Too Lean Help

[whiterabbit]

Just had my 1984 911 ROW dynoed, car drives great but is running too lean especially in the mid range. I have a SW chip that he will be re-programming but wondered if the readings I have are in normal parameters? The car does also have SSI's and a sport exhaust so maybe they have caused it to lean out this far.

[Steve@Rennsport]

If Steve made the chip without knowing about the SSI's and sport muffler, you WILL be too lean.

[whiterabbit]

No he knew about it and its the correct chip for my set up I think. The car was lean before the chip aswell. I am just wondering weather this AFR is considered slightly lean or way off. In other words will a chip reprogram be enough? Or is this just masking another problem?

The dyno company thought it was way too lean and could damage the engine.

[DRACO A5OG]

True too lean would be very bad for our engines.

Better to be rich then lean if worse of two evils.

If after you have Steve Tweek it out check out your AFM. DO a search I posted a thread about using the 944 Guys method of verifying the condition of our AFMs.
You want to check to make certain the voltage readings are consistent steady rise in voltage as you go WOT and do not spike or drop through out the Potentionmeter Travel/Range.

I bet Steve will fix it just right ;D

[whiterabbit]

Originally Posted by DRACO A5OG

True too lean would be very bad for our engines.

Better to be rich then lean if worse of two evils.

If after you have Steve Tweek it out check out your AFM. DO a search I posted a thread about using the 944 Guys method of verifying the condition of our AFMs.
You want to check to make certain the voltage readings are consistent and do not spike or drop through out the Potentionmeter Travel.

I bet Steve will fix it just right ;D

Hi thanks, yes I already did the AFM check/adjustment and it seems good however someone had tampered with it beforehand to pass emissions

I am sure Steve will get it right with the re-programme just wondered whether the car also had an underlying problem.

[DRACO A5OG]

I'm preparing to Dyno my car with Steve to optimize the chip programming and max out the HP potential.

Can't wait, got go save my pennies.

I wonder if Steve can do this remotely with those PC programs tha allow remote control of a PC? It will be like him being there. I'm going to talk to him right now.

[whiterabbit]

Originally Posted by DRACO A5OG

I'm preparing to Dyno my car with Steve to optimize the chip programming and max out the HP potential.

Can't wait, got go save my pennies.

Exactly the same as me

[DRACO A5OG]

Yes,

He does indeed does Remote Dyno Tuning.

[Steve W]

Yes, there is something seriously wrong with your car to go this lean, or the dyno's wideband is off. With the chip you got, you should be around 13.0 +/-., and will be much, much leaner with the stock chip. There's no way I would attempt a remap on the chip to bandaid the situation. If you can provide the dyno chart with the HP/torque #s, I can better determine the accuracy of the data.

[TimT]

The dyno company thought it was way too lean and could damage the engine.

You should also ask for a more informative dyno graph..

Yours is an a/f vs speed graph ... I suppose that is kind of useful... but you should get a graph with rpm and load (either manifold pressure or throttle opening) and a/f. We tune our EFI installs to totally cut fuel in certain operating conditions... i.e. closed throttle over run... then fuel comes back on with tip in.

The engine runs quite lean sometimes..

[whiterabbit]

Originally Posted by Steve W

Yes, there is something seriously wrong with your car to go this lean, or the dyno's wideband is off. With the chip you got, you should be around 13.0 +/-., and will be much, much leaner with the stock chip. There's no way I would attempt a remap on the chip to bandaid the situation. If you can provide the dyno chart with the HP/torque #s, I can better determine the accuracy of the data.

Thanks Steve I sent the graphs to you via email.