K-Spaz

I'm trying to learn how to tune my car, and I'm having issues with MAP, or I think I am. Everywhere I look on the web at other people's tunes and logs, I see they have MAP values of 100Kpa when they go max load. Mine tops out at 45Kpa and now, rarely even gets there. Yesterday I logged the car and got max numbers of 35Kpa so I went to the store and got a new MAP sensor. Installed that, and today again I can get 45, but only with WOT or very near.

I verified the 5V reference and that is good. Ground reference is good. Open air output is ~4.5V (Was only 3.5V on the old sensor) and with max vacuum, output drops to ~0V. So ok, the input and output appear to be fine, at least on the new sensor.

So I go to log with HPT and this is what I get.


My question is, does that look like it's hitting all the proper values for a 1998 cam/headers car? Any idea why it quits at 45Kpa?

Side note. The car appears to run fine for as far as I've gotten the tune. It's possible I tuned VE/MAF for it to work in spite of this being wrong. I'd like to hear some other opinions.

RedRiderZR1

First off, Do a test and scan the car, key on engine off. Should read 100 kpa. Usually low kpa readings reading low are because of a restriction causing vacuum. Although a 45 kpa reading at WOT I think you would recognize the restriction. If you don't get a 100 kpa reading with that scan, you have an issue on the car or the scanning software has an issue.
Did you create any custom PIDs on the scanner software. If you did, that could cause a problem. Deleting the vcmscanner.cfg file will fix that, but any custom PIDs will not be there anymore. It will fix any MAP reading issues if any in the scanner software.
At WOT you should not have any vacuum causing the reading to go that low.

Also. Map key on engine off should be 100 kpa, engine idle around 35 kpa stock cam and around 60 kpa on a cammed car, WOT around 100 on a NA car.

K-Spaz

Well thank you very much. That's sorta what I was thinking but I had assumed everything was fine since the car ran ok, or at least as expected since the engine change.

I want to say then that it's got to be HP Tuners. I looked into units on that PID but as far as I know, it's not a custom channel. I do have a custom channel for my wideband. As best I know there might be one more using "Maths" for AFR error, but this MAP sensor has been deleted and re-configured more than once. I'm using the 3.0 software and using default layouts with some added gauges and tables for scanning. Nothing too fancy, I'm a noob at this.

Key on, engine off, it shows 40Kpa. Pretty much that log shown above was representative of what I get. That was about 5 miles of driving if not more. I'm going to try that cfg file now and see if that fixes it.

Thanks!

K-Spaz

Just deleted the VCM Scanner.cfg file and same results. Still reads 6.1psi with the engine off. 45 max.

There's only 2 choices for MAP channel. One is pressure, the other volts. I've already verified the sensor itself is working at 0-5Vdc so it's not that. It also has a range of values that coincide with what online info says it should. Hmmm.

Well, at least I know I need to look for something in HPtuners. What I don't understand is how all the changes I've made to the VE table have worked properly.

K-Spaz

I looked at that config file and the XML in there seems to indicate that's just for setup of the gauges, tables and graphs. I could be mistaken, but I think I need to look for a different cfg file. I looked at every instance of 50030 (ID of that parameter) and they all look like they're just referring to it, not determining how it's translated.

But I think you've got me in the right church, just wrong pew.

K-Spaz

I can't find any other CFG files that look like anything to do with those channels. I also can't find a default channels 'file' though I know that on the menus there is such a thing.

Even if there were a mismatch between a 1Bar OS and 2Bar whatever, there should not be a scaling of these values, should there? My values on the tables/tune all stop at 105Kpa so I want to believe this is a stock 1Bar OS.

RedRiderZR1

The vcmscanner.cfg file is the file that HPTUNERs support has people delete to fix issues like this. If still having issues I would contact HPTUNER support and see what they say. Personally, I went back to version 2.24 because of issues I had with ver 3.0 and then 3.1. Ver 2.24 worked perfectly for my car and never had any issues. I don't like the way ver 3 works and the bugs were driving me nuts. Anyways sorry for my rant. HPTUNERS support could find the solution to your issue right away.

