WOT AFR vs Target AFR?

[LZeppelin513]

What is the difference between "WOT AFR" (in the data stream) and "TARGET AFR"? I did a WOT run to 4000 RPMs this evening. I have my PE target set to 12.6 throughout but my Wideband seemed to follow the "WOT AFR" nearly dead on the whole run...

for example, one data frame: map 100, RPM 3600, Target AFR 12.6, WOT AFR 13.8, Wideband AFR 13.84

[TGP37]

HPT or DHP?

Your WOT fueling should have more then 1 table. There is the table for AFR vs ECT and then a table for RPM vs TIME. They combine values set, which you probably have 1.2 AFR addition in one fo your WOT fueling tables.

[LZeppelin513]

I will probably feel dumb after asking, but what do the acronyms; HTP, DHP, and ECT stand for?

I am using OBD1 7730 tunerpro v5 $A1.

I looked through all my tables again and did not find another wot fueling table other than the "power enrichment" table, RPM vs AFR. I'll comb through it some more after work.

[3400-95-Modified]

HPT or DHP?

Your WOT fueling should have more then 1 table. There is the table for AFR vs ECT and then a table for RPM vs TIME. They combine values set, which you probably have 1.2 AFR addition in one fo your WOT fueling tables.

owned... its in the OBD1 tuning section...lol

HPT means HPTuners and DHP is DigitalHorsepower... Both OBDII tuning suites. ECT is engine coolant temp btw.

Bottom line you should try to get the Target to match your wideband... The WOT afr I've never heard of before regarding a pid that you can scan, except for it being what TGP suggested... There is a base AFR fueling table and then there are modifiers such as time in PE vs RPM as noted above, so the longer your in PE the richer it wants the mixture... and going by your wideband not matching the target then your running leaner than what your ECU is wanting... I'm not saying that's too lean or anything, it just means that your tables that you can scale, typically VE or IFR tables for OBDI are not 100% correct and they are calculating fuel incorrectly.

I'm a sucker for making sure that the metered tables are dead on to what they are doing so I spent a lot of time getting my fuel trims to be as close to zero as I can get them, in your case its watching your BLM's and then I do WOT runs and compare Target and Actual and then adjust the top of my MAF table to get those two numbers to match. I do this because now I can go in and just change a AFR value in my ECU if I want it richer and I can actually pick numbers that mean something to me. Back when I started they were telling people to just scale the maf higher if you want more fuel... granted that will do what you want but your just lying to the ECU on the amount of air going into it to get the result and I don't like doing that.

[robertisaar]

WOT AFR is my attempt at matching a narrowband in open loop(and warmed up/functional) mode to a wideband AFR.... sounds like i did pretty well.

it's a narrowband voltage converted to an AFR via a transfer table. not the greatest method, but it certainly is better than nothing.

however, it sounds like you're getting a lot leaner AFRs than what is being commanded... 13.8:1 in PE is really lean. you may never actually get your target AFR and read AFR to match due to the stupid BPC setup.

[LZeppelin513]

WOT AFR is my attempt at matching a narrowband in open loop(and warmed up/functional) mode to a wideband AFR.... sounds like i did pretty well.

U did very well. On this run, (for 100 kpa only) out of 34 samples, 28 were within .1! The first few were off and then a couple in the middle were just slightly off. Nice work.

[3400-95-Modified]

I'm surprised the narrowband is able to get that close with just a calculation. Quite impressive really.

[robertisaar]

it's not perfect, but it's certainly better than nothing and costs $0.

[TGP37]

I'm surprised the narrowband is able to get that close with just a calculation. Quite impressive really.

it's not perfect, but it's certainly better than nothing and costs $0.

That is impressive. Could use those results to smooth the wideband signal some.


LZeppelin, didn't realize I was in OBD1 section, lol. I don't know squat regarding OBD1....OBD2 is my thing.