ben.farnath

takes about 7 or so trys to start s4 with s5 13bt (series 4 loom everything on engine s5) then have to hold throttle above 1000rpm for a minute or two or it wants to stall . then it idles sometimes with a miss(suspect my leads need replacing) it idles at about 1000-1200. if I turn it off and on again it idles at 800ish but give it throttle and it's back at 1000. my next step is going to be cleaning all my grounds. also note my tps has right value at idle but goes up to 7.5k ohms with throttle open so needs replacing. can't adjust idle at bac. it appears to not be adjustable (jap spec) plus master cylinder is in the way. the way I tested bac was just adding 12v and it clicked pulsing. any ideas and suggestions will be much appreciated. could take a video tomorrow if it'll help

ben.farnath

I haven't checked for vac leak at injectors. do it same as everywhere else? with engine start spray and see if idle changes?

ben.farnath

hmmm...no thoughts?

ben.farnath

cleaned main ground up (the ecu to engine) changed my leads still hard to start but no miss. swapped in my other afm and it revved up to 3k rpm.ill test it again when it cools. how long should it stay high revving? it still idles high unless you push on one of the adjustment screws or cruise control lever, then it's at 750. then rev it and it idles high again after slowly returning like the throttle sticks in the last part of it's return. is there some adjustment or should I just clean the tb out again better this time.

satch

iTrader: (1)

High rpm start lasts for 17 seconds unless you step on the throttle. Your Cruise Control cable might be sticking so disconnect it and see if it changes anything. If that doesn't change things for the better then examine the throttle cable. If you believe there is no problem there then your throttle plates might be sticking due to some carbon buildup.

ben.farnath

I pulled off the tb last night. and the adjustments were all out.reassembled and it started but no accelerated warm up but was idling at 750ish.again rev it and 1200.slowly build revs up to 3 and it would sometimes returning going to reset tps again as at about 1500 rpm the engine was pulsing so now the tb is set right the tps will be out again right?

and I don't have cruise control I just mean when you push the cruise control cable lever the idle would return

ben.farnath

Update: slightslight surge still, will try tps one more time now ihave a fan shroud. Cold start solved, the thermosensor had the earth pin pushed out of the plug. And no idea whether it was cleaning earths or setting all the adjustments on the tb or what I did but the idle is now more or less bang on. The only thing that is bugging me is the cold accelerated warm up isnt happening, I'm picking bac is to blame, I've had it off and powered up via jumper leads and it pulses but haven't checked resistance to it

satch

iTrader: (1)

The high rev 3000 rpm start up only works if the coolant is above 60 F degrees or so. If it's colder than that it won't engage so as to prevent a cold engine from being reved.

ben.farnath

Oh didn't know that. Could be fine then. I'll have to wait for a warmer day.

GuiltySoul

iTrader: (7)

Hey I have the same problem too can u give me more info on which/where the thermosensor is.

satch

iTrader: (1)

The temp switch is located at the bottom of the radiator and towards the driver's side and has a two wire plug connected to it. And again, it only should rev to 3000 rpm upon start up 'if' the coolant temp is about 60F or warmer. If it is cold outside and it drops the coolant temp below 60 F then on a cold start the high rev system will not be activated. This protects a cold engine from being reved. If the temp of the engine is warm enough to accept reving then it activates. If the BAC is not working properly then that could prevent the system from working as the BAC is what allows the rpm to climb to 3000 rpm.

ben.farnath

Which problem lol. I had several. The thermosensor related to the hard cold start, with it not connected properly it will revert to a fail safe telling the computer the coolant temp is 80C, therefore running very rich making it hard to start, or so is my understanding. It is located on the back of the water pump housing sort of under the alternator, green square injector style connector. G/w wire and b wire.

If your problem is no accelerated warm up, as satch said, coolant temp switch, located at the bottom left of the rad or bac valve could be to blame or something else, unsure.