tempestram

I normally see 23psi boost max. I installed the 3 bar sensors and now read 16psi boost max. Is the rpd being affected by the sensors? The car still performs like it has 23psi.

RJ_RS_SS_350

You had 23 psi without the 3 bar sensors. Now you've changed your configuration, but you haven't changed your tune? A call to your tuner is advised, see what he says.

lazaino

Unless you tell the car you changed the sensor it will read off, if you went from 2 bar to 3 bar sensor it will probably read about 2/3 of the value. It may also mess up the tune under some conditions. In your case, 2/3 of 23 is 15.3. If if ever decides the MAF is off and tries to run SD, it may go very lean, hopefully lean enough to die and not just lean enough to destroy a piston.

Ira

tempestram

I have the Trifecta tune and the new tune for the 3 bar sensors was programmed in.

donbrew

Perhaps the new tune didn't really get into memory. Computers are strange.

RJ_RS_SS_350

In any case, tuning is the problem. Call your tuner.

Hmmm... Did you trim the tab before you installed the lower TMAP sensor?

tempestram

I hate to sound stupid but it may just be that. I bought the bosch 3 bar sensors and pigtail cables from ZZP and they bolted right up without any clearance issues. By tab do you mean the little tab on the pipe next to the TMAP?

Oldblue

https://www.chevyhhr.net/forums/how-...ive-way-62943/

RJ_RS_SS_350

That's my alternative way to mount the lower TMAP sensor. I'm looking into the tab issue. I can't remember if you only have to trim it when rotating the sensor 180*, or if you trim for the standard position.

I'll be back

EDIT: Looks like the tab is on the sensor itself. Look at post # 20. https://www.chevyhhr.net/forums/hhr-...p-58960/page2/

You can see the anti-rotation bar molded into the charge pipe, in the second pic that Oldblue linked to. The tab on the sensor will ride on top of the bar, creating a vacuum/boost leak. This is in the standard position, like you have yours.

donbrew

I posted the TSB regarding the Tmap installation somewhere. Here is a pdf.
Tmap.pdf