Hi all, Just got the car back from painter after 3 days and the car starts like crap, has a rough idle that dips up and down from 900-500rpm, at times nearly stalling out. Also has a whistle/hissing from the engine bay, near the back of the engine (closest to windscreen). Sequence of events that took place: I fitted front bumper along with installing some fender braces I got. Deleted 2x black boxes in the driver's (right) side fender that were in the way. First box was sitting higher up and its hoses were not even connected so I figured if the car was running fine like that then no harm in just unbolting and throwing it out. Second box which was slightly bigger and underneath the first box had one hose connected to it and sealed off everywhere else. I did a quick google search which suggested it was a clutch booster and could be deleted. So I took it out and plugged the hose. Car ran fine after I was done for a couple days while I fitted the rear bumper too. Clutch didn't feel much different from before (6 puck clutch), fairly heavy. Both bumpers on, drove around for a couple more days with no issues. Dropped the car off at painters. 3 days later, I pick it up and on start up it idled like crap and there was a constant whistle and hiss. Car also sounded like it was just on the verge of stalling a few times. Painter just mentioned it had this rough idle starting the day before and the car had only been put into first gear to move in and out of the paint booth. Whether it was taken for a joyride and something broke, who knows - I can't really do much as I can't prove anything... On driving the car, could feel it was sluggy and hesitant. After it got abit warmer I tried boosting it a little and didn't seem to go past 5-7psi (was tuned to 15psi). Once it was warmed though, I pulled over to pop the bonnet and hear it idle - whistle and hiss is more or less gone. Playing with the throttle cable, you can hear the whistle/hiss for abit as it revved up to a higher rpm and came back down. Thoughts? EDIT: car is 1989 manual twin turbo (import). Also did more research on the black boxes I pulled, some mentioned AIV and leaks - is this something that is applicable to me? Could this be the cause?
Don't take much to up set them,bit like chicks,if me id check PTU wires cut power from battery to re set ptu :rolleyes2:
Thanks Gunwarm, so just unplug battery for abit then plug it back? Edit: should just mention, I think I have the S2 ptu (Jinxed has seen my car and said so)
When running just jiggle wiring near ptu see if it changes idle . Cut battery power at least 2 hours. That resets ecu,good luck. Lot of Guys on here will offer you help. I don't think much is wrong as lot of things get up set with new paint job. :br::zlove::rolleyes2:
as a panel beater we move cars around a lot but they dont get a good run, on some cars this can cause the plugs to foul or fail altogether (mine did this when I had it at work for a couple of weeks) I would consider pulling the plugs and trying a cheap set of copper cores.
Checking the ECU for codes should be your first stop with this sort of problem, could just be in limp mode due to something being unplugged. http://www.pexcom.com.au/z32cms/e107_plugins/content/content.php?content.417 Also double check the plug in the clutch line is still there and piping around the AFM is all still securely attached, might of bumped something when swapping the bonnets and it's started leaking now.
"Also has a whistle/hissing from the engine bay, near the back of the engine (closest to windscreen)." This is typical of a vacuum leak. In your eagerness to delete things you may of omitted to plug, or cap a vacuum hose. Or, a vacuum hose may have fallen off/come adrift. Or, a vacuum hose has cracked/broken, which occurs easily if silicon hoses are used. Locate the source of the 'whistle/hissing' sound & you'll find your leak.
Update: I had to leave the car and hop on a plane, headed overseas so didn't have a chance to do any of the suggested things, except disconnect battery for the entire 4/5 days I was away. Just got back, reconnected battery and fired car up - no more issues....crap idling has gone but more importantly that whistle has gone?! Don't have much time as I'm now behind with work so I'm glad that the issue sorted itself out....I'm just really puzzled as to what was wrong in the first place. If I get the chance, I'll plug in the consultz to check for fault codes - but so far when I drove it today it was as smooth as before any of these issues came up!! Still be interested to know what exactly happened though...
There was probably a fault code in there that was putting it into a limp mode and affecting the idle control valves, will be gone now after the battery disconnection. Could also be an O2 sensor and fuel trim issue, if the problem reoccurs head straight for consult so you can track it down if it's loose wiring or an intermittent fault in a sensor.
I would still definitely do a test for vac leaks, sounds like some hoses might be old and perished. have you done regular maintenance such as fuel hose clamps etc?
Ok, had the car at a mechanic near my work to do a quick leak test. They had a tool that runs smoke through the intake. Report came back as negative to leaks. I've tightened up all the fuel hose clamps I can get to a couple weeks back. I do know that my O2 sensors are pretty much dead and need replacing (did a consult few weeks back to test them and I can get a reading but there is barely any movement at 2000rpm - leads me to believe the connection is fine but sensors themselves are probably shot. Rather than pulling it out just to clean, I've gone ahead and ordered new ones to replace as it isn't that costly). I've now got the cable in my car at all times - if the issue were to happen again on a cold start I'll immediately check the fault codes. So its likely the o2 sensors would have caused it?
Yeah, during closed loop fuel maps (extended idle and low load, low revs cruising) the ECU attempts to trim the mixture so that the O2 sensors bounce around with the 0.50V as the average. If the ECU cant get the readings it wants within a set range of the original map it will start adding %trim to the injector duty cycle which is used under all conditions. It's worth noting though that the O2 values could be out due to other faults like a vacuum or faulty fuel reg, not just the O2 sensors themselves being old and damaged.
Regarding smoke test: they also then took it out for a spin (after warming the engine I hope!) and found that it was boosting to 15psi. So I guess its still process of elimination for me then? Replace the O2's then plug in the consult and do the 2000rpm test again. Hopefully that fixes it!
if its all back to normal i would just monitor the situation. the original issue sounds like it may have been a blow off valve stuck partially open, may have got some panel beaters dust (from sanding) into it while they had the front bar off. This is just a wild geuss but if the problem has "fixed itself" then monitor and log time and circumsyances if it reoccurs
