1G Electronic Boost Data Logging

[QuasiMondo]

I redid the sensor wiring today. Took her out on a run....and got the same results(!) So I went back, double checked the wiring, and verified voltages. All were good. So I figured that I have the sensor tapped into the wrong vacum port, and even pulled the hose off to see if it would read any different, no change.

Then it hit me like a light bulb. I remembered that when I first upgraded the MMCD software, I saw two MAP readouts, one matched what I would expect, and the other didn't move. I selected the one that didn't move, and it worked.

Sweet success of mine!!!!!!

Then I got to thinking about why it didn't work before, and I remembered what Clint said about what the EGRT would read when nothing is connected to it. Turns out that when I had the MAP sensor wired in backwards, the EGRT saw nothing because pins 4, 5, and 6 were open. No different than if I had nothing there.

So what about the 'other' MAP reading? I got the sensor working right, I did a few runs, graphing both readings side-by-side. I discovered that the 'bad' MAP reading would peak right around 10 psi on the 'good' MAP reading. I also noticed that the factory boost gauge would hit its peak around the time the mechanical gauge reached 10 psi. This leads me to believe that the 'bad' MAP reading is actually what the factory boost gauge reads.

So to sum it all up, the wiring colors for DSM's is correct. If you're using MMCD, make sure that you're selecting the first MAP reading (the one after TPS) and not the second one (listed with the eight new inputs)

Many thanks for the help on this, Clint. With your permission, I'm going to put your FAQ on dsmtalk.com, they've been asking about it. I'm also going to see if any GVR4 people have done this as well so they can tell us what wiring colors they use, I'm sure it's going to be different as well.

[cbatters]

Originally Posted by QuasiMondo

I redid the sensor wiring today. Took her out on a run....and got the same results(!) So I went back, double checked the wiring, and verified voltages. All were good. So I figured that I have the sensor tapped into the wrong vacum port, and even pulled the hose off to see if it would read any different, no change.

Then it hit me like a light bulb. I remembered that when I first upgraded the MMCD software, I saw two MAP readouts, one matched what I would expect, and the other didn't move. I selected the one that didn't move, and it worked.

Sweet success of mine!!!!!!

Then I got to thinking about why it didn't work before, and I remembered what Clint said about what the EGRT would read when nothing is connected to it. Turns out that when I had the MAP sensor wired in backwards, the EGRT saw nothing because pins 4, 5, and 6 were open. No different than if I had nothing there.

So what about the 'other' MAP reading? I got the sensor working right, I did a few runs, graphing both readings side-by-side. I discovered that the 'bad' MAP reading would peak right around 10 psi on the 'good' MAP reading. I also noticed that the factory boost gauge would hit its peak around the time the mechanical gauge reached 10 psi. This leads me to believe that the 'bad' MAP reading is actually what the factory boost gauge reads.

So to sum it all up, the wiring colors for DSM's is correct. If you're using MMCD, make sure that you're selecting the first MAP reading (the one after TPS) and not the second one (listed with the eight new inputs)

Many thanks for the help on this, Clint. With your permission, I'm going to put your FAQ on dsmtalk.com, they've been asking about it. I'm also going to see if any GVR4 people have done this as well so they can tell us what wiring colors they use, I'm sure it's going to be different as well.

Sorry for the confusion caused by the version of MMCd you are using that had HSLogger expansion channels pre-configured on page 4. (HSLogger is a new high speed expansion unit that supports higher baud rates, additional high speed analog sensor inputs and odometer/speed.)

Without the HSLogger expansion unit, the MAP sensor on sensor page 4 would be reading data from ECU register E0 which I believe on a DSM is airflow - which from a distance looks kind of like boost.

Again, sorry for the confusion and any time you wasted but happy to hear that you were successful. (Also good to know that hooking up the sensor backwards using pins 4-5-6 does not cause any damage.)

Two features to check out that I think you will enjoy.

