Grant 4 Report post Posted March 2, 2004 Hi All From time to time when starting my car from cold, the idle is all mucked up. It will pulse (sorry best word I could think of) inbetween the normal 700rpm up to about 2000rpm. This does not happen all of the time (maybe 1 in 10 times I start the car), and it quickly settles down after about 1 minutes driving. It is not a real bad problem, just more of an inconvenience. Any ideas? I thought that it might be the flap in the AFM sticking a bit, but this seems free and there seems to be nothing that makes it stick. Cheers Quote Share this post Link to post Share on other sites
tHrEEtWoFiVe 0 Report post Posted March 2, 2004 Likely to be ICV. Quote Share this post Link to post Share on other sites
Grant 4 Report post Posted March 2, 2004 Yeah, I was thinking that maybe, but I replaced the Idle Control Valve about 18 months ago, when it used to idle badly all of the time....maybe the one I put in is a bit of a dud? Is there any way to test this? Cheers Quote Share this post Link to post Share on other sites
Guest hizza bizza Report post Posted March 2, 2004 your throttle cable isin't just sticking abit when its cold is it?, I had that problem in one of my other cars, it was real bad though, it was kinda like having cruise control in a manual haha. Nothing abit of CRC 556 didn't fix. Quote Share this post Link to post Share on other sites
tHrEEtWoFiVe 0 Report post Posted March 3, 2004 Yes it can be tested. (to a degree) have you got a Bentley manual its in there. If not yell out. Was the icv new or from a wreckers? Check for any airleaks in the intake system. It can be linked to a few different causes, but my guess would be either a air leak or icv. I believe on the 325i it is controlled by the engine management. which monitors the coolant temp sensor and adjusts the injection cycle depending on that. If its only inially on start for a few seconds and not all time, I dont know if I would worry to much about it. Runs some fuel injector cleaner thre it check the above thing s and dont worry unless it gets worse. Quote Share this post Link to post Share on other sites
Grant 4 Report post Posted March 3, 2004 it was a second hand ICV, so it may be faulty. I have not been too worried about it, but am now going to start getting all of the niggly little issues like that sorted on my car....bit by bit. My injectors are pretty new (about 10 months old...as they were leaking). Cheers. Quote Share this post Link to post Share on other sites
*sic 1 Report post Posted March 3, 2004 it was a second hand ICV, so it may be faulty. thats my thoughts exactly, but what is the cost of a new one anyone know? Quote Share this post Link to post Share on other sites
OLLIE 26 Report post Posted March 3, 2004 a question relating to this, my car often idles too low when cold this may sound silly but lets say you give it some revs let go and the rev needle drops back down a lil too low and the car shudders as if stalling. kinda annoying and possibly unhealthy, i was thinking it was to do with the automatic choke any other ideas?? Quote Share this post Link to post Share on other sites
nico 0 Report post Posted March 3, 2004 I have a similar problem to OLLIE's... My friends say my car's 'rotoring out again', cause it 'pulses' to about 300rpm, kinda 'shudders', then back up to ~700rpm... sorta sounds like a rotor idling slowly I just hold the rev's at about ~900rpm at the lights/stopped, and after a few minutes of driving it goes away. Quote Share this post Link to post Share on other sites
Gus 5 Report post Posted March 4, 2004 odd....i had exactly the same prob a while back....its now not as bad....occasionly happens though.....check you distributor is bolted on properly...that was part of my prob....dont actually know the reason though...it sounds scum when i had the milo can...sounds like your revving at the lights Quote Share this post Link to post Share on other sites
gmccormack 0 Report post Posted March 4, 2004 Grant do you have your foot on the gas when you start it ? This can upset the ecu as it expects the T.P.S to be at idle & when it "sees" its not it tries to adjust the idle down to compensate .Then the ecu thinks the engine is about to stall & throws the ICV open again sending the revs up . The problem get compounded if the ICV is sticking a bit , the engine responds to the ICV faster than the ecu can move the ICV & the revs start to yoyo . It can also be an intake leak, faulty TPS ,bad temp sensor etc . The printed circuit board inside the ICV can get worn out just in one place creating a dead spot ,usually exactly where it needs to be for correct idle speed but cleaning it in alcohol can help if its just gummed up .Can you hear a slight humming from it when you switch the ignition on ? usually if its dead it wont make any noise Quote Share this post Link to post Share on other sites
