When starting cold, I get an instant stall and then I restart and work the peddle a little to get it to smooth out. I'm not sure how to go about fixing this. Would Datalogging in tunerpro while starting the car show me what is happening? Trying to get car running correctly after summer Mods... see signature.

 

Make a change, and note what it does, ie actually write it down.

Then try something else, again note what it does.

Try something else, yada yada.

Quickly you'll not trends forming.

Once you get an idea of at least doesn't work you can look for things that might.

There are so many things going on during crank, first run it's really hard to guess what you need. *Often*, adding a little *choke* fuel helps.

 

Because of a Cold start/open loop issue. I guess I should mess around with the "Temp" tables. like the Cold loop tables/PE tables/AE dacay/Lv8 AE Factor and Crank Fuel which are all relative to temp. Am I on the right track?

 

You need to try adding some afterstart enrichment found here:
Edit your .ecu to include:
Start Address 3ED
Rows 14 (columns and element size 1)
Multiplier of .39025
Deg C (Y-axis breakpoints) :
-40, -28, -16, -4, 8, 20, 32, 44, 56, 68, 80, 92, 104, 116
Most engines can run and start on as rich as 10:1 pretty easily, so I'd guess you're a little lean. Add this until it stays running. This fuel will decay out over a few seconds (10-40), and after that, it uses mainly the Open Loop % change vs Coolant temp.

Here's what I use (insert disclaimers here):

 

THANKS!!!

Posting what you are doing takes time and I appreciate you doing it. Unfortunately I do not have the Afterstart table you show. I am using TunerProRT and $6E code. I do notice that my Open loop tables are a lot lower than yours so maybe I will start tweaking those first.

 

I found this: AE decay Factor vs Coolant Temp

Which is probably similar to what you got.

 

I'm using $6E too. You have to edit the .ecu file. It's real easy with Tunerpro RT. The afterstart enrichment is actually in your code already, you just have to edit the .ecu to access it with Tunerpro RT.
First, in Tunerpro RT, open your bin and .ecu.
In the bottom left, in the area with all the names of the tables, right click once. A window will pop up, in which you can select "Insert New ECU Item."
Then type in numbers to match the following attached picture. Then use the pull down for the Y-axis labels to finish entering in the Temperature breakpoints for 11-14, as in my previous post.

I hope this helps. Also, there are many other things that aren't in the normally available .ecu files for $6E that are in $6E. The stuff is in the code in each ECU and the factory calibrated it and all, and it's all editable, you just have to change the viewing software to access it. I used the old $32 BUA hack to find interesting tables, then hunted through $6E to find the same calibrated values (but in different locations). Many parts of $32 and $6E use the same calibration, but they are located in different areas (but things were moved around in large chunks). Good luck. BTW, I'm in China (Nov - Feb), calibrating our new fuel injection computer for an OEM customer, and I need something to do in my spare time, so I'm glad to help.

 

As far as I know, AE Decay factor vs Ctemp is for Acceleration Enrichment decay. Accel Enrich is basically only a quick bit of fuel that is decayed out quickly, that is in effect when you press the throttle or change loads (LV8) quick enough. It's a fudge factor to make up for manifold wetness differences between different loads, and sensor lag to airflow changes. It only lasts for less than .5 seconds, and pretty much only effects throttle response, not actual acceleration up to speed (other than that first instant).

 

Wow China? I bet the food is terrible huh.. Anyway, I did the stuff you suggested and I didn't have any luck fixing the problem. The weird thing is I did not have the cold start problems right after I put the motor in. It was fine for a few weeks (had issues but not cold start). I now have to press the gas to start it cold or hot. The only thing that I have done to the car since this started happening is I put on a new MAF(for code 33 issue), TPS and IAC. I did that to see if I can improve idle quality, it was a little rough and it has a slight mis. Pulled the cap and tried to shimmy the rotor to see if there was any play (Distributor is stock from '87) because when I set the timing to 8degrees EST disconnected, the timing was jumping up and down a degree or two. The distributor did not have play. I can not rule out mechanical failure but I don't want to start swapping parts blind. Another thing I did today is change my ijector constant. I have 24lbers and have chip set to 25.5. I was seeing 124/110 on INT/BLM when datalogging at idle. I changed my constants to 29.5 and got a 124/128. then drove it around the block and datalogged again - got 130/116. Whats up with that? I am almost to the point of giving up. I put $7000 into car and now I am broke with a car that runs badly... Any insight on the issues I mention?

