Jake Posted March 20, 2005 Share Posted March 20, 2005 I disconnected my battery of my '98 VVTi Tiptronic while wiring in a Thor FCD (VFCC) and tidying up the existing SLD wiring but when I first started the car after putting it all back together it was idling at 1,600 RPM. I took the car out for a 5 mile drive but when I got back home the idle was still at 1600 RPM. I lifted the bonnet and was checking for loose pipe and noticed that the revs where gradually dropping without me doing anything. It's now ticking over at 1000 RPM but doesn't seem to be getting any lower. Any suggestions? Thanks Quote Link to comment Share on other sites More sharing options...
Zed Posted March 20, 2005 Share Posted March 20, 2005 I've always found that resetting the ecu (by pulling the efi fuse) usually causes the revs to go low, ie 700 rpm as if the engine is warm, even if it's cold. You could possibly try resetting it again by pulling the fuse for 30 secs. Hope you get it sorted. Quote Link to comment Share on other sites More sharing options...
Ian C Posted March 20, 2005 Share Posted March 20, 2005 Resetting it again is worth a try. Generally an ECU reset means the car runs at a too low idle than too high though, and it has a slightly hard time catching a revup and release until you've done it three or four times. An air leak past the throttle body is THE way of getting a too-high idle, check all the hoses that come off the manifold - brake booster, charcoal canister, MAP sensor, FPR, PAS bypass valve, and cam breather. in fact you could unplug them and see if the idle goes even higher - if not, you may have found your leak -Ian Quote Link to comment Share on other sites More sharing options...
Jake Posted March 20, 2005 Author Share Posted March 20, 2005 Sorry, I forgot to update this thread. The car was fine the next time I started it. Quote Link to comment Share on other sites More sharing options...
Ian C Posted March 20, 2005 Share Posted March 20, 2005 -Ian Quote Link to comment Share on other sites More sharing options...
Jspec Germany Posted May 25, 2005 Share Posted May 25, 2005 I recall reading somewhere on this site that after an ECU reset the ECU will adjust revs while relearning the MAP/timing and the such. Quote Link to comment Share on other sites More sharing options...
Alex Posted May 25, 2005 Share Posted May 25, 2005 I recall reading somewhere on this site that after an ECU reset the ECU will adjust revs while relearning the MAP/timing and the such. it does, but sometimes it get's it's knickers in a twist...as Jake found out. Quote Link to comment Share on other sites More sharing options...
foodfreak Posted May 25, 2005 Share Posted May 25, 2005 Mine's allways been a B****std after a reset. Give it a 5 minute run & it's fine after. Quote Link to comment Share on other sites More sharing options...
Aerotop Dave Posted May 25, 2005 Share Posted May 25, 2005 I still haven't done this after my decat - very naughty. Do I disconnect the battery for 30 seconds or pull the fuse? People seem to do either and I can't work out if one is a better method than the other. Quote Link to comment Share on other sites More sharing options...
Alex Posted May 25, 2005 Share Posted May 25, 2005 The battery will reset everything inc ABS and ECU... The 2 fuses only the ECU... It really shouldn't matter and the fuse way is much faster! Quote Link to comment Share on other sites More sharing options...
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