Z doesn't work..

[stevofoxono]

Hi all. my z's buggered and i'm stumped.

It was off the road for about a month (because i was lazy) I replaced the exhaust/intake gasket (old gasket was stuffed) and put in a new shaved intake manifold. When i finally bolted the fuel rail and all back together and jumped started the car it had no problems. Drove 150kms from wednesday to saturday and didnt have any problems at all..

 

Saturday the car stopped working so i got it towed back home. I assumed it had something to do with the fuel rail or fpr so i put in my pallnet fuel rail and sard fpr sunday. Engine bay looks much sexier now but still no success so i ruled out fuel. I played around with the tps with little affect then unplugged the afm. under the little black cover of the afm one of the copper arms had broken off so i got a new afm last night from dat2kman

 

hooked everything back up and now my car holds idle.. Blows a fair bit of black smoke when rev'd. Putting it in gear it can get to 1500rpm but after that it stumbles and stalls. The fuel pressure is set at 38psi. My old afm had a sticker that it was serviced/tuned so the new afm may need to be looked at aswell?

Just wondering if theres something i should check/may have missed. Only have a few weeks till the chrissy cruise and i need to get it back up and running . Should i just take it to a mechanic?

 

update

Mechanic slugged me $150 and got the apprentice to glue up a few possible air leaks and unplug the tps. I drive about 200meters and the car breaks down.

So it went back to the mechanic, Next day they replaced the fuel pump, fuel filter and put a new serviceable filter infront of the pump. Bits of gunk/rust scales clogged up the old pump and filter.

I once again was told this would fix the car and I payed another $250.

Drove it for one day. Tried starting it up and the same problem the lack of power under load.

I called up the mechanic and they wanted nothing to do with the car anymore, told me to get my fuel tank cleaned then they'd consider looking at it again.

 

I gave up for awhile. Put some fuel doctor in (hoping for a miracle clean of my recent topped up to full) the tank and changed the plugs. Car turns over but won't even idle now.

In the week I haven't started the z the battery died. Called up racq to get them to give me a jolt and apparently what the bloke recons the problem is spark. Somethings buggered ie coil/dizzy cap/rotor.

 

Is it worth getting carbs? Efi is bullshit

 

[Scoota G]

Try reset ecu, disco battery to drain power.

[.]

It might help if you describe your setup. Is it a standard 280zx EFI setup? aftermarket ECU, Ignition system? Distributor? HAve you checked your fuel filter?

 

I know I get a similar issue every time (and I mean EVERY TIME) I degrease my engine because moisture gets into one of my plugs. All I do is blow the moisture out, plug it back in and away I go. Check the connections on your throttle position sensor and the plug to your air flow meter. Of course this assumes it is a standard system.

 

Alternatively the flap in your air flow meter could be stuck. Usually this is because the flap has been bent as a result of a back fire but I guess it could also be caused by crud getting caught in there. Just disconnect the piping to the front and stick a screw driver in (gently) to check that the flap swings freely (you should only feel light pressure from the spring.

 

If all else fails you can just give me the car problem solved.

[stevofoxono]

I've disconnected the battery, i'll venture outside when it cools down abit

 

definitely not getting my car i'd have to much money with out it lol. standard efi setup, stock dizzy, ecu is still the factory brick, Fuel filter isn't very old, injectors are about 11 months old, Only difference atm is the intake manifold (non egr) fuel rail (pallnet) 3 core aluminium rad, sard fpr. I'll check out the plugs when i re-connect my battery. funnily enough i did degrease it yesterday haha..I'll give it a blow out when its cooler also, I only got the afm yesterday and the flap seem'd to move freely. atleast as good as my old afm.

 

heres a pic from yesterday (before i picked up some extra fittings from ye old autobahn)

 

got burnt from the sun and from the reflection off my rocker cover 

[Scoota G]

I think you've changed bits with the power still connected! Can confuse the ecu. Keep us updated.

[.]

I think you've changed bits with the power still connected! Can confuse the ecu. Keep us updated.

