Please help!No ones on 280ZX. Fuel pump problem

[280TurboZX]

Hi sorry I dont own a 240,260or 280z Mines a 1982 280ZX Turbo/Automatic. But maybe you have the answer . Any ideas? I turn the key on(before cranking)and I hear clicking under the dash on the passenger side and hear my fuel pump pulsating. After a few dozen give or take clicks it stops and I hear my fuel pump,pump up and stop,I then can start the car. And occasionally while driving it will go into the clicking mode and die or spit and sputter. I have a new pump.Please tell me a simple fix. I tried a switched hot wire to the pump but no help. Thanks so much.

Edited February 3, 2011 by 280TurboZX
No year added

[grantf]

hmm It should not be to different from the late 280z cars, I am not sure though. Does the xenon site have you FSM?

[280TurboZX]

I bought a FSM on Ebay. A (DVD) for $10.00 and it's the best(cheapest purchased) manual I have ever bought and it's the BEST I ever owned. Boy it shows you how to rebuild everthing on the car,Shows ALL wiring,How to check EVERthing electrical. It covers years from 1971-1983 240,260,280. Wow its the greatest. I thought for $10.00 bucks it would be like a haynes or chilton, But it's like a Full 708 page book for the 1982 model alone. I just hate reading and thought someone on hear might have had the same problem with an easy fix.

[FastWoman]

Well, I have a '78 280Z, the last model of the Z lineage. I'll assume yours is wired the same, although it might not be. Assuming it is...

The fuel pump will energize for 5 sec when you turn the key to "start," and then it will click off, unless the engine is actually running. (I'm pretty sure I have that right.) The system knows the engine is running when either the alternator is putting out voltage, there's oil pressure, or both. These inputs feed to the fuel pump control relay, which is not the same as the fuel pump relay. The fuel pump control relay then actuates the fuel pump relay. Either or both of these relays could be clicking out on you. You might get some advice that there's a fuel pump shutoff switch in the AFM, but that wouldn't apply in the '78, and I'm almost certain the switch isn't even present in the ZX AFMs. (I have one as a spare part.)

So I'd just start tracing signals -- oil sender, alternator fault signal, fuel pump control relay, fuel pump relay. You might have a bad connection, corroded wire, and/or faulty sender. Sorry, no quick/easy fixes. There's not anything that "usually" goes wrong up to the level of the relay. Beyond the relay I suspect there is a common corrosion problem in one connector, but it wouldn't cause your relays to click.

[Nigel1943]

There are 2 fuel pump relays in the engine compartment passenger side sidewall. These are probably the cause of your problem.

[280TurboZX]

I did some tinkering and when my relay started clicking I tapped on the ECM near the driverside foot, and it stopped clicking and would run.So I either have faulty wire connection or maybe my box is going bad[internal short] Found a bunch on Ebay for $60-150.

[FastWoman]

Ah, the kick test! (Why else would they name that the kick panel?)

Seriously, you might undo that big connector on the ECU and clean the terminals. If that doesn't solve the problem, you might try re-flowing all the solder connections on the ECU circuitry boards. ZTrain had an ECU with some solder joints that had fractured and gone cold.

[280TurboZX]

Yep, I sprayed all connections with Electric Contact cleaner. And it seemed to help until this morning. While it was running, I jiggled on the wires and at one moment saw my tach/engine take a dive. either still contact points of wires, or like you mentioned possible solder break on circuit board. Reflow sounds like a viable(do-able) idea.

[FastWoman]

Hmmmm.... FAIW, the tach and ECU have something in common. (I'm assuming your ZX is similar to my '78 Z, which I think it is.) The ignition module drives the (-) post of the ignition coil, grounding it to generate a spark. The (-) post then has a wire leading to both the tach and the #1 pin of the ECU. The input to the ECU is used to time injector pulses. If there's no signal, then no fuel is delivered.

I suppose it's possible the ECU could detect a no-run condition by sensing no spark, at which time it could kill the fuel pump relay. The '78 doesn't work that way, but your ZX might. Dunno. Only speculation.

But I think you should trace out the mutual ignition coil (-), tach signal, ECU trigger connection, which I believe might be a crimp connection embedded somewhere in the wiring harness. Oddly, the crimp would be wrapped in black electrical tape. (That's how branch lines were done at the factory.) I bet that's where your problem lies.

Edited February 6, 2011 by FastWoman

[sblake01]

If his is a turbo, the ECU wouldn't be at all similar to the one in a 78.

[280TurboZX]

Well I still have an intermitant problem. Seems more likely for the relay to do it's clicking thing more in the morning at first start-up. Once after I give the ECU a bump from my left foot, the relay will stop clicking and I can hear the fuel pump,pump up(about 5 seconds)then I know if I start cranking it will fire.So I have cleaned the three plugs mine has.And used Electric cleaner as well. So maybe I have an internal problemin my ECU and I should replace it. It's very anoying and not very trust worthy. I am almost at wits end and thinking of Replacing the Car. With a simple one. I love it, but would rather walk sometimes. I've replaced Fuel tank(leaked)Fuel Pump(leaked)Spark plugs,Wires,Cap,Rotor,Pump Relay,Mufler and Water pump. Still needs New Radiator but I ain't going to replace that until I get the fuel clicking,thing figured out. Or maybe sell the car for $1000.00 and walk. I found a use ECU on ebay for $75.00 but my money tree is not sprouting this year. So I have no clue what to do. When running right the car is a blast to drive and boy when that Turbo kicks in, WOW. I think too many kicks to the ECU may kill it then I will be thumbing it(walking):tapemouth

[FastWoman]

It would be a pity to walk away. These old cars usually take quite a bit of effort to get them running right, because they usually have a neglected past. But once you work through the problems, they're the picture of reliability. You have only to keep up with the maintenance the way the PO should have done.

Re-read my post #9. There may be differences between my n/a Z and your turbo ZX, but I bet I'm right about how your ECU is triggered. The common link between your tach and fuel delivery by the ECU is that branched connection off of the coil. But of course you'd be wise to download a free copy of your ZX Factory Service Manual (assume it's available) to check the schematic. I bet it works that way, though.