Bad MAP sensor? Reads 100kpa on overrun.
#1
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Bad MAP sensor? Reads 100kpa on overrun.
I've been chasing a problem that started after my car sat for about a month. It sat through rainy days and then well below freezing days/nights and i'm wondering if some moisture froze in the MAP sensor and fuxored it.
Then again, it seems to be RPM dependent. When I let off the gas at 4krpm + it does this weird overrun thing where the map reads 100kpa and my LC1 reads full rich. Overrun works fine below 4k.
Also, above 4k at part throttle the car runs extremely lean. It doesn't matter how much fuel I add in those cells it still leans waaaaay out.
So far I replaced my FPR thinking that might be the problem, no change. Swapped CAS thinking that would do it, still no different. Checked my coils for looseness and they're fine. Reburnt firmware and MSQ, checked all my settings (barometric correction is off), triple checked base timing, etc. Checked all my grounds. All the ground pins on the DB37 run straight to the lug on the intake mani. Been fine like this for a really long while. I'm really not sure where to go from here.
Here is a datalog of the problem.
Then again, it seems to be RPM dependent. When I let off the gas at 4krpm + it does this weird overrun thing where the map reads 100kpa and my LC1 reads full rich. Overrun works fine below 4k.
Also, above 4k at part throttle the car runs extremely lean. It doesn't matter how much fuel I add in those cells it still leans waaaaay out.
So far I replaced my FPR thinking that might be the problem, no change. Swapped CAS thinking that would do it, still no different. Checked my coils for looseness and they're fine. Reburnt firmware and MSQ, checked all my settings (barometric correction is off), triple checked base timing, etc. Checked all my grounds. All the ground pins on the DB37 run straight to the lug on the intake mani. Been fine like this for a really long while. I'm really not sure where to go from here.
Here is a datalog of the problem.
#3
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The weirdest part is that under overrun, when it reads 100kpa, its going full rich (8.5:1) which I've never seen before. The LC1 is only setup to go from 10 to 20 so I suppose I should try the reflashing to an older firmware and see what happens.
#4
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those map sensors will go bad if the condensation in the lines freeze up the sensor. I've had to replace a few before on other's units, I think Curly's failed last year for the same reason.
you're supposed to try to make it so the sensor always points down, I couldn't make that a reality so I have a large loop in my map line just before the MS unit.
if you need a new 2.5bar map sensor I can send you one.
you're supposed to try to make it so the sensor always points down, I couldn't make that a reality so I have a large loop in my map line just before the MS unit.
if you need a new 2.5bar map sensor I can send you one.
#5
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those map sensors will go bad if the condensation in the lines freeze up the sensor. I've had to replace a few before on other's units, I think Curly's failed last year for the same reason.
you're supposed to try to make it so the sensor always points down, I couldn't make that a reality so I have a large loop in my map line just before the MS unit.
if you need a new 2.5bar map sensor I can send you one.
you're supposed to try to make it so the sensor always points down, I couldn't make that a reality so I have a large loop in my map line just before the MS unit.
if you need a new 2.5bar map sensor I can send you one.
I think you're thinkiing of cueball's and yes I remember his thread about that last year. I hadn't thought about putting it with the map facing down.
I'm going to investigate the possibility of a pinching hose first then i'll let you know on the sensor if I need it. It's still suspect.
#9
I can't get a map reading over 74 kpa blowing as hard as I can into the line from the engine side. While driving I don't see over 65-66kpa anymore. Car runs fine and I am watching the wideband to make sure it doesnt lean out. Anyone got a link on a diy for replacing the map sensor? It's a 9495pnp. I am also naturally aspirated
#14
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I should mention that I tested the map sensor by way of mouth. It seemed to be working fine. I swapped ECUs and i'm still having weird *** problems (like tach jumping around?) so I'm just going to keep hunting for the issue.
#15
map sensor issue on my 99 miata
I have just recently bought a 99 miata and the check engine light has been on since the purchase. I have already taken my car to an advance auto shop and they plugged their computer in and told the check engine light was a result of my map sensor. the car seems to run perfectly fine so i can be pretty sure the problem isn't to serious. Now, my knowledge on this very limited so im not really sure wat to do about this problem exactly and was hoping some one could help me out.. PLEASE!
Last edited by NateA99; 08-21-2011 at 02:25 PM.
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