too much fuel + w/i = bad timing???

[alex027]

I could see the cut in my logges on the palm. Under wot when fuel cut occurs I would see a sharp down fall in the o2's. like a sharp spike pointing straight down. I would hit cut like three times as I went through third gear until I put in the injectors. So in the o2's you would see a steady line at like .91 then when the cut occured you see a shard spike dropping down pretty far. But I was able to drive through these as well. it's not like hitting a brick wall but it does give you a good jolt.

This is exactly what happened to me. It didn't feel like the same thing as a full blown fuel cut brick wall, but it wasn't just a bogging down either. How did you tune it out?

 

[sweet97]

Thank you for the links! can you tell me a bit of your experience with water/alkyinjection? It sounds like a "cool" idea but not widely used. Thanks! Mark

 

[alex027]

From what it seems evryone who has used w/i has only good things to say about it. It does work wonders. I personally like it, but just need to fine tune it for my setup. It is a good mod for any level of modification, from stock to full blown (no pun intended) race cars. In my opinion a great bang for your buck.

 

[Joesmoke]

Yes Mark, it is a great bang for the buck! It works well on any car at any level of performance.

I have started to see more DSM's trying it, so I think we're on the tip of the iceberg for a widespread outbreak!

Tuning for any individual system is very easy. Just dont get too complicated your first time and it will be more fun. Keep it simple.

The only problem is that I would prefer a never ending tank of methanol, but what are you going to do? I believe that an aftermarket IC is still a good idea, but this works well right now, and will only compliment that IC later.

Personal experiences? What do I say? Even on a tuning run, with a pretty small jet, you would not believe the power increase that came from the 14b @ 18 psi. Onced leaned out, the car was considerably quicker. Its something that you just need to try yourself!

Jason

 

[Joesmoke]

Hey Alex027, could you also describe this as a bad stutter or miss-fire?

 

[alex027]

Hey Alex027, could you also describe this as a bad stutter or miss-fire?

Yes I suppose you could.

 

[Sk8er07999]

This is exactly what happened to me. It didn't feel like the same thing as a full blown fuel cut brick wall, but it wasn't just a bogging down either. How did you tune it out?

I put in PTE 780cc injectors and ran some crazy negative correction but found out I was getting crazy knock. THis is only because I am getting too much timing advance because the ecu thinks that barely any air is coming in. The car if haulin ass though but the knock freaked me out and it looks like the answer to the problem is the keydrivers chip at DSMchips.com. As they change the fuel maps according to your injectors. This way you will be able to run around the zero correction mark as now the ecu knows you have 780's or whatever but will give you the correct timing advance. Just specify when ordering. Can't wait to get one.

 

[Joesmoke]

Hows the problem going Alex?

A "drive through" stutter sounds more ignition related to me. Wires and plugs.

Whats your knock readings?

Jason

 

[alex027]

Me and my buddy took it out for some tuning runs last night, and had great success. I took out about 5% fuel across the board and started fresh from there. It ran without hitting fuel cut , but my timing wasn't looking so good. Im only hitting like 5* of timing at 3500, but it started climbing pretty nice until like 5000 where it held at 10*. It hovered around 10* until about 5800 and then climbed again until it hit 15* at 6500 and stayed there. We added a little more fuel and then it ran great. Tipped in at 5* at the same 3500 and then climbed nice all the way to redline. I was only able to see a 15* max timing though. It was a cool night out would that have caused the timing to not advance as far? The next time out i'm going to try and add a couple psi more (around 22) and tune for that. I definitely got the jist of it though. If you can think of any more tips on how to tune it, feel free to let me know. And again thanks for all of the help.

 

[alex027]

Although my timing looks good, There were a few spots where it is still a little richer than it was previous. And it seemed necessary to do to keep the timing from being pulled or not advancing fully. This still seems wierd to me? Any thoughts on this.

