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i have a 76 280z.that is running rich i have check just about every thing.i got the car from a friend for free it was in bad shape but i'm bring it a round.but i just can't figure this out.i replaced the thermotime switch.i changed the injectors.i got a new cold start injector.i checked the tps to make sure it was set right.when i was checking every thing i found the srew on the afm was loose the one that holds the big black gear looking thing with the spring on.i start the car up and turned it till it start to idel smooth.now the car idels smooth and revs up fine but when i got to take off the car starts to back fire till about 3500 rpms.after i did every thing above i changed the plugs,wires,and the cap and rotor.and put a accel coil on it.any help or suggstion will be appererated thanks ahead of time
 

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has the exhaust manifold gasket been replaced? I ask this because when i purchased my header i was given a gasket for a carbbed car...i was in such a hurry toget it on i didnt catch it and my car ran like dudoo for 2 months...it would barley idle and sputter and choke till about 3g rpm then it would take off like a bat outta ****....didnt catch it till i threw a rod going about 130mph and had to dissasemble the engine....sounds like you have a similar problem...but it takes a while to remove the manifolds, so i would ask you friend if he replaced it, and if so did it run bad afterwards.....the other thing you might check useing a big screw driver is listen to you injectors....put it on the base and then put the handle right on the bump of your skull behind you ear...it will transfer the noise great....listen for any irregular injectors...you should hear the tick tick tick....if one soundes different pull it off clean it and test it outside the car....good luck

jon
 

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sorry I havent read your posts so I'm not up to speed on your progress...
Are you sure your timing is right? could the other owner have put the distributor in 180 off??
Just a suggestion....

Z ya later
Mike K
 

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Also check for intake air leaks particularly between the AFM and the head. check the intake boots and injector o-rings . . One easy way is to grab some WD40 and spray it all over the boots and such with the engine running . Listen to the idle. if it rises then you just found a leak. amount of rise indicates severity of leak . I found a boot on one car that only opened up under load. almost impossible to find any other way. Also works great for finding vacuum hose leaks.
Luck
 

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first you will probably need a new air mass meter. the gear and spring of which you speak controlls the flap opening speed, which in turn controlls at what rpm and how much fuel the engine gets. the factory and rebuilders are the only people I know who would have the proper equipment to set it. the original problem of rich running was probably the water temp sensor it is the two wire sensor next to the thermotime switch. make sure the connectors are hooked up right -- white connector to water temp sensor brown to thermotime. check the other end of the harness as they can be switched. if there is any corrousion on the harness replace it, it is one of the few subharness available.
 

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IMHO, you are doing it backwards.

I think it is fantastic that you got the car for free, but the very first thing you should have spent money on was a Factory Service Manual.

I will agree with changing plugs, wires, distributor cap and rotor. They would be items I would change on any used vehicle I just got regardless of having a Service Manual.

What Accel coil did you get? 12 volt? 7 volt?

Of the other items that you changed how did you test them?

$70.00 US for a FSM has to be cheaper than a Cold Start Valve especially if there was nothing wrong with it.

Most people that have played with the AFM without a FSM or lots of experience usually end up destroying it. Even a used AFM usually costs more than a FSM.

Sorry if I sound negitive, but, I hate to see people throw money away.

Wayne Monteath
Masham, Quebec.
 
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