Wednesday 26 October 2011

Need help fixing my 280ZX (fuel problem)

Alright, here's the scope. I've asked before about my problem and alot of suggestions were to change the fuel pressure regulator. Here's the problem. The damn car burns rich and boggles. It's a 1979 Datsun 280ZX. So Far this is what ive done %26amp; changed: Plugs, Furl Pressure Regulator, hoses, EGR valve, Distributor, Injectors, Cap %26amp; Rotor, ECU, cold start injector, %26amp; fuel pump. The car still burns rich. I've done a timing light check and here what the results: the car is supposed to be at idle around 800 RPM @ 10 degrees Over TDC, the car runs a steady idle and RPM @ an estimated 35-40 Degrees over TDC. Also, when the vacuum hose that connects the valve cover gaskets to the intake is connected correctly, the car boggles, but when you disconnect it from the valve cover and leave it sucking free air, the car idles fine, but still has a boggle. It's drivable but when trying to open up, it boggles and sort of stress, and it eats up alot of gas. when i checked the plugs, all of them are carbenated at the spark. So what im asking is can anyone else tell me what the problem could be that i've missed or can anyone tell me what can i do to solve the problem? Someone suggested the timing might of slipped, but its a timing chain not belt, but can it still slip, and would that also be the problem for the boggling and fuel consumption? Please anyone; help me out. Thanx.Need help fixing my 280ZX (fuel problem)my guess is that your problem is in the inlet air cleaner,there is a vacuam operated damper in there that restricts the air when the engine is cold and opens as the engine heats up should have a vacuam hose connected to it..disconnect the hose from its source put it in your mouth and suck real hard if it don't open and close rip it apart oil it up and make it work if not replace it this little damper shuts the air supply down ..like driving with the choke closed
Need help fixing my 280ZX (fuel problem)
HI

Sounds like everything is still out of wack.. or maybe there is a vacuum leak.

RPM at idle should be 650 to 750 rpm's not 800.. and Your timing is way off... You said it should be 10* yet its at 35-40*.. is that with the vacuum line off and pluged?? Also make sure your fireing order is right.. and going the right direction on the cap. it would only take it being off one plug wire to thro the timing to 35*..

timing is set with the vacuum line off and pluged going to the carb. I'd start dropping the timing and move the idle up to compansate.

good luck

Tim
Need help fixing my 280ZX (fuel problem)
Yes a timing chain can stretch. And something is wrong 'cause there's no way it would run @30deg. BTDC. Are you sure the O2 sensor isn't giving a bad reading.
yeah ..you gotta %26quot;air%26quot; problem ...think about it ..air pressure is changing the way it runs

make positive sure your egr valve is moving back and forth and that it works ...carbon build up can stop it from releasing internal pressures



I think you have what is called a recirculating fuel system ...its basically a loop fuel feed system ..it is suppossed to maintain equal fuel pressure



Take a vise grip and try clamping off or squeezing tight on some of the vacume lines and fuel lines while its running...it will start telling you a story

those little solinoids can really mess things up ...you will find the problem