fuel injector relay

[kassim503]

On gassers, is there 4 fuel injector relays with green housings?

Shouldnt there only be one?

Does that mean I have to buy 80 dollars worth of realys?

[kassim503]

my bad, i forgot there is a relay for the wire harness and the ovveride switch.
is there a distinct way to find out which relay is the fuel pump relay? i dont want to sit around jumping connections all day until i get the right one

[83_maxima]

Do you have a FSM?

[asavage]

is there a distinct way to find out which relay is the fuel pump relay?

1983 FSM pg EF/EC-24, Figure SER235.

Hard to describe. There are two rows of five relays. They show the relay panel unbolted and flipped upside down. The EFI and Fuel Pump relays are side by side in adjacent columns-of-five, second row-of-two from one end, but I don't see an easy way to describe which end to count the "second from" from.

Wire colors to FP relay:
BW (Black w/White stripe)
Lg (Light Green)
LgR (Light Green w/Red)
B (Black)

Wire colors to EFI relay:
LgW (Light Green w/White)
BW (Black w/White)
LgB (Light Green w/Black)
B (Black)

HTH

[kassim503]

anybody know if i can run a headlight relay in place of the fuel pump relay?

what about a "fuel injection relay" as the pump relay?

http://www2.autopartsauthority.com/part ... y&dp=false

NAPA dosent carry the FP relay and it is causing me all sorts of problems

[asavage]

anybody know if i can run a headlight relay in place of the fuel pump relay?

In general, a relay is a relay is a relay . . . except for certain "features", like a spike suppresion diode, and xPDT setups.

what about a "fuel injection relay" as the pump relay?

They appear to be the same part.

http://www2.autopartsauthority.com/part ... y&dp=false

Yeah, that one.

http://www.nismoparts.com/cart/?pn=25230-W1300 , $24

The 1983 FSM (EF/EC-27) shows the FP relay to be a SPDT type, with the NC contact unused. You could probably wire in any decent-sized relay and have it work OK -- unless you go overboard: if the coil draws too much, the sourcing transistor in the ECM will fry.

[Note: Nissan uses an unusual setup here. Normally, the ECM provides the ground for the relay's coil. According to the FSM, the ECM actually provides the hot for the relay's coil -- unusual.]

For a non-OEM relay, you'll also have to determine which two terminals are for the relay's coil, which one is the movable contact, and which the fixed NO contact. Some aftermarket relays (notably Bosch) have those diagrammed on the relay, but most don't. Since there are four identical relays in that panel, you should be able to get an idea which ones you can steal from a donor car to try out on yours. My Parts Catalogue only has arrows to six of the ten relays, go figure.

Are you really sure the relay's bad, or are you guessing and hoping? There's a right way to diagnose a faulty relay, but a lot of relays are replaced in the hope that it will cure a problem. For example, if a corroded relay connector is the fault, and you touch it when replacing a relay, and the problem "goes away", was the problem the relay or the connector? I've had far more bad connectors and bad grounds than bad relays -- and I've done a fair amount of this kind of thing.

If you can get the relay to be in a supposed bad state, you can check its inputs/outputs:

• Signal ground (Black): never hot (if any voltage whatsoever, bad ground)
• Signal input (Light Green) from the ECM pin 13: hot with engine running and/or in pressurize mode
• Load input (Black/White): hot with key ON
• Load output (Light Green/Red): hot with engine running and/or in pressurize mode

The wiring diagram shows at least four connectors and two splices in that circuit. Test the relay's inputs/outputs before condemning it.

(There's another half-hour shot to hell.)

[kassim503]

really, im just guessing and hoping, a bad connection may be as possible as a bad relay, but the bad connection may not be on the relay, could be on the fuel pump connector that was just opened a week or two ago for when i replaced the pump.

it seems like a bad relay, the pump is only heard a second or two after the key is put in the on position, also the familiar clicking of the relay when you turn it to ON dosent sound for a second or two as well (i pulled the relay and just put my ear onto it while a buddy turned the key.)

[asavage]

it seems like a bad relay, the pump is only heard a second or two after the key is put in the on position

[I bought a second FSM (both '82 & '83) so I have one at work and home now.]

Most EFI systems run the fuel pump for approx. two seconds in the key ON engine OFF condition. That behaviour is normal. The fuel pump should run when in START position and (RUN position & engine running). If engine dies, ECM turns off fuel pump relay immediately or more usually about two seconds after RPM hits zero.

also the familiar clicking of the relay when you turn it to ON dosent sound for a second or two as well (i pulled the relay and just put my ear onto it while a buddy turned the key.)

???

[kassim503]

it seems like a bad relay, the pump is only heard a second or two after the key is put in the on position

[I bought a second FSM (both '82 & '83) so I have one at work and home now.]

Most EFI systems run the fuel pump for approx. two seconds in the key ON engine OFF condition. That behaviour is normal. The fuel pump should run when in START position and (RUN position & engine running). If engine dies, ECM turns off fuel pump relay immediately or more usually about two seconds after RPM hits zero.

also the familiar clicking of the relay when you turn it to ON dosent sound for a second or two as well (i pulled the relay and just put my ear onto it while a buddy turned the key.)

???