tHrEEtWoFiVe 0 Report post Posted March 6, 2004 LOL gmc are you reading the same book as me, lolol. Quote Share this post Link to post Share on other sites
gmccormack 0 Report post Posted March 7, 2004 LOL gmc are you reading the same book as me, lolol. Book??? What makes you think I can read Quote Share this post Link to post Share on other sites
Guest Andrew Report post Posted March 7, 2004 Grant do you have your foot on the gas when you start it ? This can upset the ecu as it expects the T.P.S to be at idle & when it "sees" its not it tries to adjust the idle down to compensate .Then the ecu thinks the engine is about to stall & throws the ICV open again sending the revs up . The problem get compounded if the ICV is sticking a bit , the engine responds to the ICV faster than the ecu can move the ICV & the revs start to yoyo . It can also be an intake leak, faulty TPS ,bad temp sensor etc . The printed circuit board inside the ICV can get worn out just in one place creating a dead spot ,usually exactly where it needs to be for correct idle speed but cleaning it in alcohol can help if its just gummed up .Can you hear a slight humming from it when you switch the ignition on ? usually if its dead it wont make any noise That sounds right for a Motronic system - but not for L-Jet.. coming to think of it I haven't seen L-Jet have the idle problem except when I had the timing completely wrong on my car. L-Jet has a little rod thing connected to vacuum - as the vacuum decreases (motor about to stall) the rod pushes out and manually moves the throttle body open again. Quote Share this post Link to post Share on other sites
gmccormack 0 Report post Posted March 7, 2004 Ollie your L-jet idle problem sounds like the water heated air bypass valve might be stuck in the "hot" posistion . Its the thing on the side of the throttle body with 2 water hoses attached to it .Maybe try cleaning it out (they corrode inside & get stuck) & see if it runs any better. The vacuum plunger that Andrew is talking about is only their to hold the butterfly in the correct posistion for starting ( so the driver doesnt have to touch the gas pedal ) & shouldnt be coming into play with the engine at idle . The temp sensor or temp/time switch or cold start injector could also be at fault but these are all easy to eliminate , just disconnect each of them 1 by 1 if the engine runs better with each of them connected they are probably not at fault but if their is no change when you disconnect then they arent working .Note- you must do the test while the engine is still cold as none of these components has an effect on the idle speed once the engine is warm (execpt the temp sensor) Quote Share this post Link to post Share on other sites
Grant 4 Report post Posted March 8, 2004 Grant do you have your foot on the gas when you start it ? This can upset the ecu as it expects the T.P.S to be at idle & when it "sees" its not it tries to adjust the idle down to compensate .Then the ecu thinks the engine is about to stall & throws the ICV open again sending the revs up . Yup, I do. I always give the go pedal a little press as I am starting the car.I am a creature of habit, and know that this in not needed. I will make a conscious effort not to do this, and see if this does the trick. Cheers Quote Share this post Link to post Share on other sites
speakeasy 0 Report post Posted March 10, 2004 dont want to sound like old mr negative but reading this thread is like the story of my life. about a year ish ago i started getting the same intermitant start up problem. it has been getting gradually worse and ive been to jerry clayton, 2 bmw specialists (that i left my car with for like two weeks, to fully experience the problem) and mah mate (a toyota mechanic) and ive come across pretty much everything metioned in this thread and nothing has helped. the best so far has been replacing the fuel and ignition relays, but this certainly hasnt cleared up the problem. ive been told if i really want a perfect startup and idle, theyd wanna take the top off, and then it might as well be time for a rebuild while their in there.... at 170,000 kms. gay. like you this is more of a nusace than anything, but now on most mornings it does sound like theres a dirty little rotary under the bonnet and it runs soo rich that it smells like an out board motor or something. not to mention embarrasing smoke from unburnt gas. this is still slowly getting worse, so if you find a miricle cure, sent it my way..... Quote Share this post Link to post Share on other sites
