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Please Help 77 280Z MAF


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I've been looking all over for a new Mass Air Flow sensor for my 77 280z and everywhere I look all the Air Meters are for 78 Z's and 79+ ZX's. My Question is, will a 78 280z mass air flow sensor work perfectly fine on my 77 280z? In particular this one?

 

http://www.ebay.com/itm/SMP-STANDARD-MF4211-Mass-Air-Flow-Meter-MAF-/200739876366?pt=Motors_Car_Truck_Parts_Accessories&fits=Model%3A280Z&hash=item2ebd076e0e&vxp=mtr#ht_1852wt_1177

 

Please, Any help is greatly appreciated.

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There's a possibility that the AFM won't come with a fuel pump relay cutoff switch since 78 didn't use it, although my 78 AFM still had the switch. If you get it and it doesn't have it, you'll have to short the contacts in the connector, at the relay, or rig up a fuel pump switch.

 

Motor Sport Auto sells AFMs, although their core charge is huge, $400. The one I got ran rich though, but it did work fine otherwise. Cheaper too. http://www.thezstore.com/page/TZS/PROD/11-3040

 

Are you sure you need a new AFM? Its a part that's often replaced with no effect on the real problem. Knowing what I know now, if I needed one, I'd take an ohm-meter to the salvage yard and test and inspect, before buying new. If the yards had them.

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Trust me, mines junk. I had two bad AFMs. One with bad circuitry, one with good circuity and a dented case jamming the flap. So I took the good circuitry and mounted it in the good case. Needles to say it didn't work. So now I need a new one and I need one bad. I just Bought a "new" ECU and Harness because mine was blown and the harness was chewed up. So with the new harness I need a new AFM to go with it so I dont short out the new (To me) ECU.

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Core Charge is only "huge" if you don't support the vendor by returning the core!<br><br>I walk in, give them my crap part, and walk out with the new remanufactured part. No core 'charge' is ever mentioned or charged!<br><br>If you know the part is bad, drive to MSA (takes 45 minutes from Temecula, depending on which route you take) and exchange it for a reman unit.<br><br>No $400 Core Charge will ever come into the picture.

 

<div><br></div><div>-- EDIT -- Customers would complain our core charges were 'excessive' as well---something on the line of $16K for a $16K part. The philosophy was simple: if you did't get the part back to us within 90 days, you were billed for it. It sure helped deadbeat and otherwise unmotivated lumps get off their butt and HONOR the sales contract they entered into: we give you a part, no questions asked, but we need your old one back! If you want the system to work, you gotta hold up YOUR end of it! -- EDIT --</div>

Edited by Tony D
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Im curious. I just brought an AFM from thezstore and looks great. However my situation is odd? I tried 2 other afm's both from a 77 and of course the zster afm that is for my 76. But none of them prime the fuel pump like my original afm does? Im currently fixing the z, but before the car would start and not hold idle, and removing the afm plug, it would run better but still stall out. Im guessing something somewhere a connection is bad? I mean its odd how the original afm primes the fuel pump but the other 2 afms dont, including the afm for my z. Any idea's? Im holding onto the afm before I return it to the zstore and end up eating the $580 -____-.

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From the threads I've seen, especially Heroez's recent poll, only the ZXes had a "priming" feature, and it didn't appear to be tied to the AFM. It seemed to be controlled by a relay or the ECU, depending on which electronic control system you had. Heroez never did tie up the loose ends on his priming problem, and I've only worked with 280Zs so can't be positive, but that's the way things look.

 

Are you saying that you're searching for an AFM that powers the fuel pump for five seconds (which your 76 shouldn't do anyway), and you're going to return one because it doesn't? 5 seconds of pump operation doesn't seem worth it, and you'll probably never get it with a 76, unless I've misunderstood something.

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So what im saying is my current afm primes the fuel pump and DOES NOT stop, it keeps going until the car turns on. The other 3 afm's that I put in dont prime the fuel pump at all, no buzzing sound. Being that it was a track car, im not entirely sure what they did, but from my understanding you arent the first to tell me my 76 shouldnt have the fuel pump prime and hear it. But I never had a car where you didnt hear it prime? That's how I know things are working? To me I think somewhere down the line something is not wired right, or its corroded? I only would return it, if in fact it is faulty.

