Thread: Any input on this data log from yesterday?

My number 6 Cyl now has a misfire issue, but I know for a fact that it is the fuel injector. there is some negligible misfiring in a couple of the other cylinders (maybe a 2-4 count periodically), but my map readings are significantly higher when #6 is going apey.

enh.....disregard HTML fail above. Datalog can be viewed here

your car needs lots of help. trims are all over the place, kr starts when it goes lean, misfire city on 6 like you said.

tune cant fix these issues. you need to fix the misfires and injectors first or you'll never run right.

im sure most of that knock is from one cylinder being lean. cause you got kr when your hardly in the gas.

looks like your set to 15º wot, thats stock on most cars, 97-03.

as long as you have headers or a at least a 3 inch down pipe you should be ok on the stock tune. stock manifolds and stock dp wont work out so well.

and after you fix all the issues and its running better if you still have kr a set of rockers could really aid in getting rid of a few degrees of kr. my car had 8 bone stock, no tune. rockers killed off 5 degrees of kr, then a u bend delete killed off the last 3 i had. that was a stock pulley tho. but my car was also clearly a kr monster.

Scotty is right on the money...

You CAN NOT tune around mechanical issues. EVEN if you tuned your car right now, after you fix your issues your tune would be way outta whack.

Fix the issues FIRST then worry about a tune.


Im willing to bet that most of your KR is due to the misfire and fuel being wasted.


Misfires make your FTs see a lean condition since they are seeing a butt load of unburnt air.

a 3.4 pulley on a stock tune is enough to peg the LTFT to 16.4% even without misfires.

truth be told, that 185 t stats not helping a damn thing. fans tuned or not, your engine will still hit and break 200º in summer heat.

i ran stock 195 and tuned fans, it would always reach 200. and the engine runs best at 200. not cooler. its was made to run that hot.

Oh yes.. The age old argument of does a cooler TSTAT help or not. Some say it does, some say it does not. It really boils down to who you want to believe. I personally ran a 180* and saw cooler operating temps once I tuned the fans correctly. BUT not everyone agrees. The concept was all about keeping the water jacket a touch cooler to help cool off the ICT. Just my input on it.

my ss has 160, it hit 225 on a 100 degree day. tans are tuned ect ect....

So it will likely be the weekend or next week before I am able to replace the last couple of injectors, so as an experiment, I decided to attempt some creative underhood temperature control, just to see what happened. I had read somewhere about someone being able to temporarily reduce underhood temps by placing aluminum foil in some specific places. While I didn't anticipate really reducing radiant heat, I figured maybe I could prevent some of the heat soak that is at least a factor in my issues. I put a few layers of foil between the crossover and the TB, and placed a 3 or 4 ply rectangle between the #6 area of the fuel rail and the EGR. Janky setup? Absolutely. Effective? Sort of! I keep forgetting to add coolant temp back to my data log, but just from the occaisional spot check on live data, I saw it hit as high as 221, and average was 204-ish during this particular drive. Even knowing that there is an issue with the #6 fuel injector, it did not count anywhere near as many misfires as it did in the previous log. My LTFT's seem to start fluctuating more as the car gets warmer, so I still need to figure out what's going on there, but from the aspect of it behaving better while a little cooler, it seems like fan adjustments would help (at least a little). Anyway, see new .xls readout HERE ​.

-since I can't edit.....maybe all I need is more reynolds wrap in my life! lol

New Injector and another set of o- rings will be here some time tomorrow, and I'll probably get those put on Saturday. Curious to see what the logs look like then, but that's a start.

Latest data log. All injectors and O- Rings are new, and the bulk of the misfires are gone. Still looks like I get some occasionally, but nothing more than a 2 count, and nothing noticeable. I'm going to start with checking plugs once I can get a consistent fix on where the misfires are. As far as LTFT's, they are largely high negative numbers at idle, Implying that I'm running rich (-16.4 + in some cases). I have not thrown a code of any sort since the last injector was in, but the high LTFT's concern me. Also, it seems like I am seeing a little more KR with that particular issue fixed. I see my B1S1 o2 has some really low readings at times also (<10 mV), so I'm wondering if the O2 is symptomatic of the LTFT issue, caused by some other, yet undetermined factor, or the other way around, that the LTFT is because of an out of spec o2. Also, Maf g/s readings are a little high at idle, but I attribute that to the smaller pulley. What do you guys think? Other than what the data logs are telling me, it feels like it's running great.

your scanning the o2 in volts, all it does is dance up and down, thats normal. you want to scan it in MV.

the high neg litfs could be a stuck open injector, maybe the one you just put in.

Originally Posted by Scottydoggs

your scanning the o2 in volts, all it does is dance up and down, thats normal. you want to scan it in MV.

the high neg litfs could be a stuck open injector, maybe the one you just put in.

Welp, back to the drawing board, I guess. At least it's driving better. Another sign of a stuck injector would be difficulty starting after sitting for a while, yeah? I don't have that going on, but I recall reading something to that effect. Any other symptoms to look for that would indicate a stuck/ sticking injector? And I'll be a little livid if brand new injectors with maybe 500 miles on the oldest of them are sticking.