MAP issues?
07-02-2013, 01:14 AM
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MAP issues? I've been google searching and troubleshooting for over a week and i'm finally breaking down and posting.. please help!
I have a 99 Camaro ss. 5.3 bored to a 5.7 with forged rods/pistons, ported heads, custom cam, meth injection, 76mm turbo, ls6 intake and its SD tuned. the other day it started misfiring badly and would hardly stay running. it's not throwing any codes. the car doesn't have any 02's. I swapped plugs and it ran ok for a couple miles then started misfiring badly. I checked the plugs and all 8 are fouled out. I know its dumping way too much fuel. the two things I could think of was a bad ground (checked them all) and bad map. the car supposedly has a 3bar map sensor. with key on engine off I tested the volts it was reading and I only got .79v when I tested the green and gray wires (iirc) in the MAP pigtail. and with my handheld scanner I got from autozone it reads 29.9. with the engine running it reads between 17-18.8 but my boost gage only reads 11 (like it always has).
my MAP doesnt have a part number on it and the ONLY 3 bar GM map sensor I could find was the wrong style that doesn't fit in the back of an ls6 intake. so I thought maybe I got the 3.3bar MAP was what I had so I bought it and installed it and the car starts up, then dies.
SOMEONE PLEASE HELP! what other causes might there be? am I testing the MAP incorrectly? is it reading correctly? the FPR is set at 60lbs at idle like it always has. gage seems to read accurately.
thanks so much in advance!
I have a 99 Camaro ss. 5.3 bored to a 5.7 with forged rods/pistons, ported heads, custom cam, meth injection, 76mm turbo, ls6 intake and its SD tuned. the other day it started misfiring badly and would hardly stay running. it's not throwing any codes. the car doesn't have any 02's. I swapped plugs and it ran ok for a couple miles then started misfiring badly. I checked the plugs and all 8 are fouled out. I know its dumping way too much fuel. the two things I could think of was a bad ground (checked them all) and bad map. the car supposedly has a 3bar map sensor. with key on engine off I tested the volts it was reading and I only got .79v when I tested the green and gray wires (iirc) in the MAP pigtail. and with my handheld scanner I got from autozone it reads 29.9. with the engine running it reads between 17-18.8 but my boost gage only reads 11 (like it always has).
my MAP doesnt have a part number on it and the ONLY 3 bar GM map sensor I could find was the wrong style that doesn't fit in the back of an ls6 intake. so I thought maybe I got the 3.3bar MAP was what I had so I bought it and installed it and the car starts up, then dies.
SOMEONE PLEASE HELP! what other causes might there be? am I testing the MAP incorrectly? is it reading correctly? the FPR is set at 60lbs at idle like it always has. gage seems to read accurately.
thanks so much in advance!
07-02-2013, 10:28 PM
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today I checked the map again. i'm getting 4.8 volts to it and its reading 1.81 volts on the signal wire with key on engine off. so there must be a connection somewhere loose? it still sputtered a little under light load sometimes and other times it ran perfect. and it never sputters under boost.. anybody?
