been having cold start issues for quite some time now and iv had enough of it. this is whats going on: i start the car after it sitting for around 3 hours or over night and its hard to start then a few seconds later almost stalls then a few seconds after that will idle at around 1700 rpms. when i drive it bogs out like crazy!!! i press the accelerator and nothing happens at all then all of a sudden it jumps forward. it drives like a retard until my temp gauge says around 60 degrees Celsius. after its warm it drives perfect! some times it sends me into safety mode and i get detonation code but not all the time. funny thing is this...... if i leave the car sit for exactly 8 days i will start and run perfectly like a brand new car from the get go . I AM BLOODY STUCK! things iv done listed below: change temp sensor, buy new nissan maf, clean/test fuel temp sensor + new connector, clean air filter, checked tps, cleaned throttle bodies, new spark plugs. any input would be appreciated TIA GUYS!
Things to check. Use Consult to check your temp readings as the car warms up to see if they are erratic. Just because the CTS is replaced, doesn't mean the wiring is OK... These old harnesses tend to have a lot of corrosion in them. The second possible culprit is leaking injector seals - as the car warms up the seals may expand a bit and it may drive better. You can check for wetness or foulling on the plugs in the morning. Car should hold fuel pressure for a long time too after shut off - if it doesn't this is probably an issue.
grab a vacuum gauge like this one, http://www.ebay.com.au/itm/Car-Automotive-Caburetor-Fuel-Pump-Vacuum-Valve-Diagnose-Tester-Gauge-Tool-Meter-/121852824852?hash=item1c5efe8d14:g:rgQAAOSwHaBWhKAy lots of information on how to read and use them just search. Low readings usually indicate low vacuum, manifold vacuum should be steady at around 21hg. Low vacuum 5-15hg and under(read vacuum leaks)will give misfires hunting idle like you are describing, also clean up the IACV-AAC and reset your base idle like this (https://z32.wikispaces.com/Idle+Controlbefore you spend any more money chasing this problem. But fix any vacuum leaks first, clean the IACV_AAC, reset your base idle, and go from there..
yeah i have checked the temp with a scantool my temp gauge is 3 degrees off and it does warm up slow and nicely not erratic. with the fuel pressure should i put a fuel pressure gauge after fuel filter shut it off and leave it cool down. how long should it hold pressure for? untill then next morning? like 12 hours?
yeap i have a turbosmart boost/vac gauge idle holds 23hg vacuum perfectly and doesnt fluctuate. one this when i bought the car it has idled at about 500rpm. i tried to reset the base idle as it says on the wikispaces page and when i turn the idle screw it does nothing... when car is hot somtimes will idle at 750 somtimes will idle at 500 and vibrate.. also running very rich i have little misses or backfires on idle
maybe temporarily bypass det sensor first to prevent being thrown into safety mode? my TT was bogging like a dog until 4500 rpm (permanently in safety mode) until I bypassed it down near the ecu, somewhere from plug down to ecu the wiring was broken symptoms rough as dog idle, back firing, no acceleration as in could barely get up a hill until 4500 and rich as anything sometimes would stall when idling, after bypass happy days for me anyway
Not sure if you have been here before: http://www.zhome.com/ZCMnL/PICS/hesitation/hesitation.html Maybe have a read through that?
thanks for the link.. im still having troubles. il give it a good read!! also i tried to adjust my idle with the idle screw i unplugged the iacv and the revs dropped like they should but when i turn the idle screw nothing happends..... im thinking this is playing a big role in why its not cold starting
Did you resolve the problem? My 89 z32 na auto has a hunting idle problem on start up, gets worst when warm. I also unplugged the iacv. Idle would drop, however adjusting the idle screw did nothing. With the iacv reconnected idle will jump up about 500rpm but still erratic. Accelerate over 1500 rpm everything sounds perfect. When idling it also runs extremely rich. Any help would be appreciated.
Tps set at 4.4volts. Timing is correct. Resistance test on iacv is correct. Iacv was removed cleaned and reinstalled with new gasket (very clean inside) Fuel pressure is perfect. No air leaks, new o-rings on balance pipe. AFM removed and cleaned (very clean inside) however with car idling and afm disconnected the idle clears up BUT goes into limp mode (can't accelerate above 2000rpm.) Will be swapping afm today. Unfortunately this car doesn't have an operating engine light. (Replaced globe, cleaned terminals on cluster yesterday with no success) H E L P. .
Dead afm from my experience if the idle runs fine with the afm disconnected then replace it and it should fix your hunting issues. Ive been there myself.
Thanks for your reply, I swapped out the afm with a working one today with same result. From cold start up it idles fine, revs up nicely for about 3 min. Then chases idle after that. I'm thinking maybe air regulator..
We do love solving puzzles around here, you need to tell us more please So, in the space of 1 day you went from sad to happy by changing the spark plugs? I'm not taking the piss mate, I went through a similar thing years ago. Ended up using copper plugs instead of the platinum & iridium plugs. The coppers don't foul as quick as the others. Most noticeable when you're doing multiple cold starts during setup and testing after a rebuild. The funkymetal plugs don't seem to like that. They seem to foul & misbehave and can send you down a wrong diagnostic path. As in - " it can't possibly be the brand new Hi Tech expensive spark plugs I just fitted, it must be something else!! "
I replaced the spark plugs that appeared a little wet, with an old set of NGK BCPRGES. The car idled on the driveway for about an hour with no hunting issue. Still with a rich smell. The following day I drove it, within 4-5 minutes the hunting issue started. It's been parked up since.