 

He says its the original brick. Those things can't get confused because they have no brain to begin with. They are all resistors and capacitors with only one really simple chip. There is no way to reprogram them at all. My bet is still the AFM flap or a loose or dirty plug somewhere.

 

I notice in the photo the spot for the cold start injector is blank. I hope you installed the injector or blocked it off after you took that photo? If not you'll have all sorts of mixture issues.

[stevofoxono]

i can get it moving slightly now.. had it going down the road smoothly till i hit 4500 then it stumbled. I'm not sure if disconnecting the battery did anything, left it for atleast half a hour that way just in case.

Afm flap is still going. i put my hand over the front of it (took off hose infront) and rev'd it. sucks in alot of air and idle didn't drop. Blew on the afm plug+tps plug.

Normally with the z i atleast have some idea whats wrong. i'm bloody confused at the moment.

 

Cold start valve is blocked off. bit of gasket glue+gasket paper then abit of aluminium can on top. Might take it off to the mechanic tomorrow.. free tow with racq haha. bought membership on saturday and this will be my second free tow

[MaygZ]

Steve,

 

your engine photo should come with a warning.  Now I'm blind!!!

 

Lots of shiny bling, so .... damn .... just a bit of shiny car stuff and I can't remember what I was going to say ......

[stevofoxono]

It has that effect on people. Theres still alot more shiney i can cram in there to. lots of room 

[kolonelklink]

common things to check:

 

Establish if its rich or lean by reading plugs.

check integrity of temperature sensor (this is separate to the temp meter sensor)

check FP is stable. Check pump.

check ignition coil.

this sounds like an EFI problem... what has happened between the last time the car was running well and now? (what have you worked on?)

 

Cheers,

-p

[luvemfast]

The title has been changed to fixed.

What was the actual problem Stevo?

[stevofoxono]

Well it was fixed.. For about 2 days lol, It turns out that not only did the afm break but the fuel pump of 32 years was shot. Could pump fuel but only enough to keep it going at idle. I replaced the fuel pump and put another filter infront of it (to save the pump) and now I've got it pull it all apart again.. The filters blocked, There's a lot of rust/gunk in the tank so I ordered a kit to flush it.

Everything happens at once with the z. It's hard to troubleshoot problems when everything goes wrong lol

 

It's fixed as far as knowing what's wrong with it but not exactly "fixed" to drive or anything lol

[Zedback]

Steve, there is a mesh filter on the end of the pick up in the tank that can get badly gummed up and encrusted with particles.  Though if you're clogging an external filter there may not be much left of it.

[stevofoxono]

I'll stop being lazy and pull it apart tomorrow. put some fuel doctor stuff in my fuel just to see if that would make a difference before I attack the tank with the POR15. called up racq for a 2nd opinion and he recons either my coil/rotor or dizzy cap is rooted.

Do z's have a weak spark or is my car just rooted?

[dat2kman]

Steve, you didnt dismantle the afm you got from me? It was a goid one!

You mentioned fuel tank a couple of times now,

Do you have a basic low pressure type clear see through fuel filter BETWEEN the tank outlet and the pump, even though there is a filter at tje pump, it is prob on the engine side.

 

These tanks do go rusty over time, think about it, ie condensation, flakes of rust etc fall down rattle about, and all you have is a little bit of metal pipe inside diam aporox 4mm , easy to block, or get partial block, pump sucks like billy-o bit of gunk flaps up, presto no fuel, engine stumbles under load, but the idle is ok

 

Temp fix, loosen feue  cap, use comp air, blow back into line into tank, it will still block though.

Proper fix, remove tank, and sender assy, put a couple hand full of nuts and bolts in, shake the living crap out of it, turning upside down, you will amaze yuouself at tje amount of crap that will come out. It will still flake.

I have tanks from old Datsun Sports that are like a xmas fairy lantern they are so pinholey!

[MaygZ]

 

I have tanks from old Datsun Sports that are like a xmas fairy lantern they are so pinholey!

 

Jason,  I just had pictures of romantic dinners at your place sitting at the dining table with the mood lighting provided by fuel tank light shades hanging about the room.  LOL