Hi,
I recently had my car rebuilt, with a large street port. I also had a fmic, bigger rad, 1680cc secondary injectors, fuel pressure regulator, fuel pump upgrade, decat, downpipe, back box and a power fc installed. Recently i have been getting problems with my idle, once the car has been out for a nice drive I can turn it off, leave it for a while and then when i turn it on again the idle bounces about all over the place. This ranges from about 200 to 900rpm. Up and down like a yoyo. After a while this will stop but the vacuum seems a lot lower. Around 380mg/hg or whatever it is. Which seems a little low for a fresh rebuild. Sometimes it can be around 320mg/hg.
Another thing I should mention is that the car sometimes has trouble starting, it will just turn over without trying to fire. If I leave it for a while then turn the key again it seems to start after a few seconds. This only happnens when the car is starting from warm temperature. Not only am I getting these problems but the car seems to give a violent jerk around 3800rpm under moderate acceleration. I have made sure that the ground wires are all good as this is usually the case but they all seem OK. I should also mention that it only seems to do one violent jerk then other times there is a very small one or nothing at all. I have also checked for vacuum leaks but I cant seem to find anything. I have new sparks and the fueling should all be good as the car was also mapped too. I believe that all these problems could be linked but I\'m not sure.
Any Ideas would be greatly appreciated.
Thanks
The hunting idle is a common thing with using a Apexi ecu on a ported engine I believe.
My brothers does that on his half bridge.
Pete.
no ported engine should hunt, take it back to whoever built/tuned it
Once it\'s run in and tuned it should all be ok. Mine had trouble starting when I had the engine ported but once it was mapped it was alot beta. If ur worried just take it bk to the place that rebuilt it and they will check it.
As for u saying when u accelerate moderatly to 3800 u shouldn\'t reli be doin that. I drive it like it\'s broken when running in my engines! 0 boost for 1000km :5 boring but worth it!
Yeah sorry forgot to mention that the car has already been broken in, it was running fine for the first week or so then the problems started to rear their ugly heads. :( I was very careful during the run in time, No boost and only revving up to 4000rpm.
A new set of plugs might be needed to help the starting and also the manual idle might need dropping now that you have a few miles on it.
After quite a few miles compression can improve to the point where the idle wants to go higher than the ecu is set for so you get the idles settings fighting each other.
If manual idle is now dropped slightly likely the hunting will stop.
As for the plus often on running in plugs get a bit fouled so new ones should help.
How many miles since rebuild?
Regards
Carl
Similar problems here. My idle is all mechanical I have deleted the isc. Once the car is run in properly. I wilo check for vac leaks. Do the pfc re learn. I never managed to get a good idle on my old set up. I stupor have a problem with the accelerator cable having 2 let off positions. Which I\'m sure is my problem. I have to pull the pedal up with my leg sometimes
Thanks I\'ll check the plugs today. I\'ll post results later
Get in touch with the builder and explain the issues, they should help you out :Thumbsup!
I have solved my hunting idle problems today.
if you have a pfc, set all your 3 idle values to 0 and unplug your ISC. you also need datalogit to do this. uncheck o2 and idle control. My hunting was because the pfc was arsing around with the timing trying to get the idle to 1100 with no o2 sensor, no ISC. I just have a pure mechanical idle now and my timing n idle never change at idle (since 6pm this evening). SWEET potatoes.
Also my throttle is slightly stiff and still does not reset properly to its closed position. when i let off i go back to 2000rpm. solution. I installed a stronger spring so it returns back to status quo.
mine idles at 1500 but takes ages to start aswell now do you think its cause im running 2x11s plugs and 2x9s as the 2x10 plugs i ordered for the mapping did not arrive so mapped it without the 10s, i also have a new coilpack.
Quote from: HaywardRotary;720758the manual idle might need dropping now that you have a few miles on it.
Would this mean adjusting the TPS or is there something else? sorry bit of a noob lol
I took the plugs out and they didn\'t seem overly knackered, I replaced them with the ones I had in before the rebuild that had been cleaned up. The idle seems to take a little bit longer to settle now so i have lowered the TPS. The car seems happiest just below the recommended settings of 0.40 volts VTA1 and 1.00 Volt VTA2 at closed to open state. The jolting has not disappeared but i will keep on adjusting the TPS to see if the hunting idle goes. Something is still not right with the car. Could it be my mapping?
if your apexi is set to 1100rpms say. it will always try to get to that rpm even if you have your o2 and isc turned off. mine would hunt and stall 2000rpm to 500rpm back to 2000rpm with endless trys at idle re learn and adjusting the 3 screws on the throttle body. set the 3 idle settings to 0 (you cant do this on the hand controller) and the pfc just lets the air in though the gap in the butterflys and that airflow determines your idle (i.e mechanical idle with no computer intervention). My idle is now 1200rpm and is solid with no hunting since i changed the idle values to 0 the other day.