Will someone look at my log? datamaster

[justinkp]

Will someone look at my log and tell me if I should get my car retuned? I have no idea what i'm looking at but I can tell you what i have

PCM4LESS tune
37lb injectors, xtreme lt1 cam, 236/242 520/540 @ 112
Edelbrock performer lt1 heads ported and polished, 2.00 1.55 valves (or maybe 2.02 / 1.60)
stock bottom end, 58mm throttle body (IAC drilled out)
ported & polished intake

Anymore info let me know
Link: https://www.dropbox.com/sh/vugv47g0y...W5WgZtX/nw.uni

Thanks in advance!

also: My rockers are making noise, sounds like sewing machine but a lit loud for my taste in line to get tuned Monday, if i try to reschedule, it will be another month...

[bobdec]

Overall running looks OK, no major problems. Common to cam'ed cars you are not using lower BLM cells 0-5 due to high MAP. BLM boundries can fix that, but that is not urgent. Idle and low TPS shows split BLM's see further down.

Your picking up knock and retarding spark during you WOT run shown below in 1st and it was also there in 2nd gear. Could be physical noise, doesn't look very lean. Could try dropping timing in that RPM/MAP range to see if it goes away. Noisy rollers may warrant LT4 KM if timing. etc. does not help.

[IMG][/IMG]

You have split BLM's at idle and low TPS running, in this pic, what did you drill (IAC drilled out ??) did you mean TB blades ? . Your LT right side is way up there. ST's are not bad so that says PCM is correcting. I din't like your IAC count of '0' that says no air is entering the idle air plenums and all air is entering from TB or elsewhere. What brand is your TB ? . TPS voltage is at 0.71 you could shut blades a bit to see if more IAC helps split BLM's . Spark advance at idle is around high 20's, could try low 30's and again check splits. your vac is way low at idle 70 Kpa, but you have a big cam. I see a DTC 33 low vacuum (high MAP) but that could be old. It's tough getting BLM's OK with your setup.. There are quite a few checks and solutions on the web. Not sure how deep you have looked into them and if you have addressed split BLM's already. If so what have you tried ?

[justinkp]

Thanks a ton form your reply. In drilled out the IAC passage at the bottom, not the blades. I'll try to clear that 33 code and see if it comes back. The rockers are making noise so I wonder if that is what is picking up knock..the split BLMs I don't fully understand but I will try to close the blades. When I drilled out the the throttle body it was reading 50s. Don't know what changed. Its a professional products 58mm. I'm going to adjust the idle screw now and will report back with a other log. Im not sure how to change the timing otherwise I would do it myself. Also does the fuel Look OK? Not super rich?

[justinkp]

This throttle body is retarded. It's either 0 or it's 160. no in between! Logs:
https://www.dropbox.com/s/l8mtp5fo6u21zfy/new2.uni
https://www.dropbox.com/s/5uc969y9obsg4pb/new.uni

I ended up at .76 TPS v to get it to idle.. UGH!!

[justinkp]

About the split BLMs, I have not looked into the issue. In fact I'm not sure what it is, but rest assured, I will tonight. Thanks again for your help!

[bobdec]

Fueling looks OK , see pic below you are a bit lean, but not that bad and a little rich on cells 7 and 10 but not that bad either. The lean at high end cell 15 can be tuned with MAF tables, but it's not very bad. Since 15 is last cell before entering WOT, some like to richen it to insure WOT is not on lean side. Cells 17 and 18 are for deceleration, and can't be tuned so ignore them. Over all your fueling looks OK except for split at low end with LT=160 is PCM max setting, so it could be worse than log says. Right side looks like it's not getting fuel or a cylinder is not firing at idle. Hopefully IAC will fix that.


Looked at the two logs, your IAC is not working correctly. One shows count = 0 (PCM has closed IAC to slow idle yet idle is to high, 1000 RPM ) . And then I see a IAC of 160 (IAC fully open max count) and engine is running slow at idle 750 RPM. So the PCM is going nuts opening and closing the IAC to min/max travel and the engine is not responding. Indicates the IAC is not working, it's jammed up or the idle air path is messed up. For balanced BLM's air has to hit all cylinders evenly from the idle plenums in the intake. This air enters through a port in intake that is mated and gasket sealed to the TB IAC port. Since you drilled in that location you are aware of how it is set up. Since PCM is adding lots of fuel to the right at idle it could also be a lazy injector, or non firing cylinder, but it clears at higher loads. Are you sure there are no slots in the TB that allow air to pass from IAC port to the blade opening into the intake. I'd get IAC valve straightened out first priority and go from there... We need to get you PCM controlling idle not the TB screw.

here is a pic of slots in a TB that should not be there on an LT1, allows IAC air to pas to TB opening..http://i140.photobucket.com/albums/r...2/IMG_1818.jpg here is full thread http://ls1tech.com/forums/lt1-lt4-mo...an-oem-tb.html If you search " LT1 split blms " you can read for quite a while..

[justinkp]

Wow man! U really know ur stuff. Where u at in GA? I'm in SC. U want to do all this? I'll pay u well!

[Twenty8Z]

Wow..Good links. I bought a 52mm throttlebody I planned to use and it looks just like the one in the image with the slots. Why do they make them like that knowing its a problem?

[bobdec]

justinkp, Like others on this forum I do this as a hobby and enjoy assisting others building knowledge. Right after I bought my Z28 had it towed off of interstate 75, local shop replaced my PCM for a stalling/no start problem. The actual fix was a $5.00 corroded/burnt wire from my coil to the opti. That's when I decided my automotive skills needed updating. My knowledge of computers and controls and programing helped significantly and it all came together. I may help some, but I also blow a few as we all learn together.

Twenty8X, You asked ? "Why do they make them like that knowing its a problem?" Split BLM's (trims) seem to show in setups with low vacuum , lower LSA and/or intake modifications. A large cam'ed engine with inherent crappy lopey idle air flow conditions is more critical of the idle air plenum supply working. Not a lot of, if any, threads on problems with stock setups and 58mm TB's, not a hot setup. A lot that do hit the problem are experienced w/mods and once they understand what''s going on they go off and design or fabricate workarounds as part of their project. Maybe there's not enough feedback to the manufacture, or a maybe bottom line $$ decision as the base design also fits other setups and the LT1 is a dwindling 15-20 year old market.