 

[sweet97]

I am not a great tuner but it's the ECU that sets the A/F ratio and perhaps leaning the area where you are rich may allow more timing as it is the amount of air that the ECU uses to supply fuel. The ECU must think there is a lot of air at those points and leaning those areas may allow more timing. Will some of the more experieced add to ths please? mark

 

[alex027]

So you are saying that if i lean it out more that i will see more timing advance. I thought that you needed to add fuel to keep knock at bay, and in turn will get better timing advance. If i am wrong just let me know, as this is just my understanding. I should be going out tonight for a few runs, i'll post my logs and see if that helps better with diagnosing the problem.

 

[sweet97]

Alex it's the ECU that controls advance and sets the A/F ratio. We as tuners don't make our cars rich or lean. What we do is "trick" the ECU into how much air is entering. If the ECU sees a lot of air it adds fuel. Since it thinks a lot of air is entering the motor the ECU may pull the timing to keep the motor from damage.
I use the MAF-Translator to tune my motor. The instructions show turning knobs clockwise or counterclockwise will either richen or lean the mixture.
That's the result but actually turning the knobs either lets the ECU "see" more or less air so IT, the ECU changes the amount of fuel. Certainly we could be lean to a point to cause knock, without a doubt. I suggest you lean the couple of ranges you are getting knock and see if knock lowers. If it gets more knock then you will have to back. I thought that whenever I saw knock I was to richen the mixture at that rpm range, well often that made the knock worse because to get a richer mix I had to "tell" the ECU that more air was entering the motor. Our ECU's are set to have an upper limit of air allowed. In order to run bigger turbo's we tune so that the ECU is happy because it thinks the motor is under it's preset max. Just adjust in small increments to see how the knock responds.
Or try adding fuel nd you may very well see the knock go up. That will show you that richer can cause knock.
I have a 1g so I run the "Scanmaster" from fullthrottlespeed.com I can see the knock on my readout and switch to timing and see what the timing is doing and it makes tuning easier for me.
I had my car very rich under WOT trying to get more boost with a 50 trim and what I got was more knock! I leaned the mix and am able to run 13 PSI. Now I am installing a frontmount IC.
Try richening those spots where you get knock and see if it gets more knock or less. That is a safe way to see which way you need to go. Let us know how you make out. mark

 

[alex027]

Thanks a lot sweet97. That will definitely help. And it makes perfectly good sense. I will give it a shot and see how it works. I will let you know how it comes out. I will post my logs too, so you can take a look. I ask one question and find out so much about my car. Gotta love tuners.

 

[sweet97]

Alex, remember I am new and am sharing what i have found out. To be safe richen the areas whereyou get the knock, if the knock gets worsr you know you need to lean it out. At first it did not make sense to me until it was explained that the ECU sets the A/F and the ECU is pre set to a max on air flow and if that max is exceeded it will pull timing to save the motor. We want to run as much boost as possible with no knock and with as lean a mix as possible along with the most timing!
What I do is tune out the knock. By the way I also have a wideband A/F meter. A lean condition will cause knock for sure as will a very rich mix for different reasons.
Start by increasing the fuel where you see knock. If it removes the kock, great. If it gets worse then start slowly leaning until you elimiate most of the knock, or all of it. I tune allowing 3 knock counts. Just go slow to avoid damage. Let us know how you make out and how you did it. mark

 

[Bohrn]

yep, take out fuel on an SAFC or similar ECU "fooler" and it will give you more timing.

Now this in itself can cause knock. If you have huge injectors and stock or higher fuel pressure, you will have to compensate too much on the SAFC. Your settings will be like -35 or something. This will give too much timing and it will cause knock.

As does too lean an air/fuel ratio as stated above.

What I do is set a realistic boost goal for the octane rating of the fuel, intercooler, fuel system, turbo etc that I will be running. Then tune for 0-3 counts of knock. Best to get 0 counts or the occasional 1 count in lower gears as it will knock more in higher gears or pulling up hills etc.

 

[alex027]

How will i know if the ecu is pulling timing because of actual knock, or just because it is seeing too much air going into the engine? It sucks that 2gs didn't come with a knock sensor to read off of a dattalogger.

