A 4age will run without a map sensor, If its hunting at 4000rpm then I would be checking the TPS.
I had something stupid happen with my engine where it wouldn't get over 3500.
Turned out when I put the fuel tank back in I had somehow managed to crimp the rubber main hose from the tank underneath the tank. Soon as I loosened the straps holding the tank in it ran fine.
If you read what I posted I technically said that. He also said it was hunting at 1500-2000rpm which is a common vac leak problem (possibly linked to the limp mode issue). Tps tries to retain closed throttle status so it cuts fuel when the idle gets too high (causing the hunting).
Its running in limp mode, no doubt about it. The ecu is forcing this base/safe map as it's detecting a serious issue (confirmed by disconnecting the map sensor causing no change - the engine should stall if map sensor is disconnected). Make sure all earths are good and all the sensor earths are fine.
1983 AE86 ADM rust spec goodness track car build - end of the road
1984 AE86 Silver ADM mk2 daily build - SOLD
1984 AE86 ADM granny car daily now 4AGZE - SOLD
1983 AE86 ADM Engine Conversion Slut - SOLD
2002 IS200 6spd - new daily in progress
1986 AE86 JDM GT-Apex Levin Notchback ready to roll......
i changed the map sensor and ecu and now im getting a code one... but its still not running properly...
any ideas?
Loom earthed properly? No visible damage to the loom? Check the continuity of wires from sensors to their corresponding ecu pins and make sure none (other than the earths) are earthing out.
1983 AE86 ADM rust spec goodness track car build - end of the road
1984 AE86 Silver ADM mk2 daily build - SOLD
1984 AE86 ADM granny car daily now 4AGZE - SOLD
1983 AE86 ADM Engine Conversion Slut - SOLD
2002 IS200 6spd - new daily in progress
1986 AE86 JDM GT-Apex Levin Notchback ready to roll......
i had this exact same problem when my 4age got thrown it... basically took 3 weeks of pulling shit apart and seeing what would be wrong... after going over EVERYTHING, i found it that if the engine was running, you could move the wiring loom and the engine would stall (lol...) anyway, Medicine_Man came round and rewired everything, including the MAP sensor wiring as it was your average twist-n-tape job, and it sings a perfect sound ever since.
id seriously reccomend you check all earths, proper wiring terminations, and TPS and MAP sensor wiring. all of this caused the exact symptoms on my engine, and redo'ing it all fixed it.
thanks for that, ill definately will check for earths in the loom,
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