FlrSupra Posted July 15, 2010 Share Posted July 15, 2010 (edited) I`m making new thread of my idle problem and try to tell as much information of my car that more experienced Suprapeople here could help. My car is -94 N/A manual J-spec. There is no other problem on the car. Accelerates smooth etc. This problem is when I`m on stationary and it`s not constant. Sometimes it happens less and sometimes more. --------------------- #1 Video - When the revs make a drop it can be felt as shake on the car. (that one over 1000rpm rev is made by me) #2 Video - There is also this sound from exhaust everytime with the rev drop. Also when I recorded this I noticed there is strong petrol smell behind the car. ------------------------ I`ve been searching info here on the forum and I tried following to cure this problem: - New spark plugs. NGK BKR5EYA-11 - New spark plug wires - New OEM distributor cap - New OEM rotor arm - New K&N panel filter in stock airbox - 2 new OEM Oxygen sensors - New OEM fuel filter - New tested TPS-sensor and adjustment - New MAP-sensor - Checked for error codes. No codes. - Checked for vacuum leaks. - Cleaned ICV valve - Resetted ecu - Checked timing. Ok. Nothing of above have not made any change to that idle problem. What to do next? I`m so frustrated. Prize for the correct answer would be amazingly good finnish beer posted to your front door Edited August 17, 2010 by FlrSupra (see edit history) Quote Link to comment Share on other sites More sharing options...
David P Posted July 16, 2010 Share Posted July 16, 2010 Is the air con turned on? Quote Link to comment Share on other sites More sharing options...
w41k3r Posted July 16, 2010 Share Posted July 16, 2010 lol thats normal idle aint it around 700rpm wish mine were that low mine idles at 1000rpm and does a little fluctuating like in the video Quote Link to comment Share on other sites More sharing options...
FlrSupra Posted July 16, 2010 Author Share Posted July 16, 2010 (edited) lol thats normal idle aint it around 700rpm wish mine were that low mine idles at 1000rpm and does a little fluctuating like in the video Air con is off. This can`t be normal idle. This is not just revs fluctuating because I can feel the whole car shake when the revs are making a sudden drop. Also when I`m on stationary and try to make revs go higher the car fights back and shakes very hard. Every problem and shaking disappear when I take off. Edited July 16, 2010 by FlrSupra (see edit history) Quote Link to comment Share on other sites More sharing options...
jevansio Posted July 16, 2010 Share Posted July 16, 2010 (edited) What MAP/MAF setup does the N/A run, won't a dodgy MAF cause issues like erratic idle? EDIT, silly me, N/A won't be using MAP now will it , I would look into your MAF sensor. If it's one of those filament type ones can you remove it & clean it? Or get a mate with a working one to test swap? Edited July 16, 2010 by jevansio (see edit history) Quote Link to comment Share on other sites More sharing options...
nevins Posted July 16, 2010 Share Posted July 16, 2010 Take it to see what the mixture is like if its rich as hell this will cause the problem and may point out a faulty lambda sensor mate. Mine had a idle issue and turned out to be a earth problem. The problem was that some fool fitted a amp meter backwards and once removed it cured the problem. Quote Link to comment Share on other sites More sharing options...
FlrSupra Posted July 16, 2010 Author Share Posted July 16, 2010 What MAP/MAF setup does the N/A run, won't a dodgy MAF cause issues like erratic idle? EDIT, silly me, N/A won't be using MAP now will it , I would look into your MAF sensor. If it's one of those filament type ones can you remove it & clean it? Or get a mate with a working one to test swap? Thanks for the tip. As far as I know my J-spec N/A is running MAP-sensor and from outside it looked fine and was electronical connected and also vacuum was fitted. Can it be tested somehow? Also behind my air filter is only IAT-sensor which is connected. Quote Link to comment Share on other sites More sharing options...
Rob_Mitchell Posted July 16, 2010 Share Posted July 16, 2010 under the inlet manifold there is spagetti junction of vaccum pipes could check them and check other breather pipes for signs of splits, blockages or not even fitted ** popped off** just ideas dude Quote Link to comment Share on other sites More sharing options...
FlrSupra Posted July 16, 2010 Author Share Posted July 16, 2010 Take it to see what the mixture is like if its rich as hell this will cause the problem and may point out a faulty lambda sensor mate. Mine had a idle issue and turned out to be a earth problem. The problem was that some fool fitted a amp meter backwards and once removed it cured the problem. Thanks for sharing experiences. Great tip. I fitted 2 new OEM lambda sensors recently. No cure Where was your earth problem exactly and there can fool fit amp meter backwards? (I`m stupid I know.. please bare with me ) Quote Link to comment Share on other sites More sharing options...
FlrSupra Posted July 16, 2010 Author Share Posted July 16, 2010 under the inlet manifold there is spagetti junction of vaccum pipes could check them and check other breather pipes for signs of splits, blockages or not even fitted ** popped off** just ideas dude I fiddled with fingers all the vacuum pipes I could reach on. Seems fine. Maybe I should remove the inlet manifold to get them all checked. Thanks. Quote Link to comment Share on other sites More sharing options...
jevansio Posted July 16, 2010 Share Posted July 16, 2010 Sounds to me like some sensor is giving up, I would start at MAP/MAF, but as you say others such as AIT, CAM or CRANK could be culprits Quote Link to comment Share on other sites More sharing options...