1. Check out the peak/hold/reset function as well as the Min/Max in big number mode. (I leaned more about my car from using peak than I did in months of logging.)

2. Check out the autolog trigger in the alarm configuration. If you set up autologging trigger on KNOCK>3 it will automatically start the log whenever you get knock.

Actually it is much better than that. There is a pre-log that provides several seconds of data BEFORE the trigger and a post-log that will turn off logging in 30 seconds if there are no more triggers.

Setting up a trigger on TPS > 70% allows you to automaticlly log every WOT run.

You can also use the smart O2 alarms which are only active when TPS > 80% so you can alarm/log on O2 < .91 or whatever value you desire.

NEXT MMCd VERSION
Next version of MMCd will have a number of DSM / 3SI configurable options as other options to support new HSLogger functions. ETA ~ 1 week.


Clint

[rdmelton]

I tried to find the harness to connect to the MAP sensor today, but ran into difficulties. no one has this harness in stock (pep boys, autozone, advance auto, and GM dealership), and even if they can get it, it is expensive. (pep boys could order conduct-tite PN 85146 for $23, or GM dealer could order 15305891 for $35, or gmpartsdirect.com has it for $25 shipped)
At Advance Auto, I did finally find a book by Calterm with pictures and descriptions of electrical connectors/harnesses, and I found two possiblilities but they claimed that they couldn't order either of them. (wtf?)
In case anyone else is able to find these parts, here is the information:
Calterm PN 08658 replaces GM part number 12085502, and it is for a GM MAP sensor (the picture looked like the correct style). this one should be a direct fit, with the notch in the harness.
there was also Calterm PN 08826 which replaces GM part number 12085507, and it is for a GM A/C pressure switch. (I think that this is the same as the conduct-tite PN 85146 harness. Calterm PN 08826 will probably require modification like the conduct-tite harness).
so that's the best that I've been able to find so far. I saw that others have found the conduct-tite harness for ~$10 at pep boys, but no such luck for me.

Also, it appears that the 3 bar map sensor is available through many auto parts stores if you ask for a MAP (or barometric) sensor for an 89 Transam 3.8L V6 turbo.
edit - see http://rdmelton.autoeducation.com/ca.../boostlog.html for MAP sensors that will work

[TurboBob]

Full Throttle Speed carries the harness as an accessory to the Scanmaster.

It as the GM MAP sensor plug on it.

I believe the price is under 20.00.

Its not on their web site yet, so you need to call them.

TurboBob

[cbatters]

I have had pretty good luck getting connectors from NAPA... A phone call in the AM and you can usually have the part either that afternoon or the next day. (although after looking at the GM sensor I went with the 4250 MAP sensor to simplify mounting.)

http://www.napaonline.com/cgi-bin/nc...3&prmenbr=5806

[rdmelton]

Ok, after one minor wiring issue, I am now logging boost. After doing this, I can't believe that this isn't more popular. I can only guess that people wouldn't do it because 1. they don't know that it's possible, 2. they think that it doesn't give enough value/benefit for the cost. If someone has a logger cable (starting at $50?), I can't imagine that it doesn't seem worthwhile to spend <$75 for the sensor, wires and vacuum hose/fittings. (much less than $75 if using digikey sensor, but I personally didn't want to go with it because the sensor and wires didn't seem well protected )
The one issue that I noted above is confusing. A few weeks back, I made some notes about how to hook up the wires from what was stated in the first post (without first checking voltages - I know, you said to do it). When I hooked everything up, I didn't get accurate pressure/vacuum readings. So I used a voltmeter, and found that the black wire on the A22 EGRT connector was ground, and the white wire with a black stripe (you said that the manual says that it's light green, but it looks white to me) has voltage, but my notes had it listed the opposite way........ so apparently I goofed when I wrote it down originally. So I switched the two wires, and all was fine. So, like someone else said, hooking up the wires wrong (at least in this way) doesn't seem to damage the sensor.

