Mr Polson 10,214 Posted August 27, 2013 Hi all, The wagon has developed an awfully high idle. About 1200rpm in P or N, and 900-1000ish in D or R. Being auto, its causing an awful slam into gear, so I kinda need to fix it. Also not good for fuel economy. As far as I can tell, its not an air leak - everything is tight/sealing, and it idles smooth, not rough. Idle speed screw on throttle body is turned all the way in, if I unwind it idle goes higher. Throttle stop screw is correctly adjusted. Wondering if the ISC is to blame? Unplugged it at temp and there was no noticeable difference in the idle. Share this post Link to post Share on other sites
Thom 6,651 Posted August 27, 2013 Does It still do it If you disconnect the throttle cable? Share this post Link to post Share on other sites
Thom 6,651 Posted August 27, 2013 Unplug the hoses off the ISC and block them, it should stall the engine of not isc may be to blame Share this post Link to post Share on other sites
Mr Polson 10,214 Posted August 27, 2013 Haven't tried disconnecting the throttle cable, but the cable has slight slackness when throttle is closed. Share this post Link to post Share on other sites
n00bus m@x1mus 465 Posted August 27, 2013 Get some vice grips and crimp the hose to the ISC shut, it should die right off if your ISC is jambed open. If it is then just disconnect all the hoses and plug them in the manifold and throttle body and set your idle manually to 850ish in D when warm. It will drop to around 600rpm in R when cold so u need a little up your sleeve for cold mornings but not too high that its fighting your brakes at the lights. 1 Crazy2287 reacted to this Share this post Link to post Share on other sites
Mr Polson 10,214 Posted August 27, 2013 Cheers, I'll give that a go tomorrow morning. Share this post Link to post Share on other sites
Mr Polson 10,214 Posted August 28, 2013 I don't know what I've done, but its worse. "Idle" is now 2,000-2500rpm. Use the self diagnostic method to see if ECU was putting out fault codes, got code 23 - TPS signal out of range. Checked for voltage - 5V going to TPS but no voltage back. Swapped TPS, still got high idle. Blocking the ISC hoses has no effect. Share this post Link to post Share on other sites
Thom 6,651 Posted August 28, 2013 Unplug the tps and see of it still happens Share this post Link to post Share on other sites
n00bus m@x1mus 465 Posted August 28, 2013 Check to see if anything is jambed in the throttle plate? Also go right over iy for leaks... dipstick, oil cap, no perished hoses anywhere? Share this post Link to post Share on other sites
Mr Polson 10,214 Posted August 28, 2013 Unplugging of TPS has no effect. Idle speeds seems to vary each time I start it, one start up it might be 2,000rpm, then it might be 1,300. I think it only goes up to 2,500rpm when motor is cold. Throttle body is clear and good, no blockages. I'm 95% certain it's not an air leak, it idles smooth still. Dipstick and oil cap are good, as far as I can tell all hoses are good - I think it was all replaced when Nova had the motor rebuilt. Share this post Link to post Share on other sites
Mr Polson 10,214 Posted August 28, 2013 Could it be the vane/airflow meter? Share this post Link to post Share on other sites
SPACK 68 Posted August 28, 2013 Run the engine and spray some WRC? over the engine/hoses see if it changes note..if it does you have an air leak..you could also try checking the rocker cover bolts, see if any are loose...sucking in air.. Share this post Link to post Share on other sites
Grimmy 312 Posted August 28, 2013 A faulty break booster will cause it to suck air , something a bit left of field but worth checking Share this post Link to post Share on other sites
n00bus m@x1mus 465 Posted August 28, 2013 Ok road test... what happens if you block the opening on the airbox with something? Jamb a bit if rag in there or something to try and snuff it. If it comes to a hault then u know there is no air leaks feeding it. Share this post Link to post Share on other sites
Mr Polson 10,214 Posted August 28, 2013 Will check that tomorrow noobus. I don't think it is an air leak. The idle speed will increase itself with no apparent pattern. It's smooth, not rough. If I disconnect a hose or oil cap then it goes rough and all over the place. I checked all the EFI gear (lower manifold, runners, plenum, throttle body) for leaks when I installed my polished gear. Rocker cover is siliconed down with bolts done up to the 20nM max torque. Wondering if the ECU could be at fault? Share this post Link to post Share on other sites
Clevo120Y 815 Posted August 28, 2013 TFI module on the dizzy or an ecu fault possibly. Share this post Link to post Share on other sites
Clevo120Y 815 Posted August 28, 2013 Is your car a manual? Share this post Link to post Share on other sites
n00bus m@x1mus 465 Posted August 28, 2013 Disconnect the SPout wire and that should eliminate ecu/tfi fault. Asside from idling high how does it drive? Is it underpowered at all? Share this post Link to post Share on other sites
SPACK 68 Posted August 28, 2013 could be the AFM, try another one on... Share this post Link to post Share on other sites
gerg 10,871 Posted August 28, 2013 If it's idling high, it's getting air from somewhere. The AFM only tells the computer how much air is going in, it doesn't control it. I'd keep looking at throttle body, PCV and ISC valve. These are all things that let air into the engine. I can't remember if these were vacuum sealed engines, but if they are, you could have a dud seal somewhere on the engine: another potential cause of getting unwanted air. Have you completely isolated the ISC? They have a habit of sticking/seizing. Share this post Link to post Share on other sites
Mr Polson 10,214 Posted August 29, 2013 It's a BW40 auto. Is the SPout the green plug near the dizzy? It drives fine, well the same as it always has, it's no rocket (BW40 and 2.77 diff), but feels like its got all the power it's meant to. They are vacuum sealed motors. All seals on the motor should be newish - less than 10k kms old. I tried blocking the outlet to the ISC and then the inlet to the plenum from the ISC, still idled fast. Share this post Link to post Share on other sites
n00bus m@x1mus 465 Posted August 29, 2013 Yeah spout wire is the green plug near dizzy, if u unplug it it will run at base timing (10degs) and not get ignition advance from the ECU. This will eliminate any fault from the ECU regarding ignition, it will only control injector pulse. If it is running lean a idle it may increase idle a bit but it would have a horrible time starting and running when cold. Share this post Link to post Share on other sites
Mr Polson 10,214 Posted August 29, 2013 Idle drops slightly if I unplug the Spout connector, but I'd say that's due to change in timing. Doesn't drop down to proper idle. Tried suffocating it, not easy to do, but once I got a couple of rags jammed in the air intake it died - so no airleaks, I think. Share this post Link to post Share on other sites
n00bus m@x1mus 465 Posted August 29, 2013 Ok so wtf.. gots me beat. Are u sure your tacho isnt out lol. If u block the isc circuit so the only air it is getting is past the butterfly, and then blocking the intake air up snuffs it then that means it has to be too much gap in the throttle body at idle. Can u remove the intake hose akd check that its sealing up shut when at idle?? Its not the kickdown cable holding it open slightly is it? Share this post Link to post Share on other sites
Mr Polson 10,214 Posted August 29, 2013 I should point out that all the fiddling I done today was without taking it for a drive to get it to proper stable temp. Dunno about the tacho. Its just the normal Ghia one - your old one actually. I'll check throttle butterfly tomorrow. One other thing I've had suggested is the EGR? Share this post Link to post Share on other sites
