Just brought the car home. just put on brand new random tech high flow cats and havn't tuned it yet. have had some basic help setting the car up so it will idle good and is driveable. When I got home i noticed under the car that the cats were glowing orange !!

Car has a gen 7 DFI, stock ecm removed. I have no tuning experience and am clueless. Willing to learn but i dont have the slightest clue where to begin. I plugged in the laptop and on the display screen that shows the rpm guage and basic #s the a/f is showing 10. I went to some other settings and i remember seeing 14.7:1 as target. I went to fuel curves and it shows the 14.7 basically throughout most of the slots in the table.

Anyone offer me some sort of idea where to begin? I plan on ordering a wideband o2 from accel tommorow but want to drive the car and at least have the a/f in a safe zone while everything is broken in (alignment, suspension, gears, tranny, clutch etc etc). I don't plan on beating on the car until everything is broken in and reset (shaft rockers) and rechecked with all fluids changed. Then with a wideband We plan on going to a dyno and letting her fly.

Any help is appreciated... Im so frustrated because i don't know where to begin

 

what kind of car is this?

 

sorry! 93 corvette. Solid roller 388 ci LT4. I just have 1 heated o2 sensor in the drivers side header collector, and it is before the cat. Is there anything i can look for specifically on the dfi display if it is running rich.. or even lean?

 

I'm really sorry, man, I'm unfamiliar with your set-up. But I'm sure someone else will be along shortly. Good luck.

 

Make sure the Exhaust Feedback Sensor Switch on the Controls Configuration Screen is set to HEGO (Standard). The display on the main screen should be reading HEGO Voltage between 0 and 1, not O2 Air:Fuel Ratio if you don't have a wideband on it yet.

It sounds like you have your ECM set to the wrong sensor type. The ECM is reading the (lower) voltage from the HEGO sensor as a very rich condition, causing you to run very lean -- as shown by your glowing exhaust parts.

 

thanks DFIguy ! Im going to take a look at that right now (just woke up ). I'll snap a pic of the main screen and post her up maybe you or someone might notice something.

 

Here's some pics i took from cold start to a few minutes of idling. AFter 3 mins of idling the cats do start to glow a bit and i shut her off.

First a pic of a plug i pulled.



The header tubes right at the first bend show signs of the ceramic coating birning off. I think that and the plug which is a little white shows something is a little hotter than it should be ?

Heres a startup display, Open loop


Display after 2 mins of idleing


Other things i wanted to add that i noticed while i could (wanted to shut the car of soon as i saw the cats get too hot).

At startup theres the smell that was there without cats, and my eyes were stinging.

HEGO voltage is going from .2-.7

02 square shows readings varying very fast from -0.06 up to 1 and everything in between

Timing is moving fast from 11-18 degrees (display on main page)

DFIguy- here's a pic of the 02 page i pulled up. I'm clueless what o2 type (1 or 2) means.



Some more engine details... Have an adjustable fuel pressure reg. pressure set initially at 40 psi. I tried 44 and down to 38 but no change. Again im only judging change on wether the cats are glowing Seemed to run the same. Im not too sure but when i cranked the fuel pressure up to 44 lbs and before i set the dfi injector pressure square i think the cats stopped glowing. I should recheck this but i realize i shouldn't be judging the cars tune by that so i didnt bother trying it again.

Running custom fuel rails to the regulator, returnless system with Siemens #60 injectors. I do realize that most people freak when they see #60 but many tuners seem to have success with these injectors including Lingenfelter (able to act just as good as small injectors). We wanted #42 but decided on these since they were reccomended by racetronix.

Solid roller LT4 guesstimating to be 400rwhp + easy and built to rev safely to 7800 rpm (cam peak probably around 6.5-7k). Im being conservative so i don't dissapoint myself Motor has every single goodie and more. This was a fully forged/lightweight no expense spared project that has taken me 4 years to complete.

