Cloudio

Hey guys were having some problems with my 2.4 SC MAP sensor right now its running through the 2.5 bar map and the car wont rev past 4k.. checked the throttle body, it seems to be opening completely... Has anyone got the 2.5 bar map to work properly on the 2.4 or are you guys using the 1 bar map sensor and teeing it in so it sees boost and tuning from there????

its not a tuning issue, Vince at trifecta is all over it

any input/ suggestion???\

Bump

HunterKiller89

iTrader: (1)

if you're going with the 2.5 bar MAP, then you have to wire it in like Beck did in his how-to. My guess is that you either didnt do this, didnt do it correctly, or you have a bad connection. Its not a simple swap with the stock sensor

Cloudio

ya i wired it right off of becks' how to diagram, i am definately thinking ur right about that bad connection as i did it in a hurry ...ill have a looksy after work and keep u posted, thanks for chiming in...

pjk91

should be pretty straightforward. check your connections

Cloudio

went ahead and resoldered everything again according to those diagrams an iam still having bogging issues/ still wont rev past 4k .. any ideas????

HunterKiller89

iTrader: (1)

did you tune for it correctly then?

IonNinja

why even bother with it when you can tune off MAF?

sounds like un-needed trouble

Zooomer

iTrader: (1)

ZZP has a solution to do this the proper way:

http://www.zzperformance.com/cobalt_...=991&catid=144

pjk91

^^you don't need that sensor. Are you sure you are hooked up to the correct MAP sensor and not the SCIAP sensor? you should be getting MAP from the sensor on the IM.

Jn2

iTrader: (1)

will that work on a 2.2?

Zooomer

iTrader: (1)

Technically you don't "need" anything but you do need the sesnor to do the job properly. Absolutely you do. The factory sensor is single bar and will not allow you to compensate for boost in the PCM. You can tune around it but the tune will never be fully accurate. You could use a 2.0 MAP sensor and rig it to. That requires cutting wires, programming your PCM and again rigging it. The PCM won't allow a 2.5 bar MAP (used in the 2.0) to scale properly.

Our unit is plug and play and required to do the job the way it should be done.

slowswap

If you can just tune off the MAF, that would be a way easier route.

Zooomer

iTrader: (1)

You can tune off the MAF but the PCM is only aware of how much air is coming in the engine then and not how much fuel it's providing. This means you can guess tune it close but it will never be fully accurate and the tune will change as air conditions change. If this is your only option then it can be used but it is not ideal.

slowswap

MAF sensors in combination with a intake air temp sensor can provide better changes to air conditions then a MAP sensor. You have to do a bit more data logging and tuning then with a MAP sensor, but it's a way better option.

Matt M

Tuning with a 1 bar MAP sensor on a boosted application with a fixed fuel pressure will never be consistent between different boost levels. We don't use the 2 bar MAP for a speed density tune, we use it to allow the ECM to calculate the correct injector flow rate at different boost levels. Without this, the ECM has no idea that your relative fuel pressure is falling as boost rises. If you never plan to change the boost level, it can be done easily by falsifying the MAF chart and/or dialing in based on RPM in the EQ ratio chart. The problem is that if you add more boost, the tune will need to be modified. The 2 bar MAP solution allows you to set it up once and change pulleys if you choose. Turbo setups with boost controllers benefit from the 2 bar MAP swap tremendously.

pjk91

Yeah but he's got the 2.5 bar map. If he scaled it correctly, wired it correctly, and setup the tune correctly it shouldn't have any problems. If he scaled the IFR vs pressure delta table correctly then the ecm DOES know that fuel pressure falls as boost rises.

Matt M

Yes, we weren't saying the 2.5 bar can't work. We were only correcting Slowswap for saying that you don't need a MAP that reads boost.

As far as a 2 bar vs. 2.5 bar, the 2 bar is the better choice for turbo swaps. It plugs right in and mounts the same as the factory 1 bar sensor. The ECM file only allows you to program up to 1.8 bar anyway, so the 2.5 bar has no advantages over the 2 bar. Either one requires changes to the ECM.

For M62 swaps, the 2.5 bar mounts easier, but requires wiring modifications.

Jn2

iTrader: (1)

still waiting to see if this will work on the 2.2? we use the same MAP as the 2.4 i believe, i had bought a 2.4 manifold that came with the stock MAP, p#'s were the same when i compared to mine, only thing is idk if vince can tune using the newer MAP sensor, i could email him to find out

Cloudio

very interesting you guys.... ill have to talk to vince about it ill keep you posted on what i find out....

VinceTrifecta

We have scaled the 2.5bar MAP sensor in the tune. We are tuned off the MAF. But we use the MAP as a threshold for PE fueling.

However, the ECM has some factory boost related torque management settings that come into play at around 150 kPa boosted manifold pressure, and that's where we start seeing trouble with this car (when the manifold reaches about 250 kPa).

A 2bar sensor would prevent this from happening in this application because it wouldn't ever read 150kPa boost in the manifold.

I may have to rescale the MAP to max out at 200 kPa and proportionately adjust the MAP threshold for PE fueling to avoid this or he can go to a 2bar or 1bar MAP sensor.

HunterKiller89

iTrader: (1)

Well Vince, since you're in this thread..would you reccomend I get the sensor ZZP is selling to plug into my manifold, since the sensor that your tune is currently reading pressure from is pre-compressor? Or should I just move the sensor over?
basically, should i stick with the 1 bar? or move to the 2bar ZZP sells?

Jn2

iTrader: (1)

good question i would like to know this aswell for when i boost supercharge my car...i was planning on map sensor ebing located on the intake manifold and if it helps you make a better tune id buy it; consider u can tune for the 2bar map

VinceTrifecta

If it were my car, I'd stick with the 1bar MAP sensor since the OS and ECM we're using is calibrated for a 1bar MAP sensor. Who knows what MAP based thresholds might exist in the ECM. The issue the car owner that started this thread is running into could very well be caused by some unknown threshold that GM put in there for some factory boosted application.

The only thing we care about with regards to MAP for tuning this particular configuration is when to enable PE mode, which we do before the MAP goes out of the MAP sensor's range.

Jn2

iTrader: (1)

oh ok thats fine, im actually supercharging my car using a stock m62, i believe u have a perfected tune ready to go from another local here in my city, so when im ready to order the tune i think it should be pretty dead on; look forward to dealing with you later around may-june

Matt M

You don't use the MAP sensor to adjust injector flow rate since boost is basically decreasing the fuel pressure relative to manifold pressure?