 

IIRC, both Grumpy and I went through this last winter. I thought I needed more fuel but the wideband showed that I didn't. Bruce then posted about getting his IAC to open up more. I tried it on mine and it helped a little. The biggest help was ...

Adjust the throttle body stop screw to produce your desired idle (or slightly above) WHILE yielding ZERO IAC counts when the car is fully warm and in gear.

This is a pretty noob thing that most people know about. However, some of us old farts sometimes think it's close enough when it really isn't. Furthermore, I added something in the above statement ... "and in gear". The "and in gear" is extremely extremely important for those running huge cams or TH400s that might eat up a lot of power when you finally shift into drive. In fact, I just did this yesterday to a buddy's car (Wassup Craig!). I also did this on another car a month ago.

Don't underestimate the position of the throttle blades.

Now, with that said, I wouldn't just arbitrarily do what I just said. Verify with a wideband that you aren't running too lean on initial startup. Who knows - maybe you are lean. However, if the AFRs look good and you have enough timing for a cold start (with your mods) ... then take a look at what I said above.

t

 

China's not so bad. I was in Beijing last year for 3 months and got used to it - food, lifestyle, language barrier. It's fun to be able to design fuel injection algorithms from scratch - the programming guy we have is awesome at adding any features we think we need. Debugging them and calibrating them is even more fun.

When you installed a new TPS, did you set the TPS to .54 volts at closed throttle? That's where it's supposed to be set to, and can cause problems like this I would imagine. There's a lot of posts that can tell you the proper way to reset the actual throttle - search for minimum throttle position or something like that. Vader used to always post it in the Tech section.

 

Ya, I know how to do all that stuff... I found a local Chip tuner in town and I am going to give him a shot. Maybe I can learn from him. He said I can be there and help out while they do it. He has a Chassi Dyno and specializes in street/race cars. When i told him about my issues he said it sounded like it was related to timing calibrations in the chip. Once hooked up to the wide band O2 and on the dyno, I think things will start to really get resolved. After reading lots of tuning posts I have come to the conclusion that tuning cars with big cam is not for the novist. I will have the car there in about 3-4 weeks so I will keep you posted on what happens. Thanks for all your help.

 

I had the same problem the car would stall it got worse as i richened the idle up. But the idle got smoother each time i made it richer, so i didnt want to lean it out. I thought i was lean as well (not enough choke)but ended up having to take fuel out on the cold/warm start. It stopped stalling after i did this.

Like Tim was talking about, openiing the throttle blades more. I found as i richened the mixture at idle i had to crack the blades open more or it would surge. And when i leaned it out i would have to close them some to get it stop surging as well.

I just set the minimum air, right around my set idle speed in the chip. This was also where it idled the smoothest. It idles great and doesnt stall when put in gear.

 

MikeH...

Looks like you have a Superram like me. I got a 355 which is a lot smaller than your 406 but maybe this intake has the same characteristics. What are your cam specs? Just curios. Anyway, would you mind telling me what exactly you changed? Maybe a JPEG too? I changed my open loop settings similar to the guys suggestion above (higher than ARAP). I guess I was going richer. The car is puffing a cloud of fuel so I guess I should have realized that going even richer was incorrect. The only theory I was using is that engines need to be rich when you start them cold and leaning it out would be a bad thing.

 

Hi Jack....The cam IM using works pretty well with this intake. I got it from LPE, its there 213 SuperRam cam, 224/234* duration 465/488 lift something like that. The specs are on The LPE website.

Mine is SD...But, I leaned out the startup enrichement vs coolant temp.

 

One more thing. What does your spark table look like at idle? What is your base timing set at? I have mine at 8degrees EST disconected. And around 30 degrees in the chip. to high?

 

I started out using stock tables for a 90 L98. Ive found best power using a modifed corvette spark table. With no pe adders for spark. My car likes more spark at cruise then a stock fbody bin. But not to much at wot. It took me awhile to realize, that the heads IM running. Just dont need alot of spark at wot to make good power.

I have mine set at 6* at the crank. Tried increasing it, but got too much knock. I have a lot of compression. Seems to work well there with the table im using.

I have 20* at idle in the chip. It was 14*.. but as i increased it the idle got smoother. Havent tried anything higher, it smoothed out pretty good there. So i moved on to other things. Its still just a little bumpy but i think its time for an ignition tuneup.

Just have to jump in and see what works for your setup. Ive burned ALOT of chips to get my car to run as well as it does.