The Table indicates "Airflow vs Voltage", but, there is a PID available for MAF frequency, is there a mistake or is some conversion required?
The Table indicates "Airflow vs Voltage", but, there is a PID available for MAF frequency, is there a mistake or is some conversion required?
Yea I was pretty curios about that one,too. I thought the Maf was 0-5v? Does the PCM have the opamp circuitry in there?
All the other GM MAF's I've seen have been frequency. The Ford's are voltage based. Based on that I would imagine the Solstice is frequency based as well but thats just a guess and I could be 100% wrong. I say add the PID and see what happens.It will either show Hz, unsupported or V. It's got to be a bug/typo in either the table or the PID. I'd post in the bug forum.
Bill Winters
Former owner/builder/tuner of the FarmVette
Out of the LSx tuning game
The Maf is definitly different then other GM's. PRolly cause this is a Bosch based system.
The MAF table is g/s vs V and is 0-5 volts. However there is an availible PID for both MAF voltage and frequncy. Weird.
i'll look into it, but i believe the PCM has the ability to use both voltage and frequency style MAF's hence both PID's being available. Only the voltage one's seem to be used in these applications.
I count sheep in hex...
Chris, is the (4 right?) VE tables gonna be in the next Beta? I have been going over in my head how to go about tuning them. Is there a PID for exhaust/intake cam phasing?
Is the boost control referenced off cam timing?
Wifey's driving her winter Whip. So Im stickin' the GT30R-wg on this weekend.
I fully expect the PCM to piss it's pants.
i really don't know, i need to look into it.Originally Posted by Baldturbofreak.com
Chris...
I count sheep in hex...
well if there is anything that I or the solstice GXP community can do to help/bribe/etc let us know! lol
Old man winter and the inherent road salt is going to limit the SOl's duty to the Chassis dyno soon.
I imagine like I said above the PCM is going to get all pissed off at me. Maybe some of that data (from it going far out of parameter) will reveal some more about how the Bosch ecm's op system runs.
I was looking at a forum memeber's log (Dejon Dave)
He uses a manual boost controller. Whats pretty damn strange is the throttle (TPS,not ETC) reports nothing over 87% and on top of that the calc VE goes to 68lbs/min!!!!! all while the regular maf is reading 28-29. pretty weird.
The 87% is the absolute value and the represents 100% open, you have to compare commanded pedal position to the the TPS PID to see if it is pulling back throttle. I have discussed this with dave and when he is in high manual boost, the absolute drops from 87% to about 75%, while the commanded is 100%.
Last edited by Jack B; 11-11-2007 at 11:25 PM.
I too asked dave to relog with The ETC stuff to see if there is throttle angle being reduced. It's something I watch in our car all the time.
Your saying you think the throttle might be 100% open? the 87% is "what's left" after idle?
The thing that trips me is is that the PCM caclulates 68lbs/min during high manual boost mode, to my knowlege he has a voltage clamp or boost bleedoff device on the map sensor.
It is not a full 5 volts, I believe it shows wot at 4.5 volts. The ecu is looking for 5 volts so it show approximately 85% at wot. Mine actually shows 83%. Dave was saying that when he manually controlled the turbo, the ecu would back off the throttle into the mid 70% region. That was when he was pushing greater than 20 psi.
I tried the wastegate mod while I wait for the actuator for the garrett turbo. It spikes to over 20 psi then settles at 17 or so. consistently 2 more psi, but going lean. I have the dashhawk monitoring the difference between cmd and act. and I t seems I need more MAF signal up high.
4" pipe is making things asymtotic with the maf sig, but I figure it's better to work out the MAF now while I still have the stock calc. VE still in line. (KO4's still on there)
Okay Ive got the fuel trims back to where they need to be. holds 18psi consistently. no throttle closure until 62xx rpm.
I think you were right jack, more or less it's any deviation from CMD a/f that causes boost reduction. It wasnt until I could see the factory w/b that I had proof.
I have had to add sooooo much signal to get a 4" cross-section pipe to work with that sensor, 40% in most areas.
Bump for boost control!
Did you use fuel trim histograms to offset the MAF sensor? If so did you use just ST or a combination of the two? Which beta are you running on the DH.
I am going to dyno next week, anything you want me to try?"
How are you seeing the WB? I havent found that yet, of course I havent had time to look.
Im using the third beta on the DH, which is how I'm tracking deviations from CMD to WB.
I got the cruise trims in line using a histogram of ST fuel trims, i looked at the bulk average the signal is off with the 4"pipe. I used that as my Inital Bias and that got me pretty close (just like the first time with the 3" pipe)
Hstgram of ST fuel trims plotted on the MAf correction table was used to put the rest in line.
Step three is to log with the DH to look for WOT deviations between cmd and WB A/f again looking at load vs rpm and going back and doing a nice 9 cell pimple (you know what I mean im guessing from your demonstrated skillset)
wherever an deviation's epicenter is.
Ive been quelling knockcells with 12.0 a/f. casue to be perfectly honest, If afraid to fark with the timing until i know for sure which table is active I E some sort of Cam position readout in the scanner.
bump for Rpm control beta action!
Not to get to far off topic, perhaps a new thread(?) but what is everyone's thoughts on trying a 3 or 4 bar map sensor? Im thinking we have the motorola 2.5bar.
PErhaps one of the PCM guru's could step up here, but could'nt there be a table in there to assign the A-D values for the MAp sensor just like the MAF?
Reply With Quote