# Engine Problems



## whis5555 (Jun 2, 2004)

Hey all,
I have a detonation problem. I had the problem before but I advanced the timing and that seemed to fix it. It would detonate only after it had reach operatating tempature and only above 2000 rpm. It took about 10 min for it to start detonating. Now it takes 30 min and only detonates at 2500 rpm. I advanced it about 1 degree. I run regular fuel.

Thanks


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## Zen31ZR (Mar 24, 2004)

whis5555 said:


> Hey all,
> I have a detonation problem. I had the problem before but I advanced the timing and that seemed to fix it. It would detonate only after it had reach operatating tempature and only above 2000 rpm. It took about 10 min for it to start detonating. Now it takes 30 min and only detonates at 2500 rpm. I advanced it about 1 degree. I run regular fuel.
> 
> Thanks


Usually advancing timing _increases_ risk of detonation.....


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## asleepz (Feb 24, 2004)

Do you have a turbo or NA


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## whis5555 (Jun 2, 2004)

NA

Maybe I did do deadvance it(can't think of the word for it)
I know I made the spark go off later in the cycle than it was before.


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## '85 fairlady (May 1, 2004)

do yourself a favor and get a hanes repair manual if you dont all ready have one


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## Marc Z31 (Jul 25, 2004)

retard the timing and run premium fuel.


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## whis5555 (Jun 2, 2004)

Have the service manual and another book on the Z, have scoured it many times. No clues has to what is happening. 

Thanks for the help


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## Zen31ZR (Mar 24, 2004)

whis5555 said:


> NA
> 
> Maybe I did do deadvance it(can't think of the word for it)
> I know I made the spark go off later in the cycle than it was before.



"Retard" is the word you are looking for. I'm not being a smartass , _retard_ is the opposite of _advance_. And yes , thats seems to be what you did.


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## asleepz (Feb 24, 2004)

ahhh come on just tell him the truth don't lie and make it a technical term :fluffy:


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## whis5555 (Jun 2, 2004)

ROFL!!!!

Okay, I retarded the timing all the way, got there in one degree increments, and still no luck. Time to try the better fuel.....


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## Zen31ZR (Mar 24, 2004)

whis5555 said:


> ROFL!!!!
> 
> Okay, I retarded the timing all the way, got there in one degree increments, and still no luck. Time to try the better fuel.....


What octane fuel are you using right now?


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## nispulsar (Mar 6, 2004)

I would try to use higher octane gas, and see how that goes for you. And make sure that your engine is running at the proper opperating temp, and not to high. If your car is too hot it can detonate.

Maybe you are running rich and the extra fuel in the cylinders might be detonating. 

The other thing is that maybe you have the wrong spark plugs in your car with the wrong heat range.


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## Zen31ZR (Mar 24, 2004)

nispulsar said:


> I would try to use higher octane gas, and see how that goes for you. And make sure that your engine is running at the proper opperating temp, and not to high. If your car is too hot it can detonate.
> 
> Maybe you are running rich and the extra fuel in the cylinders might be detonating.
> 
> The other thing is that maybe you have the wrong spark plugs in your car with the wrong heat range.



A rich knock would also create tons of black smoke out of the exhaust.


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## ♣300zx♣ (Aug 6, 2004)

*Timing*

Sounds like you timing advance control is bad, so its not adjusting your timing for a cold engine-to a warm engine-.


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