 

[sweet97]

That's easy Alex. Just add fuel to the points where you are seeing knock. Actually you are tricking the ECU that more air is entering so it will richen the mix. If you get more knock it's because the ECU thinks a lot of air is entering so go back and lean that spot and see if the knocking lessens or completely dissapears. I think you need to lean those areas but by addin fuel you will safely determine which way you need to tune.
Be sure to let us knw what happens. Mark
Alex I apologize but I did not look at your mods, such as turbo and injectors being used, exhaust. That info may help so I will go look see what you have. Mark

Alex, I looked at your mods and you can drown the motor if you wanted to! You have plenty of fuel available. Can you disable the water injection for getting a good timing/knock tune through out a run and then retune with the water? I feel with the water you may have too many factors affecting your tuning. I will PM you later as I want to go to water/alky injection myself.
Pease allow me to repeat myself. Add fuel at the rpm ranges where you get knock and see if it gets better or worse. This is the safe way rather than jumping in and lean it 10% and fly! Ifyou get moreknock then you need to lean out those areas. If knock goes down you were truly lean there and needed more fuel. I suspect the first scenario. Mark

 

[alex027]

My car was tuned with the setup that i have now minus the w/i on a dyno with an a/f sniffer. There is really no need to tune it with the water injection turned off. It runs great, with great timing advance with the water turned off. I am going tonight to get some more tuning runs in. I know i said that a couple of days ago, but ive been busy. I'll post my results when i get home from the tuning runs. Thanks again.

 

[cfisher]

i've actually been having the opposite problem. i was orig tuning off my logger but got ahold of a wideband and found out i was at 9.1 afr. at -38 safc highs. so i kept going -45, -48, finally hit -50 which maxed out the safc but had my 11.1 afr. thought everything was gravy. so i got the logger back out and did another pull and only got 14 deg timing by 7K. and .92 on my o2's. so i started to richen it back up and got the timing back to 18 deg by 7K with a 10.1 afr at -45. car seemed to be faster 11.1 afr -50 14 deg timing than the 10.1 -45. hmmmmmmmmm! so i'm not getting the best of both worlds right now.

680cc inj, 255 fp, frank 2 turbo, supra smic, 38mm tial external gate, 3" turboback, 3" intake, blah,blah,blah. so i've figured my problem is no afpr and i'm installing it today with 6AN lines, aeromotive afpr, russell hf fuel filter. i'm crossing my fingers and hoping this is my problem because i should not be pusing this much fuel.

 

[alex027]

afc settings:

1-4000 -12%
4600 -11%
5200 -1%
5800 -2%
6400 +2%
7000 +5%
7600 -2%

Well i went out last night for the tuning runs and had great success. I leaned out 7% across the board from what you see above and the thing just felt stronger. Some spots i leaned it out more and others i had to richen up a little to get my timing right. I only tuned for 20 psi, hopefully i can go back out tonight and tune for a couple more pounds. I left my logger at home, but i will post the best log this afternoon when i get home.

 

[alex027]

I finally got a logged run:

rpm tima
2100 20*
3312 8*
3920 10*
4532 9*
5104 10*
5652 13*
6144 14*
6596 15*
6980 15*

This was on my fifth straight run, and the max. coolant temperature hit 213*, and my max intake temp was 102* so i'm assuming on another run my timing would advance further across the board. I added a little bit of fuel at 4600 to compensate for the drop in timing that i saw. But i didn't get a chance to log the next run. The red sox and yankees game was on and i wanted to get home. I will go back out and see what else i can do though.

My final afc settings:

1000 -17
1600 -17
2200 -19
2800 -19
3400 -20
4000 -18
4600 -16
5200 -9
5400 -7
5800 -7
6400 -5
7000 -2

 

[alex027]

well i went back out tonight for some more tuning runs and everything went great. My peak timing is still only at 16* but the car seems to be running strong. Thanks everyone for your help.