diagnosing possible air leak in intake system

1
My Syncro (2.1L MV) has always exhibited (last 10 years from purchase) a slight hesitation on takeoff after fuel injection system has gone into closed loop mode. It accelerates well from cold but becomes noticeably slower as the engine gets hotter. It feels as though the engine is running lean. The oxygen sensor has been replaced with a genuine article and the coolant and air temp sensors resistance has been checked as per Bently. Nothing has ever been diagnosed as wrong by the tune up people but the difference between hot and cold is very noticeable to me. After reading the adventures associated with the Syncro driving across to WA I thought I might investigate the possibility of an air leak somewhere, slightly leaning out the system, especially on takeoff from standstill. My questions are:how do I check for an air leak. I have heard of using water spray or spraying something like Aerostart but am not sure of the procedure. Do I have to disengage the Idle stabilizer unit, If so, how? Could some budding mechanic please give me some advice. If there is anyone here in Adelaide who would be interested in taking a look or comparing it to theirs, that would be fantastic.

Thanks.

Nick.B
2
Hi Nick
 
I am in adelaide and may be able to help you, my number is 83444463.
 
Alf

From: nickbellau <nick.bellgrove@tafesa.edu.au>
To: Syncro_T3_Australia@yahoogroups.com
Sent: Sunday, 17 May, 2009 6:55:38 PM
Subject: [Syncro_T3_Australia] diagnosing possible air leak in intake system

My Syncro (2.1L MV) has always exhibited (last 10 years from purchase) a slight hesitation on takeoff after fuel injection system has gone into closed loop mode. It accelerates well from cold but becomes noticeably slower as the engine gets hotter. It feels as though the engine is running lean.. The oxygen sensor has been replaced with a genuine article and the coolant and air temp sensors resistance has been checked as per Bently. Nothing has ever been diagnosed as wrong by the tune up people but the difference between hot and cold is very noticeable to me. After reading the adventures associated with the Syncro driving across to WA I thought I might investigate the possibility of an air leak somewhere, slightly leaning out the system, especially on takeoff from standstill. My questions are:how do I check for an air leak. I have heard of using water spray or spraying something like Aerostart but am not sure of the procedure. Do I have to disengage the Idle stabilizer unit, If so, how? Could some budding mechanic please give me some advice. If there is anyone here in Adelaide who would be interested in taking a look or comparing it to theirs, that would be fantastic.

Thanks.

Nick.B


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3
Hi there the problem you have might even be an exhaust leak !!! Even just a slight one, this may only occur once the exhaust starts to get hot and expand thus creating a leak. Try disconnecting the green wire only  on the oxygen sensor and drive the syncro and see if that over comes the problem. l have found that works in some cases where hundreds of dollars have been spent on injectors and so forth.............

--- On Sun, 17/5/09, nickbellau <nick.bellgrove@tafesa.edu.au> wrote:

From: nickbellau <nick.bellgrove@tafesa.edu.au>
Subject: [Syncro_T3_Australia] diagnosing possible air leak in intake system
To: Syncro_T3_Australia@yahoogroups.com
Received: Sunday, 17 May, 2009, 7:25 PM

My Syncro (2.1L MV) has always exhibited (last 10 years from purchase) a slight hesitation on takeoff after fuel injection system has gone into closed loop mode. It accelerates well from cold but becomes noticeably slower as the engine gets hotter. It feels as though the engine is running lean. The oxygen sensor has been replaced with a genuine article and the coolant and air temp sensors resistance has been checked as per Bently. Nothing has ever been diagnosed as wrong by the tune up people but the difference between hot and cold is very noticeable to me. After reading the adventures associated with the Syncro driving across to WA I thought I might investigate the possibility of an air leak somewhere, slightly leaning out the system, especially on takeoff from standstill. My questions are:how do I check for an air leak. I have heard of using water spray or spraying something like Aerostart but am not sure of the procedure. Do I have to disengage the Idle stabilizer unit, If so, how? Could some budding mechanic please give me some advice. If there is anyone here in Adelaide who would be interested in taking a look or comparing it to theirs, that would be fantastic.

Thanks.

Nick.B


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