Fluke Posted February 16, 2015 Share Posted February 16, 2015 I have 2003 350z that has cold air induction, plenum spacer, berk HFC's, Milltek exhaust and I has an Up Rev. The past few weeks I noticed that when I start the car first thing in the morning the rev counter starts bouncing between 300rpm and 1.5k rpm. The car seems on the verge of cutting out, a couple of times it has done so and yesterday it took a lot of cranking to get it started. The car has been serviced about 4 months ago, its had new plugs and a new battery within the past few months and I only use V-Power fuel. Apart from the cold start issue the car runs fine. Can anyone point me at what I should be looking at to solve the issue? Quote Link to comment Share on other sites More sharing options...
Keyser Posted February 16, 2015 Share Posted February 16, 2015 VVT's or oil that is to thick is my guess - only because you seem to have everything else that would need checking covered and also because it's fine when it warms up. What oil did you use at the oil change? Quote Link to comment Share on other sites More sharing options...
spursmaddave Posted February 16, 2015 Share Posted February 16, 2015 Mine used to be the same in the cold, I just waited 5 minutes for everything to warm up and it was fine... Lots of members on here don't drive when it is cold/wet/icy or at all in the winter so take some replies with a pinch of salt Quote Link to comment Share on other sites More sharing options...
GT Driver Posted February 16, 2015 Share Posted February 16, 2015 (edited) Sounds to me like a faulty or dirty air flow (MAF) sensor? Is it down on power or any flat spots through the rev range? Edited February 16, 2015 by GT Driver Quote Link to comment Share on other sites More sharing options...
Fluke Posted February 16, 2015 Author Share Posted February 16, 2015 VVT's or oil that is to thick is my guess - only because you seem to have everything else that would need checking covered and also because it's fine when it warms up. What oil did you use at the oil change? I used Fuchs Titan Race Pro S 5W-30 Ester Synthetic Engine Oil for my Oil change. Can you explain VVT's and what I need to do to check? Quote Link to comment Share on other sites More sharing options...
Fluke Posted February 16, 2015 Author Share Posted February 16, 2015 Sounds to me like a faulty or dirty air flow (MAF) sensor? Is it down on power or any flat spots through the rev range? Power is fine, I dont have any flat spots, The car runs fine after the initial start problem. Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted February 16, 2015 Share Posted February 16, 2015 I suffered similar on my 350GT and ended up modifying the breathing system, however since the idle control is throttle plate based it might be worth doing a throttle plate reset/relearn. Quote Link to comment Share on other sites More sharing options...
Keyser Posted February 16, 2015 Share Posted February 16, 2015 (edited) VVT's or oil that is to thick is my guess - only because you seem to have everything else that would need checking covered and also because it's fine when it warms up. What oil did you use at the oil change? I used Fuchs Titan Race Pro S 5W-30 Ester Synthetic Engine Oil for my Oil change. Can you explain VVT's and what I need to do to check? That should be fine The VVT's (Variable Valve Timing) are at the front left and right sides - if they have sludge in them or the oil is thick then they may not work properly but as the oil heat up and becomes thinner they come back to working fine again. You could take them off and give them a good clean - or just put new ones on to test - only 4 bolts and an electrical connector - I think I have a spare set you can borrow I would agree that a throttle plate reset/relearn from above is a good one to try and costs nothing to try - not sure about the MAF clean although it will do no harm (if done carefully) why would it be OK hot - usually you get rough running associated with a dirty MAF as well - which you don't have. Hope it helps Edited February 16, 2015 by Keyser Quote Link to comment Share on other sites More sharing options...
Fluke Posted February 16, 2015 Author Share Posted February 16, 2015 VVT's or oil that is to thick is my guess - only because you seem to have everything else that would need checking covered and also because it's fine when it warms up. What oil did you use at the oil change? I used Fuchs Titan Race Pro S 5W-30 Ester Synthetic Engine Oil for my Oil change. Can you explain VVT's and what I need to do to check? That should be fine The VVT's (Variable Valve Timing) are at the front left and right sides - if they have sludge in them or the oil is thick then they may not work properly but as the oil heat up and becomes thinner they come back to working fine again. You could take them off and give them a good clean - or just put new ones on to test - only 4 bolts and an electrical connector - I think I have a spare set you can borrow I would agree that a throttle plate reset/relearn from above is a good one to try and costs nothing to try - not sure about the MAF clean although it will do no harm (if done carefully) why would it be OK hot - usually you get rough running associated with a dirty MAF as well - which you don't have. Hope it helps Thanks, I will take them off and clean them with some brake cleaning fluid in the meantime I will try resetting the throttle plate once I've found out how to do it. Quote Link to comment Share on other sites More sharing options...
Toon Chris Posted February 16, 2015 Share Posted February 16, 2015 (edited) A third vote for the throttle butterfly. Sounds like it has god some crud build-up. The MAF is not as likely when its only affecting cold start running. Take off the air inlet pipe to reveal the throttle unit and the butterfly throttle plate and spray liberally around the edges with carb cleaner (not brake cleaner). Leave to dissolve the muck for a few minutes. A lot of folk will tell you not to do this next bit but I have done it many times on all my cars and to no bad effect. Wearing thin plastic gloves (like you get at the garage at the diesel pump) , or with cling-film or a plastic bag over your hand, slowly push the top of the throttle plate and it will open. The gloves stop the carb cleaner irritating the skin. Do not force it or you may break the mechanism. Gentle and slow is all you need. Agitate the crud along the line where the throttle butterfly closes. You are likely to be able to see this line quite easily. Agitate the crud with a toothbrush and spray again as necessary. Reassemble and despair as your car ticks over at a healthy 2.5K revs . Don't worry, all you need to do now is the idle learn procedure and you are done. Edited February 16, 2015 by Toon Chris Quote Link to comment Share on other sites More sharing options...