K-Spaz

Bugs? Wow, I'm shocked, SHOCKED I tell ya.

It feels like that's all I've dealt with. Go to scan and certain PIDs don't connect. This MAP issue... Wiped out a PCM doing an upload. Yea, this 3.2.xxx is a real gem. I just downloaded another .msi a while ago but didn't install yet. I'm really new to this so just amplify the frustration by 10x and you get my aggravation level.

I don't even know where to ask for support. I've tried that HPT forum and found that positively worthless. Don't even get me started on what I think of that site. Starting to think the HPT was simply a bad investment. What a pos. There's got to be a better alternative out there.

RedRiderZR1

I have never used the support forum but know people who had. They didn't seem to have that issue. But in any case I didn'tlike 3. 0,1,or 2. So I went back to 2.24 tht just works. That and I have all these custom configs, PIDs, and Histograms that do not translate well to ver 3. But I assume your issue is software related and not a hardware issue. Your OS looks like 1 bar OS, and I assume you are using a 1 BAR MAP sensor. So unless your data wire is messed up (which from earlier post looks OK) I feel you have a software issue.

K-Spaz

Well, I once again spent several hours tonight trying to either google answers or find it on my own on the pc here. To no avail. I agree now that I've got a software issue I'm chasing. I find it hard to believe there is no posts about it on the HPT forum, but I've come to the conclusion that there isn't enough activity there to make it worthwhile. I know I'm probably exaggerating to say I haven't found a single piece of info on there that was worthwhile, I've searched the web a lot. But I honestly can't recall one.

Between them removing ALL attachments to posts (pics, tunes, cfgs, etc), it basically makes the site 100% worthless. Add that to the fact that there are not many good technical writers there, and well, it is what it is.

I have only gotten an answer to ONE question on that forum. I asked (after long hours of more searching), wtf the sticky was talking about, I can't find these items, this menu item doesn't exist, that toolbar button doesn't exist, w..t..h..??? Someone replied (a miracle) that I should look for 'this xxx' thread... Well golly gee, so the sticky refers to software that's 10 years old and so depricated it no longer even used the terminology of the past. Wonderful... What a coincidence, the rest of the stickies are equally devoid of content, superseded or have all references to pics/screencaps removed. And the entire forum is basically devoid of info pertaining to V3 which has been out for 9 months now.

I asked a question using their email form on the site. I'd just about bet the price I paid for the package that it won't get a response. I would be VERY surprised if I hear anything back from them.

I've already gotten more info and in less time on the CF than I ever did on that pos site.

RedRiderZR1

Sent you a pm

Also it would help to upload your log file from the pic you took from the first post. It would help if I or someone else could see what you see in the scan.

K-Spaz

Here's the tune and log files. As I mentioned, I'm new to this so it didn't dawn on me that this has been wrong. Changes appeared to work and the car 'is' tuned to run half decent. I think though I'm going to be re-tuning from scratch now that this has been found.

I got an automated response from HPTuners. We'll see if that ever translates into a response from a human with an answer. I am not hopeful however. That would mean that this issue is new with me and I seriously doubt that is the case.

Tune

Log

K-Spaz

Well this ain't funny at all. I just looked back at the very first tune I ever pulled from the car and both that tune, and the one I pulled from the new PCM after putting that in and getting a new tune from AcDelco (with my Tech2), BOTH are a 2 bar OS.

So why then is it that the tune that was pulled only shows values to 105Kpa in the charts, and why is the stock MAP sensor a 1 bar sensor?

I'm totally lost now. This is most confusing. I just put in a SU1176 Map sensor and that clearly is a 1 bar sensor. It's entirely possible that the one that was in the car was a 2 bar, and that that's why I saw 3.5vdc when it was in open air. Still doesn't explain any of the rest of this not matching up.