Guest Andrew Report post Posted March 11, 2004 perhaps there is a software problem? Get it hooked up to a diagnostic computer - it should tell you wants wrong. Quote Share this post Link to post Share on other sites
gmccormack 0 Report post Posted March 11, 2004 dont want to sound like old mr negative but reading this thread is like the story of my life. about a year ish ago i started getting the same intermitant start up problem. it has been getting gradually worse and ive been to jerry clayton, 2 bmw specialists (that i left my car with for like two weeks, to fully experience the problem) and mah mate (a toyota mechanic) and ive come across pretty much everything metioned in this thread and nothing has helped. the best so far has been replacing the fuel and ignition relays, but this certainly hasnt cleared up the problem. ive been told if i really want a perfect startup and idle, theyd wanna take the top off, and then it might as well be time for a rebuild while their in there.... at 170,000 kms. gay. like you this is more of a nusace than anything, but now on most mornings it does sound like theres a dirty little rotary under the bonnet and it runs soo rich that it smells like an out board motor or something. not to mention embarrasing smoke from unburnt gas. this is still slowly getting worse, so if you find a miricle cure, sent it my way..... Dirty injectors Quote Share this post Link to post Share on other sites
Grant 4 Report post Posted March 11, 2004 It isn't dirty injectors for me, my injectors were replaced less than a year ago. Cheers Quote Share this post Link to post Share on other sites
m325i 709 Report post Posted April 6, 2004 MAN! Its just started to happen to me too! These cold mornings i get a pulsing idle, goes away when she warms up but annoying and feels unhealthy. So what is the cure? There have been about 10 suggested? Quote Share this post Link to post Share on other sites
Grant 4 Report post Posted April 6, 2004 I think mine was solely due to me pumping the gas pedal a little bit when starting the car. I have made an effort to remember not to do this lately and the idle has been as good as gold (touch wood). Cheers Quote Share this post Link to post Share on other sites
m325i 709 Report post Posted April 7, 2004 its just getting worse every day! it almost stalls now. its ok when its warm. is tis going to be expensive? Quote Share this post Link to post Share on other sites
Grant 4 Report post Posted April 7, 2004 As Andrew said, go to a BMW Service Department and get it plugged into a diagnostic computer, it sounds like yours could be one of a number of things such as: 1) Leaking Injectors 2) Vacuum Leak 3) Stuffed ICV. 4) ... The diagnostic computer should pinpoint straight away what the problem is. Cheers Quote Share this post Link to post Share on other sites
Guest hizza bizza Report post Posted April 11, 2004 like you this is more of a nusace than anything, but now on most mornings it does sound like theres a dirty little rotary under the bonnet and it runs soo rich that it smells like an out board motor or something. not to mention embarrasing smoke from unburnt gas. this is still slowly getting worse, so if you find a miricle cure, sent it my way..... Why, why, why. Right, I was going to start my own thead but me problem is similar to this so I'll try here. My car has been sitting in the shed for about the past week as I had been cleaning the engine bay and painting me valve cover. Tday when I put it all back together it took a few goes to get started (wasnt to concerned seeing it had been sittin round for awhile) but once I finally got it to start (and not stal straight away) it sounded like someone had stolen my pistons and put in a bridgeport . Went for a blat, didn;t really seem like it was obviously missing, sweet prob solved I thought. Got home and it was stil ruff as guts at idle, had a look under the hood, engine was shaking something cronic . Out of desperation I thought perhaps the plugs might have come out of the block, so I gave them all a giggle and they were sweet, found out that the rubber cover thing on the last plug was abit worn though, christ it gave me the mean shock, I can still feel it haha. Quote Share this post Link to post Share on other sites
