91 camry crappy gas milage

i put a 2 1/4 inch exhaust with a magnaflo and a k&N Air filter i checked the o2 sensor and its fine iv retarded the timing to 7or8 degrees past tdc

Reply to
91camryjosh
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4 cil? Retarded timing reduces milage, power and cilinder temp It should be 10 btdc, T&E1 bridged a idle. 13-22 btdc T&E1 disconnected at idle. Retard 4 degrees power and milage will be bad and motor-plugs run colder. Try 11 btc but watch for nock and plug temp. You should get 4 mpg and alot more power at stock 10 btdc
Reply to
m Ransley

Retarding would be to go to 7 Btdc from 10 btdc. Advancing would be going from 7 to 10 Btdc. Advancing gives power-milage, to go further to

11 Btdc will make plugs hotter, more power and milage. But you have to watch for nock and a too hot a plug. To advanced-hot you melt, to advanced you get pre ignition. Way to advanced past the power curve you loose power , but I have no idea of the power curve, but it probably peaks at 14 idle for a wild guess. You can get a basic by seeing when rpm does not increase , if the computer will let you. Id just try 11 Btdc. 7 Btdc that you have, is killing your power-milage
Reply to
m Ransley

And you do mean you set timing to Before Tdc not Past as you said , I hope. That is Btdc, I never heard of Ptdc or you are way way off.

Reply to
m Ransley

Not sure if you made a typo and meant "7or8 degrees (b)tdc". If not then you have severely retarded the engine to the point it should have lost significant power.

The engine management computer relies on the base timing to be 10 degress BTDC (checked with diagnostic socket pins: Te1 and E1 connected together with a straightened paperclip or similar). If you move it away from that point,..then the comp is operating off a false reference (for timing changes) as the engine does not have a crankshaft angle sensor.

Jason

Reply to
Jason James

Even 2 degrees off I notice reduced power and milage with the 4

Reply to
m Ransley

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