ECMlink bad MAP sensor signal??

[Desert DSM]

i had just ran the tank dry of e85 so filled up with 91. when saving my 91 pump gas map tune to the ecu my car idles exremely lean and dies. is there something up with my MAP sensor signal? at the end of my log its reading -2psi while the car is off (which should read 0) therefor its off throught the log. seeing less air so dumping less fuel. i double checked all wires and sensor and i was having no problems when running e85 and e85 map. Any ideas? thanks in advance for the much apreciated help. a little new to tunners so if im posting or dooing something wrong please redirect me. thanks!

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[casperfast]

if it is reading -2 with engine off, key on then yes, you have a bad map sensor

 

[Desert DSM]

Thanks for the help casperfast! You don't think it can be bad wire somewhere? With the key on car off map should read barometric pressure -14.7 give or take depending altitude correct?

 

[casperfast]

well the map at 14.7.... not likely. u might be confusing it with af ratio. the map it idle should read the same as your boost/vac gauge. for example, i have cams in my engine so mine has less vacuume at idle around 12in/hg so my boost gauge and map read the same.

 

[Desert DSM]

Thanks man. Yes. I believe 14.7 afr is 14.7psi per fuel is the right amount for a clean burn. Boost gage and map sensor read a little different. Map sensors read starting at vacuum (0)or in kPA or hg To my understanding with the key on engine off it should read atmospheric pressure (14.7Psi) or whatever that is in hg or kpa?? Anyone else care to chime in to clear this up?

 

[casperfast]

not really. 14.7 is stoichiometry of gasoline. 14.7 parts air to one part fuel. there is not psi in this just 14.7/1 ratio. the map with the engine off should read 0 not -14 atmospheric. the 0 should be at atmospheric on you map, and read a negative (vacuume/ inhg) the atmospheric really depends on your altitude and you shouldnt worry about that. engine off=0 , idle= whatever your engine vacuume is (10-17 in/hg) . still sounds like you have a bad map sensor, check your lines running to your map and your boost gauge

 

[Desert DSM]

Oops Typo i didnt mean psi i ment parts. OK I'll check it out.