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Symptoms of bad 3 bar MAP sensor?

Motorhead said:
Checking for moisture or oil in lines the other day, and found none. But during this process I noticed that the 3 bar sensor once removed, has that aluminum adapter for the boost line, and that is only held in place with an O ring!

I am having no issues with boost, but just noticing how easy this adapter could come off, so I added a few drops of glue to mate the adapter top to bottom of the sensor!

What do you think, good or bad?
Click to expand...
The original Gap 3 bar sensors with the aluminum adapter have a potential to leak around the adapter O ring...sealing the adapter to the sensor sure wouldn't hurt.
As I indicated earlier in this thread I recently replaced my adapter type map sensor after 3+ seasons not because of the adapter issue but because it was not accurately showing boost pressures and would indicate zero boost until mid rpm.
 

can 4 bar sensor be put in place of 3 bar? what would need changing, just cuz i have a brand new 4 bar sensor sitting here. also... what about the manifold pressure sensor on top of right side of fuel rail... apparently this adjusts effects your idle til tps takes over.... these sensors are fckn expensive 600.00!!! there must be a match for one thats cheaper.
 
sideshowBob said:
The original Gap 3 bar sensors with the aluminum adapter have a potential to leak around the adapter O ring...sealing the adapter to the sensor sure wouldn't hurt.
As I indicated earlier in this thread I recently replaced my adapter type map sensor after 3+ seasons not because of the adapter issue but because it was not accurately showing boost pressures and would indicate zero boost until mid rpm.
Click to expand...
Took my sensor off and didn't like what I saw, and that's why I added glue. Then I read your comments on the different style sensors that you have used. Good info whereas I was thinking that they are all the same with that aluminum adapter. A better design sensor would certainly be one without that aluminum adapter and o ring on sensor! If and when, I change that 3 bar sensor out, I would look for one that looks more like the stock 2 bar set up, to the boost line!

So far no problem reading boost at any rpm once it's not idling!
 
max rolph said:
can 4 bar sensor be put in place of 3 bar? what would need changing, just cuz i have a brand new 4 bar sensor sitting here. also... what about the manifold pressure sensor on top of right side of fuel rail... apparently this adjusts effects your idle til tps takes over.... these sensors are fckn expensive 600.00!!! there must be a match for one thats cheaper.
Click to expand...
Your tunes are catered to a specific Map Sensor so you would have to get your tunes updated from the vendor if you wanted to change to a four bar map sensor from a three bar.
The Map sensor on the throttle body is a two bar sensor and is the same part number as the OEM 2 bar map sensor that you replaced with your three bar map sensor. If you kept the original one that came on the sled you could install it on the throttle body if you ever needed to.
 
I don't like the look of that top pin with all the green around it. Also, the plastic around that pin is broken down and deteriorated. What's going on inside?
 

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Just FYI -
Update on this:
Friends '17 TCat w PEFI Stage 3R (300HP). TS BOV, PEFI big FP kit w FP direct connection to battery thru relay, PEFI CAI, 2.5" Tech2 muffler, AEM AFR gage
Symptoms were: erratic idle - engine rpm hunting up and down, AFR erratic everywhere - not stable at constant throttle, engine misfire at idle. Sled ran ok while riding it but AFR erratic. WOT AFR would sometimes flicker to 10 and then back to 12.
Worse when sled is hot, better when cold.

It WAS the MAP sensor. Traded it for a known good one and presto - all symptoms gone. Sled runs perfect. IMO the pic with the green around one of the pins was a dead giveaway that the bad sensor got water in it (obviously through hose connection at boost) and corroded something inside.
 
The 3 bar map sensor from GAP.. Are these all the same from different vendors? So I could buy one from Hurricane and use it for TD tunes? Its maybe a stupid question but just wondering as I see different pricing (slightly).. I was thinking about getting another one for a spare.
 
jonlafon1 said:
The 3 bar map sensor from GAP.. Are these all the same from different vendors? So I could buy one from Hurricane and use it for TD tunes? Its maybe a stupid question but just wondering as I see different pricing (slightly).. I was thinking about getting another one for a spare.
Click to expand...
I did just a little research about this myself wondering the same. As far as I know, they're all automotive off some car.
Pin-outs vary from MAP to MAP in auto world. I don't know if TD or Hurricane use same one (I think they're both Gap Innovation).
PEFI in this case uses a Omni Power USA K style. I think MAPs all have 3 pin-outs: one is +5V reference, one is ground, and the other is sensor output to ECU. Configuration of pin-out can vary.
In this case, I pulled the PEFI sticker off the bad one, and low & behold, underneath sticker was Omni part number. Can't believe they didn't grind it off. It is a stock Omni MAP sensor used on Acura and Honda. PEFI gets $217CAD for one, I bought replacement for my friend for $110 US.
Works perfect.
 
