mjshira

that is a good point. I can try that.

mjshira

I appreciate what you are saying. But I CAN NOT understand this being the case if the car pings, and trust me, she does!

MisterRisky

I'm speaking out of ignorance here, but might this be an issue of the computer not advancing/retarding timing properly?

I guess, as mentioned earlier, you should calibrate your sensor to ensure it really is lean... it could be pinging for other reasons and you could spend a lot of time under the assumption it is too much air causing it.

sperki11

I agree with JD on the timing issue and looking for other reasons. From what little I know, I don't think "pinging" is caused by incorrect a/f mixture (except maybe in an extreme lean condition). If the problem is ping (detonation issue), probable causes are improper fuel octane rating, advanced timing, or higher than normal compression. Experts?

fast951

The safest way is to use a smoke machine, more than likely you don't have one.
You can pressurize the intake system, it's fairly simple. Remove the AFM, connect some sort of a canister with a vacuum fitting on it to the rubber boot/elbow, use compressed air 10-20psi and listen for leaks. If you have a old fuel filter, cut one end off, and install it where the AFM goes. The Fuel filter can be made to accept a hose for the pressurized air.

fast951

Running 15AFR under load between 4000-5000RPM is not good. This may be causing it to knock. However there might be other issues as well.

Ignition can also cause knock.The ignition is handled by the chip, and he's using the factory chip! I would think the CR must be higher than stock for knock to happen or there is a mechanical issue(s).

I would fix the AFR first. Then if there is knock, it's time to start looking at other possible causes.

MisterRisky

Thanks for your input here John. Always good to have input from someone who speaks from experience not just theory.

fast951

My pleasure, tnank you.


James, set the FQS to position #6. (#0 is all of the way counterclockwise), #1 is one click to the right...
#7 is all of the way to the right (clockwise). #6 is one click counterclockwise from #7.

#6 should richen the mixture and will pull timing as well. I would operate in this mode while testing, for added safety.

Keep in mind I reprogram the FQS differently, so the above FQS settings do not apply to the chip I'm sending you.

Have fun.

mjshira

Thanks John.

I've got a lot of work to do.

It is important to understand that the DME is new, the AFM is new, the ICV is new, the fuel pump is new, the fuel filter is new, the chip is stock, so I am really lost here. With this thread I am better positioned to start to look for the cause. I am going to check fuel pressure. Just need to order the kit to do that as pepboys (best local option here) didn't have one that would work. Great being in BFE.

deoxford

This sounds like a distributer issue, maybe it is not retarding as the computer calls for it.

mjshira

How is this possible? Is there someone that rebuild the dizzy?

slammed1000

derek, with the bosch hammer hooked up the timing advanced and retarded within the set limits. i think it is a vaccum issue or the fpr bad..
just wish i had more tme to help...

for all interested the higher the a/f number the leaner....the lower the richer.
motorcycles that i tune is optimized around 12.5-12.8. the leaner they are the moe power they make but you also run the risk of detonation.

mjshira

Thanks Brent, I appreciate the post and your help. The silver lining of all this is that I get to learn more with each project. I forgot about our testing with the hammer, we did see the timing across the hammer function properly.

jneteler

That is not quite correct. There is an ideal mixture to produce peak power and it can be approached from either the rich or lean side of the mixture curve.

The best info I have come across comes that other domain of air cooled engines - general aviation.

Goto www.gami.com and then click on the "Lean Test" button. Near the bottom of the page there is a graph that depicts mixture vs. power vs. fuel consumption.

Regards,

JNeteler

mjshira

I think it is hard to compare these two scenarios. Consider the impact of altitude on air density for example.