen to me, then all it takes is a 12v source and a ground to power the pump. So basically run 12v to the switch (put a fuse inline). Then from the switch run 12v to the pump. The pump will then only need a ground which can be run directly to a bare spot on the chassis. You can run 12v straight to the pump and have the switch on ground side as well.

Anyone please correct me if im wrong. Im not responsible if you burn down the car though.

theboy wrote:

I wouldnt wire in a switch for the pump unless its going to be driven on the track only. The pump runs on a swtiched 12v power (key on=power) and a ground. Once i get home i can post wiring diagrams. I cant rite now since im at work.

If you dont want to listen to me, then all it takes is a 12v source and a ground to power the pump. So basically run 12v to the switch (put a fuse inline). Then from the switch run 12v to the pump. The pump will then only need a ground which can be run directly to a bare spot on the chassis. You can run 12v straight to the pump and have the switch on ground side as well.

Anyone please correct me if im wrong. Im not responsible if you burn down the car though.

Yeah, that's all you need, but remember, you need a HEAVY DUTY TOGGLE SWITCH that can handle the amperage that the pump draws. That means, whatever the stock fuel pump fuse is, (15A, 20A, etc.) you need a switch that can handle that load.

I in no way recommend this though.

ok, before you go butchering up the wiring for your fuel pump, you need to try these simple tests first.


Test #1: Check fuel pump relay to see if its good.

Step 1) pull relay
Step 2) grab favorite multi-meter and set it to test continuity (horse shoe looking icon, ohms)
step 3) probe terminals 1 & 2

looks like this:

4__3
_12_

You should have 0 continuity without a 12v source. If you leave it in and back probe from under it, with the key on, you should have continuity.


Test #2: Check for power at the pump.

1.Remove upper and lower portions of rear seat.
2.Remove round fuel pump access panel.
3.Remove fuel pump electrical connector.
4.Check for continuity between terminals A and C. Replace the pump if the circuit is open.

__[]__
A B C
D E F


This is all per alldata. If you want to send me an email addy ill send you some wiring diagrams. Its not leeting me upload my copies through photobucket.

You never test for continuity with 12v present. Testing for continuity should only be done when the wires are disconnected from the circuit.

Wait, so it now has a new fp and relay. It drove then died. Then started up agian, you turned it off and it won't start back up? All this on the same relay? Doesn't sound like a dead relay but something loose/bad connection, if it's even electrical related. If something in the wiring is shorting, the fuse would go out. Unless the short is before the fuse. Either way: [You must be registered and logged in to see this link.] page EL-6 or pdf page 6 is the power supply routing page. I'd disconnect battery and check resistance.

600SX wrote:

You never test for continuity with 12v present. Testing for continuity should only be done when the wires are disconnected from the circuit.

Im going off what alldata is saying, If you have 12v power run to it then you will have continuity. If you unplug it (like i figured you do to test) then it should not have continuity. I agree 100% with you. Im just going off its telling me. If you would like, ill give you my info so you can log into it as well. Youll probably find more on it then me. I couldnt really find a specific diagram on the matter.

Well there is power source from the multimeter's battery so you need to take the car's battery out of the picture or you'll get wrong readings.

no you dont, leave the battery alone it will not screw with continuity readings. Cause all your looking for is if there is resistance in the circuit/wire.

heres pics of the tests:

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fuel pump test


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fuel pump relay test

600SX wrote:

You never test for continuity with 12v present. Testing for continuity should only be done when the wires are disconnected from the circuit.

What he stated is how to test a relay. You have to energize the coil in order to test if the relay clicks over, and completes the circuit.

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^^ Then you should check the voltage coming out of the relay when energized. I still stick with my previous statement.