Running Rich after Chip Install ??

I recently installed a HyperTech Chip in my 89 5.0.

It made a noticeable difference and the throttle response is a lot snappier.

I've noticed now that the tailpipes are "sooty" and the exhaust smells "rich" pungent actually.

Is there anything (short of reprogramming the Chip) I can do to lean it out a bit ?

Reply to
Katmandu
Loading thread data ...

Sounds like a 302 without cat converters.

Are you *sure* you want to do this? Do you have cat converters? You could do things like tweak sensors and/or lower the fuel rail pressure, I suppose, but why? Are you frying a cat converter?

Dana

Reply to
Dana H. Myers

That's the point. That's part of the upgrade. To quote a old drag racer I know after riding in my car, "Yeah it is fast, just watch out for those F Bodys you see with the carbon around the pipes from running ritch..."

Reply to
WindsorFox[SS]

Running rich actually lowers power output. A leaner mixture will make more power (to a point), but with more power comes more heat. A rich mixture also aids in cooling the charge. I'd get the car on a dyno that has wideband O2 measurement and check the AF ratio across the rpm band. If it's too fat, send the chip and the data from the dyno to a reputable programmer and have them reprogram the fuel tables.

Reply to
Keith

Well I guess that obviously Hyper-Tech and all the cars I see at the track are completely wrong and you are correct. I'll bee sure to tell them next time I'm there. All of These guys have run on a dyno as well...

Reply to
WindsorFox[SS]

Yea, it's got a 2.5" O/R H-pipe on it. No Cats of course. What would NO Cats have to do with it running rich though ???

Still has the O2 sensors installed in the H-pipe though.

ERIC

89 5.0 LX Vert, Cobra long block, 2.5" O/R H-pipe, 2.73s w/Locker 40 Series Deltas and some kinda Wild Assed Cam!

Check out the Ford Engine Heaven!

formatting link

Reply to
Katmandu

What are you talking about? HyperTech ( a less than stellar chip, BTW) programs their chips to provide a rich fuel table? It's basic chemistry. The stoichiometry dictates 14.7:1 is the exact proportion of air to fuel, but in reality the AF will never be there exactly. The closer you get to it, the more power you'll make. Too much fuel and there's no oxygen to consume it. The extra fuel absorbs heat and passes to the exhaust. What's this give you? Less power. Some of this is good because without it the cylinder temps will crawl too high, at which point detonation ensues and pistons/rings tend to break. Too much fuel is not as good. A rich condition indicates you're running too far on the not-so-good side of the equation. If you go from the factory (good and safe, but room for improvement) fuel table to a more rich mixture, you'll lose power. To make more power, the chip programmers lean out the fuel table so it's closer to the 14.7:1 magic number. FWIW, those aftermarket MAFs that advertise mucho power by just swapping in their meter? They make power the same way. They fool the computer into thinking there is less air coming in than there actually is, so the computer puts in less fuel. Less fuel gives a leaner AF, and makes ... you guessed it ... more power. Problem is that sometimes they push it too lean and engine damage ensues. I've seen people in the forums who've done it.

BTW...why the bad attitude?

Reply to
Keith

You wouldn't be able to smell the rich exhaust if you had a cat, and it would likely run pretty hot and possibly fry. Since you have no cat, running a little rich is probably giving you the best power over-all. I still don't know why you want to lean it out; without looking at it myself, it sounds like it's running pretty well. What color are your plug electrodes?

Right - there are probably being ignored by your new chip ;-)

>
Reply to
Dana H. Myers

Running *too* rich lowers power output, sure. But running a perfect stoichiometric mixture, not too rich or lean, generally doesn't yield best power either. Slight on the rich side of perfect stoichiometric is where best power is made and it's not clear we're past that. I suppose we're quibbling over the definition of "rich" here.

Excellent advice. Get an objective measurement.

Dana

Reply to
Dana H. Myers

There's a pretty good chance that Keith isn't disagreeing. Too rich is a problem. Slightly rich past a "perfect" mixture where there's just enough gasoline to consume the available oxygen gives best power. That's why closed-loop systems ignore the O2 sensor under hard acceleration and run a little rich, but observe the O2 sensor to run stoichiometric at cruise for best fuel efficiency (as well as HC emissions).

Dana

Reply to
Dana H. Myers

Roger that.

I haven't pulled the plugs yet, but I bet they are carbon coated.

Reply to
Katmandu

I bought the Hypertech from a buddy for $100. Couldn't pass on the price.

Who does reburns CHEAPLY ?

BTW, my car still has the OEM 55mm MAF. Maybe the chip was burned for a larger unit at some point in time ??

Maybe I could try a larger 70mm MAF and see what that does ? Anyone have a

70mm MAF for cheap ?? :>)

ERIC

89 5.0 LX Vert, Cobra long block, 2.5" O/R H-pipe, 2.73s w/Locker 40 Series Deltas and some kinda Wild Assed Cam!

Check out the Ford Engine Heaven!

formatting link

Reply to
Katmandu

I haven't driven my 5.0 for several days and decided to drive it to work last night.

This AM the Temperature was in the mid 50s and the Humidity was pretty High.

It felt like there was another 50HP under the hood! Thing was responsive as hell and the Torque was never ending (so it seemed)!

Do you thing the weather conditions help "Lean" out the fuel mixture a bit ?? Do to the denser atmosphere ??

Reply to
Katmandu

I dunno. I can't really intuit much more. It sounds like you plugged in a chip that doesn't match your engine configuration (even if it was cheap, it's not cheap if it's not right :-) ). Higher humidity actually reduces available O2 but a lower temp is does increase available O2. So I just don't know.

Like another poster mentioned, stop guessing and take it to a shop where you can measure your air/fuel on a dyno and see what's up. Otherwise, put the stock chip back in.

Dana

Reply to
Dana H. Myers

Reply to
Michael Johnson, PE

Actually, running at 14.7:1 lowers power output at WOT conditions. It seems most tuners like about a 13:1 AFR for N/A engines. The stock programing in the EEC has the tables set to under 13:1 under high load and WOT conditions. I'm not sure why this is so, maybe at high rpm's the fuel doesn't have enough time to burn at an AFR of 14.7:1 and richening up the mixture corrects for this condition.

Reply to
Michael Johnson, PE

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.