Drunken ECU Experimentation

[Gimpster]

I'm going to post this against my better judgement. Tonight I got a bit tipsy and thought it would be a good idea to try something out. I pulled the 2008 HHR GMPP tune out of the repository, and then proceeded to write it into my 2009 Cobalts PCM. Normally I wouldnt try this because I'd be afraid of bricking my PCM.

The drunken leap of faith + usage of 2 credits = the results look good. Lets hear it for liquid courage

Here are the details from my PCM before the flash:





And this is after:





As you can see all of the segments changed along with the OS ID. The key segment is #2 though, thats the P/N for 2008 HHR SS Stage 1 tune.

After the flash my RPD bliped and suddenly changed from 0psi to 2psi, which is obviously the result of the incorrect MAP sensor scaling. I then started the car, and voila it started nicely. Everything else in the car seemed to be working normally, which I expected since its also a Delta chassis.

I then logged the car, and what do you know the idle pre flash and post flash... the MAP and Boost Pressure sensor differe by about 30kPa, which is about right on for a .3 BAR difference. I've attached the logs of the car idling before and after flash.

So in closing, if I can ever get those 3 BAR MAP's from GM Parts Direct ... it appears I'll have a stage 1 to build a base from. It goes without saying you'd need to copy/paste all of your Cobalt centric tune stuff over.

This is good news since it appears GM raised the duty cycle of the solenoid in their tune, and so now the DAL should be much more potent

Tomorrow I'll drive around a bit to get the codes to pop for MAP sensor error and then flash back to the Cobalt tune. Obviously I'd prefer to get my hands on a real Cobalt stage tune, but the price on this was right... free.

[Jaxon]

So yes or no in buying the 09 cobalt tune, ran on ,035 pill iirc with no codes, 3* kr at max, while spinning and also hit nls. That pm i sent you is correct btw. Werent the sensors ever used on a factory vehicle. Iirc they were used on something. Cant search well enough with my cell. This was with catless dp, ic pipes, 3" exhaust, and some sorta airbox mod. The tunes maxed out as stated in my other post. So 22.5psi is actually 29?

[HawkZ28]

^X2. Or drunk dial.....Especially ex's. Or play with guns.....unless, of course, you are dove hunting, then it's a requirement.

Lock up the keys, laptop, phone, and guns. Did I cover it all?

Good job though!

[JoshMcMadMac]

Awesome, Gimpster. I am very happy to see at least a few folks making use of this information! Keep an eye on the trouble codes, just in case anything should show up other than the sensors. I am not sure what all is different between the platforms, but there must be some reason they all have different calibration codes. I am willing to bet you will be fine, though.

[Gimpster]

Let me clarify that I didn't drive drunk, only flashed + idled in the garage drunk

Jaxon, I'm not sure if I need that Cobalt tune anymore. We'll see, and keep it handy. Also I'm aware of european vehicles that also use this MAP sensor, but nothing else in the united states market. I had heard rumors the Jeep Liberty Diesel used them, but when I went to Chrysler they claimed it only used a MAF device. The Libery does appear to have a MAP on it though AND a MAF, ... so I'm trying to dig into that more.

JoshMcMadMac, hopefully this puts to bed people saying a write entire ISNT a write entire. At least from HPT's point of view, my car is now a 2008 HHR SS w/Stage 1. Except for the VIN I appreciate the encouragement and information you've posted and PM'd.

[Gimpster]

Sorry to spam the thread here, but....

Doing some digging, here is a picture of the 2005-2006 Jeep Libery CRD MAP sensor:



Physically its mostly a match, but is it the same specs? Bosch does offer these in a wide range of scale and physical packaging.

I'll keep digging. The one thing I can tell you is that Chrysler wants a lot more than GM for those. The Liberty CRD is an Italian sourced engine though, so the chances are much higher it could be a match.

EDIT: I found this on a Jeep Liberty forum where they're discussing an issue with the MAP sensor. So they seem to think its a 3bar hmmmmmmmmmmm. Its $47 though, so expensive for an experiment.

In any case the sensor cost $35 at Jeep (a standard 3 Bar Bosch sensor) part number mopar 56044591AA. This sensor MAP and the MAF sensor which is on the air filter box primarily control the EGR valve.

[JoshMcMadMac]

EDIT: I found this on a Jeep Liberty forum where they're discussing an issue with the MAP sensor. So they seem to think its a 3bar hmmmmmmmmmmm. Its $47 though, so expensive for an experiment.

I know a guy that has a Liberty TDI, so I will see if he can get the Bosch part number off of it. Otherwise, one of us can order one from the Jeep dealer and check it out. I know that it appears identical in the Jeep picture you posted.

