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Discussion Starter · #1 ·
Finally got my 280 running. Replaced a "missing" fuel pump, starts nice, idles well, go for a spin and it has lots of go but after a mile or two starts bucking and losing power (I don't hear the fuel pump whzzing away at all). Usually dies... then restarts after a few tries ( I hear the pump start whizzing). I also notice that the heater controls (air flow) all goes nuts just before everything under the hood goes haywire and starts to stall.... vacuum leak? It's been 15 years since I've had a Z and this particular car is new to me... any ideas to the stalling and wacko heater?

Many thanks, Rob
 

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I think you are on the right track. Sounds like a massive vacuum leak. Brain not fully in gear yet this morning but look at anything that is temp controlled vacuum. You don't say what year 280 but the things that come to mind are temp controlled vac advance and egr sytem. Also just might be fuel line or pickup clogging after a flog on the road. Might need to put a fuel pressure gage on, tape to the windshield and drive until it stalls, then compare what is happening to fuel pressure.
 

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have you check the gas tank? i had the smae problem. there was so much varnished gas in there that it go stuck by the pickup line in the gas tank. you need to clean your gas tank out really good. if that is not the case than i have no idea, but it sounds just like what happened to mine.

ps: check the gas tank!
 

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once the car starts the only way the fuel pump should lose power is if there is no oil pressure and no charge from the alternator. so unless these conditions are being met the only way the pump cannot work is for the relay to be bad. the only problem i have is the talk of pump whine; it is very rare to hear these pumps run, if you can the reason is because a restricted intake, which can result in pump overheating and shutdown. so the previous answer could be right a tank restiction could cause your problems.
 

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Discussion Starter · #5 ·
Thanks!

My thanks to everyone who responded both on line and in email. The tank has been steamed and coated inside to stop the scale or rust problem. The "whiney" pump is 'aftermarket' crap :( . Sounds like vacuum and electrical is going to be getting a good going-over!

Thanks again!
 

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Are you in Alberta?

There are a few from out there that frequent this site, they may be able to help you out.

I would still put a fuel pressure gauge between the fuel filter and the fuel rail and check the fuel pressure when it acts up.

Things to check:

Fuel tank vent system. If it is plugged up you end up with a vacuum in the fuel tank as fuel is removed. Make sure the carbon canister is working properly.

Restrictions in the fuel lines. If they are plugged you get high pressure but low volume. Plugged lines can be from crap inside the line or a visit to "Oil Changers R Us" and the car was hoisted up and the frame got bent (usually towards the front) and has pinched the fuel lines. It is easy to spot this one because the back breaks do not work properly also.

Put a test light across the fuel pump and put the bulb somewhere where you can see it while driving. With the engine running the pump should always be running.

You did not mention Year or Model so there are different combinations of test to get any further.

Wayne Monteath
Masham, Quebec.
 
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