Thread: Learning to tune

There isn't a single pos LTFT in my whole scan, always negative, highest is -3.125. My KR is showing up at 1800 rpm, but only if I'm getting into the throttle a little. I can't get above about 22% TPS without getting knock.

So looking at the good fuel spark table, it's RPM vs Mg/cylinder. Perhaps this is a stupid question but how do I know mg/cylinder?

I could post the scan if that would help.

It's a 98, it has a canned tune as well as a cai, slp catback, ubend delete, 1.8 (iirc) rockers and a smaller puller (believe it's a 3.4). Everything was installed by the previous owner. I'm thinking that pulley is probably too small, but I figured it wouldn't cause problems until I saw boost.

Thank you for you help btw. I'm obviously still new at this.

I wonder if you have other problems causing the kr. at 22% throttle your car isn't even in power enrichment, and obviously no boosts, so maybe you have an o2 sensor hitting on the firewall or something else causing the kr.

Originally Posted by SgtMarshal

I wonder if you have other problems causing the kr. at 22% throttle your car isn't even in power enrichment, and obviously no boosts, so maybe you have an o2 sensor hitting on the firewall or something else causing the kr.

Hmmm, hadn't thought of that, that O2 is quite close to the firewall. If the mounts are shot and giving under throttle... Is there an easy way to confirm that?

Originally Posted by Scottydoggs

with no headers that pulley is to small.

you know if this a zzp tune? (it will have a sticker on it) if so they like to set the timing to 18º wot on everything, and thats just to high with no flow mods.

Agree on the pulley, but I dont really want to put more money into this car and don't have a larger pulley. It's the family sedan. I checked the PCM, no obvious ZZP markings and the timing seems variable, certainly not 18 degrees everywhere.

Originally Posted by Mitch R

Hmmm, hadn't thought of that, that O2 is quite close to the firewall. If the mounts are shot and giving under throttle... Is there an easy way to confirm that?



Agree on the pulley, but I dont really want to put more money into this car and don't have a smaller pulley. It's the family sedan. I checked the PCM, no obvious ZZP markings and the timing seems variable, certainly not 18 degrees everywhere.

only easy way I know of is to fix it. if you can get your car on a stand and look up at the o2 sensor, there should be enough space for it to have some movement without hitting anything. if you motor and/or transmission mounts are shot then the engine/transmission will have more movement. you can also perform a free modification of flipping the upper engine mounts so there is less play on the upper side.

as far as the timing advance goes, there might be 500 different cells that the computer draws from when you are driving down the road. when you have the pedal to the floor is what we are concerned with, and like scott said, zzp likes to set their tune so you are running 18 at full throttle, which in many cases is too much.

have you downloaded your tune?

also, am I missing something? even if the pulley was too small, that wouldn't induce kr when no boost was being made, right?

Yes, I have downloaded the tune from the PCM to get started. I'm going to check out the mounts, flip them if they haven't been and try again. Also, picked up new NGK TR6 spark plugs today, I plan to install them at the same time. The ones in there now are old.

Originally Posted by Mitch R

Yes, I have downloaded the tune from the PCM to get started. I'm going to check out the mounts, flip them if they haven't been and try again. Also, picked up new NGK TR6 spark plugs today, I plan to install them at the same time. The ones in there now are old.

I just put in a set of NGK TR6's in my car, should be a good plug. I ran autolite 104's for a long time and just wanted to try something new. overkill suggests a gap of .045 for most cars. if you have a misfire that would cause kr for sure. those plugs won't last much over 10,000 miles.

if you look at your good fuel spark and in the bottom corner, where it says 6400 rpm and mg/cylinder 680, that is the most airflow you will get at the specified rpm, so depending on how your timing table looks, that whole bottom right corner could be adjusted so it reads less timing. you don't want to go lower than 10.

edit: my tune is different so the commanded timing matches the timing in the spark table. makes it a little easier to make adjustments that way.

edit: I guess kr without boost can happen even without power enrichment.

Originally Posted by Scottydoggs

when i first got my top swap together it had the 3.4 on it still and no ic, ( i did have headers tho) i was getting 6º kr part throttle like 1/4 throttle. low rpms too, aka instantly as soon as i gave it any firm gas.

so your missing the no headers and a 3.4 with a canned tune of un known origin lol

if you want email me your bin file, ill take a look at it for ya.

That would be very much appreciated, can you PM me your email?

Originally Posted by Scottydoggs

pm ed.

Sent.

Also, for anyone who wants to see it here is a segment of my scan that shows what I'm seeing, although it's missing some of the fields Scotty has setup.

Originally Posted by Scottydoggs

new tune sent

You rock! I'll give that a shot and let you know how it goes.

LTFTs haven't quite settled yet, although the way they are running, I'm thinking I'm still rich, although not near as bad as before. Timing table was changed back to stock. Logged some today, still having similiar issues although I was able to get a little further into the throttle before KR started showing up, roughly 28%, almost to boost. Then it dawned on me, TCC lock-up. Changed the tables so it would unlock at much lower TPS levels and my results are much better. Not seeing KR until boost. Since my KR levels were relatively low, I pushed past it a little to get into PE mode and my KR disappeared until I hit a little higher boost levels. Planning to change my PE enable table to get into PE sooner. Thinking the richer AFR is helping to kill the KR, and if I'm in boost at 30% TPS PE should be active anyway. Let me know if my thinking is way out in left field.

I'm using UVScan as I couldn't get DHP to log reliably, and I found a PID for mg/cylinder, but I noticed that in my scans I have values of 968 when the max listed in the spark table is 680. Is that normal?

Thanks!

I have my PE enable set to 30% tps across the board. your transmission settings should be changed so your torque converter can't lock unless you are in 3rd or 4th gear, some people just let it lock in 4th gear only. I used UV scan when I had my dhp, it is much better than the dhp scanning software.

968 sounds like an O2 sensor reading, and if that is what you are referring to, it doesn't really have anything to do with mg/cylinder as that is in relation to air flow.

I was in 3rd gear when this was showing up. My O2 levels haven't gotten quite that high as I'm avoiding WOT until I can get these KR issues worked out. On UVscan it's listed under Fake PIDS (which is why I wondered if their results were reliable) as airflow mg/cylinder and I have values ranging from 69 to 968 varying with throttle.