With the onset of the cold weather, I'm finding my car is starting to act a bit funny. It's an auto TT. On cold start up, runs sort of rough and loudly. What are the usual suspects for this? Also, when driving along at about 60km/hour and it's cold, it'll sort of act weird with increasing and decreasing revs which you can feel in the movement of the car. Is that surging? Anybody have any ideas? When cold as well, taking off from the lights slowly, the revs will seem to build but the car moves only slowly, like it's not converting the revs to the wheels. Really hoping my auto box isn't shagged!
ive got the same thing. Zed4Life pointed it out the other day. The air regulator is a heat reactant bi-metal regulator which when the engine is cold, is completely open to increase idle speed and warm the engine, as it heats up the valve closes. i havent taken mine off yet but i reckon if i chucked it in the freezer or the fridge it would still be fully closed.
Sorry mate, I wasn't ignoring you. I had an inkling that it may be my air regulator, I'm just not sure if anybody else has experienced the weird acceleration from standstill issue...and what the cause for it is!
Maybe that's your problem? Wouldn't have thought it would that cold in WA but the hoses you've had bypassed are supposed to stop the symptoms you're getting....
I think you will find it has to do with the plenum bypass. I have a converted NA/TT and I had the bypass done as well. Your symptoms sound very similar to mine. If I dont let my Z fully warm up before driving it, I get a wierd, intermittent "hesitation" effect when trying to hold a constant speed. Feels like someone occaisionally pulling briefly backwards on my car. On acceleration it doesnt occur, and it dissapears when its fully warmed up. The under plenum hoses run heated water through the throttle bodies to provide slightly heated air to the engine. Of course in Perth (where I am as well) you really dont want to heat your intake charge (especially as you've just tried to cool it via your intercoolers). Do you have an aftermarket intake? I have also been wondering if my intake is causing some wierd airflow readings in the cold.
Really? that's the first I've ever heard of a plenum bypass causing other issues! I do get a bit of the hesitation, usually when I'm in 3rd (auto) where it's exactly like you describe, though it only seems to present on that gear... Yep, K&N pod, unless you mean intercoolers which are also upgraded... Is yours an auto as well? Do you have the cold, slow to pick up from the lights (almost like revving with little to no result?). I wonder if my tranny is on the way out
If the engine is revving but you are not going anywhere, it sounds like your gearbox is slipping. When was it last serviced ? Oil level OK ? Oil color still red ?
Could be TPS. Gearbox could be hunting between 3rd and 4th while cruising if the value is incorrect. Would also affect your idle.
Hmm, is fixing a slipping gearbox expensive? I don't think it's been serviced since I've had it. My TPS value on ECUtalk is a little bit high, around the .5 at idle. would that cause the issues? It's usually only cold though...
0.5 is too high - should be 0.44 - 0.46V with throttle closed. Basically, the TPS at that setting is telling the ECU the throttle is actually open which conflicts with the closed-throttle switch input. This 'confuses' the ECU and can cause all sorts of weird issues. Adjust it, then disconnect the 3 pin connector for 10 secs. Reconnect and then adjust base idle as this will probably be out now. Many non-zed mechs try to adjust idle using the TPS or worse-via the throttle body grub screws bash.
Answers With the onset of the cold weather, I'm finding my car is starting to act a bit funny. It's an auto TT. On cold start up, runs sort of rough and loudly. What are the usual suspects for this? AAC/IACV. There's a tech on cleaning it and checking the solonoids, follow this to eliminate it. Could also be oil related...I'm assuming "loudly" mean engine bay noise. Could well be lifters sticking on cold startup. Drop the oil and put a 10W in the there. Also, when driving along at about 60km/hour and it's cold, it'll sort of act weird with increasing and decreasing revs which you can feel in the movement of the car. Is that surging? Anybody have any ideas? Hesitation/surging usually caused by air leaks or incorrect signals from TPS. These are usually much more noticable at cold temps, so check the value of the TPS, should be circa 0.45v and do a vac leak test. A mild leak will show a lot worse when cold and be almost unnoticeable when at OT. When cold as well, taking off from the lights slowly, the revs will seem to build but the car moves only slowly, like it's not converting the revs to the wheels. Box could do with a service by the sounds of things, not totally shagged, but a slipping auto needs a service Really hoping my auto box isn't shagged! [/QUOTE]
