280zeder

Hello, just wondering if anyone could shed some light for me.
I have 80 n/a 280zx had a lot of issues but now is running😄
Water temp sits just below the degrees symbol when driving but will climb up just past the symbol when driving up hill, when going down the hill the gauge will drop to 1/4. The car does seem laboured when driving anywhere,(round town or open road) feels like ya have put ya foot to the floor all the time. New fuel pump and fuel reg. timing at 12 degrees btds. New head gasket. And occasional small pop from exhaust. Plugs look ok and garage checked AFM and car runs slightly lean but not bad. Garage said they couldn't richen mixture.
Could there be another vacuum leak? Garage also replaced the advance module thing on the dizzy.
Any help would be appreciated. Thanks

borini63

Maybe a bad timing!! Is your TDC(Top Dead Center) is correct??

https://www.zdriver.com/forums/240z-...e-l28et-30099/

L28 Timing - Nissan L6 Forum - HybridZ

Google this and enjoy (TDC timing 280ZX)

zxguy1986

Agree with Borini.

Could be a lot of other stuff, of course, but check back in here after you verify your timing. I have a couple of other ideas.

Your factory service manual is a freebie at XenonS130 - S130 Reference Other cool docs there, too. Your manual probably has pages and pages of inspection and troubleshooting procedures, all easy to follow. Let us know what you find. We like the feedback and the input. It helps others.

280zeder

Timing 12degrees advanced. Just been for 200+km drive to a mates and defiantly got power issue. Runs ok but feels like it's running with potatoes in thexhaust or its being forded to run. Seem to have put foot right down just to move. When flooring it kind has very light surge feel like it could be starving. takes for ever to rev out. Good to about 4k then flatish. Tdc checked and good.

280zeder

The last garage tried adjusting afm to slightly richen car but then car idle was up n down and somtimes stall. Been thru all vacuum lines twice and with a mechanic.

zxguy1986

May be time to start checking your vacuum controls and your sensors. Do you have a way to check the vacuum pump power? It sounds like you don't have the vacuum force to run the controls. Those 280Zs are really reliable when all the kinks in their systems are straightened out. My buddy has an '81 that is always rock solid and on the road.

Your manual has good inspect/troubleshoot pages. There's a great Z31 vacuum tube replacement post from Thumper at Vacuum Lines I'm guessing the same principles and parts apply to the 280 Zs but I can't be sure. Our 280 guys here may have some more input. Replacing sensors one at a time sounds like a waste but checking whether they are working right isn't.

Keep that baby on the road and running right!

Zdon

Air flow meter is either tired or catalytic converter is clogging up so under load it's not efficient. Good luck getting it fixed. Cheers !

280zeder

Thank for all your help. I'll go thru a big check over theft few days. I have noticed air being sucked in the idle screw part in arm. Not sure if that should be correct. I also just changed fan cluch because it was seized on hard on my last drive. Still noisy with new clutch, spins free when engine off but doesn't seem to slow down as car warms up. I'll give it a long drive and see what happens. I quickly checked that vacuum switch box thing in engine bay. While car was running I pulled a couple out and didn't make any difference to idle or running operation. I'll do some research into if the vacuum box thing is stuffed. I like a good challenge and this car is providing the mother of all challenges!! Still lovin it though!! Cheers and I'll keep updating.

280zeder

I've been thru chasing vacuum leaks and found a few. The main one was the rubber o ring was missing in the idle screw (throttle body) now car runs smooth. I can hear 1 whistle left now so I'll track that down over the weekend.
My fan clutch locked up on the open road. Just replaced that with a new on but I notice it's still quite noisy driving round all the time and temp gauge sits at 1/3. Is this normal?
I can turn fan when cars off but seems to just spin with the engine speed and still loud.

Cheers!

pete8717

A fan clutch will free spin with a cold engine and will lock up when it warms up. If it's not locking you may have bought a bad one. If you're still hearing a lot of noise it wouldn't be a bad idea to pull your belts and spin the pullies by hand and see if they spinning smoothly or making noise. Maybe make sure your cooling fan isn't on back words too. I'm guilty of that one.

William Wyrick

what did you set your rockers to? i set both at cold .007 & .009

280zeder

Changed new fan clutch to a used one and car now revs right up now. Car runs heaps better now. When driving I feel like gas pedal kinda is average for 3/4 of it but goes good with foot right down so I'm picking maybe a throttle position set wrong or something like that.

William Wyrick

have you tested your vac for bleed off on the timing advance