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Still can't really understand what you're writing. Your last post implies that fuel pump turns on as soon as the AFM is installed and does not turn off until the key is at Run. That would mean the pump runs constantly with the key Off, draining your battery to death, and the car won't run because the pump turns off when you trun the key to Run. If that's the case, the problem is not your AFM, it's probably a shorted relay.

 

"Prime" is the word ZX people use to describe the 3-5 seconds that the pump gets power when the key is turned to Run. The word "prime" confuses things.

 

The 75-77 AFMs use a switch inside that makes contact when the AFM vane opens, sending power to the fuel pump relay. Some of the 78 AFMs still have the switch but it's not used at the connector.

 

It's easy to adjust with a pair of pliers. Pop the black cover off of the side of the AFM, it's just glued on. Move the counterweight and you'll see how the switch is supposed to open and close. Tweak the metal rod until the switch opens, (fuel pump stops) just as the counterweight and vane are about to hit the stops. You can do the adjustment on the car or use an ohm-meter and do it on the bench. If you do it on the car, the pump should be off with the key at Run, then on when you barely move the counterweight.

Edited by NewZed
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^ Really appreciate that info. I have seen the write-up to do what you describe with the afm. Im sorry to confuse you, as I am still confused on the situation lol. Basically what I mean by prime is the key is in the on position the fuel pump buzzes aka priming the system and does not stop until the engine turns over. So you get that part, and now I understand its actually only supposed to last 3-5 seconds for a s130. On a s30 it wouldnt be audible? But the thing is when the key is off the battery is not drained its fine, the pump does turn off. It's just when its on the ON position it stays on until you start the car. The car DID idle, so long as you had the flap in the afm held open. I still have to test the continuity, but I see where you are getting at. Could be a bad relay? I havent checked if it was functioning, however I looked at it to see if everything was connected.

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^ Really appreciate that info. I have seen the write-up to do what you describe with the afm. Im sorry to confuse you, as I am still confused on the situation lol. Basically what I mean by prime is the key is in the on position the fuel pump buzzes aka priming the system and does not stop until the engine turns over.

 

Like "kid", you need to get the FSM for your model year and run through the troubleshooting steps in the EFI section. When you read the FSM you'll note that the electric fuel pump is wired to come on with the "start signal" (when the starter is engaged), then it's operation is supposed to be controlled by some safety mechanism that proves the engine is running (switch inside the AFM showing flapper movement, oil pressure switch, sensing the alternator spinning - Nissan used various methods (until they figured out the best way was to use the ECU to control the fuel pump - but none of the early Z's used that method)). None of the early Z's used a "fuel prime" - the fuel pump should not start at IGN ON (not until START, and after that should only continue to run if the "safties" have proved the engine is running). Sounds like something is wrong (or has been changed) with your wiring. Get the FSM, do the tests, understand how your year operates...

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I have the efi bible, and a download of the fsm. I assume what you say is true, because I have read it several times. Im starting to think the wiring is changed. I went through a bit of the fsm, I have to go through more obviously. I just needed a direction as to why it does what it does. So its NOT normal for the original afm to prime the fuel pump and hear buzzing? So the other afm's I have might not be so faulty. Like I said I am going to check hem today and see what I can do. I just needed some input, thanks guys. Sorry for the thread jack, it was a similar topic, I found no use in starting a whole new thread.

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^ It was a race car in the 80's so I wouldnt be surprised. But the thing is I wouldnt know becasue it doesnt scream 'aftermarket'. Everything looks stock, if anything they deleted more than they added or enhanced. Blu do you know exactly what they changed?

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Yeah, my po gave me a list of all his modifications along with a reciept book of all the other PO's before him, bless his soul.

 

He hot wired the started to get power from the ignition switch, so he turned the key to on, poked around with a noid light to see what wires were getting power and he spliced it. He used a relay and a direct power wire from the battery, much like how someone would wire up an electric fan to a switch, expect the switch was the "wire that got power when the key was on"

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Hmm excuse my noobness but what is the benefit to that? I think im going to check into that though. Looking at the pump itself the black and green wire are there and not spliced, so going to check on the relay for any wires that are most likely spliced.

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