What exactly happens when you pass the limit for the stock MAP sensor?

EXAMPLE:
If you were running the quarter mile at 10psi & experienced a little boost creep, it would throw a CEL right (@11.x psi)? What happens then? The reason I ask is that I would like to run about 8-10 psi and am concerned about any creep issues. Would it go into limp mode and require resetting the ECU? Is it risky to the motor?

 

You can damage the internal diaphram inside the map sensor. As far as CEL, it depends on what you've got for engine management. With Hondata, you can have it cut off fuel if boost exceeds a certain psi or you can have it do nothing.

Sonny

 

its risky. if you don't have a boost cut feature and you hit the limit of the map most likely the motor will go lean, you will be supplying more load than the computer can effectively read. if you boost 15psi it will think 11.xx, if you boost 20psi it will think 11.xx. This will lead to lack of fuel becuase the computer only thinks you at 11.xx psi.

 

So the stock ECU won't go into limp mode... lame. Thanks guys.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Crazy Cooter &raquo;</TD></TR><TR><TD CLASS="quote">So the stock ECU won't go into limp mode... lame. Thanks guys.</TD></TR></TABLE>

Yes it does. First time it happend to me, I thought I blew something. The MAP is essentially ignored by the ECU (since it determines it to be faulty) and the car won't want to move unless you give it something like 50% throttle. Trust me when it happens, you'll know right away when you go to put your foot down and your car simple doesn't respond. My guess is the ECU runs the car max rich as well because when it happens to me, the car smokes considerably (black) at idle, and I've pulled the plugs after an occurance and they looked black as night.

 

Only time i did it, it threw cel and then car shutoff, from what im told it shoudl start right back up, but i blew a fuse at the same time so mine didnt start right away

My dumbass thought i blew the motor

 

I am boosting 12 psi spiking to 14 with the safc hack on my car...No cels...Runs fine....a/f looks good...via wideband......dont be scared, just boost her up.....make sure tuning is good though...

 

sorry about my explanation, seems that it more applies to an aftermarket ecu, not a factory honda one.

 

Damn, Adam...your CRX is haulin' ***. How much does that thing weigh?

Sonny

 

just get a GM 3 bar...... problem solved

 

mine has always kinda cut out

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Sonny &raquo;</TD></TR><TR><TD CLASS="quote">
Damn, Adam...your CRX is haulin' ***. How much does that thing weigh?

Sonny
</TD></TR></TABLE>

i'd have to guess around 2200 lbs. never been on a scale so I can't say for sure.

 

Good luck getting a Honda MAP sensor to read 11.x psi. I wish Hondata would remove that little bit of misinformation from their website.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 94goldjungsr &raquo;</TD></TR><TR><TD CLASS="quote">mine has always kinda cut out</TD></TR></TABLE>

Cool, that's what I want it to do. I would rather blow the diaphram in the map sensor with boost creep than twist a rod (or worse).

 

It depends what set up you are using. When the ecu sees any positive pressure it will go into limp mode. Depending on what setup you use the ecu might not even be able to see positive pressure.

Jake d.

 

blacknight7........good post about "depends on what set-up u are using" I myself keep telling people the same thing....I am using the safc hack pushing 12 psi spiking into 14 w/ no problems at all...

 

when I trip a MAP code with the hack i just get a light and the engine runs just slightly rougher. If the light wasn't there I probably woulden't know for a half a minute or so. Never tried to boost after it came on. Mine is not nearly as poorly running as some of you guys. not even sure if it is in limp mode. it definatly doesn't shut off or anything.