Foxy Green Foxbody Build

Was tuning a car today, customer wants it to run 14.6 A/F at part throttle. Well, the engine wanted no part of that, so 13.5 A/F it is. Have to listen to and feel what the engine wants, can't force it to do what it doesn't want to, unless you want it tun run like a turd. Performance cams rarely like to be run on the lean side.
 
Mike Beck said:
Was tuning a car today, customer wants it to run 14.6 A/F at part throttle. Well, the engine wanted no part of that, so 13.5 A/F it is. Have to listen to and feel what the engine wants, can't force it to do what it doesn't want to, unless you want it tun run like a turd. Performance cams rarely like to be run on the lean side.
Click to expand...

I don't really care what the gauge says at this point. But a spike to 18 afr, sounding bubbly, and running like shit, you don't need an automotive degree to know it ain't right.

ATM still wants me to set my idle afr to 12.5 and see if the lean spot disappears
 
89 Fox 427 said:
I don't really care what the gauge says at this point. But a spike to 18 afr, sounding bubbly, and running like shit, you don't need an automotive degree to know it ain't right.

ATM still wants me to set my idle afr to 12.5 and see if the lean spot disappears
Click to expand...

What's your idle AFR currently? It definitely needs to be on the fat side of 14.7.

Just an FYI but with a decent cam, idle AFR won't necessarily be accurate. AFR gauge reads oxygen and any form of misfire or incomplete burn will show as being leaner than it is because even though there is a bunch of unburnt fuel there's also the oxygen that wasn't all used. This is one reason they say to aim for a richer AFR, the other is that with a bit of cam overlap you won't get a complete charge of fuel/air at idle and the extra fuel gives it a better chance of lighting off. This also gives you a more consistent idle speed.
 
hq308 said:
What's your idle AFR currently? It definitely needs to be on the fat side of 14.7.

Just an FYI but with a decent cam, idle AFR won't necessarily be accurate. AFR gauge reads oxygen and any form of misfire or incomplete burn will show as being leaner than it is because even though there is a bunch of unburnt fuel there's also the oxygen that wasn't all used. This is one reason they say to aim for a richer AFR, the other is that with a bit of cam overlap you won't get a complete charge of fuel/air at idle and the extra fuel gives it a better chance of lighting off. This also gives you a more consistent idle speed.
Click to expand...
Many people do not understand that. Hell, I see so many people that think with a laptop and a wideband they can tune any EFI engine. I just walk-away, let them burn and learn.............

A performance cam will always look leaner at idle then it truly is inside the combustion chambers. Just give the engine what it wants.
 
Pippin has a diagnosis.

Copper storage disease.

She'll be on steroids for a bit, and penacillamine for life. She may or may not tolerate the drug well. Not the worst news, but really don't know the prognosis, as it varies greatly. Hug your pups. Or cats. Or raccoons, whatever ya got.

She needs to be on a special diet, which will be the hardest part.
 
89 Fox 427 said:
Pippin has a diagnosis.

Copper storage disease.

She'll be on steroids for a bit, and penacillamine for life. She may or may not tolerate the drug well. Not the worst news, but really don't know the prognosis, as it varies greatly. Hug your pups. Or cats. Or raccoons, whatever ya got.

She needs to be on a special diet, which will be the hardest part.
Click to expand...

I see what you did there
 
Mike Beck said:
And it begins................. Kid doesn't know what he's getting himself into. Good for mom! :)

Hey, now that we are done with Iran (I think) maybe silver and gold will start to surge again. If silver gets to $200 an ounce, and I expect it will before year end, I know someone that can sell some stuff and convert to EFI............... ;)
Click to expand...

A guy on Fox Business said he expects gold to be 5500 by the end of the year. 🚀
 
Mike Beck said:
I have a really old timing light from Sears, works great. I bought another light from Horror Freight, it matches the Sears light. I don't use the dial-back lights, I know they can be an issue with multiple spark ignition systems, besides, all my engines have ATI balancers which are degreed 360* so no need for that type of light.
Click to expand...

Years ago MSD or somebody said one of the best timing lights was a specific Craftsman, which by dumb luck was what I bought as a youth.
I still have it, tomorrow I'll go out and see if it's the same one you have.
 
89 Fox 427 said:
Pippin has a diagnosis.

Copper storage disease.

She'll be on steroids for a bit, and penacillamine for life. She may or may not tolerate the drug well. Not the worst news, but really don't know the prognosis, as it varies greatly. Hug your pups. Or cats. Or raccoons, whatever ya got.

She needs to be on a special diet, which will be the hardest part.
Click to expand...

At least you know the culprit now. Good luck, Dickless! :thumbup:
 
Backed out the mixture screws to 1.5 turns out in front, 3/4 rear, and the fucker was idling at 10.5 to 11 afr.

11.5 to 12 when warm.

Rich in almost all conditions on the throttle

Lean spot is better but not gone at cruise.

Plugs are either speckled, or have oil spots on them. Am I crazy?20260619_160417.jpg
 
My opinion you really can't get a good read on the plugs in the short times your driving it it need good long real life driving and see what plugs are doing .then I a feel your relying on the afr guage to much .I feel your close but the sound and throttle respons of the engine will tell you what it wants.
You built a race car to drive on the street you need to take the nasty street habbits for what they are .
Like driving a car with very radical cam and 3500 stall convertor on the street it just dont do well
 
Well not celebrating yet. Pretty sure my pistons are falling apart in there. Doesn't look like carbon to me



 
You must log in or register to reply here.
Back
Top