running rich

gorgo · Post by **gorgo** » Tue Dec 16, 2008 1:20 pm

ok here goes. i had to pull my trans because of a leak. because my exhaust is so tight it just works better to remove the exhaust (cut). well here is the problem looking into the exhaust it is just black with carbon. my milage is about 10-12. i have 3:73 and at 70-75 you can watch the gas gauge move. i know the truck weights 4600 lbs. it is a 4x4 long box.
am i wanting to much to have better milage? im not throwing any codes up. i still cant hookup my idle control without the engine going to about 3000. still cant find out what is causing this. short of data logging i dont know how to find the reason for the poor milage. any ideas. im just about ready to go carbed and get it over with.

MalcolmV8 · Post by **MalcolmV8** » Tue Dec 16, 2008 1:37 pm

What are the gear ratios like in a C4? I'm not familiar, do you have O/D with it? I thought the C4 was a three speed? I have a similar setup, 94 4x4 ext. cab, regular 6 foot bed. I have a 2000 Explorer motor, A9P. I'm running a full time AWD t-case though and I'm using the 4r70w which keeps rpms around 1900 at 70mph. I also have 3:73 gears. So if you're seeing 12 mpg and I'm seeing 15 mpg right now we're not to far off. Depending on the differences between the C4 and the 4r70w that might make it up.

In the summer instead of 15ish mpg I'll see around 16 to 17 and at times (although very rare) I'll see 18. My most common is 15. Sometimes in the heavy winter snow and very very cold temps I'll see 13 or 14.

BTW - I didn't realize these trucks were that heavy. 4600 lbs?

gorgo · Post by **gorgo** » Tue Dec 16, 2008 1:54 pm

the c4 is 3 speed and third is 1 to 1. the 4r70w i think is .64 to 1 in od. i was suprised at the weight. i went to the dump last year and on the weigh out there was a 88 short box 2 wheel ranger in front of me and he weighed out at about 2800. when i got on the scales it was a little over 4300. what was with my lard butt and my dog. that was before i did the conversion to the 302. your blue truck is about the same as mine except it is a short box extended cab. mines std cab long box.

plowboy34 · Post by **plowboy34** » Tue Dec 16, 2008 10:45 pm

With 3:73 gears an a C4 I wouldn't expect much better than 12. I have a 77 Stang with C4 and 3:00 gears and get 15 tops.

87ranger · Post by **87ranger** » Wed Dec 17, 2008 6:54 am

i know im gonna buck the trend a little but im gonna advise you to buy an aem standalone wideband o2 guage and weld a bung in the exhaust and see what your actuall o2 ratio is you might be running rich or your truck is just a heavy slug then you have the aem that you can use for diagnostic purposes in other vehicles if you wish. they are reasonably priced and are a two wire hookup and come with everything you need

MalcolmV8 · Post by **MalcolmV8** » Wed Dec 17, 2008 9:27 am

I second that. I'll be purchasing a wideband in the near future myself. I plan on doing some tuning on the cobra and figured it would be nice to check my truck out too while I'm at it and see how it's running.

cgrey8 · Post by **cgrey8** » Wed Dec 17, 2008 12:42 pm

AEMs are good. I can't say a whole lot negative about them.

However the Innovate LC-1s are probably the most affordable. I got my LC-1 off eBay for $160 brand new. I think they are up in the $180s now. When looking for WBs on eBay or anywhere else, you want to make sure you are getting the WB controller as well as the WB sensor itself. Some companies, like Innovate, sell them as kits OR separately. So for instance if you do an eBay search for LC-1 and find some kits cheaper than others, make sure the description includes the sensor itself.

The Innovate LC-1 kits come with the WB controller, the sensor, a bung, a bung plug to block the bung when you have the sensor removed from the vehicle, serial cable, software to load onto a laptop, a feedback LED, and a switch to do manual calibrations of the sensor. The sensors will need calibration every few months which consists of removing them from the bung and letting them hang in open air for a few minutes with power to the controller. After the sensor has heated up (20-60 seconds), then you push a calibration button which forces an open-air calibration of the sensor. Once the LED indicates the calibration is complete, you can kill power and reinstall the sensor back in the exhaust pipe.

Innovate LC-1s also have 2 analog outputs, a feature that doesn't seem to be the norm amongst WB controllers. This allows you to run 1 output to an AFR meter that you install in your dash so you can see AFRs while you drive. The other output, you can run to a datalogger or what some people do is use it in its default setting which is as a HEGO emulator. As a HEGO emulator, you can remove one of your existing HEGOs and install the WB sensor in an existing HEGO bung. Then wire the computer to the HEGO-emulated analog output. I've never tried this, but I don't recommend that. For me, the stock HEGOs seem more responsive than my WB sensor. The WB seems to get saturated sometimes and take a moment to stabilize immediately after a large swing in AFR (i.e. returning to Closed Loop from a rich WOT or from open-air Decel Fuel Shutoff). Perhaps that's a side effect of my LC-1? Or maybe its a characteristic of where, in my exhaust pipe, the WB is located? Although I've heard similar reports from others that use a WB and actually pay attention to how the WB reacts compared to their datalogged HEGOs.