Rob_Mitchell Posted July 16, 2010 Share Posted July 16, 2010 Sounds to me like some sensor is giving up, I would start at MAP/MAF, but as you say others such as AIT, CAM or CRANK could be culprits why is no codes showing up though? im not saying your wrong but surely it would store a code if a sensor is intermittent? trust me major job taking the lower runners off to check the pipes... so last result i think for you Quote Link to comment Share on other sites More sharing options...
jevansio Posted July 16, 2010 Share Posted July 16, 2010 Will a dodgy MAP/MAF give an error code though? I doubt the ECU will log a dodgy temp code either. Not really advising on the correct way forward, but I'd be elliminating these sensors one at a time after the inital plug/lead/rotor/distcap checks have been done Quote Link to comment Share on other sites More sharing options...
David P Posted July 16, 2010 Share Posted July 16, 2010 (edited) U.S. spec N/A's have MAF, and J spec N/A's have MAP. If the cam position sensor in the distributer was the culprit, the rev counter would be more eratic. If yours has MAP, the sensor is fitted to the bulkhead just above the 'knuckle' of the inlet manifold, check the vacuum pipe that connects this to the inlet manifold for cracking and that the electrical connector is good. P.S. You can get to all the vacuum pipes without stripping off the manifold. Edited July 16, 2010 by David P (see edit history) Quote Link to comment Share on other sites More sharing options...
Homer Posted July 16, 2010 Share Posted July 16, 2010 Many sensor faults will not trigger a fault code, but from what's been posted I doubt it's anything related to a sensor fault. Has the IACV been checked and cleaned? Vacuum issue is also a good thing to check. The 2nd vid in the first post sounds fairly normal to me on a Supra that has a pretty much open exhuast. Most of the noisy single cars have that 'pop' from the exhaust, it's just you can't hear it on most supra's due to the exhaust/TT silencing. Here's my one (4inch system with a T67, so comparrible to a decatted NA): Quote Link to comment Share on other sites More sharing options...
jevansio Posted July 16, 2010 Share Posted July 16, 2010 On the 911, the MAF sensor will cause erratic idle without throwing an error code, mine is doing it at the mo and will be getting a new MAF at next service, it's not a show stopper, but when you expect it to run silky smooth it is a pain. As Darrly says though my single Supra runs like that too, the pop is only present at idle and doesn't affect normal running at all Quote Link to comment Share on other sites More sharing options...
Rob_Mitchell Posted July 16, 2010 Share Posted July 16, 2010 Will a dodgy MAP/MAF give an error code though? I doubt the ECU will log a dodgy temp code either. Not really advising on the correct way forward, but I'd be elliminating these sensors one at a time after the inital plug/lead/rotor/distcap checks have been done yeah i suppose mate, just trying to help eliminate easy things first or it could get exspensive for him. Quote Link to comment Share on other sites More sharing options...
David P Posted July 16, 2010 Share Posted July 16, 2010 Keep an eye on this thread too. http://www.mkivsupra.net/vbb/showthread.php?t=223136 Quote Link to comment Share on other sites More sharing options...
jevansio Posted July 16, 2010 Share Posted July 16, 2010 Oh I know, it's best in this case if we throw ideas at him, it's better than nothing at all At least he has a head full of possibilities to start tracking down the problem That pop could sound suspiciously like over fueling exploding in the exahust though, which could be cuased by a dodge MAF/MAP sensor Quote Link to comment Share on other sites More sharing options...
FlrSupra Posted July 16, 2010 Author Share Posted July 16, 2010 (edited) Great conversation. I`ve been listing all the possibilites you guys throw on the air and everything is logged and someone will have great prize for helping Wanna make sure one thing and also I found one thing that looks weird to me. #1 Picture Is that really the MAP sensor I checked? And also what is that "blue thing"? Doesn`t look original part because of it`s color http://gto.kuvat.fi/kuvat/up1.jpg/full Edited July 16, 2010 by FlrSupra (see edit history) Quote Link to comment Share on other sites More sharing options...
nevins Posted July 16, 2010 Share Posted July 16, 2010 Please tell me that there is a pipe on the blue connector. Quote Link to comment Share on other sites More sharing options...
FlrSupra Posted July 16, 2010 Author Share Posted July 16, 2010 Please tell me that there is a pipe on the blue connector. Of course there is. Just removed it for better picture. Quote Link to comment Share on other sites More sharing options...
nevins Posted July 16, 2010 Share Posted July 16, 2010 Its standard mate. Quote Link to comment Share on other sites More sharing options...
nevins Posted July 16, 2010 Share Posted July 16, 2010 Also give your ICV a clean (idle control valve) Quote Link to comment Share on other sites More sharing options...
David P Posted July 16, 2010 Share Posted July 16, 2010 Yes that's the MAP sensor, and yes that is the OEM rocker breather that should be piped up to the Y branch. Quote Link to comment Share on other sites More sharing options...
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