[Jaxon]

If you want me to send you the 09 cobalt ss stage tune, please send me a pm, maybe we can figure something better out...

[camaro1]

i installed a couple of the hhr stage kits at our dealer but never kept the gm part number off the map sensor box,

[Gimpster]

The GM P/N is: 55206797, but is on national back order. I went to another GM dealer today and they likewise said sorry.

Josh, I went by a Chrysler dealer today and they did have the sensors available to order, but want $72! You can get them online for $47. Way too much money for a sensor that might/might not be right. If you get a chance to eyeball that sensor on the TDI Jeep that would be cool

FWIW, the guy at the GM dealer I stopped at said hes been having issues getting a lot of service parts. Everything from sensors to transmissions and I wonder if the whole bankruptcy thing didn't screw up the parts funnel a bit?

On another note I did find the datasheet for Bosch TMAP's, and while ours specifically isnt on there... it does have a voltage conversion chart for another 3 bar. Perhaps it might be possible to find a substitute MAP sensor thats a close match and retain the one stock TMAP in the cold charge pipe just for the IAT.

[Gimpster]

Alright folks, tell me what you think of this. I realize im likely the only person who cares about this, but what the hell.

The situation for finding the exact GMPP TMAP seems sort of bleak. I was doing quite a bit of research today, and it seems the Mazdaspeed 3/6 guys have done the heavy lifting for me. Using some of the data they had posted I made this Excel.

Consider the following screen shot:

http://www.ecimulti.org/scratch/HPTu...comparison.jpg

Green = Standard GM 3 BAR MAP P/N# 12223861
Blue = GMPP Stage 1 3 BAR MAP P/N# 55206797
Red = Bosch 3 BAR MAP P/N# 0 281 002 437

With this data in hand, here are the options as I see it-

Option 1: As you can see the GMPP and the standard Bosch are pretty much in the same ballpark. The areas they differ the most are the lower ranges, and ... well your car is pretty much never there. I did some datalogging and fully warmed up my car is never below 38-40kPa.

The bummer being that Bosch MAP sells for about 80-90 bucks.

Option 2: The standard GM 3 BAR MAP sensor is in the "ball park" most places, and would likely work. Once again my car never seems to be below 38-40kPA. Also something tells me that a difference of 1-3% in the upper ranges is going to be acceptable to the PCM, but you never know.

The cheapest I can find those is for $41.99 w/pigtail each. Since the car is REALLY only using one temperature probe (in the cold charge pipe), its my thought a guy could leave the TMAP in the pipe and splice the sensor into the pressure wiring. Not very sexy, but hey...

Option 3: The final option is the possible 3 BAR sensor on the Jeep Liberty TDI/CRD. My hope is that its the same as P/N# 0 281 002 437. Looking through the Bosch website, they really only have a couple 3 BAR options in that form factor.

This sensor is available for about $47 the cheapest I've seen thus far. I might be able to get it cheaper through a buddy.

Option 4: Chill out, its Winter and hope GM Parts Direct gets them back in stock.

Right now I'm going to pick option 4, especially since they have my money.

In the mean time I'd like to continue down the path of the seeing what sensor is really on the Jeep.

Happy Winter!

[Iam Broke]

Option #4

[JoshMcMadMac]

My buddy with the CRD actually has a spare one sitting around. He is going to check the Bosch number on it and get back to me.

[Gimpster]

Was he having issues? I saw a lot of threads out there about people needing to swap those on the CRD. Guess they get gunked up with crapola.

My buddy with the CRD actually has a spare one sitting around. He is going to check the Bosch number on it and get back to me.

[JoshMcMadMac]

Was he having issues? I saw a lot of threads out there about people needing to swap those on the CRD. Guess they get gunked up with crapola.

He was troubleshooting, but it was actually not the issue. They do get gummed up, but it is the location and the diesel that is to blame for it.

[mkriebs]

I'M BAAAACCCCCKKKK!!!!


Lol. Glad I could take part of Gimps drunken night, lol. Wish I would have had my car to confirm this. I am intrigued by the Jeep MAP. I think I would wait it out til spring and see if we can get the GMPP sensors, but if that fails still by spring, then I wouldn't hesitate to go with the Jeep one.

[mkriebs]

And I am wondering what VW sensor that spreadsheet was referencing?

I found a few on fleabay for $25.

[Gimpster]

Its not an official VW MAP, I just called it that because its what they're using when reflashing.

[mkriebs]

Oh... what MAP are they using then? The 1.8t MAP sensors have the same basic shape, and I know all VW electrics are Bosch.

[Jaxon]

The 1.8t maps are only 2 bar, I remember this because my friend had a 1.8t bug that had a downpipe and stuff. A chip is only a 1bar tune for them because of the map.