The only thing negative I can say specifically about the Innovate LC-1 is the update rate over the serial connection is a tad slow for my taste. But then again, I'm used to the update rate of the TwEECer which can update about once every 50ms. The LC-1 is on the order of once every 200ms...maybe a tad faster. That's still multiple times a second and is still a useful update rate, but just not as fast as I'd like. Fortunately the analog outputs are MUCH faster. So if you want to datalog one of the AOs from a DataQ A/D converter, you can get much faster updates from the WB. It would be nice if Innovate sold an affordable USB-based WB controller. Currently if your laptop doesn't have an RS-232 serial connection, you have to connect the LC-1 to the laptop via a USB-to-232 adapter.

And finally, you never leave a WB installed in an exhaust system without the controller powering it. Unlike stock HEGOs, WB sensors are active samplers and their heater gets about twice as hot as a normal HEGO does so they can burn off any carbon particles before they can enter the sensor and clog it up. I've heard of people damaging their sensor in less than 10 minutes by not having it connected to the controller while running the engine. I bring this up so people don't plan on buying multiple WB sensors and moving the WB controller between vehicles as they need it. If the controller is removed, the WB should be removed as well.

gorgo · Post by **gorgo** » Wed Dec 17, 2008 3:36 pm

here is a thought. if my eec thinks that im at full throttle all the time it would run rich. that is if my tps is screwed up. this off the subject but it has been snowing for 2 days and in the teens here. rain i can deal with snow and really cold sucks. i work out side.

MalcolmV8 · Post by **MalcolmV8** » Wed Dec 17, 2008 9:14 pm

You can read TPS voltages with a digital volt meter (cheap and easy).
I hear you on the snow. We have about 6" of it right now and it's in the single digits.

MalcolmV8 · Post by **MalcolmV8** » Wed Dec 17, 2008 9:49 pm

Chris, I need to fix the knock in my Cobra's motor first. Either a new rod bearing (fingers crossed) or else a new long block. At that time I'll hit you up for some more info on the wide bands. There's also a ton of guys using them on the Cobra forums, I may see what they're using too.

Thanks
Malcolm

cgrey8 · Post by **cgrey8** » Thu Dec 18, 2008 6:40 am

AEM, PLX, Innovate LM-1 and LC-1 are the most common. There are a few others but I can't recall them at the moment.

There was a Ford Muscle review of various WBs a few years ago. The Innovate LC-1 came out on top, but there was a lot of criticism and controversy over their methods of testing that non-Innovate customers claim the test was BS. They even have a note about that at the top of the online article. Here's a link:
Air Fuel Meter Shootout!
Unless you are a subscriber, you may not be able to read the entire article.

The one thing I want to point out is every WB offering out there that I'm aware of uses the same Bosch LSU4.2 O2 sensor. The differences between the units are in the controller, not in the sensor.

87ranger · Post by **87ranger** » Thu Dec 18, 2008 7:06 am

well the nice part about the aem is its 200$ and it all in the kit and it has several outputs to interface with factory and aftermarker (0-5v) computers and it fits in a normal guage pod so it blends in with any other guages you might have and used versions are available from all the supra and honda guys that have stepped up to the aem computer and fjo setup, and no the ngk sensor that is offered as an option with most of them is more lead tolerante for the race gas users out there you just have to change your scaler in the program for specific voltage/airfuel output

cgrey8 · Post by **cgrey8** » Thu Dec 18, 2008 7:44 am

I found a link to someone that posted up the entire article without needing a subscription to the magazine to get it:
FordMuscle Wideband Shootout! PDF

gorgo · Post by **gorgo** » Fri Jan 30, 2009 8:55 am

it goes to show you its the little things that count. when i had the tranie out i noticed that there were some little biger than pin holes in the welding around the 02 bungs. while i had it apart i went ahead and welded them up. low and behold i am now getting around 14 mph versis less then 9 before. it must of been sucking air in and it being right at the sensors it was always reading too lean because of the added oxygen. my gauge for the 02 sensers is reading like i thought it should now.

MalcolmV8 · Post by **MalcolmV8** » Fri Jan 30, 2009 9:57 am

Very glad it was an easy fix. I noticed the same thing when my header gaskets would leak. Gas mileage goes south cause of all the air that gets sucked in there leaning out the readings on the O2 sensors.