Anyway, I wanted to say thanks for all the work you've done on boost logging and the MMCd. Unless pocketlogger comes out with a comparable feature for reading the EGRT input and scaling, their software will be permanently put into retirement for me. In case this hasn't been mentioned before, this is MUCH better and safer than trying to watch a boost gauge while going WOT!!!! and it even gives way better info than a peak only boost controller or gauge because it shows the full boost curve and all other typical logging parameters with it (I know this is really obvious and it is the whole point of logging, but I just felt the need to reinforce that it's really great)

Also, I am working on putting together a webpage with info and pictures about my experience (of course with full credit to you, and links to this post). I wanted to put it together to try to document some of the different sensors that were out there, so people could more easily find the parts, and at a better price. I also wanted to have lots of pictures available for those who might otherwise be intimidated from attempting this.

http://rdmelton.autoeducation.com/ca.../boostlog.html

I am still trying to collect 3 bar sensor part numbers, harness part numbers, and key/keyway locations for all of these sensors and harnesses. (I know that if the keyways don't line up it is a very minor issue,and that they can be fixed in a matter of a few seconds or a couple of minutes at the most, but it is a bit annoying, and would be nice if they matched up correctly. So, if anyone has information about the GM style 3 bar MAP sensors and/or harnesses(part numbers and/or key/keyway locations), please let me know and I will update the page.

[skunkworks]

Isn't it wonderfull? Sometimes I take it out of graphing so I can see the boost on the large number display. Plus remember you can measure peak boost. I used that to set my mbc.

One reason why it may be not so popular is it only works on first gen cars.

sam

[cbatters]

I got interested in boost logging after I nearly collected the rear end of a GMC truck while distracted by a boost gage. Opinions obviously vary, but I found it distracting to attempt to monitor boost while driving. (An occasional glance is fine but looking at the gage for 1-2 seconds during WOT can be very dangerous.)

RDMELTON - Appreciate your detailed instructions - I will add a link at the start of this thread to your site.

Three thoughts:

1. Might be worth adding pics of Samco's MPX4250 sensor install

2. Might be worth adding pics of MMCd config screen to make sure that the right sensor has been selected (attached)

3. Make sure you check out Autolog triggers / Alarms and Peak - Great way to automatically record / alarm on any WOT events.

Again.. thanks for your more detailed instructions/pics.



Clint

[cbatters]

Originally Posted by samco

Isn't it wonderfull? Sometimes I take it out of graphing so I can see the boost on the large number display. Plus remember you can measure peak boost. I used that to set my mbc.

One reason why it may be not so popular is it only works on first gen cars.

sam

Boost logging also works on the Hybrids using the unused EGRT input (and we'll have Boost lgging for the masses soon with HSLogger that works on any car to log Boost / Speed / Fuel Pressure / Wideband / EGT etc.)

Would you mind posting an MMCd graph display of your MBC boost at WOT. I am very intersted in how much boost overshoot you are seeing.

Two cases:

1. WOT starting at 3000 RPM (in 2nd or 3rd gear)

2. WOT starting at 4000 RPM (in 2nd or 3rd gear)



Clint

[skunkworks]

I really don't think I have a problem with spiking now. But when I first got my mbc (cheap one off of ebay - pretty much a home depot one) I had a heck of a lot of problems getting it set. It spike bad also - quite a few lbs over. Anyway after taking it apart and looking it over I figured the bleeder hole was too big. I soldered over there hole - 1/16" and drilled in my hole - think it was about .025". (I also preset it with an air compressor and regulator.) Now I can't really see a spike. It goes to maximum boost and dies down as I would expect from 9b's.

Anyway the Logs are not that great - I just took what I had saved locally. The first three are wot runs - not sure what gear - you can see the rpm range. The last one is to show you the knock I am getting off and on. Notice I am running 14.5 peak with no knock and when I slowly accellerate I get knock - see the boost at <0. Still anoying.