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Forum namePerformance/Engine
Topic subjecti need help
Topic URLhttps://forums.2gnt.com/dcboard.php?az=show_topic&forum=i5&topic_id=126147
126147, i need help
Posted by badasshorne1, Jun-17-09 11:04 PM
i need help map sensor is not working right and i think there is a short somewhere and i was wondering if it would be better to just cut wires and run new ones to the ecu
126148, RE: i need help
Posted by ez, Jun-17-09 11:19 PM
So what do you need help with?

Do it. If it doesn't work, come back.
126149, RE: i need help
Posted by DR1665, Jun-17-09 11:46 PM
How do you know the MAP is not working right? Check engine light? Erratic idle? Bad gas mileage or something? :wary

Disconnect the MAP sensor (but don't remove it or you'll get a sweet vac leak and crazy high idle), then ohm out the lines to it at the ECU. Particularly, you want to make sure that the signal line isn't shorting anywhere. Connect your ohm meter probes to the MAP signal line and ground at the ECU connector. With the MAP disconnected, you should NOT get continuity there. If you do, it means the problem is NOT the MAP, but a damaged wire somewhere between the sensor and ECU.

If, however, you get an open circuit this way, try ohming out each line from that connector to the ECU/source. They should all come up continuous. If any one of them doesn't, trace that line down for your damaged wire, but if they DO ohm out right, you don't want to be cutting and replacing wires as the problem is going to be looking more like the MAP sensor at that point.

Of course, if you remove the MAP sensor and it looks all gummy and dirty, it could just be that the sensor is too dirty from over-oiling a K&N filter or generally poor maintenance habits. You might be able to clean it, but you might have to replace it.

Good luck.
126151, RE: i need help
Posted by badasshorne1, Jun-17-09 11:54 PM
when i tested it my friend told me that i probably have a short somewhere cause i kinda get shitty gas mileage sometime i get high idle and sometime idle drops like it wants to cut off sometimes idle goes way up to like 2000 rpm and comes down real slow
126169, RE: i need help
Posted by ez, Jun-18-09 05:41 PM
so... you might have a vac leak and an old o2 sensor instead of MAP/wiring problems
126153, RE: i need help
Posted by bzoss, Jun-18-09 08:02 AM
Take a minute and step away from the wires!...
You do NOT want to just go randomly slicing away wires, then try and put them all back. I bet you would definitely have a short if that were the case...

If you do have a short, it is most likely somewhere in the bundle of wires that runs along the EGR pipe. It is not uncommon to have that pipe melt through that bundle causing a short. Otherwise, random shorts are not "common" so to speak. You probably have other issues you need to look into before jumping into something irrational like this.
126170, RE: i need help
Posted by badasshorne1, Jun-18-09 06:09 PM
o2 sensors are new i blocked off the egr and i tested the map and its not reading right but someone gave me some pointers on how to test it from the ecu and try it from there and then i will repost tom to let yall know