I think you misunderstood me, I guess its because ive been up way past my bedtime for the past month and its catching up to me.

When relays turn on and off they make a faint clicking noise, you can hear it if you stick the relay on your ear and electrify it.

I do know it cycles the pump for a two seconds or so after turning the key to the ON position, after turning the key to the ON position there is a 1-2 second lag before the relay clicks. The lag goes away when its hot outside or whenever the ambient temperature under the hood is above 75ish degrees

[asavage]

. . . after turning the key to the ON position there is a 1-2 second lag before the relay clicks. The lag goes away when its hot outside or whenever the ambient temperature under the hood is above 75ish degrees

Hmmm. That does sound abnormal. But a relay that is sticking open is unheard-of (by me). I've seen several that stick shut, but open?

That relay's power is sourced by the ECM. This could as easily be an faulty ECM or sensor input to the ECM as it is a relay. I'd want at least a test light on that relay's input, watch it when turning on the key to see what is feeding the relay's coil, before condemning it. But if a relay is cheap enough and you want a spare, throw a relay at it, see if the symptom changes. And let us know the "rest of the story" (for those of you old enough to recognize the phrase).

[kassim503]

Well, I got a new relay (napa-17 dollars), OEM quality and whatnot, plugged it in and so far, it runs great.

Spotted another problem- something is discharging the fuel system while im not looking. I was running a new coax through the engine bay, one second the FP gauge read 40 psi, then the next it read 5. I didnt hear any hissing noises or anything that could of hinted fuel discharge. It dosent seem to be a regular thing, I drove and stopped and checked the gauge some 30 odd times today and it only happend once. The gauge is working properly and does not stick, even when the engine is hot.

[kassim503]

Is it normal for them to get a little warm after going for a little while?

In this sceneario which is more likely- a bad connection or a faulty relay?
Has trouble starting when cold (below 60F), and takes some time for the fuel injectors to power up after not driving for a day (10-15 seconds) (there is fuel pressure). When its warm it starts and runs just fine, no power problems or stalling.

What does that sound like, its really becoming a hassle and today I had to shoot it with starter fluid to get going, actually I had to shoot with more fluid even after it started to keep it running for 10-15 seconds and then the injectors started firing, which is quite dangerous and I really hope I dont have to do that again. Also it was backfiring a little bit so it sorta gets the hairs on your neck to stand up while shooting some ether in there

[asavage]

There are a whole lot of things that could cause poor cold start, aside from fuel pressure (which you say is OK).

* Thermo-time switch
* Cold start valve
* Cyl. head temp sensor
* Water temp switch

And of course the airflow meter as well. Being pre-OBD, these early EFI systems require more expertise and knowledge than later systems where at the least you can get the OBD to lie to you convincingly.

You have the FSM? Start with the EFI wiring diagram on EF/EC-27 and find the diagnostic procedure for the above pieces. You can check the thermo-time switch and the temp sensors easily with a basic ohmmeter. The cold start valve is best checked by pulling it off the manifold and watching it during a cold crank test.

You can't tell if the injectors are firing unless you use a noid or a 'scope (or pull them out of the manifold and watch them). You can't hear them at cranking speed -- at least, I can't.

[kassim503]

Fuel pressure might not be ok, like a previously stated. This morning before starting the gauge read 30 something pressure, holding perfect pressure overnight? With all the old parts that are still in there? I doubt it. Problem is the new fuel pump is very quiet and I cant hear it run unless I stick my ear right on the rear wheel and listen, which I cant do unless I have a partner.

The thermo time switch, cold start valve, and water temp switch are reading normal, also I cleaned all the connectors to each of them after testing, didnt do the cyl head temp sensor yet.

I got the FSM at work, and im in the process of getting one for home through ebay now, but I have mitchell online which is ok, its not as in depth as the FSM.

Al, you talked about the Cyl head sensor and the water temp sensor functioning for the EFI, I do know they control high idle speeds and warmup but do they do anything else? Does the AFM do anything during starting, like if the flap was stuck closed would the ECU prevent the injectors from firing, never know it might be stuck- I did spray alot of ether in the idle air hose inlet that might run down into the AFM.

I doubt the Cold Start valve sytem has a problem, the car starts in cold weather without it, but it takes a little bit and you have to step on the gas, and now its not nearly cold as before.

I do know that the engine is getting absolutley no fuel when cranking, not something like a few squirts here and there, Al thanks for the helping me on this one, its really driving me crazy and im afraid that ill run out of ether in a parking lot 100 miles away from home.

Tonight im going to replace the other relay for good luck, check the connections on the ecu and clean the connections on the fuel pump and try to replace the gauge with something that would last a little more than 4 weeks.


Also the windsheild leaks, but it only rains on the passenger so thats for another day

[kassim503]

Found the problem, the fuel pump I bought from NAPA ($139- federal mogul) was defective, went back, exchanged a new one, went through R&R again, runs great.

Also the car seemed to be leaning out before with the defective pump because I have more power.

Does anybody know how fast the oil pressure gauges go up with rpm?
I remember other vehicles I drove with mech oil pressure gauges went up right when I step on the gas, but the one I installed in the maxi goes up fast but still slow. Is this normal? or did I kink a line somewhere