got a 2001 8.1 burb. Power enrichment tab shows 4900rpm activation of PE mode and 60s. Does this mean that I have to wait 60s b4 it happens and keep it above 4900rpm? That is the stock tune numbers.
got a 2001 8.1 burb. Power enrichment tab shows 4900rpm activation of PE mode and 60s. Does this mean that I have to wait 60s b4 it happens and keep it above 4900rpm? That is the stock tune numbers.
yeah, pretty much. You can lower it all down to fit what you need. I usually drop the RPM delay to about 500 below whatever my stall is, or if its factory setup i drop it to about 3000rpm, 0.0 sec delay, min map 55-65...the pic is attached is just for reference. DO NOT set it to 0 like in the picture
so, setup PE as suggested. PE doesn't seem to work as engine missfires due to lean mixture. Ill include graph and tune. Look at o2 sensor graphs toward end of log. That is where I noticed it. They go full Lean.
If the engine is leaning out, you have a fuel delivery problem. If the commanded AFR is dropping to 11.83 like the tune is asking for and the o2 sensors drop way low, it's running out of fuel. I can't view the log to see what is happening.
You should also make these adjustments to PE. Set the enable torque to 50% and lower the throttle hot/cold enable to like 65-70% instead of 90% which is nearly full throttle.
2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.
If you don't post your tune and logs when you have questions you aren't helping yourself.
I may be wrong but in reading in this forum that misfires will cause the O2's to read lean as the misfire means that
the exhaust has a lot of free O2.
My $.02 .
81 Malibu Wagon
Specs:
Stock 6.0 LQ9 1 3/4 Long Tubes
Sheet metal Manifold, Custom 4" CAI
TH350 Trans 8 1/2" Diff 4.10 & Spool
3200 Stall Torque
Best time 1/8 mile - 8.05 @ 85MPH
I agree with 5FDP that youre probly not getting enough fuel, so throw a gauge on there and run it up by the wiper cowl and go take a cruise and watch to see what its doing. Definitely take care of that problem ASAP then tune the VE and MAF for better performance. I adjusted your PE settings and posted the tune, maybe this will help. Let me know, post another log as well with some info on what you find about the fuel pressure...
The original tune was set at 4900rpm and 60s. Looking at all what yall have said and considering the original tune I guess PE was never meant to be used from the factory at all. I mean who wants to be turning 5g for 1min with an 8.1. Sounds like it might scatter b4 time elapsis. However I will put a gauge on it and check FP. May have an underlying issue and dont know it.
i have a fueling problem. idle pressure is 260kPa and drops to 150kPa at 4500rpm 1-2 shift. No difference in pressure when regulator is unplugged. Ill try fuel filter first. should be 400kPa if I converted right. My gauge is ex GM dealership Kent-Moore in kPa.
That's what I already asked you. I don't understand that's 3 days and a lot of ppl's time wasted.
https://forum.hptuners.com/showthrea...072-8-1-tuning
Im sorry to waste your and others time. Ill be the first to admit im not the sharpest tool in the shed. Trying to learn HP and also keep in mind there are other engine functions not controlled by the PCM. The engine miss fire did not happen until yesterday along with the lean condition. It seemed to run fine at WOT. But not great. It wasnt until the miss fire started that I began to suspect it wasn't a tune or pcm problem. Someone else also suggested that I check fuel pressure after I posted about the missfire. So I had to round up a gage which I forgot I had and then purchase a hose extension to get it where I could see it. I made a mistake. Hope I learn from it. Ill keep everyone posted. Going to change filter tomorrow. Cheapest and easiest for now.
Honest mistake then no big deal. Might just be the filter.
This is common for a lot of HD OEM GM tunes. The new 6.0 express vans are even worse. Huge gains getting it into PE sooner and if you do it modestly you won't notice a fuel mileage drop.Originally Posted by clevor
Tuner at PCMofnc.com
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Replacing fuel pump cured all my drivability issues. Apparently, it had been getting worse over time. My next question is my knock sensor appears to retard timing by a factor of 2 to 2.5. Notice I said appears. Im watching this on hp scan screen. I hear no knocking when the scan indicates it. Even when the sensors show constant knock. Am I looking at this wrong or right? Trying to learn all I can about tuning so I have to ask questions. Thanks all for your help.
You need to post a new log and tune.
Have you tried higher octane fuel or reduced timing to see if it has an affect?
It could be false knock. when is it detecting knock? do you have headers and exhaust?
run 93 octane and going to log my latest tune. Ill pull my trl also b/c that is what i bought the burb for. scanner shows lots of knock. ill post as soon as i can.
no headers but duel exhaust. running 93 octane. i'll post tune and log when i can. and yes it may be false knock. i certainly cant hear it. use to work on GM cars in the 80s so heard lots of knock. carbureted buick v6 would knock when brake torqued.
Add octane booster or race gas and see if it reduces.
So, I watch Goat Rope Garage for pointers on tuning. Back story here is what I thought was a knock or timing issue was actually a fuel pressure issue. Long story short and after urging from tuners here was to check fuel pressure. Should have done this first. Live and learn. That issue is taken care of. 58psi at idle and a little more when driving.
Now Im tuning the timing as I have to wait for my money to be right to afford WB sensors and tune AFR. In the meantime, I have tuned mostly spark. On GRG, dude says to zero out two tables which I have. These are under the header: engine, retard, burst knock retard. B4 I zeroed those tables, I was getting constant retard events. Now I do not, I have not modified spark tables, only those tables that modify the spark tables. I also run 93 octane and have removed the thermostat in an effort to get the engine to run cooler. There are other changes I have made so Ill post as built and final tune. I still get knock, but not like before. I will also try to fabricate some kind of ducting to the airfilter as IAT affects retard. K&N is a poor design. Great for pulling in underhood hot air.
So, any ideas as to why zeroing those two tables had so much observable effect on knock. I have also not adjusted knock sensor sensitivity. This vehicle is an 01 suburban with and 8.1 and true duel exhaust, no headers and as aforementioned a K&N air filter. Thanks all for any input.
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