There is nothing beyond the maps in these tunes that is truly proprietary. The industry has standardized around certain sensors, sensor voltage ranges for those sensors, and output formats (pulse, level, etc) so the only real difference is the harness that connects the sensor to the 'system', and of course build quality.
 
earthling said:
There is nothing beyond the maps in these tunes that is truly proprietary. The industry has standardized around certain sensors, sensor voltage ranges for those sensors, and output formats (pulse, level, etc) so the only real difference is the harness that connects the sensor to the 'system', and of course build quality.
Click to expand...
Thanks for explanation! That's what I figured but thought I would ask
 
I was testing a 2 bar map sensor for a guy about a week ago. He has one TD flash and no flasher.
Plugged in his 2 bar map sensor into my sled with a 3 bar tune. Key on engine off it showed 4.3 psi. I swapped out my 2 bar map sensor and read the same as his on my tablet thru my flasher.
So I put my stock tune back in my sled and both of the 2 bar map sensors read 0 psi.
He had a 3 bar tune and had no way of knowing it.
My 3 bar is just below 0 psi when key on engine off.
They are not all the same.
Don't know why they would not read zero.
He was running a 2 bar map sensor and was getting overboost code with a 3 bar tune.
 
1nc 2000 said:
I was testing a 2 bar map sensor for a guy about a week ago. He has one TD flash and no flasher.
Plugged in his 2 bar map sensor into my sled with a 3 bar tune. Key on engine off it showed 4.3 psi. I swapped out my 2 bar map sensor and read the same as his on my tablet thru my flasher.
So I put my stock tune back in my sled and both of the 2 bar map sensors read 0 psi.
He had a 3 bar tune and had no way of knowing it.
My 3 bar is just below 0 psi when key on engine off.
They are not all the same.
Don't know why they would not read zero.
He was running a 2 bar map sensor and was getting overboost code with a 3 bar tune.
Click to expand...

A map sensor translates pressure to voltage. The voltage levels are always 0-5v no matter what sensor you put in. (unless ford made it) A 2 bar sends 0-5v to the ECU and means 0-29.4 PSI , a 3 bar sends 0-5v and means 0-44.1 PSI and so on.

The tune on the other hand has to take the voltage reading coming from the sensor and turn it into a number to display (and use in its calculations). If you put a 2 bar sensor on a 3 bar tune I would expect high pressure readings. If you put a 3 bar sensor on a 2 bar calibrated tune I would expect the opposite.

The 2 bar sensor showing overboost with a 3 bar tune makes sense. Where the 3 bar tune would expect say 4 volts to mean 18 psi, the 2 bar would show 5v.. which means that the ECU or tune in this case is interpreting that as 44.1PSI.
 
I don’t think the stock. Map sensors are a full 2 bar .

Usually if u put a 2 bar in a sled where the flash is built around a 3 bar you get a boost calibration error and vice versa.
 
earthling said:
A map sensor translates pressure to voltage. The voltage levels are always 0-5v no matter what sensor you put in. (unless ford made it) A 2 bar sends 0-5v to the ECU and means 0-29.4 PSI , a 3 bar sends 0-5v and means 0-44.1 PSI and so on.

The tune on the other hand has to take the voltage reading coming from the sensor and turn it into a number to display (and use in its calculations). If you put a 2 bar sensor on a 3 bar tune I would expect high pressure readings. If you put a 3 bar sensor on a 2 bar calibrated tune I would expect the opposite.

The 2 bar sensor showing overboost with a 3 bar tune makes sense. Where the 3 bar tune would expect say 4 volts to mean 18 psi, the 2 bar would show 5v.. which means that the ECU or tune in this case is interpreting that as 44.1PSI.
Click to expand...

You must misunderstood my post.
He had a 3 bar tune installed where he was told it was a 2 bar tune. The sensors I tested were fine.
They did not read the same pressure with the different tune compaired to stock. He was showing 6 psi on his dash with key on engine off with a TD tune. Same sensor on my Hurricane tunes showed 4.3 psi key on engine off.
The tuner writes the pressure they want you to see.
 
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