RedRiderZR1

Well if you truly do have a 2 BAR OS that would explain the MAP values halved. On a hptuners 2 BAR OS you will see the table doubled. Why it is not on your OS if it is a 2 BAR OS idk. A 2 BAR MAP sensor at Atmosphere (14.7) would be about 2.45 volts. Lower if not at sea level.
Have you tried to scan the car with the old MAP sensor? You can go out and get a verified 2 BAR MAP sensor and put in. Voltages would read correct for the table to read 100 kpa if you are sure you have a 2 BAR OS.

K-Spaz

All my logs up till the day before yesterday were all with the old map sensor. 100+ of them.

I just looked back and found logs I did of the car before it was ever torn down, before the PCM got the P0601 error that hosed it. Those logs showed the full spectrum of MAP rows being filled with data. It was after the engine swap the PCM had fits and needed replaced. I replaced the PCM with one from a 98 car with rear EBCM (mine is front EBCM so late model year 98). Everything worked fine so I assumed I was good to go. All logs since show the MAP being scaled to 1/2.

I found a truck tuning site that had a thread discussing this very issue. The gist of what they said was yes, you can get it to work but it'll be lower resolution and a real pita to deal with when tuning. That last part at least seems true.

After some more research I'm inclined to believe that the PCM I have may not be compatible with the tune that came with the car. I don't know how to resolve this. Perhaps it's possible I have a bastard car from late in MY1998 which has the newer 1999 and up PCM? To be honest, this entire process is fatiguing. Were it not for a checksum error that came about after the first time programming with HPT, none of this would have ever taken place.


If I open the tunes, both before the PCM swap and after, both do read 2 Bar OS in the OS dialogs. So, that leads me to believe the PCM is a 2 bar (much like the later 99 and up). But if that's the case, why has HPT always shown tables with the 0-105kPa MAP range? That leads me to belive it's a 1 bar. To be honest I'm so confused with this, so many things seem contradictory to others when you look closely at them one makes me believe one thing, another points at something else.

romandian

can you scale the sensor in hp-tuners somewhere? (i use efilife.)

K-Spaz

Not that I know of. Unless you mean to say, can I make the graph look different to which I would say yes, I think... I think I could create custom PIDs with different voltage offsets and fill out more of the graph. But that would only be what HPT is seeing (as far as I understand it). This is so confusing I can't begin to describe it. HpTuners says it's not their software, and I did load V2.24 (older release) and scan with that, to no avail.

I have a new OEM matching PCM on the way. I expect that by Wednesday.

But what you're saying also falls in line with the circumstances I am seeing. The way I see it, my situation should show exactly the opposite of what I see. If indeed I have an original 1Bar map OS (which HPT is showing and has shown since day one as a 2 bar Os), then it would stand to reason the original MAP sensor is a 1 bar. Well I checked the output and that goes from 0-4.5Vdc at atmosphere to max vacuum. So ok, 1 bar right? Well then that would indicate to me that if the PCM is a 2 bar, mine should be showing 14 pounds of boost at WOT due to the sensor being interpreted incorrectly. NOT 45kPa at WOT.

I have not ruled out HPT being a Fed up mess. It certainly has enough reputation for V3 being buggy. I have only experienced minor glitches that I've noticed, but this does definitely lead me to believe there's an issue with it because none of what I see adds up.

Cliff8928

It appears that your calibration is the one correct for the VIN according to http://calid.gm.com/

The option to update to the 2 Bar OS is there, but it wasn't applied.

K-Spaz

Again, I'm a noob at this. Are you saying the calibration has two possible configurations and that the 2 bar OS is something configurable?

If so, is that to say that the "Apply Code Modification" button on the OS tab needs clicked? I had no idea what that did.

Cliff8928

You would only "Apply Code Modification" if you were tuning for boost.