78 burning too rich, cant seem to get grey smoke t

h1shutterbug · Jan 19, 2003

ive got a 78 280 that screams like a cat when it's right. from the beginning i had fuel probs so i replaced a bad fuel tank and it ran good for a while. when it started running bad again, i replaced the afm and same thing, ran good for a while.
compression good in all cyl's. plenty of fuel coming although i have not put a pressure guage on it. lately it has fouled the plugs with regularity. replace them, tinker with the afm and it runs fairly good but still grey smokes. seems like it loads up on fuel and just gets worse and does the same thing.
is this simply needing to replace the injectors? seems if i'm getting that much fuel they are putting it out.
someone said maybe move the cam over to -2?
any ideas??? could it be the ecu is bad? my mechanic has basically quit and is 80 miles away so im looking to try to fix it myself.
any comments would be appreciated

zaddict · Jan 19, 2003

Re: 78 burning too rich, cant seem to get grey smo

try changing the fuel pressure regulator. two of my 78's had the same problem recently and that fixed the problem. And gas milage has noticebly improved. Hope this helps.

Long Live the Z

h1shutterbug · Jan 19, 2003

Re: 78 burning too rich, cant seem to get grey smo

zaddict, thanks, im gonna try, the fuel mileage, of course, has been horrible.

zaddict · Jan 19, 2003

Re: 78 burning too rich, cant seem to get grey smo

hey man one more thing, be sure and use NGK spark plugs too.

Long Live the Z

wolf88 · Jan 19, 2003

Re: 78 burning too rich, cant seem to get grey smo

clean all your sensor connections/grounds----head temp sensor and especially your coolant temp sensor by the thermostat housing--------mine was dirty and was litterally flooding the engine.----its too way too early to replace inj. and i wouldnt jack with the cam at all.--youre problem is somthing else.are you getting good spark?why is it grey if its running rich?
what does "tinker" with the afm mean????? you replaced the tank because of not eneogh fuel correct and the afm because of to much fuel right?(2 diff demons)...now you have to much fuel again.are you sure youre afm is good?

slightly_imperfect15 · Jan 19, 2003

Re: 78 burning too rich, cant seem to get grey smo

start by checking with a ohm meter from the connecter to the ECU the following.
Cylinder Head Temp sensor- (temp senor 2)
Air temp sensor (temp 1)
Air flow meter
Cold Start valve
altitude sensor if equiped.
Throttle position switch (TPS)
Check fuel pressure
before replacing the FPR check it with a fuel pressure guage...otherwise you may end up wasting $45.

A good way to start on this is to get a Factory service manual on cd...I can get you part of a 78 manual under the understanding that you will purchase a manual as i do not wish to prevent any of these great supplers that we have from getting business. The price for a manual on cd i believe is $15.

e-mail me at benjlv@chartermi.net if you would like to do this.

78 burning too rich, cant seem to get grey smoke t

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