Fluke Posted February 17, 2015 Author Share Posted February 17, 2015 A third vote for the throttle butterfly. Sounds like it has god some crud build-up. The MAF is not as likely when its only affecting cold start running. Take off the air inlet pipe to reveal the throttle unit and the butterfly throttle plate and spray liberally around the edges with carb cleaner (not brake cleaner). Leave to dissolve the muck for a few minutes. A lot of folk will tell you not to do this next bit but I have done it many times on all my cars and to no bad effect. Wearing thin plastic gloves (like you get at the garage at the diesel pump) , or with cling-film or a plastic bag over your hand, slowly push the top of the throttle plate and it will open. The gloves stop the carb cleaner irritating the skin. Do not force it or you may break the mechanism. Gentle and slow is all you need. Agitate the crud along the line where the throttle butterfly closes. You are likely to be able to see this line quite easily. Agitate the crud with a toothbrush and spray again as necessary. Reassemble and despair as your car ticks over at a healthy 2.5K revs . Don't worry, all you need to do now is the idle learn procedure and you are done. I will give it a go this weekend a report back. Quote Link to comment Share on other sites More sharing options...
RobPhoboS Posted February 17, 2015 Share Posted February 17, 2015 I had this on my old MR2, turned out to be the thermostat, so at least it was easy to sort out. Quote Link to comment Share on other sites More sharing options...
bamdc2 Posted February 17, 2015 Share Posted February 17, 2015 Maybe try the reset and throttle body re learn before messing with the cleaning of it? Just an idea, may save you the hassle of cleaning it. link on reset http://www.350z-uk.com/topic/53148-how-to-ecu-accelerator-pedal-throttle-valve-resets/page__hl__throttle Quote Link to comment Share on other sites More sharing options...
Fluke Posted February 21, 2015 Author Share Posted February 21, 2015 (edited) Maybe try the reset and throttle body re learn before messing with the cleaning of it? Just an idea, may save you the hassle of cleaning it. link on reset http://www.350z-uk.c...e__hl__throttle Thanks I will give it a go later on today. I took a quick video this morning showing what the cold start looks like. Edited February 21, 2015 by Fluke 1 Quote Link to comment Share on other sites More sharing options...
Toon Chris Posted February 21, 2015 Share Posted February 21, 2015 (edited) Meh Maybe try the reset and throttle body re learn before messing with the cleaning of it? Just an idea, may save you the hassle of cleaning it. link on reset http://www.350z-uk.c...e__hl__throttle Meh, all throttle bodies get dirty, every one, and all throttle bodies will have to be celaned at some time. The Z uses a common crank breather system where any blow-by gases are fed back into the intake to burn them off. In the old days they were shunted out to the fresh air, but of course that eventually stops the air being fresh for everyone. Slowly but surely oily crud will build up, especially if you happen to use higher revs regularly on an engine that is no longer in the first flush of youth (or you have a HR engine which IMO are practically diesels with the amount of oil they get through . BIg up the DE's ) Basically, clean it or at least whip the pipe off and visually check it Edited February 21, 2015 by Toon Chris Quote Link to comment Share on other sites More sharing options...
steve916 Posted February 21, 2015 Share Posted February 21, 2015 Meh Maybe try the reset and throttle body re learn before messing with the cleaning of it? Just an idea, may save you the hassle of cleaning it. link on reset http://www.350z-uk.c...e__hl__throttle Meh, all throttle bodies get dirty, every one, and all throttle bodies will have to be celaned at some time. The Z uses a common crank breather system where any blow-by gases are fed back into the intake to burn them off. In the old days they were shunted out to the fresh air, but of course that eventually stops the air being fresh for everyone. Slowly but surely oily crud will build up, especially if you happen to use higher revs regularly on an engine that is no longer in the first flush of youth (or you have a HR engine which IMO are practically diesels with the amount of oil they get through . BIg up the DE's ) Basically, clean it or at least whip the pipe off and visually check it Just wanted to say, I haven't got a clue where you got your idea about HR engines?? They burn NO oil whatsoever. I think the revup engines do, but being an HR owner, I can say mine doesn't burn a drop, and neither does a lot of other HR owners on here. Quote Link to comment Share on other sites More sharing options...
hawker1986 Posted February 21, 2015 Share Posted February 21, 2015 Meh Maybe try the reset and throttle body re learn before messing with the cleaning of it? Just an idea, may save you the hassle of cleaning it. link on reset http://www.350z-uk.c...e__hl__throttle Meh, all throttle bodies get dirty, every one, and all throttle bodies will have to be celaned at some time. The Z uses a common crank breather system where any blow-by gases are fed back into the intake to burn them off. In the old days they were shunted out to the fresh air, but of course that eventually stops the air being fresh for everyone. Slowly but surely oily crud will build up, especially if you happen to use higher revs regularly on an engine that is no longer in the first flush of youth (or you have a HR engine which IMO are practically diesels with the amount of oil they get through . BIg up the DE's ) Basically, clean it or at least whip the pipe off and visually check it Just wanted to say, I haven't got a clue where you got your idea about HR engines?? They burn NO oil whatsoever. I think the revup engines do, but being an HR owner, I can say mine doesn't burn a drop, and neither does a lot of other HR owners on here. +1 neither our DE or HR ever burned any oil, just went from service to service Ed Quote Link to comment Share on other sites More sharing options...
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