Any help is appreciated. if anyone is a tuner and doesn't mind spending a little time with me to go over tables or settings over the phone i would appreciate it and don't mind paying for your time at all. At this point im scared of driving the car to the alignment shop and even to the dyno (good 20 min drive ) in fears of burning my car down or destroying the brand new Random tech mettalic high-flow cats.
(lol some of these toons are awesome !)

 

I spoke to someone who tunes and the first thing they said is the timing needs to be in the 22-27 range. Mine was way way lower. I went to the base ignition table and sure enough the numbers in the first 1/4 were all from 10-16. I went and started from 26 from the top down to 23 in the first couple of rows. Sure enough after an hour of idleing the cats weren't glowing ! Unfortunately it wasn't long lasting as about 10 minutes after that of idleing the passenger side cat did start to glow a bit so i shut her off The timing is now staying from 21-25 ish. The o2 however is showing readings from -8 to -10 . On the closed loop correction meter its hovering around -8 .

 

email me direct at Lcvette1@aol.com.. tried responding to ya but it was returned from the provided emaila nd corvette forum says you are checked as not wanting to receive emails..

Chris

 

yikes, must have checked it by mistake ! Thanks Chris I'll email ya.

 

Glad to see you got it (somewhat) figured out... here are some quick answers to your questions:

Type 1 or Type 2 refers to model of DFI wideband. If you buy a new one, it'll be a Type 2. Newer software has the ability to set it for a generic input that can be supplied by 3rd party controllers.

Timing moving around at idle is normal; it's used to control the idle speed. See Ignition Menu -> Steady State -> Idle Spark Control for details on that.

HEGO voltage will move around at idle, it should become steady at higher RPMs. Your target A:F ratio of 14.7:1 equates to about 0.45 volts. You should see the voltage average about that value.

The increase in O2 correction is ok. If you want to lower it, just take some fuel out of the VE table (lower the VE numbers) in the idle region and you'll see it decrease.

You may want to take a look at the Base Timing Map that is in the sample calibration file (should have been installed with your software). If your table differs significantly from that, you may be better off copying some timing values from that table into the same MAP/RPM locations on your map.

 

thanks dfiguy. I have no clue where the base sample timing maps are but im going to start looking for them. At least this way I'll have something to compare it to.

 

Launch CalMap, Click the OFFLINE FROM FILE button. When asked for a calibration to edit, select "sample_v0x0.ecm", where x is a number depending on the version CalMap that you are using. Once you are on the main screen with the gauges, press the F3 key. This will get you to the base timing map of the sample calibration file. The whole file is based off of a small block chevy. Nearly every table in it is a pretty good example of how a calibration should look.

 

Thats neat ! I found the file and the numbers sure are way off from those that I currently have running. In the config setup If i change all the settings for cr, injector size fuel pressure etc will this have an effect on all of the numbers?

Im wondering if i plug these in the car might at least run better.

 

If you use that file, tweak the parameters to match what you have, and create new VE table using the utility in Fuel Menu -> Utilities -> VE Predictor, you should be in the ballpark.

The VE Predictor will make you a VE (Main Fuel Modeling) table that will be a little rich, but good enough to safely run the engine. You'd then want to fine tune the VE table so that you are actually running at the Air:Fuel ratio that you have specified in your Target Air to Fuel Ratio table. A wideband O2 sensor will make that much easier to accomplish.

 

I hate to ask a million questions but thats a start. So i tweak the VE to get the a/f ratio that i targeted? Is this even worth trying or impossible to do with a narrow band? My best guess is tweak it until the closed loop correction is near zero, would that mean im close to target and its not needing to correct too much ?

 

Correct. You can adjust the VE numbers until closed loop correction as as low as you can get it. However, with a narrowband sensor, you can only really accurately target A:F ratios right around 14.7:1. The ECM will force open loop operation with no correction once your targeted A:F ratio gets outside of +/- 0.5 AFR from 14.7:1 anyway.